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Virginia Tech
1.
Ray, Partha Pratim.
Digestion of inositol phosphates by dairy cows: Method development and application.
Degree: PhD, Dairy Science, 2012, Virginia Tech
URL: http://hdl.handle.net/10919/27737 
► Successful implementation of dietary P management strategies demand improved understanding of P digestion dynamics in ruminants and this is not possible without a reliable and…
(more)
▼ Successful implementation of dietary P management strategies demand improved understanding of P digestion dynamics in ruminants and this is not possible without a reliable and accurate phytate (Pp) quantification method.
The objective of the first study was to develop a robust, accurate, and sensitive method to extract and quantify phytate in feeds, ruminant digesta and feces. Clean-up procedures were developed for acid and alkaline extracts of feed, ruminant digesta and feces and clarified extracts were analyzed for Pp using high performance ion chromatography (HPIC). The quantified Pp in acid and alkaline extracts was comparable for feed but alkaline extraction yielded greater estimates of Pp content for digesta and feces than did acid extraction. Extract clean-up procedures successfully removed sample matrix interferences making alkaline extraction compatible with HPIC. The developed method was applied to investigate the disappearance of Pp from the large intestine of dairy heifers. Eight ruminally- and ileally-cannulated crossbred dairy heifers were used and each heifer was infused ileally with 0, 5, 15, or 25 g/d Pp and total fecal collection was conducted. On average 15% of total Pp entering the large intestine was degraded
but the amount of infused Pp did not influence the degradability of Pp. Net absorption of P from the large intestine was observed.
A feeding trial was conducted to investigate the effect of dietary Pp supply on ruminal and post-ruminal Pp digestion. Six ruminally-and ileally-cannulated crossbred lactating cows were used and dietary treatments were low (0.10% Pp), medium (0.18% Pp), and high (0.29% Pp) Pp, and a high inorganic P (Pi; 0.11% Pp; same total P content as high Pp). Ruminal Pp digestibility increased linearly with dietary Pp. As in the infusion study, net disappearance of Pp from the large intestine was only 16% of total Pp entering the large intestine and not influenced by dietary Pp. Fecal P excretion increased linearly with increasing dietary Pp but was not affected by form of dietary P. In lactating cows Pp digestibility was not affected by dietary Pp and fecal P excretion was regulated by total dietary P rather than by form of dietary P.
Advisors/Committee Members: Knowlton, Katharine F. (committeechair), Shang, Chao (committee member), Pearson, Ronald E. (committee member), Hanigan, Mark D. (committee member), James, Robert E. (committee member).
Subjects/Keywords: high performance ion chromatography; phytate; phosphorus; dairy cow
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APA (6th Edition):
Ray, P. P. (2012). Digestion of inositol phosphates by dairy cows: Method development and application. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27737
Chicago Manual of Style (16th Edition):
Ray, Partha Pratim. “Digestion of inositol phosphates by dairy cows: Method development and application.” 2012. Doctoral Dissertation, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/27737.
MLA Handbook (7th Edition):
Ray, Partha Pratim. “Digestion of inositol phosphates by dairy cows: Method development and application.” 2012. Web. 11 Apr 2021.
Vancouver:
Ray PP. Digestion of inositol phosphates by dairy cows: Method development and application. [Internet] [Doctoral dissertation]. Virginia Tech; 2012. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/27737.
Council of Science Editors:
Ray PP. Digestion of inositol phosphates by dairy cows: Method development and application. [Doctoral Dissertation]. Virginia Tech; 2012. Available from: http://hdl.handle.net/10919/27737
Virginia Tech
2.
Baughman, Curtis Andrew.
Influence of in vitro elaidic acid or trans-vaccenic acid uptake and lactogenic hormone stimulation on fatty acid content of mouse mammary cells.
Degree: MS, Dairy Science, 1996, Virginia Tech
URL: http://hdl.handle.net/10919/45087
► The objective of the study was to examine the effects of trans-9-octadecenoic acid (elaidic) and trans-II-octadecenoic acid (trans-vaccenic) on uptake and alteration of exogenous fatty…
(more)
▼ The objective of the study was to examine the effects of trans-9-octadecenoic acid
(elaidic) and trans-II-octadecenoic acid (trans-vaccenic) on uptake and alteration of
exogenous fatty acids by mouse mammary epithelial cells. Cells from a subclone of the COMMA-D cell line were plated on uncoated plastic petri dishes and grown to confluence. Supplemental fatty acids bound to bovine serum albumin were added to the medium applied to the confluent cell cultures. Treatments included 200 JlM octadecanoic acid (CI8:0) as a control and 100 JlM CI8:0 with one of the following JlM ratios of cis-octadecenoic acid (cis-CI8:I) to elaidic or trans-vaccenic: 100:0, 75:25, 50:50, 0:100. In addition, all treatments were conducted with or without lactogenic hormone supplementation. The cellular protein to DNA ratio and total amount of fatty acids per mg protein were decreased (P < .05) by addition of lactogenic hormones. In treatments without hormone supplementation, however, the total amount of cellular fatty acids per mg protein was decreased (P < .05) by addition of either trans-CI8:I isomer. Results indicated a significant (P < .05) relationship between the concentration oftrans-C18:1 in the media and uptake of trans-C 18: 1 isomers, and retroconversion of trans-C 18: 1 to trans-C 16: 1. The
slopes of the lines for cellular C16:0, cis-C16:1, and cis-CI8:1 were less (P < .05) than
zero as concentration oftrans-CI8:1 in the media increased. However, trans-CI8:1
isomers did not influence the proportion of polar and nonpolar lipids synthesized by the cells. It appears that trans fatty acids may depress milk fat output by decreasing de novo fatty acid synthesis and cis-C 18: I content.
Advisors/Committee Members: Herbein, Joseph H. Jr. (committeechair), Keenan, Thomas W. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: trans-vaccenic acid; elaidic acid; trans fatty acids; milk fat; LD5655.V855 1996.B384
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APA (6th Edition):
Baughman, C. A. (1996). Influence of in vitro elaidic acid or trans-vaccenic acid uptake and lactogenic hormone stimulation on fatty acid content of mouse mammary cells. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/45087
Chicago Manual of Style (16th Edition):
Baughman, Curtis Andrew. “Influence of in vitro elaidic acid or trans-vaccenic acid uptake and lactogenic hormone stimulation on fatty acid content of mouse mammary cells.” 1996. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/45087.
MLA Handbook (7th Edition):
Baughman, Curtis Andrew. “Influence of in vitro elaidic acid or trans-vaccenic acid uptake and lactogenic hormone stimulation on fatty acid content of mouse mammary cells.” 1996. Web. 11 Apr 2021.
Vancouver:
Baughman CA. Influence of in vitro elaidic acid or trans-vaccenic acid uptake and lactogenic hormone stimulation on fatty acid content of mouse mammary cells. [Internet] [Masters thesis]. Virginia Tech; 1996. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/45087.
Council of Science Editors:
Baughman CA. Influence of in vitro elaidic acid or trans-vaccenic acid uptake and lactogenic hormone stimulation on fatty acid content of mouse mammary cells. [Masters Thesis]. Virginia Tech; 1996. Available from: http://hdl.handle.net/10919/45087
Virginia Tech
3.
Schmotzer, Carolyn Anne.
Assessment of Murine Embryo Development Following Electroporation and Microinjection of a Green Fluorescent Protein DNA Construct.
Degree: MS, Dairy Science, 2001, Virginia Tech
URL: http://hdl.handle.net/10919/34369
► Transgenic techniques have rapidly evolved in recent years. However, the efficiency of these techniques to produce viable offspring is still disappointingly low. The purpose of…
(more)
▼ Transgenic techniques have rapidly evolved in recent years. However, the efficiency of these techniques to produce viable offspring is still disappointingly low. The purpose of this study was to assess in vitro development, transgene expression, and integration following pronuclear or cytoplasmic microinjection of condensed or linear green fluorescent protein DNA into murine embryos using electroporation. In experiment 1, the effect of embryo orientation (group or linear) within the electroporation chamber on development was evaluated using zygotes which received one pulse duration (10 msec), and one of two voltages (250 or 400 V). Zygotes that received 400 V had the lowest development score (Group, 2.06 ? 0.12; Linear, 1.97 ? 0.13), irrespective of orientation. Embryos that received 250 V had the highest development of the voltage treated groups (Group 3.42 ? 0.12; Linear 3.32 ? 0.12), irrespective of orientation, and development was lower than the control embryos (Control 4.28 ? 0.12; Mannitol control 4.36 ? 0.18). In experiment 2, the efficiency of utilization of the prepared enhanced green fluorescent protein (EGFP) construct as a visual marker of protein expression was evaluated using pronuclear microinjection. Embryo development and fluorescence were evaluated following pronuclear injection of EGFP at a concentration of 3 μg/ml and compared to an uninjected control. Embryos injected with the EGFP had lower development scores (3.85 ± 0.15) than uninjected control embryos (5.72 ± 0.2). Of the embryos injected, 32.4% fluoresced due to expression of EGFP. Experiment 3 evaluated the effect of combining cytoplasmic injection of EGFP (425 μg/ml) with electroporation at 250 V on EGFP expression. The non-manipulated control embryos had significantly higher (P < 0.01) 4 d development scores (5.57 ± 0.11) than manipulated control embryos (4.6 ± 0.18), where the injection needle was inserted into the cytoplasm and no DNA was injected. Combining cytoplasmic DNA injection and electroporation caused a significant (P < 0.01) decrease in development scores, irrespective of DNA construct, when compared to embryos injected with a DNA construct alone. The mechanical effects of needle insertion combined with electroporation were not significantly different (P > 0.05) from embryos injected with DNA alone, irrespective of construct injected. Cytoplasmic injection of condensed DNA (0.38%), linear DNA (0.38%), and condensed DNA combined with electroporation (0.36%) resulted in one fluorescent embryo respectively. Cytoplasmic injection of linear DNA when combined with electroporation (3.57%) resulted in 13 fluorescent embryos. Pronuclear injection of the prepared EGFP construct results in lower development than control embryos. Electrical stimulation of zygotes reduces early embryo development. However, low amounts of electrical stimulation may allow for enhancement of gene integration in transgenic embryos.
Advisors/Committee Members: Gwazdauskas, Francis C. (committeechair), Akers, Robert Michael (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: Green Fluorescent Protein; Embryo; Microinjection; DNA; Electroporation
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APA (6th Edition):
Schmotzer, C. A. (2001). Assessment of Murine Embryo Development Following Electroporation and Microinjection of a Green Fluorescent Protein DNA Construct. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/34369
Chicago Manual of Style (16th Edition):
Schmotzer, Carolyn Anne. “Assessment of Murine Embryo Development Following Electroporation and Microinjection of a Green Fluorescent Protein DNA Construct.” 2001. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/34369.
MLA Handbook (7th Edition):
Schmotzer, Carolyn Anne. “Assessment of Murine Embryo Development Following Electroporation and Microinjection of a Green Fluorescent Protein DNA Construct.” 2001. Web. 11 Apr 2021.
Vancouver:
Schmotzer CA. Assessment of Murine Embryo Development Following Electroporation and Microinjection of a Green Fluorescent Protein DNA Construct. [Internet] [Masters thesis]. Virginia Tech; 2001. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/34369.
Council of Science Editors:
Schmotzer CA. Assessment of Murine Embryo Development Following Electroporation and Microinjection of a Green Fluorescent Protein DNA Construct. [Masters Thesis]. Virginia Tech; 2001. Available from: http://hdl.handle.net/10919/34369
Virginia Tech
4.
Meinert, Todd Richard.
Effects of within herd variation on the relationship between genetic evaluations and performance of offspring.
Degree: MS, Dairy Science, 1987, Virginia Tech
URL: http://hdl.handle.net/10919/41548
► 1,032,438 Jersey and 1,162,578 Holstein official Dairy Herd Improvement Association (DHIA) records from 20,380 and 34,000 herd-years, respectively, were used to compute herd-year means…
(more)
▼ 1,032,438 Jersey and 1,162,578 Holstein official Dairy Herd Improvement Association
(DHIA) records from 20,380 and 34,000 herd-years, respectively, were used to compute
herd-year means and within herd-year standard deviations for individual mature equivalent
(ME) milk, fat, and fat percent. These herd-year means and within standard deviations
were used to stratify records into five classes. Regressions for individual
daughterâ s modified contemporary deviation (MCD) on sireâ s predicted difference (PD)
were calculated for each class. The within herd-year standard deviations were also used
in some of the six different MCD calculations used to compute six different cow indexes
(CI) for each cow and trait. The six MCDs calculated were either the current deviation,
log adjusted deviation, or the deviation standardized to a constant variance in combination
with either the current correction for contemporaries merit or an adjusted correction.
