You searched for +publisher:"Virginia Tech" +contributor:("Greiner, Scott P.").
Showing records 1 – 20 of
20 total matches.
No search limiters apply to these results.
Virginia Tech
1.
Riley, Elizabeth.
Fecal Phosphorus Characteristics of Forage-Fed Beef Cattle.
Degree: MS, Animal and Poultry Sciences, 2013, Virginia Tech
URL: http://hdl.handle.net/10919/23230 
► Phosphorus loads in waterways are a focus of environmental concern. Animal agriculture\'s contribution to this problem has been documented and efforts are focused on mitigating…
(more)
▼ Phosphorus loads in waterways are a focus of environmental concern. Animal agriculture\'s contribution to this problem has been documented and efforts are focused on mitigating the issue. The effect of increasing amounts of mineral
P supplementation on fecal
P characteristics was studied in forage fed beef steers. Eight Hereford steers were fitted with total fecal collection bags and fed four diets with a low
P grass hay and supplemented with increasing amounts of a mineral source of
P, dicalcium phosphate. Dietary DM
P concentrations were 0.10 (no
P supplementation), 0.23, 0.34, and 0.45%
P. Manure was sampled and dried, followed by analysis for total
P and inorganic
P (Pi). Blood was collected via jugular venipuncture following each collection period and plasma Pi was quantified. Total fecal
P increased linearly with increasing dietary
P concentration: 6.44, 10.6, 16.1, and 18.8 g/d (
P < 0.0001). Fecal Pi increased linearly with increasing dietary
P concentration: 1.58, 2.43, 2.74, and 3.84 g/d (
P = 0.0119) Manure
P solubility, however, did not increase with increasing dietary
P concentration: 23.6, 22.3, 17.3, and 20.2% (
P = 0.3646). Plasma Pi increased linearly with increasing dietary
P (
P = 0.0047). ADG and G:F were not affected by increasing dietary
P content. Reducing or eliminating mineral
P supplementation to forage fed beef animals is possible, if forage base proves to be adequate in
P. Reducing dietary
P reduces fecal
P excretion and the pollution potential in ecologically sensitive areas like the Chesapeake Bay watershed.
Advisors/Committee Members: Greiner, Scott P. (committeechair), Knowlton, Katharine F. (committee member), McCann, Mark A. (committee member).
Subjects/Keywords: phosphorus; beef cattle; forage
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Riley, E. (2013). Fecal Phosphorus Characteristics of Forage-Fed Beef Cattle. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/23230
Chicago Manual of Style (16th Edition):
Riley, Elizabeth. “Fecal Phosphorus Characteristics of Forage-Fed Beef Cattle.” 2013. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/23230.
MLA Handbook (7th Edition):
Riley, Elizabeth. “Fecal Phosphorus Characteristics of Forage-Fed Beef Cattle.” 2013. Web. 09 Mar 2021.
Vancouver:
Riley E. Fecal Phosphorus Characteristics of Forage-Fed Beef Cattle. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/23230.
Council of Science Editors:
Riley E. Fecal Phosphorus Characteristics of Forage-Fed Beef Cattle. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/23230
Virginia Tech
2.
Echols, Allison Clare.
Relationships among lifetime measures of growth and frame size for commercial beef females in a pasture-based production system in the Appalachian region of the United States.
Degree: MS, Animal and Poultry Sciences, 2011, Virginia Tech
URL: http://hdl.handle.net/10919/35076
► The beef cattle industry has placed increased focus on mature cow size as a result of its influence on production efficiency and profitability. The objectives…
(more)
▼ The beef cattle industry has placed increased focus on mature cow size as a result of its influence on production efficiency and profitability. The objectives of this study were to evaluate relationships among lifetime measures of body weight (BW) and frame score (FS) in commercial beef females, and to assess the value of immature measures as predictors of mature cow size. Measurements of BW, hip height (HH), body condition score (BCS), and calculated FS were recorded at weaning (WN), breeding at 13 mo age (BR), and 8 subsequent periods, ceasing at approximately 5 yr of age for 232 Angus-cross females born 2004 through 2008. Correlation analysis revealed significant (
P < 0.001) relationships among BW taken at WN and BR with BW measurements taken at 2.5, 3.8, and 4.8 yr of age (WN r = 0.70, 0.51, 0.61; BR r = 0.65, 0.57, 0.64, respectively). Significant relationships (
P < 0.001) existed between FS collected at WN and BR, and FS at 2.5 and 3.8 yr (WN= 0.70, 0.72; BR= 0.79, 0.82, respectively). Repeatability of lifetime FS measures was 0.73. BCS was a significant (
P < 0.001) source of variation in mature BW, with a unit change in BCS accounting for 41 kg BW change at 4.8 yr (
P < 0.001). BW and FS were moderately to strongly related (
P < 0.001) at WN, BR, 2.5, 3.8, and 4.8 yr (r = 0.62, 0.49, 0.62, 0.62, and 0.47 respectively). Prediction models for BW at 4.8 yr were similar using weaning BW alone, or with inclusion of both weaning BW and HH (R2 = 0.57 and 0.56). Similarly, breeding BW and HH were non-additive for prediction of 4.8 yr BW (R2 = 0.68, 0.58, and 0.68 for BW, HH, and BW +HH respectively). Performance at immature ages proves to be a satisfactory indicator of mature size, supporting continued incorporation of immature BW and HH and/or FS measurements into selection practices.