The six different CI for each trait were compared by how accurately they
predicted the son's MCD trait and the daughter's MCD trait.
Advisors/Committee Members: Pearson, Ronald E. (committeechair), Cassell, Bennet G. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: Milk yield; LD5655.V855 1987.M45
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APA (6th Edition):
Meinert, T. R. (1987). Effects of within herd variation on the relationship between genetic evaluations and performance of offspring. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/41548
Chicago Manual of Style (16th Edition):
Meinert, Todd Richard. “Effects of within herd variation on the relationship between genetic evaluations and performance of offspring.” 1987. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/41548.
MLA Handbook (7th Edition):
Meinert, Todd Richard. “Effects of within herd variation on the relationship between genetic evaluations and performance of offspring.” 1987. Web. 11 Apr 2021.
Vancouver:
Meinert TR. Effects of within herd variation on the relationship between genetic evaluations and performance of offspring. [Internet] [Masters thesis]. Virginia Tech; 1987. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/41548.
Council of Science Editors:
Meinert TR. Effects of within herd variation on the relationship between genetic evaluations and performance of offspring. [Masters Thesis]. Virginia Tech; 1987. Available from: http://hdl.handle.net/10919/41548
Virginia Tech
5.
Guyton, Autumn Deanne.
Starch Digestion and Phosphorus Excretion in Lactating Dairy Cows.
Degree: MS, Dairy Science, 2002, Virginia Tech
URL: http://hdl.handle.net/10919/34778
► The effects of starch and phosphorus (P) source on P partitioning and ruminal phytase activity were evaluated in eight lactating cows (113 DIM). Four cows…
(more)
▼ The effects of starch and phosphorus (P) source on P partitioning and ruminal phytase activity were evaluated in eight lactating cows (113 DIM). Four cows were ruminaly cannulated. Cows were randomly assigned to treatments in a duplicated 4x4 Latin square with four, 18-d periods. Diets included dry ground corn (DG) or steam flaked corn (SF), with a no supplemental P (low P diet; 0.34% P) or supplemental purified phytic acid (PA; 0.45% P) to provide additional P from an organic source. Total collection of milk, urine, feces, and feed were sampled each period, while rumen fluid was sampled on d 18. Excretion of feces, urine, P, and N was lower in cows fed SF than in cows fed DG. Milk yield was unaffected by diet despite a lower DMI by cows fed SF. Cows fed SF tended to have a higher feed efficiency and lower milk urea nitrogen (MUN) concentration than cows fed DG. Rumen pH was unaffected by diet, but milk fat content was lower for cows fed SF. Milk yield, DMI, and feed efficiency were not affected by PA. Cows fed PA had increased P intake and excretion, but a lower milk P as a percentage of intake compared with cows fed the low P diet. An interaction of starch source and P source was observed for ruminal phytase activity. Altering dietary sources of starch and P offers opportunity to improve P availability and reduce manure nutrient excretion.
Advisors/Committee Members: Knowlton, Katharine F. (committeechair), Polan, Carl E. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: phytase activity; Phosphorus and nitrogen excretion; starch digestion
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APA (6th Edition):
Guyton, A. D. (2002). Starch Digestion and Phosphorus Excretion in Lactating Dairy Cows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/34778
Chicago Manual of Style (16th Edition):
Guyton, Autumn Deanne. “Starch Digestion and Phosphorus Excretion in Lactating Dairy Cows.” 2002. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/34778.
MLA Handbook (7th Edition):
Guyton, Autumn Deanne. “Starch Digestion and Phosphorus Excretion in Lactating Dairy Cows.” 2002. Web. 11 Apr 2021.
Vancouver:
Guyton AD. Starch Digestion and Phosphorus Excretion in Lactating Dairy Cows. [Internet] [Masters thesis]. Virginia Tech; 2002. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/34778.
Council of Science Editors:
Guyton AD. Starch Digestion and Phosphorus Excretion in Lactating Dairy Cows. [Masters Thesis]. Virginia Tech; 2002. Available from: http://hdl.handle.net/10919/34778
Virginia Tech
6.
Forrest, James Walter.
Effects of varying energy intakes on mammary growth and development in prepubertal heifers.
Degree: MS, Dairy Science, 2003, Virginia Tech
URL: http://hdl.handle.net/10919/32980
► Rapid rearing of dairy heifers during late prepuberty has been linked to impairments in mammary development and reductions in milk yield. Our objective was to…
(more)
▼ Rapid rearing of dairy heifers during late prepuberty has been linked to impairments in mammary development and reductions in milk yield. Our objective was to determine how varying energy intakes between 2 and 14 wk of age affect mammary parenchymal development. At 2 wk of age, Holstein calves were assigned to 1 of 4 treatments (HH, HL, LH, and LL) with 2 levels of energy intake (High or Low) and 2 periods of growth (2 to 8 and 8 to 14 wk of age). At 14 wk, parenchyma at the stromal interface, mid-gland, and above the cistern were collected, fixed, and embedded in paraffin. Digital images of stained sections were used to determine tissue composition (% epithelium, lumen, and stroma). Immunochemistry revealed estrogen receptor (ER) and Ki67 (nuclear proliferation antigen) positive cells, type IV collagen, fibronectin (FN), and laminin. Images representing 4 increasing grades were used to quantify ECM protein deposition. Lumenal and stromal areas were 3.5 ± 1.4% higher (p<0.01) and 4.0 ± 1.7% lower (p<0.01), respectively, in HH and HL heifers. Ki67 labeling in terminal ductular units and subtending ducts was 2.1 ± 0.8% (p<0.01) and 1.4 ± 0.7% (p<0.05) lower for the same feeding level combination. FN deposition was also increased (p<0.05) in HH and HL heifers. High rates of gain between 2 and 14 wk of age resulted in greater lumenal area and reduced cell proliferation in mammary parenchyma at 14 wk of age. Changes in FN deposition could have mediated growth differences.
Advisors/Committee Members: Akers, Robert Michael (committeechair), Howard, Rick Dale (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: estrogen receptor; heifers; mammary; extracellular matrix; nutrition
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APA (6th Edition):
Forrest, J. W. (2003). Effects of varying energy intakes on mammary growth and development in prepubertal heifers. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/32980
Chicago Manual of Style (16th Edition):
Forrest, James Walter. “Effects of varying energy intakes on mammary growth and development in prepubertal heifers.” 2003. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/32980.
MLA Handbook (7th Edition):
Forrest, James Walter. “Effects of varying energy intakes on mammary growth and development in prepubertal heifers.” 2003. Web. 11 Apr 2021.
Vancouver:
Forrest JW. Effects of varying energy intakes on mammary growth and development in prepubertal heifers. [Internet] [Masters thesis]. Virginia Tech; 2003. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/32980.
Council of Science Editors:
Forrest JW. Effects of varying energy intakes on mammary growth and development in prepubertal heifers. [Masters Thesis]. Virginia Tech; 2003. Available from: http://hdl.handle.net/10919/32980
Virginia Tech
7.
Peralta, Oscar Alejandro.
Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd.
Degree: MS, Dairy Science, 2003, Virginia Tech
URL: http://hdl.handle.net/10919/33659
► The objective of the study was to compare three systems for detection of estrus and combinations of these systems on a large commercial dairy (1000…
(more)
▼ The objective of the study was to compare three systems for detection of estrus and combinations of these systems on a large commercial dairy (1000 lactating cows) during stress of summer heat. At 37 to 45 days in milk (DIM), 266 cows were fitted with a HeatWatch (HW) device (HeatWatch; DDx Inc., Boulder, CO), an activity (A) sensor (ALPRO; DeLaval Inc., Kansas City, MO), and observed visually (V) twice daily. Pregnancy status was determined by uterine palpation 35 to 49 d following artificial insemination (AI). The effects of DIM, parity, physical activity, standing events, months, AI technician, and interval between onset of estrus and AI on conception rate were determined using linear contrasts and logistic regression. Efficiencies for detection of estrus, determined by comparing detected periods of estrus with a theoretical total of 707 periods, were 45.8% (V), 33.2% (A), 40.3% (HW), and 71.6% for all three systems simultaneously. Conception rates (LSM ± SE) by method of detection were 16.7 ± 4.9 for HW, 19.8 ± 5.5 for A, 7.9 ± 3.4 for V, 16.3 ± 6.0 for V + A, 27.6 ± 4.6 for V + HW, 21.1 ± 4.9 for A + HW, and 21.9 ± 4.5 for V + A + HW. Conception rate and number of mounts decreased for cows in first versus second and third parity (P < 0.05). For periods of estrus detected by A, the lowest conception rate (P < 0.05) occurred >18 h after the onset of estrus (16.7 ± 7.9). The highest conception rate occurred with the combination of V + HW, which confirms the premise that combination of multiple systems enhances both the efficiency and accuracy of detection.
Advisors/Committee Members: Nebel, Raymond L. (committeechair), Pearson, Ronald E. (committee member), Swecker, William S. Jr. (committee member).
Subjects/Keywords: Detection of estrus; efficiency; ALPRO; HeatWatch; heat stress
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APA (6th Edition):
Peralta, O. A. (2003). Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/33659
Chicago Manual of Style (16th Edition):
Peralta, Oscar Alejandro. “Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd.” 2003. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/33659.
MLA Handbook (7th Edition):
Peralta, Oscar Alejandro. “Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd.” 2003. Web. 11 Apr 2021.
Vancouver:
Peralta OA. Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd. [Internet] [Masters thesis]. Virginia Tech; 2003. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/33659.
Council of Science Editors:
Peralta OA. Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd. [Masters Thesis]. Virginia Tech; 2003. Available from: http://hdl.handle.net/10919/33659
Virginia Tech
8.
DeStefano, Anita Louise.
Exploitation of nonadditive variance through nonrandom mating.
Degree: MS, Dairy Science, 1990, Virginia Tech
URL: http://hdl.handle.net/10919/42398
Subjects/Keywords: Dairy cattle; LD5655.V855 1990.D477
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APA (6th Edition):
DeStefano, A. L. (1990). Exploitation of nonadditive variance through nonrandom mating. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/42398
Chicago Manual of Style (16th Edition):
DeStefano, Anita Louise. “Exploitation of nonadditive variance through nonrandom mating.” 1990. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/42398.
MLA Handbook (7th Edition):
DeStefano, Anita Louise. “Exploitation of nonadditive variance through nonrandom mating.” 1990. Web. 11 Apr 2021.
Vancouver:
DeStefano AL. Exploitation of nonadditive variance through nonrandom mating. [Internet] [Masters thesis]. Virginia Tech; 1990. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/42398.
Council of Science Editors:
DeStefano AL. Exploitation of nonadditive variance through nonrandom mating. [Masters Thesis]. Virginia Tech; 1990. Available from: http://hdl.handle.net/10919/42398
Virginia Tech
9.
Bower, Laurie A.
Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow.
Degree: MS, Dairy Science, 1986, Virginia Tech
URL: http://hdl.handle.net/10919/41540
► Twenty first-calf heifers and 24 cows in their second or greater lactation were randomly assigned to 4 dietary treatments from day 15 to day 61…
(more)
▼ Twenty first-calf heifers and 24 cows in their second or greater lactation were randomly assigned to 4 dietary treatments from day 15 to day 61 postpartum. Mixed diets consisted of corn silage, alfalfa haylage, orchard grass hay, and a pelleted concentrate. Concentrates were control (C), C + additional corn (H), C + 4% calcium stearate (S), or C + 4% tallow (T). C, S, and T contained 50:50 forage and concentrate dry matter and
H contained 40:60.
Advisors/Committee Members: Herbein, Joseph H. Jr. (committeechair), Polan, Carl E. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: Cattle; LD5655.V855 1986.B6837
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APA (6th Edition):
Bower, L. A. (1986). Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/41540
Chicago Manual of Style (16th Edition):
Bower, Laurie A. “Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow.” 1986. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/41540.
MLA Handbook (7th Edition):
Bower, Laurie A. “Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow.” 1986. Web. 11 Apr 2021.
Vancouver:
Bower LA. Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow. [Internet] [Masters thesis]. Virginia Tech; 1986. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/41540.
Council of Science Editors:
Bower LA. Comparison of lactational and metabolic responses of postpartum dairy heifers and cows fed diets supplemented with corn, calcium stearate and tallow. [Masters Thesis]. Virginia Tech; 1986. Available from: http://hdl.handle.net/10919/41540
Virginia Tech
10.
Walters, Anneke H.
Analysis of early lactation reproductive characteristics in Holstein cows.
Degree: MS, Dairy Science, 2000, Virginia Tech
URL: http://hdl.handle.net/10919/9859
► Ultrasound-guided transvaginal follicular aspiration was used to obtain oocytes from cows to study follicular development and oocyte morphology. Follicular aspiration was conducted once during wk…
(more)
▼ Ultrasound-guided transvaginal follicular aspiration was used to obtain oocytes from cows to study follicular development and oocyte morphology. Follicular aspiration was conducted once during wk 1 to 12 postpartum on 120 lactating cows with 6 groups, separated by biweekly intervals. Approximately one half of the aspirated cows at each session were from the early groups (wk 1-2, 3-4, or 5-6) and the other half from the later groups (wk 7-8, 9-10, or 11-12). On the day of aspiration the number of follicles on each ovary, and their sizes, small (2-5 mm), medium (6-10 mm) and large (≥ 11 mm), were recorded. The collected oocytes were morphologically classified into 4 grades, with 4 = excellent, 3 = good, 2 = fair, and 1 = poor. Blood samples from the jugular vein and follicular fluid samples from the largest follicle were collected in order to perform hormone and metabolite assays. Environmental data were obtained from the local airport. There was a significant (P < .01) quadratic days pre- and postpartum by parity interaction for BCS. Body condition score for older cattle was the lowest at 90 d prior to calving and changed the least amount over time, while youngest cattle had the highest initial BCS at d 90 prior to calving and had the greatest change in BCS over time. Body condition score was the highest during summer calving season (3.3 ± .06) compared to BCS during winter calving season (2.6 ± .06). But the loss in BCS was greater for cows that calved in summer (-0.53 ± .06) compared to cows that calved in winter (-0.07 ± .08). Increased serum NEFA concentrations with simultaneous decreases in serum insulin concentrations for younger cattle implied a more negative EB status than for older cattle. The total number of follicles and total number of oocytes retrieved was significantly (P < .001) affected by a linear days postpartum by parity interaction with younger cattle having linear increases compared to decreases in the total number of follicles for older cattle. Oocyte quality score was affected by the quadratic days postpartum by parity interaction (P < .01) and calving season (P < .01). Younger cattle had higher initial quality scores compared to older cattle, but older cattle had higher quality oocytes towards the end of the 12 wk period compared with younger cattle. Younger cattle had higher E2 and IGF-I concentrations in follicular fluid associated with a higher number of total follicles and number of oocytes, compared to older cattle. However, oocyte quality of younger cattle seemed to be reduced and oocytes were less competent than for older cattle. Cattle in 3rd and greater lactation showed very little change in BCS and hormone and metabolite measures during early lactation, with no apparent decrease in oocyte quality, despite the aging effect on follicle numbers. This study demonstrated that conditions related to early lactation have a negative effect on oocyte quality and endocrine measures of dairy cattle and that animals of different ages are differentially affected.
Advisors/Committee Members: Gwazdauskas, Francis C. (committeechair), Nebel, Raymond L. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: Oocyte; Follicle; Quality; Calving Season; Parity; Cattle
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APA (6th Edition):
Walters, A. H. (2000). Analysis of early lactation reproductive characteristics in Holstein cows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/9859
Chicago Manual of Style (16th Edition):
Walters, Anneke H. “Analysis of early lactation reproductive characteristics in Holstein cows.” 2000. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/9859.
MLA Handbook (7th Edition):
Walters, Anneke H. “Analysis of early lactation reproductive characteristics in Holstein cows.” 2000. Web. 11 Apr 2021.
Vancouver:
Walters AH. Analysis of early lactation reproductive characteristics in Holstein cows. [Internet] [Masters thesis]. Virginia Tech; 2000. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/9859.
Council of Science Editors:
Walters AH. Analysis of early lactation reproductive characteristics in Holstein cows. [Masters Thesis]. Virginia Tech; 2000. Available from: http://hdl.handle.net/10919/9859
Virginia Tech
11.
Green, Ronald T.
Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle.
Degree: MS, Dairy Science, 1987, Virginia Tech
URL: http://hdl.handle.net/10919/45650
► To evaluate the importance of non-linear relationships between Relative net income per day of productive life (RNI/DPL) and individual traits, 921,915 potential offspring were…
(more)
▼ To evaluate the importance of non-linear relationships between Relative net income
per day of productive life (RNI/DPL) and individual traits, 921,915 potential offspring
were simulated from all possible matings of 20,487 Jersey cows and 45 active AI sires.
Predicted milk yield, fat yield, and 13 linear type traits of potential progeny were used
to predict RNI/DPL of all potential progeny.
Five methods of mate selection and pairing were evaluated for their effectiveness in
choosing mates and the amount of computer time required to choose those pairings.
Results of a linear programming (LP) method were used as a comparison for the other
four more easily applied methods. Two of the other four methods were not significantly
(P > .01) different from the LP method. Although the random pairing method was
significantly different, similarity of results, for this method indicated non-linear relationships
between RNI/DPL and individual trait scores are of minor importance. A11 four
methods used considerable less computer time than the LP method.
Analysis of variance for predicted RNI/DPL (all possible offspring) indicated herd,
dam within herd, sire, and inbreeding class to be significant (P < .01) variables in determining
RNI/DPL. However the sire by dam within herd interaction did not significantly affect RNI/DPL, again indicating non-linear relationships between traits and
RNI/DPL were not very important.
Regressing PDâ s, Clâ s, and their crossproducts for milk yield, fat yield, and 13 linear
type traits showed the relative importance of crossproducts to be minimal in comparison
to the linear ellects of parental genetic evaluations.
Advisors/Committee Members: Vinson, William E. (committeechair), Pearson, Ronald E. (committee member), Cassell, Bennet G. (committee member).
Subjects/Keywords: Dairy cattle; LD5655.V855 1987.G746
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APA (6th Edition):
Green, R. T. (1987). Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/45650
Chicago Manual of Style (16th Edition):
Green, Ronald T. “Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle.” 1987. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/45650.
MLA Handbook (7th Edition):
Green, Ronald T. “Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle.” 1987. Web. 11 Apr 2021.
Vancouver:
Green RT. Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle. [Internet] [Masters thesis]. Virginia Tech; 1987. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/45650.
Council of Science Editors:
Green RT. Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle. [Masters Thesis]. Virginia Tech; 1987. Available from: http://hdl.handle.net/10919/45650
Virginia Tech
12.
Mink, Matthew Ryan.
Evaluation of 72 h Cosynch and 5 or 7 d post-AI gonadotropin releasing hormone on first service pregnancy rate in lactating dairy cows.
Degree: MS, Dairy Science, 2006, Virginia Tech
URL: http://hdl.handle.net/10919/42590
► Two studies were conducted to evaluate the effects of 5 or 7 d post-AI GnRH on first service PR, plasma P4, and CL volume in…
(more)
▼ Two studies were conducted to evaluate the effects of 5 or 7 d post-AI GnRH on first service PR, plasma P4, and CL volume in lactating dairy cows synchronized using 72 h Cosynch. All cows were synchronized and randomly assigned to one of three treatment groups: Control â no additional GnRH; 5 d â GnRH 5 d after TAI; 7 d â GnRH 7 d after TAI. In the first study, P4 concentrations were evaluated in samples collected at five separate times and CL volume and number were recorded at 30 d pregnancy examination for Holstein (n = 77) and Jersey (n = 33) cows. GnRH treatment did not affect PR (Control - 47.2%, 5 d GnRH - 40.5%, 7 d GnRH â 44.7%) or P4, but increased TCLV compared to controls (Control â 7.33 cm3, 5 and 7 d GnRH â 10.77 cm3). Incidence of accessory CL increased PR (94.7 vs. 60.6%), P4 (6.95 vs. 5.88 ng/mL), and TCLV (15.51 vs. 6.78 cm3) compared to cows with a spontaneous CL. Cows classified as cycling based on P4 evaluation had significantly higher PR than acyclic cows (54.4 vs. 16.1%). In the second study, Holstein cows (n = 1055) were submitted to the same experimental protocol and evaluated for first service PR. Post-AI GnRH treatment did not significantly affect PR. Primiparous cows (32.8%) tended to have higher PR than multiparous cows (27.6%), but GnRH treatment had no influence on this relationship. In conclusion, GnRH post-AI did not affect PR. Further evaluation of accessory CL incidence is warranted as it significantly affected PR.
(Abbreviations: AI â artificial insemination, CL â corpus luteum, PR â conception rate, P4 â progesterone, TCLV â total corpus luteum volume)
Advisors/Committee Members: Nebel, Raymond L. (committeechair), Kasimanickam, Ramanathan (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: post AI; gonadotropin releasing hormone; synchronization; dairy cow; conception rate
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APA (6th Edition):
Mink, M. R. (2006). Evaluation of 72 h Cosynch and 5 or 7 d post-AI gonadotropin releasing hormone on first service pregnancy rate in lactating dairy cows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/42590
Chicago Manual of Style (16th Edition):
Mink, Matthew Ryan. “Evaluation of 72 h Cosynch and 5 or 7 d post-AI gonadotropin releasing hormone on first service pregnancy rate in lactating dairy cows.” 2006. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/42590.
MLA Handbook (7th Edition):
Mink, Matthew Ryan. “Evaluation of 72 h Cosynch and 5 or 7 d post-AI gonadotropin releasing hormone on first service pregnancy rate in lactating dairy cows.” 2006. Web. 11 Apr 2021.
Vancouver:
Mink MR. Evaluation of 72 h Cosynch and 5 or 7 d post-AI gonadotropin releasing hormone on first service pregnancy rate in lactating dairy cows. [Internet] [Masters thesis]. Virginia Tech; 2006. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/42590.
Council of Science Editors:
Mink MR. Evaluation of 72 h Cosynch and 5 or 7 d post-AI gonadotropin releasing hormone on first service pregnancy rate in lactating dairy cows. [Masters Thesis]. Virginia Tech; 2006. Available from: http://hdl.handle.net/10919/42590
Virginia Tech
13.
Borg, Randy Charles.
Developing Breeding Objectives for Targhee Sheep.
Degree: MS, Animal and Poultry Sciences, 2004, Virginia Tech
URL: http://hdl.handle.net/10919/9973
► Breeding objectives were developed for Targhee sheep at different levels of prolificacy and triplet survival. Economic weights (EW) were derived for estimated breeding values (BV)…
(more)
▼ Breeding objectives were developed for Targhee sheep at different levels of prolificacy and triplet survival. Economic weights (EW) were derived for estimated breeding values (BV) from National Sheep Improvement Program genetic evaluations for 120 d weaning weight (WW), maternal milk (MM), yearling weight (YW), fleece weight (FW), fiber diameter (FD), staple length (SL), and prolificacy (PLC; lambs born/100 ewes lambing). A commercial flock was simulated, accounting for nonlinear relationships between performance and profit. Ewes were assumed mated to sires of specified BV and profit was derived from lifetime performance of lambs and replacement females from that lamb crop. Economic weights were determined as change in profit from use of sires with BV that were one additive standard deviation above the mean for each trait [1.98 kg for WW, 1.62 kg for MM, 2.90 kg for YW, 0..36 kg for FW, 0.99 microns for FD, 0.74 cm for SL, and 17.58 lambs/100 ewes for LC], while holding all other BV at breed average. Separate breeding objectives were derived for different ways of meeting increased nutrient needs (P = purchase hay, R = rent pasture, and L= limited flock size) and for different market lamb values (D = discounting lamb value for heavy weights, ND = no discount for heavy lambs). Based on replicated simulations, relative EW did not vary with prolificacy or triplet survival (P > 0.15) but were affected by feed costs and lamb market values (P < 0.01). Selection indexes were derived within and across simulated scenarios, and correlation (r) among indexes of > 0.90 indicated that an index could be used across multiple scenarios with little loss of selection efficiency. Indexes derived within feed cost scenarios (P, R, and L) and lamb value scenarios (D, ND) were strongly intercorrelated (r > 0.97). Correlations among average indexes for feed cost scenarios (0.97 for R and P, 0.70 for R and L; 0.85 for P and L) indicated that two feed cost scenarios could be used depending on whether winter forage was limited (L) or not (NL). The correlation between average indexes for these two scenarios was 0.78. Indexes were presented for combinations of feed cost and lamb value scenarios. Two indexes were suggested, representing the scenarios that apply to a large portion of Targhee producers. These indexes were for discounting heavy lambs with limited winter forage (D-L: 1.0 WW + 0.14 MM __ 0.76 YW + 1.22 FW __ 0.36 FD - 0.09 SL + 0.25 LC) and discounting heavy lambs with additional available forage (D-NL: 1.0 WW + 0.24 MM __ 0.34 YW + 1.65 FW __ 0.41 FD - 0.14 SL + 0.33 LC). For a standardized selection differential of one for the index, the expected changes in mean index value were 2.17 and 1.92 per ewe per generation for D-L and D-NL, respectively.