Advisors/Committee Members: Swecker, William S. Jr. (committee member), Greiner, Scott P. (committeecochair), Wahlberg, Mark L. (committeecochair).
Subjects/Keywords: frame score; mature size; beef cow; body weight
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Echols, A. C. (2011). Relationships among lifetime measures of growth and frame size for commercial beef females in a pasture-based production system in the Appalachian region of the United States. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/35076
Chicago Manual of Style (16th Edition):
Echols, Allison Clare. “Relationships among lifetime measures of growth and frame size for commercial beef females in a pasture-based production system in the Appalachian region of the United States.” 2011. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/35076.
MLA Handbook (7th Edition):
Echols, Allison Clare. “Relationships among lifetime measures of growth and frame size for commercial beef females in a pasture-based production system in the Appalachian region of the United States.” 2011. Web. 09 Mar 2021.
Vancouver:
Echols AC. Relationships among lifetime measures of growth and frame size for commercial beef females in a pasture-based production system in the Appalachian region of the United States. [Internet] [Masters thesis]. Virginia Tech; 2011. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/35076.
Council of Science Editors:
Echols AC. Relationships among lifetime measures of growth and frame size for commercial beef females in a pasture-based production system in the Appalachian region of the United States. [Masters Thesis]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/35076
Virginia Tech
3.
Claire, Olivia Mary.
Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers.
Degree: MS, Animal and Poultry Sciences, 2020, Virginia Tech
URL: http://hdl.handle.net/10919/98826
► Grazing beef cattle tend to follow a general pattern of grazing, rumination, and digestion that coincides with their environment and the time of year. Backgrounded…
(more)
▼ Grazing beef cattle tend to follow a general pattern of grazing, rumination, and digestion that coincides with their environment and the time of year. Backgrounded cattle managed in pasture-based systems are traditionally offered supplemental feedings in the morning. However, this practice could be decreasing how efficiently cattle utilize forage resources. Natural grazing behaviors are more intense preceding the heat of the day and interruption of morning grazing bouts could decrease forage intake by causing cattle to come to the feeder to consume supplement feedings. To examine how feeding time potentially influences performance and grazing behavior of backgrounded beef cattle, 52 crossbred beef steers 7 to 8 months of age and weighing 243 kg were grazed on tall fescue pastures at the Southwest
Virginia Agricultural Research and Extension Center from October 1 to November 8, 2019. Cattle were supplemented with either a commodity blend or cracked corn mixed with an intake limiter. Cattle were sourced from 4 local producers and allotted to 9 pastures by body weight (BW) and source. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Adjustments were made to the average BW of pasture groups, following three interim weigh dates at d 11, d 21, and d 30, to keep intake levels accurately at 1.5% BW. Flesh condition scores (FCS) were assigned on a scal of 1 to 9, with 1 considered emaciated and 9 excessively fat. 12th rib fat thickness (FT) was measured using an Aloka 500SC ultrasound. Both measurements were taken on the first and final day of the experiment. Motion-sensing cameras were installed in each pasture to capture pictures every one-minute following motion detection. Subsequent pictures were used to analysis the number of feed and water visits, along with time of day, in an attempt to characterize intake behavior. There were no major differences seen by treatment groups for BW, flesh condition score, DMI, ADG, and backfat thickness. Cattle on the SELF treatment had greater G:F than AM, with PM cattle being intermediate and not different than either. Steers with access to a self-feeder visited the feeder more than double the number of times in a 24 h period than either of the hand supplemented group. Despite differences in observed cattle behavior, any disruption in natural grazing behavior did not negatively influence performance of backgrounded steers.