Advisors/Committee Members: Notter, David R. (committeechair), Lewis, Ronald M. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: Selection Index; Breeding Objective; Sheep
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APA (6th Edition):
Borg, R. C. (2004). Developing Breeding Objectives for Targhee Sheep. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/9973
Chicago Manual of Style (16th Edition):
Borg, Randy Charles. “Developing Breeding Objectives for Targhee Sheep.” 2004. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/9973.
MLA Handbook (7th Edition):
Borg, Randy Charles. “Developing Breeding Objectives for Targhee Sheep.” 2004. Web. 11 Apr 2021.
Vancouver:
Borg RC. Developing Breeding Objectives for Targhee Sheep. [Internet] [Masters thesis]. Virginia Tech; 2004. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/9973.
Council of Science Editors:
Borg RC. Developing Breeding Objectives for Targhee Sheep. [Masters Thesis]. Virginia Tech; 2004. Available from: http://hdl.handle.net/10919/9973
Virginia Tech
14.
Ahmadzadeh, Amin.
Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows.
Degree: MS, Dairy Science, 1994, Virginia Tech
URL: http://hdl.handle.net/10919/42551
► Four experiments were conducted to investigate the effect of naloxone, an opioid receptor antagonist, on pituitary LH secretion in Holstein cows during two periods…
(more)
▼ Four experiments were conducted to investigate the effect of naloxone, an opioid
receptor antagonist, on pituitary LH secretion in Holstein cows during two periods after
parturition and two phases of the estrous cycle. In experiment 1, 24 cows (12
primiparous; 12 multiparous) received either saline (n = 12) or 1 mg/kg naloxone (n = 12)
i. v. at 14 1 days postpartum. Blood samples were collected at 15-minute intervals for
2 hours before and 2.5 hours after naloxone or saline. Serum LH concentrations
increased (P < .05) in response to naloxone injection in both primi- and multiparous
cows. Saline injection did not affect LH concentrations. In experiment 2, 27 cows (13
primiparous; 14 multiparous) received either saline (n=14) or 1 mg/kg naloxone (n=13)
i. v. at 28 ± 1 days postpartum. Blood samples were collected as in the previous
experiment. Naloxone did not affect serum LH concentrations in either primi- or
mUltiparous cows at 28 days postpartum. In experiment 3, estrous cycles were
synchronized via prostaglandin administration (25 mg) in 22 cows (10 primiparous; 12
multiparous). Cows received either saline (n=11) or 1 mg/kg naloxone (n=11) Lv.
during the luteal phase of the estrous cycle. Blood samples were collected as in the previous experiments. Luteinizing hormone concentrations were not affected by naloxone
in either primi- or mUltiparous cows during the luteal phase of the estrous cycle. In
experiment 4, the same cows used in experiment 3 received a second dose of
prostaglandin (25 mg). Thirty-six hours later, during the follicular phase of the estrous
cycle, the cows received either saline (n =9) or 1 mg/kg naloxone (n = 11) i. v. Naloxone
increased (P < .05) serum LH concentrations in both primi- and mUltiparous cows in
the follicular phase. These results suggest that LH release in the early postpartum dairy
cow is regulated, at least in part, by endogenous opioid pep tides , and the ability of
naloxone to affect LH secretion may change as days postpartum increases, perhaps due
to changes in degree of inhibition by endogenous opioid peptides, and (or) changes in
serum progesterone concentration due to onset of ovarian activity during postpartum
period. It appears that the modulation of LH secretion may be mediated via opioids
during the follicular phase of the estrous cycle. However, an opioid-mediated mechanism
for modulation of LH secretion was absent or overridden by progesterone feedback
during the luteal phase of the estrous cycle.
Advisors/Committee Members: Barnes, Michael A. (committeechair), Denbow, D. Michael (committee member), Pearson, Ronald E. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: Holstein-Friesian cattle.; LD5655.V855 1994.A363
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APA (6th Edition):
Ahmadzadeh, A. (1994). Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/42551
Chicago Manual of Style (16th Edition):
Ahmadzadeh, Amin. “Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows.” 1994. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/42551.
MLA Handbook (7th Edition):
Ahmadzadeh, Amin. “Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows.” 1994. Web. 11 Apr 2021.
Vancouver:
Ahmadzadeh A. Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows. [Internet] [Masters thesis]. Virginia Tech; 1994. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/42551.
Council of Science Editors:
Ahmadzadeh A. Effect of naloxone on serum luteinizing hormone concentrations during the early postpartum period and the estrous cycle in primiparous and multiparous holstein cows. [Masters Thesis]. Virginia Tech; 1994. Available from: http://hdl.handle.net/10919/42551
Virginia Tech
15.
Mahrt, Garry Sonn.
Comparison of expected and actual progeny growth differences in crossbred calves.
Degree: MS, Animal Science, 1987, Virginia Tech
URL: http://hdl.handle.net/10919/45794
► The growth performance of Angus-Polled Hereford F1 calves was compared to the expected progeny differences (EPD) estimated by the American Polled Hereford Association to…
(more)
▼ The growth performance of Angus-Polled Hereford F
1 calves was
compared to the expected progeny differences (EPD) estimated by the
American Polled Hereford Association to evaluate the usefulness of EPD
estimates for improving commercial beef production.
Polled Hereford sires were selected from the high accuracy sires
listed in the American Polled Hereford Association's sire summary. Four
types of sires were used: 1) Sires with high yearling weight and high
maternal EPD's; 2) Sires with high yearling weight and low maternal
EPDâ s; 3) Sires with low yearling weight and high maternal EPD's; and
4) Sires with low yearling weight and low maternal EPD's.
The resulting progeny were weighed at birth, approximately 135
d, weaning and approximately 1 yr. Hip heights were also measured
at weaning. Linear regressions of progeny performance on EPD indicated
that birth and yearling weights were accurately predicted by their respective
EPD estimates. Weight and height at weaning were not accurately
predicted by weaning weight EPD. Partial regressions of progeny performance
on yearling weight and maternal EPD's were also calculated.
Regression of progeny performance on yearling weight EPD resulted in .16 ±.09 kg/kg for 135-d weight, .28 ± .09 kg/kg for weaning weight,
.073 ± .020 cm/kg for weaning hip height and .93 ±.19 kg/kg for yearling weight. Comparable regression values for maternal EPD were
.44 ± .18 kg/kg, .31 ± .17 kg/kg, .100 ± .040 cm/kg and .22 ± .36
kg/kg for 135-d, weaning weight, weaning hip height and yearling
weight, respectively. These results indicate that maternal EPD values
predicted some differences in preweaning growth that were not predicted
by yearling weight EPD.
The progeny performance data was also used to calculate independent EPD estimates for birthweight, weaning weight, and yearling
weight. Correlations between these EPD estimates and those made by the
American Polled Hereford Association were .49 for birthweight, .26 for
weaning weight and .66 for yearling weight. The low correlation between
weaning weight EPD estimates was significantly below expectation and indicates that the American Polled Hereford Association estimates were
inadequate for predicting preweaning growth differences in these crossbred
calves.
Advisors/Committee Members: Notter, David R. (committeechair), Eller, A. L., Jr. (committee member), Pearson, Ronald E. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: Beef cattle; LD5655.V855 1987.M343
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APA (6th Edition):
Mahrt, G. S. (1987). Comparison of expected and actual progeny growth differences in crossbred calves. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/45794
Chicago Manual of Style (16th Edition):
Mahrt, Garry Sonn. “Comparison of expected and actual progeny growth differences in crossbred calves.” 1987. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/45794.
MLA Handbook (7th Edition):
Mahrt, Garry Sonn. “Comparison of expected and actual progeny growth differences in crossbred calves.” 1987. Web. 11 Apr 2021.
Vancouver:
Mahrt GS. Comparison of expected and actual progeny growth differences in crossbred calves. [Internet] [Masters thesis]. Virginia Tech; 1987. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/45794.
Council of Science Editors:
Mahrt GS. Comparison of expected and actual progeny growth differences in crossbred calves. [Masters Thesis]. Virginia Tech; 1987. Available from: http://hdl.handle.net/10919/45794
Virginia Tech
16.
Loor, Juan Jose.
Postruminal flow, digestibility, and utilization of fatty acylamides or conjugated linoleic acid for milk fat synthesis by lactating Holstein cows.
Degree: MS, Dairy Science, 1997, Virginia Tech
URL: http://hdl.handle.net/10919/45637
► Four Holstein cows with ruminal and duodenal cannulas were used to evaluate the effects of dietary fatty acylamides (canolamide) or abomasally infused conjugated linoleic acid…
(more)
▼ Four Holstein cows with ruminal and duodenal cannulas were used
to evaluate the effects of dietary fatty acylamides (canolamide)
or abomasally infused conjugated linoleic acid on milk production
and composition. In the first experiment, cows were fed diets
with no supplemental fat(control), or the control diet supplemented
at 3.3% of DM with canola oil, canolamide, or a mixture of equal
amounts of canola oil and canolamide in a 4 x 4 Latin square.
DMI and milk yield were decreased when cows were fed canolamide.
Intake and duodenal flow of diet components and fatty acids
were decreased by canolamide, but their apparent digestibilities
were not affected by treatment. Fat supplementation decreased
concentrations of fatty acids with 8 to 16 carbons and increased
oleic acid in milk. In the second experiment, cows were infused
abomasally with 100 g Linoleic acid (LA) or a mixture of 100 g
LA plus 100 g conjugated linoleic acid (LA-CLA) for 24 h in a
single crossover design. Infused CLA was a mixture of 70%
cis-9, trans-11-18:2 and 30% trans-10, cis-12-18:2. Milk yield
and DMI were not affected by treatment. Milk fat percentage
and yield were decreased by LA-CLA. Concentration and yield of
oleic and arachidonic acid and fatty acids with 6 to 16 carbons
in milk were reduced by LA-CLA. Stearic acid and CLA concentrations
in milk, however, were higher in response to LA-CLA. Infusion
of LA-CLA led to increased (from 23 to 45%) concentration of
unsaturated fatty acids with a concomitant decrease (from 70 to 42%)
in saturated fatty acid concentration in milk fat. Feeding
canolamide at 3.3% significantly decreased DMI and milk yield
compared with canola oil or the mixture of canola oil and
canolamide. However, results indicated that oleic acid and CLA
concetration in milk fat can be increased proportionally to
their flow into the small intestine. Utilization of these fatty
acids for milk fat synthesis may cause a reduction in the amount
of medium and short chain fatty acids synthesized de novo within
the mammary gland. Furthermore, CLA appears to be a potent
inhibitor of milk fat synthesis and desaturation of stearic and
linoleic acid.
Advisors/Committee Members: Herbein, Joseph H. Jr. (committeechair), Keenan, Thomas W. (committee member), Vinson, William E. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: CLA; bovinic acid; oleic acid; dairy cow
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APA (6th Edition):
Loor, J. J. (1997). Postruminal flow, digestibility, and utilization of fatty acylamides or conjugated linoleic acid for milk fat synthesis by lactating Holstein cows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/45637
Chicago Manual of Style (16th Edition):
Loor, Juan Jose. “Postruminal flow, digestibility, and utilization of fatty acylamides or conjugated linoleic acid for milk fat synthesis by lactating Holstein cows.” 1997. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/45637.
MLA Handbook (7th Edition):
Loor, Juan Jose. “Postruminal flow, digestibility, and utilization of fatty acylamides or conjugated linoleic acid for milk fat synthesis by lactating Holstein cows.” 1997. Web. 11 Apr 2021.
Vancouver:
Loor JJ. Postruminal flow, digestibility, and utilization of fatty acylamides or conjugated linoleic acid for milk fat synthesis by lactating Holstein cows. [Internet] [Masters thesis]. Virginia Tech; 1997. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/45637.
Council of Science Editors:
Loor JJ. Postruminal flow, digestibility, and utilization of fatty acylamides or conjugated linoleic acid for milk fat synthesis by lactating Holstein cows. [Masters Thesis]. Virginia Tech; 1997. Available from: http://hdl.handle.net/10919/45637
Virginia Tech
17.
Filep, Renee.
In vitro milk protein secretion by explants of Holstein bull mammary tissue from two different genetic lines.
Degree: MS, Dairy Science, 1990, Virginia Tech
URL: http://hdl.handle.net/10919/43016
► The ability of mammary tissue from mature Holstein bulls to respond to hormonal stimuli in organ culture to synthesize and secrete milk proteins was…
(more)
▼ The ability of mammary tissue from mature Holstein bulls to respond to hormonal stimuli in organ
culture to synthesize and secrete milk proteins was studied. Sixteen bulls from the genetic selection
and control lines developed at
Virginia Polyteclmic Institute were randomly assigned to either a
non-treated or steroid pretreated group. The steroid pretreated group received estradiol 17-B and
progesterone at 0.1 and 0.25 mg/kg/day, respectively, for 7 d starting 15 d before slaughter.
Mammary tissue was explanted and cultured for up to 96 h in basal medium (B) which consisted
of Media 199 supplemented with fetal calf serum and bovine insulin, or stimulatory medium (St),
which was further supplemented with triiodothyronine, estradiol 17-B, hydrocortisone, and bovine
prolactin (PRL). Explants in duplicate multi-well culture dishes were incubated in the presence of
3H-Iabeled amino acids or 3H-Iabeled thymidine. Measurements made included: casein in media
and homogenized tissue, alpha-lactalbumin in homogenized tissue, tri-chloro-acetic acid
precipitable 3H-protein in media and homogenized tissue, and DNA content of cultured tissue. A
subset of cultured explants from each bull was fixed and embedded for histological evaluation and
auto radiographic localization of incorporated 3H-labeled thymidine. Synthesis and secretion data,
as well as growth responses of the epithelium were compared between selection and control bulls.
Advisors/Committee Members: Akers, Robert Michael (committeechair), Pearson, Ronald E. (committee member), Saacke, Richard G. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: Milk yield; LD5655.V855 1990.F644
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APA (6th Edition):
Filep, R. (1990). In vitro milk protein secretion by explants of Holstein bull mammary tissue from two different genetic lines. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/43016
Chicago Manual of Style (16th Edition):
Filep, Renee. “In vitro milk protein secretion by explants of Holstein bull mammary tissue from two different genetic lines.” 1990. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/43016.
MLA Handbook (7th Edition):
Filep, Renee. “In vitro milk protein secretion by explants of Holstein bull mammary tissue from two different genetic lines.” 1990. Web. 11 Apr 2021.
Vancouver:
Filep R. In vitro milk protein secretion by explants of Holstein bull mammary tissue from two different genetic lines. [Internet] [Masters thesis]. Virginia Tech; 1990. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/43016.
Council of Science Editors:
Filep R. In vitro milk protein secretion by explants of Holstein bull mammary tissue from two different genetic lines. [Masters Thesis]. Virginia Tech; 1990. Available from: http://hdl.handle.net/10919/43016
Virginia Tech
18.
Peeler, Iris Dawn.
Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers.
Degree: MS, Dairy Science, 2004, Virginia Tech
URL: http://hdl.handle.net/10919/9880
► This study was conducted to evaluate the efficacy of intravaginal progesterone (P4) inserts (CIDR) in synchronization protocols combined with timed artificial insemination (TAI) as related…
(more)
▼ This study was conducted to evaluate the efficacy of intravaginal progesterone (P4) inserts (CIDR) in synchronization protocols combined with timed artificial insemination (TAI) as related reproductive performance. In the first study, heifers were synchronized with CIDR inserts followed by TAI. Heifers in the estradiol cypionate (ECP) group were synchronized with a combination of ECP, CIDR, prostaglandin (PGF2α), and ECP (CIDR-ECP), while the gonadotropin-releasing hormone (GnRH) group was synchronized using a combination of ECP, CIDR, PGF2α, and GnRH (CIDR-GnRH). All heifers were bred at either 48, 56, or 72 hours (h) after CIDR removal. Overall pregnancy rate (PR) for synchronized heifers was 60.1%, and embryo survival rate (ESR) was 98%. Pregnancy rate for CIDR-ECP treated heifers was influenced by artificial insemination (AI) time. In conclusion, ECP or GnRH may be used effectively in a CIDR-based TAI program in heifers. In the second study, cows were synchronized with CIDR devices or Ovsynch. The CIDR group received a combination of ECP, CIDR, PGF2α, and GnRH, while the Ovsynch group was synchronized using a combination of GnRH and PGF2α. Cows were bred at either 0, 8, or 24 h after the final GnRH injection. Overall PR for first service was 30.5% with ESR of 82.8%. Overall resynchronization PR was 35.1% with an ESR of 84.8%. In conclusion, Ovsynch and CIDR-based protocols are equally effective in synchronizing ovulation in a TAI program and resulted in comparable PR.
Advisors/Committee Members: Nebel, Raymond L. (committeechair), Nickerson, Stephen C. (committee member), Cassell, Bennet G. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: reproductive performance; timed artificial insemination; dairy cattle; synchronization
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APA (6th Edition):
Peeler, I. D. (2004). Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/9880
Chicago Manual of Style (16th Edition):
Peeler, Iris Dawn. “Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers.” 2004. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/9880.
MLA Handbook (7th Edition):
Peeler, Iris Dawn. “Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers.” 2004. Web. 11 Apr 2021.
Vancouver:
Peeler ID. Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers. [Internet] [Masters thesis]. Virginia Tech; 2004. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/9880.
Council of Science Editors:
Peeler ID. Synchronization and Resynchronization of Ovulation and Timed Insemination in Lactating Dairy Cows and Heifers. [Masters Thesis]. Virginia Tech; 2004. Available from: http://hdl.handle.net/10919/9880
Virginia Tech
19.
Rossini, Katherine Lynn.
Effects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Rates.
Degree: MS, Dairy Science, 2004, Virginia Tech
URL: http://hdl.handle.net/10919/10010
► Calf health data and first lactation records for 2556 cows born in a commercial dairy herd between June 1998 and June 2001 were studied to…
(more)
▼ Calf health data and first lactation records for 2556 cows born in a commercial dairy herd between June 1998 and June 2001 were studied to determine the effects of calfhood disease on survival and performance. Operator-treated respiratory disease occurrences within the first year of life and digestive disease occurrences within the first 45 d of life were analyzed to determine their effects on calfhood morbidity, age at first calving, 305-d first lactation production, and mortality in first lactation. Of the 2556 records used, 2083 calves contracted respiratory or digestive disease at least once, 1254 calves had digestive disease only, 771 had respiratory disease only, and 191 calves had both diseases. Occurrence of calfhood digestive disease increased the chance of calfhood respiratory disease 2-fold. Age at first calving increased 0.53 mo with multiple occurrences of respiratory disease versus none. Calves born in the winter calved at 25.4 mo, whereas calves born in spring calved at 24.5 mo. Respiratory disease had the largest effect on calves born in the spring, resulting in 23.9 mo age at first calving for no occurrence and 25.4 mo for multiple occurrences. No significant effect of disease was detected for 305-d milk yield, fat yield, or SCC, but protein yield decreased by 0.05 kg/d with increased calf respiratory disease. Although calfhood disease had no influence on illness as a cow, disease-free calves had a 5% advantage in probability of remaining in the herd through 305-d, and an 8% advantage at 730-d compared with calves with 2 or more disease occurrences. In conclusion, calfhood occurrences of respiratory and digestive disease had a slight impact on age at first calving, depending on season of birth, and minimal impact on production performance through 305-d of first lactation. The occurrence of respiratory or digestive disease caused a decrease in survival rate from calving through 305-d in first lactation and 730 d after calving.
Advisors/Committee Members: McGilliard, Michael L. (committeechair), Swecker, William S. Jr. (committee member), Pearson, Ronald E. (committee member), James, Robert E. (committee member).
Subjects/Keywords: calfhood disease; age at first calving; mortality; morbidity
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APA (6th Edition):
Rossini, K. L. (2004). Effects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Rates. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/10010
Chicago Manual of Style (16th Edition):
Rossini, Katherine Lynn. “Effects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Rates.” 2004. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/10010.
MLA Handbook (7th Edition):
Rossini, Katherine Lynn. “Effects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Rates.” 2004. Web. 11 Apr 2021.
Vancouver:
Rossini KL. Effects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Rates. [Internet] [Masters thesis]. Virginia Tech; 2004. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/10010.
Council of Science Editors:
Rossini KL. Effects of Calfhood Respiratory and Digestive Disease on Calfhood Morbidity and First Lactation Production and Survival Rates. [Masters Thesis]. Virginia Tech; 2004. Available from: http://hdl.handle.net/10919/10010
Virginia Tech
20.
Beaudry, Thomas Fernand.
Use of sire evaluations for first, all, and later lactations to predict lifetime profit functions of individual daughters.
Degree: MS, Dairy Science (Genetics and Management), 1986, Virginia Tech
URL: http://hdl.handle.net/10919/51125
► Sire evaluations from first, all, and later lactations for Predicted Difference milk, fat, and dollars on 226 sires were used to predict deviated relative net…
(more)
▼ Sire evaluations from first, all, and later lactations for Predicted Difference milk, fat, and dollars on 226 sires were used to predict deviated relative net income. Eleven different relative net incomes were calculated on 176,902 individual cows. Low, medium and high values were used for lifetime product value and feed price. Lifetime product value was actual milk and fat production. Individual relative net income was deviated from contemporaries in the same herd and calving in the same year of first freshening.
Advisors/Committee Members: Cassell, Bennet G. (committeechair), McGilliard, Michael L. (committee member), Pearson, Ronald E. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: Milk yield; LD5655.V855 1986.B429
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APA (6th Edition):
Beaudry, T. F. (1986). Use of sire evaluations for first, all, and later lactations to predict lifetime profit functions of individual daughters. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/51125
Chicago Manual of Style (16th Edition):
Beaudry, Thomas Fernand. “Use of sire evaluations for first, all, and later lactations to predict lifetime profit functions of individual daughters.” 1986. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/51125.
MLA Handbook (7th Edition):
Beaudry, Thomas Fernand. “Use of sire evaluations for first, all, and later lactations to predict lifetime profit functions of individual daughters.” 1986. Web. 11 Apr 2021.
Vancouver:
Beaudry TF. Use of sire evaluations for first, all, and later lactations to predict lifetime profit functions of individual daughters. [Internet] [Masters thesis]. Virginia Tech; 1986. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/51125.
Council of Science Editors:
Beaudry TF. Use of sire evaluations for first, all, and later lactations to predict lifetime profit functions of individual daughters. [Masters Thesis]. Virginia Tech; 1986. Available from: http://hdl.handle.net/10919/51125
Virginia Tech
21.
Appuhamy, Jayasooriya Arachchige Don Ranga Niroshan.
Phenotypic Relationships between Lactation persistency and Common Health Disorders in Dairy Cows.