Advisors/Committee Members: Wilson, Thomas Bain (committeechair), Greiner, Scott P. (committee member), Mercadante, Vitor Rodriques Gomes (committee member).
Subjects/Keywords: background grazing; beef cattle; grazing behavior; supplemental feeding time
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Claire, O. M. (2020). Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/98826
Chicago Manual of Style (16th Edition):
Claire, Olivia Mary. “Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers.” 2020. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/98826.
MLA Handbook (7th Edition):
Claire, Olivia Mary. “Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers.” 2020. Web. 09 Mar 2021.
Vancouver:
Claire OM. Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers. [Internet] [Masters thesis]. Virginia Tech; 2020. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/98826.
Council of Science Editors:
Claire OM. Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers. [Masters Thesis]. Virginia Tech; 2020. Available from: http://hdl.handle.net/10919/98826
4.
Hardin, Keri Nicole.
Nutritional strategies to improve performance of cattle in fescue forage-based systems.
Degree: MS, Animal and Poultry Sciences, 2018, Virginia Tech
URL: http://hdl.handle.net/10919/83500
► Two experiments were conducted to determine the efficacy of supplemented feedstuffs to improve the performance of cattle consuming fescue-based rations. The objective of the first…
(more)
▼ Two experiments were conducted to determine the efficacy of supplemented feedstuffs to improve the performance of cattle consuming fescue-based rations. The objective of the first experiment was to evaluate growth and reproductive characteristics of heifers consuming endophyte-infected (EI) fescue seed with or without sodium bicarbonate supplementation. Forty-eight heifers (8 mo; BW = 268 ± 24 kg) were utilized in a 2 x 2 factorial design. Treatments were either high-EI fescue seed without sodium bicarbonate (E+B-), high-EI fescue seed with sodium bicarbonate supplementation (E+B+), low-EI fescue seed without sodium bicarbonate (E-B-), or low-EI fescue seed with sodium bicarbonate supplementation (E-B+). At d 56, G:F (
P= 0.084) and ADG (
P = 0.071) tended to be improved for heifers fed E+B+. By d 84 bicarbonate supplementation tended to decrease ADG (
P = 0.087). Bicarbonate supplementation ameliorated the negative effects of E+ at 28 d, but by d 84 negatively impacted animal performance. The objective of the second experiment was to determine the energy content of corn gluten feed (CGF) relative to corn in forage-based beef rations. Forty-two steers (13.8 ± 0.4 mo; BW = 382 ± 8 kg) were supplemented with either corn or CGF at 0.15% (L), 0.54% (M) or 0.96% (H) BW for 63 d. Steer ADG was greater for steers supplemented with CGF relative to steers supplemented with corn (
P = 0.034). Energy value of CGF relative to corn was calculated by adjusting supplement TDN in the 2016 Nutrient Requirements of Beef Cattle Model. The energy values of CGF relative to corn were 106%, 107%, and 112% for L, M, and H.
Advisors/Committee Members: Wilson, Thomas Bain (committeechair), Greiner, Scott P. (committee member), White, Robin (committee member).
Subjects/Keywords: fescue; supplementation; beef cattle; nutrition
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Hardin, K. N. (2018). Nutritional strategies to improve performance of cattle in fescue forage-based systems. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/83500
Chicago Manual of Style (16th Edition):
Hardin, Keri Nicole. “Nutritional strategies to improve performance of cattle in fescue forage-based systems.” 2018. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/83500.
MLA Handbook (7th Edition):
Hardin, Keri Nicole. “Nutritional strategies to improve performance of cattle in fescue forage-based systems.” 2018. Web. 09 Mar 2021.
Vancouver:
Hardin KN. Nutritional strategies to improve performance of cattle in fescue forage-based systems. [Internet] [Masters thesis]. Virginia Tech; 2018. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/83500.
Council of Science Editors:
Hardin KN. Nutritional strategies to improve performance of cattle in fescue forage-based systems. [Masters Thesis]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/83500
5.
Weaver, Andrew Ryan.
Evaluation of terminal sire breeds for hair sheep production systems.