Degree: MS, Dairy Science, 2006, Virginia Tech
URL: http://hdl.handle.net/10919/35799
► Lactation persistency is defined as the ability of a cow to maintain production at a higher level after peak yield. Hypothetically, more persistent cows are…
(more)
▼ Lactation persistency is defined as the ability of a cow to maintain production at a higher level after peak yield. Hypothetically, more persistent cows are less susceptible to health and reproductive disorders. The objective of this research was to investigate the phenotypic relationships of common health disorders in dairy cows to lactation persistency. The relationships with peak yield and days in milk (DIM) at peak yield were also studied. Two separate investigations (Study 1 and Study 2) were performed. Study 1 used treatment incidence data and daily milk weights of 991 lactations from experimental dairy herds at
Virginia Tech and Pennsylvania State University. Milk yield persistency (PM) was estimated for individual lactations using daily milk weights. In Study 2, producer recorded health data of 87555 lactations from 398 commercial herds were used. PM, fat (PF), and protein (PP) persistencies were estimated from TD yields. Mastitis only in the first 100 days, only after 100 DIM, and at any stage of lactation, and reproductive disorders including metritis, retained placenta, cystic ovaries, metabolic diseases including ketosis, milk fever and displaced abomasums, and lameness were considered in both studies. Mastitis both before and after 100 DIM was considered only in Study 1. Each disease was defined as a binary trait distinguishing between lactations with at least one incidence (1) and lactations with no incidences (0). Standardized measures of the persistencies, uncorrelated with yield, were calculated as a function of yield deviations from standard curves and DIM deviations around reference dates. Peak milk yield and DIM at peak of individual lactations were computed using Wood's function. Effects of persistency (PM, PF, and PP) on probability of the diseases in current and next lactations were examined through odds ratios from a logistic regression model. Conversely, the effects of diseases on persistencies, peak milk yield, and DIM at peak milk yield were also examined. Increasing PM, PF, and PP tend to reduce the incidence of mastitis, specifically in late stages of current and next lactation. PM and PP appear to have greater impact on mastitis than PF. No other likelihood of a disease was affected by the increasing persistencies. Post partum reproductive and metabolic diseases often had substantially positive effect on persistencies of both primiparous and multiparous cows (p<0.001 in Study 1 and p<0.001 in Study 2). Mastitis in early lactation appeared to increase persistency more often in multiparous cows (p<0.05 in Study 1 and p<0.005 in Study 2). Mastitis in late lactation had considerable but negative impact on persistency in both primiparous and multiparous cows (p<0.05 in Study 1 and p<0.005 in Study 2). Cows, which developed mastitis in both early and late lactations tended to have lower PM (p<0.05 in Study 1). Irrespective to the time of occurrence, effect of mastitis on milk, fat and protein yield persistencies was negative. Most of the diseases significantly affected DIM at peak milk yield…
Advisors/Committee Members: Cassell, Bennet G. (committeechair), Akers, Robert Michael (committee member), Lewis, Ronald M. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: disease; lactation persistency; Cow
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APA (6th Edition):
Appuhamy, J. A. D. R. N. (2006). Phenotypic Relationships between Lactation persistency and Common Health Disorders in Dairy Cows. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/35799
Chicago Manual of Style (16th Edition):
Appuhamy, Jayasooriya Arachchige Don Ranga Niroshan. “Phenotypic Relationships between Lactation persistency and Common Health Disorders in Dairy Cows.” 2006. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/35799.
MLA Handbook (7th Edition):
Appuhamy, Jayasooriya Arachchige Don Ranga Niroshan. “Phenotypic Relationships between Lactation persistency and Common Health Disorders in Dairy Cows.” 2006. Web. 11 Apr 2021.
Vancouver:
Appuhamy JADRN. Phenotypic Relationships between Lactation persistency and Common Health Disorders in Dairy Cows. [Internet] [Masters thesis]. Virginia Tech; 2006. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/35799.
Council of Science Editors:
Appuhamy JADRN. Phenotypic Relationships between Lactation persistency and Common Health Disorders in Dairy Cows. [Masters Thesis]. Virginia Tech; 2006. Available from: http://hdl.handle.net/10919/35799
Virginia Tech
22.
Pence, Kristen Jean.
The effects of dietary forage, social hierarchy, and stocking density on stress in lactating cows during relocation.
Degree: MS, Dairy Science, 2005, Virginia Tech
URL: http://hdl.handle.net/10919/33830
► The objective of these studies was to determine the effects of forage fiber, social hierarchy, and stocking density on stress in lactating cows during relocation…
(more)
▼ The objective of these studies was to determine the effects of forage fiber, social hierarchy, and stocking density on stress in lactating cows during relocation to new dairy facilities. In experiment one, 23 lactating cows were fed a basal ration, or the basal ration plus grass or alfalfa hay at 10% of DM offered from 3 wk pre-move to 9 wk post-move. In experiment two, 17 lactating cows were housed together before and after relocation and evaluated for dominance rank. In experiment three, 44 cows were housed together before relocation, then in pens of varying stocking density (0.67, 0.83, 1.0, or 1.17 cows per stall) post-move. In these studies, the effects of treatment on MY, lameness, behaviors, plasma cortisol, cow cleanliness, and DMI were monitored. In experiment one, cows fed grass or alfalfa hay diets had higher plasma cortisol concentrations on the day of relocation than cows fed TMR, but there were no differences in DMI or MY. Cows fed alfalfa hay or TMR had increased lameness scores following relocation; cows fed grass hay did not have increased lameness scores. In experiment two, there were no differences in plasma cortisol or lameness scores between dominant and subordinate cows. Subordinate cows had lower MY following relocation compared to dominant cows. In experiment three, cows housed at a stocking rate of 1.17 had higher plasma cortisol than cows housed at a stocking rate of 0.67. All cows had higher lameness scores following relocation, but cows housed at a stocking rate of 0.67 tended to have higher lameness scores than cows housed at stocking rates of 0.83, 1.0, and 1.17. In summary, some management practices may decrease the negative effects of stress on lactating cows during relocation.
Advisors/Committee Members: Knowlton, Katharine F. (committeechair), Dunnington, E. Ann (committee member), Gwazdauskas, Francis C. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: stress; lactating cow; relocation
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APA (6th Edition):
Pence, K. J. (2005). The effects of dietary forage, social hierarchy, and stocking density on stress in lactating cows during relocation. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/33830
Chicago Manual of Style (16th Edition):
Pence, Kristen Jean. “The effects of dietary forage, social hierarchy, and stocking density on stress in lactating cows during relocation.” 2005. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/33830.
MLA Handbook (7th Edition):
Pence, Kristen Jean. “The effects of dietary forage, social hierarchy, and stocking density on stress in lactating cows during relocation.” 2005. Web. 11 Apr 2021.
Vancouver:
Pence KJ. The effects of dietary forage, social hierarchy, and stocking density on stress in lactating cows during relocation. [Internet] [Masters thesis]. Virginia Tech; 2005. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/33830.
Council of Science Editors:
Pence KJ. The effects of dietary forage, social hierarchy, and stocking density on stress in lactating cows during relocation. [Masters Thesis]. Virginia Tech; 2005. Available from: http://hdl.handle.net/10919/33830
Virginia Tech
23.
Vanimisetti, Hima Bindu.
Genetic evaluation of ewe productivity and its component traits in Katahdin and Polypay sheep.
Degree: PhD, Animal and Poultry Sciences, 2006, Virginia Tech
URL: http://hdl.handle.net/10919/29760
► The objectives of this dissertation were to evaluate genetic influences on ewe productivity, its growth and reproductive components, and measures indicative of accelerated lambing performance.…
(more)
▼ The objectives of this dissertation were to evaluate genetic influences on ewe productivity, its growth and reproductive components, and measures indicative of accelerated lambing performance. Genetic parameters were estimated for total weight of litter weaned per ewe lambing (TW) and its components, number of lambs born (NB), number of lambs weaned (NW) and average weight of lambs weaned (AW), measured as traits of the ewe, and lamb survival (LS) and weaning weight (WW), measured as traits of the lamb, in Katahdin sheep. Heritabilities of TW, NB, NW, and AW, were 0.12, 0.12, 0.09, and 0.13, respectively. Heritability of WW was 0.15 to 0.20. Genetic effects on LS were negligible. Genetic correlation of TW with NB, NW, and AW averaged 0.30, 0.90, and 0.74, respectively, those of NB with NW and AW averaged 0.72 and 0.01, respectively, and that between NW and AW averaged 0.50. Direct genetic effects on WW were independent of NB and NW, but correlation between maternal genetic effects on WW and animal genetic effects on NW averaged 0.35.
Ewe fertility, NB, LS, and WW were modeled using stochastic simulation and used to derive NW, AW, and TW to test alternative predictors of genetic merit for TW. A random 8% of WW observations were set to missing values and AW and TW were recalculated to evaluate the effects of data reporting inconsistencies on efficacy of different prediction strategies. Four alternative predictors of estimated breeding values (EBV) for TW involved direct univariate prediction (TW1), an index of EBV for NW and AW (TW2), indirect prediction using data for NW and AW and genetic correlations among NW, AW and TW (TW3), and indirect prediction augmenting TW3 with data and genetic correlations involving NB (TW4). To validate efficacy of predictors, daughter data sets were generated from the original ewes and their realized TW were regressed on alternative predictors. Regression coefficients from TW1, TW3, and TW4 were close to the expected value of 0.50 whereas those from TW2 were less than 0.50. Model Rsquare statistics were similar among predictors when there were no missing WW data but regressions involving TW1 had lowest model R-square when some WW data was missing.
Ewe lamb fertility (ELF), ages at first, second, and third lambings (AGE1 to AGE3), first and second lambing intervals (INT1 and INT2), and number of lambings by 38 mo of age (LAMB3) were evaluated for an accelerated lambing Polypay flock. Relationships among these traits and NB and WW were estimated. Heritability of ELF, AGE1, AGE2, AGE3, INT1, INT2, and LAMB3 were 0.14, 0.39, 0.28, 0.36, 0.00, 0.09, and 0.27, respectively. Heritability of AGE2 and AGE3 were negligible after accounting for variation in AGE1. Genetic correlations of ELF with AGE1 and AGE2 were -0.89, -0.91, respectively, and that with LAMB3 was 0.89. Genetic correlations of LAMB3 with AGE1 and AGE2 were -0.49 and -1.00, respectively. Genetic correlations of ELF and LAMB3 with direct genetic effects on WW were close to -0.70, but correlations with maternal genetic effects…
Advisors/Committee Members: Notter, David R. (committeechair), Lewis, Ronald M. (committee member), Pearson, Ronald E. (committee member), Greiner, Scott P. (committee member).
Subjects/Keywords: Ewe Productivity; Fertility; Accelerated lambing; Sheep; Heritability; Reproduction
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APA (6th Edition):
Vanimisetti, H. B. (2006). Genetic evaluation of ewe productivity and its component traits in Katahdin and Polypay sheep. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/29760
Chicago Manual of Style (16th Edition):
Vanimisetti, Hima Bindu. “Genetic evaluation of ewe productivity and its component traits in Katahdin and Polypay sheep.” 2006. Doctoral Dissertation, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/29760.
MLA Handbook (7th Edition):
Vanimisetti, Hima Bindu. “Genetic evaluation of ewe productivity and its component traits in Katahdin and Polypay sheep.” 2006. Web. 11 Apr 2021.
Vancouver:
Vanimisetti HB. Genetic evaluation of ewe productivity and its component traits in Katahdin and Polypay sheep. [Internet] [Doctoral dissertation]. Virginia Tech; 2006. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/29760.
Council of Science Editors:
Vanimisetti HB. Genetic evaluation of ewe productivity and its component traits in Katahdin and Polypay sheep. [Doctoral Dissertation]. Virginia Tech; 2006. Available from: http://hdl.handle.net/10919/29760
Virginia Tech
24.
Garst, Amy S.
In-vitro developmental potential of bovine oocytes obtained by transvaginal follicular aspiration as related to their morphological quality and after microinjection of DNA.
Degree: MS, Dairy Science, 1996, Virginia Tech
URL: http://hdl.handle.net/10919/44483
► The development of oocytes of differing quality retrieved using transvaginal follicular aspiration (TVFA) and following DNA injection was examined. Eight cows were subjected to…
(more)
▼ The development of oocytes of differing quality retrieved using transvaginal
follicular aspiration (TVFA) and following DNA injection was examined. Eight cows
were subjected to twice weekly TVF A for 16 wk. Oocytes retrieved were graded and
placed in an in-vitro maturation, fertilization and co-culture (IVMIIVFIIVC) program.