Degree: MS, Animal and Poultry Sciences, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/80300
► Terminal sire crossbreeding systems which improve growth performance while maintaining parasite resistance have the potential to enhance the profitability of hair sheep enterprises. Katahdin (KT,…
(more)
▼ Terminal sire crossbreeding systems which improve growth performance while maintaining parasite resistance have the potential to enhance the profitability of hair sheep enterprises. Katahdin (KT, n = 4), Suffolk (SU, n = 3), and Texel (TX, n = 3) rams were randomly mated to KT ewes over two years (Y1, Y2) at the
Virginia Tech Southwest Agricultural Research and Extension Center. Post-lambing until weaning (80 d), pairs were managed on fescue pasture. At weaning, lambs (n = 192) were moved to an ungrazed pasture and provided a concentrate pellet daily for a 90 d grazing trial. During this time, BW, strongylid egg count (FEC), FAMACHA score and packed cell volume (PCV) were collected every 14 d. FAMACHA score - 3 was utilized as the basis for anthelmintic treatment. Post-grazing, lambs were fed to approximately 50 kg BW. Lambs were harvested at the
Virginia Tech Meat Center and carcass evaluation performed 1 d post-harvest. Statistical analyses were conducted using SAS (SAS Institute Inc., Cary, NC) with Proc MIXED for repeated measures analysis and Proc GLM with Tukey?s test for mean separation. No differences existed between sire breeds for adjusted number of lambs born or number of lambs weaned. Adjusted birth BW was greater for SU-sired lambs than KT-sired and TX-sired (
P < 0.05) in Y2. Adjusted weaning BW was smallest for KT-sired lambs compared to SU- and TX-sired lambs (
P < 0.05) in both years. During the grazing trials, BW, ADG, lnFEC, FAMACHA and PCV varied over time (
P < 0.001) with lower FAMACHA scores for KT-sired lambs than SU- and TX-sired lambs in Y1 (
P < 0.05). A greater proportion of SU-sired lambs tended to require deworming than KT-sired lambs (
P = 0.08). Adjusted BW post weaning was greater for TX-sired lambs than KT-sired lambs (
P < 0.05) in Y1. Post-grazing, BW and ADG varied over time (
P < 0.01) with no sire breed differences for ADG. At harvest, SU-sired lambs were heavier than KT-sired lambs (
P < 0.05). TX-sired lambs had greater LM area than KT-sired lambs (
P = 0.05). KT-sired lambs had the smallest leg scores (
P < 0.05). These results indicate the potential of terminal sires (SU- and TX-sires) to improve lamb growth and carcass merit. TX-sired lambs had more similar parasite resistance characteristics to KT-sired Iambs and may have potential as terminal sires in forage based hair sheep production systems.
Advisors/Committee Members: Greiner, Scott P. (committeechair), Notter, David R. (committee member), Zajac, Anne M. (committee member).
Subjects/Keywords: sheep; breed; performance; parasite resistance
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Weaver, A. R. (2017). Evaluation of terminal sire breeds for hair sheep production systems. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/80300
Chicago Manual of Style (16th Edition):
Weaver, Andrew Ryan. “Evaluation of terminal sire breeds for hair sheep production systems.” 2017. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/80300.
MLA Handbook (7th Edition):
Weaver, Andrew Ryan. “Evaluation of terminal sire breeds for hair sheep production systems.” 2017. Web. 09 Mar 2021.
Vancouver:
Weaver AR. Evaluation of terminal sire breeds for hair sheep production systems. [Internet] [Masters thesis]. Virginia Tech; 2017. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/80300.
Council of Science Editors:
Weaver AR. Evaluation of terminal sire breeds for hair sheep production systems. [Masters Thesis]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/80300
6.
Marquez Betz, Gabriela Carolina.
Index selection in terminal sire sheep: implications for genetic improvement in a crossbreeding system.