Two thirds of oocytes were injected with DNA. Good quality oocytes from slaughtered
cows (SH) were obtained once monthly and processed the same way. Good quality
TVF A oocytes had a higher mean development score than poor quality oocytes, but not
different from that of good quality SH oocytes. Good quality TVF A oocytes produced
more viable embryos (31.7% blastocysts) than poor quality oocytes or SH oocytes (12.8%
and 20.4% blastocysts, respectively). Embryo development following injection of DNA
was the same for oocytes for each source-quality group (TVF A-good, 8.4; TVF A-poor,
5.5; SH-good, 6.3 % blastocysts). Development of good quality TVFA oocytes increased during the last 9 wk of the 16 wk collection period. Poor oocyte development increased
slightly to 9 wk and then decreased. Development of TVF A oocytes injected with DNA
did not vary during the experiment. However, development of controls increased from
a mean score of2.50 at wk 1 to 4.17 at wk 16. Oocytes from TVFA produced more PCR
positive blastocysts (95.0%) than SH oocytes (61.5%). More calves were born from the
transfer of embryos injected with DNA from TVF A oocytes (3/5) than from SH oocytes
(116), although not statistically significant. One calf was PCR positive in bone-marrow,
but was negative in other tissues. The use of oocytes obtained by TVF A may improve
the efficiency of producing transgenic cattle.
Advisors/Committee Members: Gwazdauskas, Francis C. (committeechair), Akers, Robert Michael (committee member), Pearson, Ronald E. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: transvaginal follicular aspiration; DNA microinjection; bovine oocytes; in-vitro embryo culture; blastocyst; LD5655.V855 1996.G377
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APA (6th Edition):
Garst, A. S. (1996). In-vitro developmental potential of bovine oocytes obtained by transvaginal follicular aspiration as related to their morphological quality and after microinjection of DNA. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44483
Chicago Manual of Style (16th Edition):
Garst, Amy S. “In-vitro developmental potential of bovine oocytes obtained by transvaginal follicular aspiration as related to their morphological quality and after microinjection of DNA.” 1996. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/44483.
MLA Handbook (7th Edition):
Garst, Amy S. “In-vitro developmental potential of bovine oocytes obtained by transvaginal follicular aspiration as related to their morphological quality and after microinjection of DNA.” 1996. Web. 11 Apr 2021.
Vancouver:
Garst AS. In-vitro developmental potential of bovine oocytes obtained by transvaginal follicular aspiration as related to their morphological quality and after microinjection of DNA. [Internet] [Masters thesis]. Virginia Tech; 1996. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/44483.
Council of Science Editors:
Garst AS. In-vitro developmental potential of bovine oocytes obtained by transvaginal follicular aspiration as related to their morphological quality and after microinjection of DNA. [Masters Thesis]. Virginia Tech; 1996. Available from: http://hdl.handle.net/10919/44483
Virginia Tech
25.
Yook, Eunsun.
Estimation of the Economic Impact of a Unit Change in Predicted Transmitting Ability for Daughter Pregnancy Rate and Other Predicted Transmitting Ability in the Merit Indexes.
Degree: MS, Dairy Science, 2004, Virginia Tech
URL: http://hdl.handle.net/10919/42809
► These studies deal with lifetime profit analyses for individual cows, and using these estimates to determine the economic value of genetic changes in traits for…
(more)
▼ These studies deal with lifetime profit analyses for individual cows, and using these estimates to determine the economic value of genetic changes in traits for which genetic evaluations (predicted transmitting ability, PTA) are currently available. Data were collected from six states processed by Dairy Records Management Systems (DRMS) from herds on continuous test for at least 10 yr.
The purpose of the first study was to determine how well estimators of lifetime net income based on 305-d lactation yields and a 10-yr opportunity (RNI305.10) and based on complete lactation data but a 5-yr opportunity (RNIc.5) predict the estimate based on complete lactations and a 10-yr opportunity (RNIc.10). Records for 22,854 cows in
Virginia herds born in 1988, 1990, and 1992 from the DRMS in Raleigh, NC were used. Each RNI was calculated using fluid (skim/fat) pricing and milk-fat-protein pricing. Regression analyses including herd and birth year were used in the model to estimate the regression of RNIc.10 on RNIc.5, and RNIc.10 on RNI305.10. The resulting regression coefficients for fluid (skim/fat) pricing were 1.53 and 1.12 explaining 67 and 97% of the variation of RNIc.10, respectively. The corresponding results for milk-fat-protein pricing were 1.52 and 1.14 explaining 68 and 96% of the variation of RNIc.10, respectively. Using RNIc.10 as the measure to estimate lifetime profit is strongly recommended over the two alternatives tested.
In the second study, the economic impacts of a unit change in PTA of daughter pregnancy rate (DPR) and other PTA in the merit indexes on lifetime profit estimates of a bullâ s daughters were estimated to determine an economic weight for the PTADPR and other PTA in economic indexes. Records for 71,094 cows born in 1988, 1990, and 1992 from six states processed at DRMS were used: Florida [10,940 cows], Indiana [8,231 cows], North Carolina [12,280 cows], Texas [4,786 cows],
Virginia [20,341 cows], and Vermont [14,516 cows]. The basic RNI function consisted of [total milk, fat, and protein income ?feed cost for production] (yield income, YI) + [net value of calves + net salvage value] (non yield income, NYI) ?rearing cost (RC) ?[(daily cost for labor, maintenance feed, supplies, and fixed expenses) x days in herd] (daily cost, DC). Some of the economic impacts of PTA described for the merit indexes were not included in the basic RNI. These were added to RNI by multiplying the respective sire PTA by the economic impact. These included -165*PTASCS (M); 33*udder composite + 15*feet and legs composite -14.86*body size composite (T); and 8.064*PTA for daughter pregnancy rate -4.80*PTA for daughter calving ease (PRCE). Each ARNI was calculated using all production records initiated prior to the cowâ s tenth birthday with three milk pricing systems comparable to the prices in USDA three merit indexes: fluid (skim/fat) pricing (FARNI), milk-fat-protein pricing (NMARNI), and cheese pricing (CARNI). Two levels of prices for rearing cost per day and daily cost were used for calculating FARNI, NMARNI,…
Advisors/Committee Members: Pearson, Ronald E. (committeechair), Cassell, Bennet G. (committee member), Nickerson, Stephen C. (committee member), Nebel, Raymond L. (committee member).
Subjects/Keywords: daughter pregnancy rate; relative net income; economic weight; herdlife opportunity; lifetime net income
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APA (6th Edition):
Yook, E. (2004). Estimation of the Economic Impact of a Unit Change in Predicted Transmitting Ability for Daughter Pregnancy Rate and Other Predicted Transmitting Ability in the Merit Indexes. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/42809
Chicago Manual of Style (16th Edition):
Yook, Eunsun. “Estimation of the Economic Impact of a Unit Change in Predicted Transmitting Ability for Daughter Pregnancy Rate and Other Predicted Transmitting Ability in the Merit Indexes.” 2004. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/42809.
MLA Handbook (7th Edition):
Yook, Eunsun. “Estimation of the Economic Impact of a Unit Change in Predicted Transmitting Ability for Daughter Pregnancy Rate and Other Predicted Transmitting Ability in the Merit Indexes.” 2004. Web. 11 Apr 2021.
Vancouver:
Yook E. Estimation of the Economic Impact of a Unit Change in Predicted Transmitting Ability for Daughter Pregnancy Rate and Other Predicted Transmitting Ability in the Merit Indexes. [Internet] [Masters thesis]. Virginia Tech; 2004. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/42809.
Council of Science Editors:
Yook E. Estimation of the Economic Impact of a Unit Change in Predicted Transmitting Ability for Daughter Pregnancy Rate and Other Predicted Transmitting Ability in the Merit Indexes. [Masters Thesis]. Virginia Tech; 2004. Available from: http://hdl.handle.net/10919/42809
Virginia Tech
26.
Grove, Mary Beth.
Optimal time of insemination in dairy cattle identified in estrus by HeatWatch.
Degree: MS, Dairy Science, 1996, Virginia Tech
URL: http://hdl.handle.net/10919/44510
► Estrus detection programs practiced on most U.S. dairy farms are not intense enough to provide the information needed to accurately time insemination, thus preventing…
(more)
▼ Estrus detection programs practiced on most U.S. dairy farms are not intense
enough to provide the information needed to accurately time insemination, thus
preventing AI from obtaining its full conception rate potential. Herds (n = 17)
participated in a trial designed to evaluate percent pregnant relative to various
characteristics of estrus. Herds utilized HeatWatch® electronic estrus detection
system to detect and record mounting activity for cows in estrus. Inseminations
were performed daily during a three hour interval for all cows identified in estrus
the previous 24 h. Model characterizing percent pregnant for cows (services =
2661) included effects of interval from first mount to AI (P < 0.01), mounts per
estrus (P < 0.01), DIM at insemination (P < 0.01), herd (P <0.05), and season of
AI (P < 0.05). As mounts per estrus and days in milk increased, percent diagnosed
pregnant increased. Interval affected probability of pregnancy with highest odds
ratios for percent pregnant occurring >4 to 16 h following onset of estrus. Model
for heifers (n = 306) included linear effects of interval (P < 0.01), season
(P < 0.05), and herd (P < 0.01). In dairy heifers, as interval from first mount to AI
increased, percent pregnant decreased. Timing of insemination in dairy cows can
now be performed relative to first mount of estrus, with highest probability of
pregnancy occurring between >4 to 16 h after onset. If onset of estrus is not
known, insemination should be performed at the next most convenient time
within 3 h.
Advisors/Committee Members: Nebel, Raymond L. (committeechair), Pearson, Ronald E. (committee member), Bailey, Thomas L. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: estrus detection; artificial insemination; HeatWatch; LD5655.V855 1996.G768
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APA (6th Edition):
Grove, M. B. (1996). Optimal time of insemination in dairy cattle identified in estrus by HeatWatch. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44510
Chicago Manual of Style (16th Edition):
Grove, Mary Beth. “Optimal time of insemination in dairy cattle identified in estrus by HeatWatch.” 1996. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/44510.
MLA Handbook (7th Edition):
Grove, Mary Beth. “Optimal time of insemination in dairy cattle identified in estrus by HeatWatch.” 1996. Web. 11 Apr 2021.
Vancouver:
Grove MB. Optimal time of insemination in dairy cattle identified in estrus by HeatWatch. [Internet] [Masters thesis]. Virginia Tech; 1996. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/44510.
Council of Science Editors:
Grove MB. Optimal time of insemination in dairy cattle identified in estrus by HeatWatch. [Masters Thesis]. Virginia Tech; 1996. Available from: http://hdl.handle.net/10919/44510
Virginia Tech
27.
Campbell, Davina Elaine.
Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients.
Degree: MS, Dairy Science, 2007, Virginia Tech
URL: http://hdl.handle.net/10919/33967
► Studies were conducted to investigate the tissue distribution of stearoyl-CoA desaturase-1 (SCD) and the regulation of SCD1 protein expression by dietary fat, insulin, polyunsaturated fatty…
(more)
▼ Studies were conducted to investigate the tissue distribution of stearoyl-CoA desaturase-1 (SCD) and the regulation of SCD1 protein expression by dietary fat, insulin, polyunsaturated fatty acids (PUFA), and linoleic acid (cis-9, cis-12 18:2). The first study examined tissue distribution of SCD1 protein in Holstein calves (n=6/diet) fed one of four milk replacer diets for a nine wk period after which they were sacrificed. Milk replacer diets varied in fat content and were formulated and administered as follows: 0.4 kg/d 20% protein, 20% fat (20:20; CON), 0.97 kg/d (28:20; HPLF), 0.97 kg/d (28:28; HPHF), or 1.46 kg/d (28:28; HPHF+). Samples of subcutaneous adipose tissue (AT), perirenal AT, omental AT, duodenum, proximal jejunum, distal jejunum, ileum, and liver were collected from calves fed the HPHF+ diet to determine SCD1 tissue distribution. Tissue homogenates were prepared and used for Western blotting. Additionally, dietary effects were analyzed on tissues expressing SCD1 protein for all 24 calves. The second study investigated the regulation of SCD1 protein expression by insulin, fatty acids increasing in degree of unsaturation, and increasing concentrations of linoleic (18:2) acid. Subcutaneous AT was collected from Smith Valley Meats in Rich Creek, VA and used to prepare explants cultured in treatment media for 24 h. Treatments consisted of insulin at 0, 7, 14, and 21 nM; stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids at 100 μM; and linoleic (18:2) acid at concentrations of 0, 25, 50, 75, and 100 μM. Tissue explant homogenates were used for Western blotting to detect SCD1. In the first study, we found that SCD1 protein was detectable in subcutaneous AT, perirenal AT, and omental AT; however, it was not detectable in liver or small intestine samples. Also, the HPHF+ diet increased SCD1 protein expression in subcutaneous AT and perireanl AT. In the second study, SCD1 protein expression increased linearly with insulin concentration. There was no fatty acid treatment effect, but there was a negative linear effect with increase in degree of unsaturation. Finally, there was no effect on SCD1 protein expression with linoleic acid increasing in concentration. In conclusion, results indicate that SCD1 protein expression was detected in bovine AT depots, regulated by dietary fat, insulin, and by PUFA .
Advisors/Committee Members: Corl, Benjamin A. (committeechair), Herbein, Joseph H. Jr. (committee member), Pearson, Ronald E. (committee member), Akers, Robert Michael (committee member).
Subjects/Keywords: calves; fat; explants; polyunsaturated fatty acids; regulation; stearoyl-CoA desaturase; tissue distribution
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APA (6th Edition):
Campbell, D. E. (2007). Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/33967
Chicago Manual of Style (16th Edition):
Campbell, Davina Elaine. “Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients.” 2007. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/33967.
MLA Handbook (7th Edition):
Campbell, Davina Elaine. “Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients.” 2007. Web. 11 Apr 2021.
Vancouver:
Campbell DE. Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients. [Internet] [Masters thesis]. Virginia Tech; 2007. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/33967.
Council of Science Editors:
Campbell DE. Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients. [Masters Thesis]. Virginia Tech; 2007. Available from: http://hdl.handle.net/10919/33967
Virginia Tech
28.
Larson, Ann Michelle.
Selection for milk somatic cell count in laboratory mice.
Degree: MS, Dairy Science, 1988, Virginia Tech
URL: http://hdl.handle.net/10919/44079
► A bidirectional selection experiment for high and low somatic cell count (SCC) was conducted over 14 generations with two selected lines (high line =…
(more)
▼ A bidirectional selection experiment for high and low somatic cell count (SCC) was conducted over 14 generations with two selected lines (high line = HSCC, low line = LSCC) of mice. Seven secondary traits (milk yield, total white blood cell count, percentage of phagocytic cells in blood, endotoxin challenge response, percentage of females littering, number of young born alive, and percentage of young surviving to weaning) were measured to examine correlated responses to selection for SCC.
Average response per generation for log2 SCC was small in both selected lines (HSCC = .0678 ±.0341, LSCC = .0384 ± .0390, P > .05). There was little per generation divergence between the selected lines (.0294 ± .0178, P > .05). Genetic and phenotypic selection differentials indicated that selection procedures did select the more extreme individuals for SCC, even though response to selection was poor.
Phenotypic correlations among SCC and the seven secondary traits were generally small, and near zero. Correlation coefficients ranged from -.17 to .17. Milk yield was negatively correlated with SCC (-.07, P < .05). The correlation between endotoxin challenge response and SCC was also negative (-.17, P < .05).
Components of genetic variance for SCC were estimated to explain the lack of selection response. Covariances between daughter and dam, and among full sibs were negative (-.1180 and -.0362, respectively). Analysis for offspring and maternal components for SCC yielded a negative estimate for the covariance between additive effects for the offspring and maternal components (-.1781). No biological explanation can be offered for its existence. Heritability from this same analysis was .05.
Advisors/Committee Members: Vinson, William E. (committeechair), Pearson, Ronald E. (committee member), Akers, Robert Michael (committee member), McGilliard, Michael L. (committee member).
Subjects/Keywords: Mice; LD5655.V855 1988.L372
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APA (6th Edition):
Larson, A. M. (1988). Selection for milk somatic cell count in laboratory mice. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44079
Chicago Manual of Style (16th Edition):
Larson, Ann Michelle. “Selection for milk somatic cell count in laboratory mice.” 1988. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/44079.
MLA Handbook (7th Edition):
Larson, Ann Michelle. “Selection for milk somatic cell count in laboratory mice.” 1988. Web. 11 Apr 2021.
Vancouver:
Larson AM. Selection for milk somatic cell count in laboratory mice. [Internet] [Masters thesis]. Virginia Tech; 1988. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/44079.
Council of Science Editors:
Larson AM. Selection for milk somatic cell count in laboratory mice. [Masters Thesis]. Virginia Tech; 1988. Available from: http://hdl.handle.net/10919/44079
Virginia Tech
29.
Hajdu, Melissa Anne.
Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes.
Degree: MS, Animal Science, 1993, Virginia Tech
URL: http://hdl.handle.net/10919/46281
► A series of experiments were used to evaluate three culture media and two incubation temperatures for their ability to support development of DNA microinjected…
(more)
▼ A series of experiments were used to evaluate three culture media and two
incubation temperatures for their ability to support development of DNA microinjected
porcine zygotes. Development in vitro was compared between embryos collected from
postpubertal and prepubertal donors and between embryos injected with DNA into the
pronucleus and the cytoplasm. Additionally, embryos were analyzed by the polymerase
chain reaction (PCR) for the presence of the transgene. One-cell embryos (n=458) were
recovered from 36 postpubertal gilts in Experiment 1. Injected and control embryos were
cultured in modified media NCSU-23 (mNCSU-23), NCSU-37 (mNCSU-37), and CZB at
37°C and 38.8°C for 7 d. In Experiment 2, one-cell embryos (n=245) were collected from
postpubertal (n=15) and prepubertal (n=14) gilts, microinjected with DNA, and cultured in
medium mNCSU-23. Superovulated prepubertal gilts (n=22) were flushed in Experiment
3 to yield 343 one-cell embryos which had DNA injected into the cytoplasm or
pronucleus. Whole embryos were assessed by PCR. Mean percentages of embryos
developing to the expanded or hatched blastocyst stage in mNCSU-23 and mNCSU-37
did not differ from each other (p>.05), but both were greater than the development in
CZB (p<.05). Development was greater at 38.8°C (p<.05) than at 37° C. Microinjection
of DNA decreased the developmental percentage (p<.05) from that of non-injected
controls. Embryos collected from postpubertal gilts had a higher percentage (68.0 ± 3.4)
of expanded and hatched blastocysts than embryos from prepubertal donors (29.0 ± 4.6,
p<.05). No difference was seen in development between embryos injected in the
pronucleus or cytoplasm (p>. 05), but development for both was less than for control
embryos (p<.05). Results of PCR analysis indicated that 40% of the embryos developing
to the expanded blastocyst stage were positive for the transgene compared to a rate of
60% positive for degenerate embryos. These studies show that DNA microinjected
porcine zygotes can be cultured to the expanded blastocyst stage in media mNCSU-23 and
mNCSU-37 at 38.8°C. Microinjection of DNA decreases survival of embryos collected
from both postpubertal and prepubertal sources, but postpubertal embryos exhibit a higher
rate of development. Cytoplasmic injection does not improve embryo viability in vitro
above that of pronuclear injection. Finally, whole embryo analysis by PCR is possible, but
cross specificity of human Protein C and whey acidic protein (WAP) oligonucleotides for
endogenous porcine DNA is strong and creates difficulty in applying PCR analysis to
embryos microinjected with WAP-PC transgenes.
Advisors/Committee Members: Knight, James W. (committeechair), Gwazdauskas, Francis C. (committee member), Velander, William H. (committee member), Pearson, Ronald E. (committee member).
Subjects/Keywords: microinjection; culture; embryos; porcine; Swine; LD5655.V855 1993.H346
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APA (6th Edition):
Hajdu, M. A. (1993). Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/46281
Chicago Manual of Style (16th Edition):
Hajdu, Melissa Anne. “Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes.” 1993. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/46281.
MLA Handbook (7th Edition):
Hajdu, Melissa Anne. “Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes.” 1993. Web. 11 Apr 2021.
Vancouver:
Hajdu MA. Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes. [Internet] [Masters thesis]. Virginia Tech; 1993. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/46281.
Council of Science Editors:
Hajdu MA. Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes. [Masters Thesis]. Virginia Tech; 1993. Available from: http://hdl.handle.net/10919/46281
Virginia Tech
30.
Gibbons, John R.
Ultrasound-guided transvaginal follicular aspiration to provide a source of bovine oocytes for gene microinjection.
Degree: MS, Dairy Science, 1994, Virginia Tech
URL: http://hdl.handle.net/10919/46259
► Three experiments were conducted to determine an efficient method of obtaining oocytes from cows via ultrasound-guided transvaginal follicular aspiration. Transvaginal oocyte recovery combined with…
(more)
▼
Three experiments were conducted to determine an efficient method of obtaining
oocytes from cows via ultrasound-guided transvaginal follicular aspiration. Transvaginal
oocyte recovery combined with in vitro maturation, fertilization, and culture
(IVMlIVFIIVC) can produce pre-implantation stage bovine embryos and also supply a
source of ova for gene microinjection. In Experiment 1, once- (IX) vs. twice-weekly
(2X) oocyte recovery frequencies were compared. No differences in recovery per session
were observed (IX = 6.8 vs. 2X = 6.3 oocytes/session; p>O.1 0). However, the 2X group
generated more oocytes on a weekly basis (IX = 6.8 vs. 2X = 12.6 oocytes/week;
p<O.OS). In Experiment 2, in vitro embryo production was compared among the groups
aspirated once-weekly (1 X), twice-weekly (2X), and twice-weekly after receiving I5 mg
FSH (2XF). No differences existed among the aspiration groups in the proportion of
blastocysts produced following IVMIIVFIIVC (IX = 23.10/0, 2X = 26.1%, 2XF = 18.0%,
% viable). However, the 2X group generated more oocytes and embryos throughout the
experiment (2X = 83/318, 2XF = 38/211, IX = 58/2SI viable blastocyst/total oocytes;
p<O.O5) than the other groups. A higher proportion of 2X or 2XF generated embryos
were of excellent quality (2X = 60.2%, 2XF = 60.5%) compared to the IX group (37.9%)
In Experiment 3, in vitro embryo development rates were compared among oocytes from
follicular aspiration (TVFA) and oocytes derived from slaughterhouse ovaries (SHD).
Oocytes (65%) from both sources were subjected to pronuclear-microinjection of foreign
DNA while the remainder served as non-injected controls. Only control oocytes differed,
with TVF A-derived oocytes developing to blastocyst more successfully than SHD oocytes
(40.8% vs. 30.0olo~ p<0.05). Microinjected embryo development was similar between the
groups (TVFA 15.9%, vs. SHD = 12.8% viable blastocyst/total;) with the TVFA
oocytes holding a slight but non-significant numerical advantage (p>O.IO) In these
experiments, twice-weekly follicular aspiration without exogenous FSH, was the best
scheme of oocyte recovery. This program provided a source of consistent, high quality
oocytes that responded favorable to the IVMIIVFIIVC system and microinjection.
Advisors/Committee Members: Gwazdauskas, Francis C. (committeechair), Beal, Wilfred E. (committee member), Pearson, Ronald E. (committee member), Vinson, William E. (committee member).
Subjects/Keywords: Ovum.; LD5655.V855 1994.G533
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APA (6th Edition):
Gibbons, J. R. (1994). Ultrasound-guided transvaginal follicular aspiration to provide a source of bovine oocytes for gene microinjection. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/46259
Chicago Manual of Style (16th Edition):
Gibbons, John R. “Ultrasound-guided transvaginal follicular aspiration to provide a source of bovine oocytes for gene microinjection.” 1994. Masters Thesis, Virginia Tech. Accessed April 11, 2021.
http://hdl.handle.net/10919/46259.
MLA Handbook (7th Edition):
Gibbons, John R. “Ultrasound-guided transvaginal follicular aspiration to provide a source of bovine oocytes for gene microinjection.” 1994. Web. 11 Apr 2021.
Vancouver:
Gibbons JR. Ultrasound-guided transvaginal follicular aspiration to provide a source of bovine oocytes for gene microinjection. [Internet] [Masters thesis]. Virginia Tech; 1994. [cited 2021 Apr 11].
Available from: http://hdl.handle.net/10919/46259.
Council of Science Editors:
Gibbons JR. Ultrasound-guided transvaginal follicular aspiration to provide a source of bovine oocytes for gene microinjection. [Masters Thesis]. Virginia Tech; 1994. Available from: http://hdl.handle.net/10919/46259
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