Degree: PhD, Animal and Poultry Sciences, 2013, Virginia Tech
URL: http://hdl.handle.net/10919/24774
► Using terminal sires for crossbreeding is standard practice in the UK sheep industry, where over 70% of market lambs have terminal sire breeding. Thus, selection…
(more)
▼ Using terminal sires for crossbreeding is standard practice in the UK sheep industry, where over 70% of market lambs have terminal sire breeding. Thus, selection focusing on terminal sires will translate to changes in the entire industry. Consumers perceive lamb meat as fatty and demand for it has decreased. A lean growth index was developed for terminal sire breeds to increase carcass lean content while keeping fat constant at a constant age end point. The purposes of this study were: to evaluate the effects of index selection of terminal sires on their crossbred offspring up to harvest; to evaluate the effectiveness of the index within the terminal sire breeds; to evaluate the presence and consequences of heterogeneous environmental variances and genetics by environment interactions (GxE) on genetic evaluation. The most widely used breeds of terminal sires in the UK are Charollais, Suffolk, and Texel. These breeds participated in sire referencing schemes from the early 1990s by sharing rams selected on the lean growth index. From 1999 to 2002 approximately 15 high and 15 low lean growth index score rams per breed were selected from their sire referencing schemes and mated to Welsh and Scottish Mule ewes. Their crossbred offspring were reared on 3 farms in the UK under commercial conditions. In total, 6,515 lambs were born between 2000 and 2003. Lambs were weighed at birth (BWT), 5 weeks (5WT), and 10 weeks (10WT). The average daily gain (ADG) from birth to 10 weeks was calculated. Lambs were finished to an estimated 11% subcutaneous fat by visual examination. At harvest, they were weighed (HWT), ultrasonically scanned for muscle (UMD) and fat (UFD) depth, and assessed for condition score and conformation. Lambs sired by high index rams were on average, across breeds, heavier at all ages (
P < 0.01) with 0.07 ± 0.03, 0.3 ± 0.1, 0.4 ± 0.1, and 1.2 ± 0.2 kg greater BWT, 5WT, 10WT, and HWT respectively. Their ADG was 5.1 ± 1.9 g/d greater than low index sired lambs. They had thicker UMD (0.7 ± 0.2 mm) and thinner UFD (0.08 ± 0.01 mm). High vs. low index sired lambs took the same amount of days to reach harvest fatness. Suffolk-sired lambs were on average heavier, with greater ADG, whereas Charollais-sired lambs were lightest with smallest ADG. Texel-sired lambs had thicker UMD than Charollais (0.7 ± 0.2 mm;
P < 0.001) but were not different than Suffolk. Charollais-sired lambs had greater UFD than both Texel- (0.098 ± 0.016 mm) and Suffolk- (0.061 ± 0.017 mm) sired lambs (
P < 0.001). Texel-sired lambs reached harvest condition faster than the other breeds (
P < 0.01). Index selection produced heavier and leaner lambs at finishing. Producers have flexibility in choosing the terminal sire that best fits their production system. Heteroscedascity and GxE were found to be more important for ultrasonic traits than weight traits. Fitting a farm by sire random interaction component improved model fit, but only accounted for less than 2% of the variation in weight traits. For ultrasonic traits, it accounted for at least 10% of…
Advisors/Committee Members: Lewis, Ronald M. (committeechair), Haresign, William (committee member), Siegel, Paul B. (committee member), Notter, David R. (committee member), Greiner, Scott P. (committee member).
Subjects/Keywords: crossbreeding; genetics by environment interactions; heteroscedasticity; lean growth index; sheep
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Marquez Betz, G. C. (2013). Index selection in terminal sire sheep: implications for genetic improvement in a crossbreeding system. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/24774
Chicago Manual of Style (16th Edition):
Marquez Betz, Gabriela Carolina. “Index selection in terminal sire sheep: implications for genetic improvement in a crossbreeding system.” 2013. Doctoral Dissertation, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/24774.
MLA Handbook (7th Edition):
Marquez Betz, Gabriela Carolina. “Index selection in terminal sire sheep: implications for genetic improvement in a crossbreeding system.” 2013. Web. 09 Mar 2021.
Vancouver:
Marquez Betz GC. Index selection in terminal sire sheep: implications for genetic improvement in a crossbreeding system. [Internet] [Doctoral dissertation]. Virginia Tech; 2013. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/24774.
Council of Science Editors:
Marquez Betz GC. Index selection in terminal sire sheep: implications for genetic improvement in a crossbreeding system. [Doctoral Dissertation]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/24774
Virginia Tech
7.
Langford, Taylor Andrew.
Effects of fescue cultivar on performance of beef cows grazed on summer stockpiled tall fescue pastures.
Degree: MS, Animal and Poultry Sciences, 2020, Virginia Tech
URL: http://hdl.handle.net/10919/98813
► Wild-type, endophyte-infected tall fescue (E+) is the predominant forage of use for producers within the southeastern United States. Endophyte-infected tall fescue gained notoriety due to…
(more)
▼ Wild-type, endophyte-infected tall fescue (E+) is the predominant forage of use for producers within the southeastern United States. Endophyte-infected tall fescue gained notoriety due to its drought and pest resistance as well as climate adaptability. These advantages are the result of a symbiotic relationship with an endophytic fungus that has been shown to decrease in animal performance through the production of toxic ergot alkaloids. Development of improved fescue cultivars provided producers with an alternative forage, known as novel endophyte-infected tall fescue (NE), that maintains the agronomic advantages noted with E+ fescue without negative impacts on animal gain and reproductive performance. In adopting NE tall fescue, producers are faced with the financial challenge of renovating existing stands of E+ with NE fescue; leaving pastures unusable during times of normal grazing behavior. This constraint has highlighted the need to explore forage utilization and strategies that can extend the grazing period that do not require the significant cost of total renovation with NE. Fall stockpiled tall fescue has provided producers an option to extend grazing from late November through February when pasture growth ceases and hay supplementation is normally needed. However, a 60 to 90 d period between summer and fall stockpiled grazing leaves producers looking for an additional strategy to provide standing forage for their herds. Summer stockpiling (SS), is a novel grazing strategy that bridges summer and fall stockpiled grazing through proper accumulation of 25 % of total pasture to help extend producers grazing season. The objective of the current experiment is to evaluate both E+ and NE SS pastures and its effect on animal performance, forage availability, and nutritive value. Cow BW and BCS were measured at the initiation, conclusion, and before artificial insemination. Calf BW and ADG were assessed 48 h post-calving and at weaning. Ungrazed and grazed forage mass was collected weekly, while measurements of ADF, NDF, CP, TDN, ether extract, and ash were measured every 2 weeks. After a 52 d treatment period, forage mass was similar across both cultivars, with ADF, NDF, and TDN favoring E+ tall fescue. Additionally, animal performance across both E+ and NE pastures were similar, however increased milk production was observed for cows grazed on E+. This experiment helps shed light on the concept of strategic renovation. Strategic renovation can be best utilized by producers who are interested in maximizing pasture utilization through rotationally grazing E+ and NE tall fescue pastures. By following this renovation strategy, proper allocation of NE tall fescue during times of enhanced ergotism and E+ tall fescue during low thresholds will develop a more specific rotation thus decreasing renovation costs for producers when ergotism is lowest.
Advisors/Committee Members: Wilson, Thomas Bain (committeechair), Pent, Gabriel J. (committee member), Greiner, Scott P. (committee member), Mercadante, Vitor Rodriques Gomes (committee member).
Subjects/Keywords: beef cattle; cow/calf; fescue toxicosis; novel endophyte-infected fescue; summer stockpiled fescue
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Langford, T. A. (2020). Effects of fescue cultivar on performance of beef cows grazed on summer stockpiled tall fescue pastures. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/98813
Chicago Manual of Style (16th Edition):
Langford, Taylor Andrew. “Effects of fescue cultivar on performance of beef cows grazed on summer stockpiled tall fescue pastures.” 2020. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/98813.
MLA Handbook (7th Edition):
Langford, Taylor Andrew. “Effects of fescue cultivar on performance of beef cows grazed on summer stockpiled tall fescue pastures.” 2020. Web. 09 Mar 2021.
Vancouver:
Langford TA. Effects of fescue cultivar on performance of beef cows grazed on summer stockpiled tall fescue pastures. [Internet] [Masters thesis]. Virginia Tech; 2020. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/98813.
Council of Science Editors:
Langford TA. Effects of fescue cultivar on performance of beef cows grazed on summer stockpiled tall fescue pastures. [Masters Thesis]. Virginia Tech; 2020. Available from: http://hdl.handle.net/10919/98813
8.
Pent, Gabriel J.
Lamb performance, behavior, and body temperatures in hardwood silvopasture systems.
Degree: PhD, Crop and Soil Environmental Sciences, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/76730
► Trees in silvopastures may provide forage-livestock systems with multiple goods and services, including shade, shelter, and browse. Reports of forage and animal productivity from these…
(more)
▼ Trees in silvopastures may provide forage-livestock systems with multiple goods and services, including shade, shelter, and browse. Reports of forage and animal productivity from these systems indicate that, in some cases, animal gains are similar or better despite lower forage yield. The relationship between grazing system, body temperature, grazing behavior, and animal performance was explored in this study. Black walnut and honeylocust-based silvopasture systems were compared with open pastures in a randomized complete block design (r = 3) over three summers. Pastures were rotationally stocked with 5-7 lambs depending on forage availability. Lambs were weighed every four weeks. Behavior measures were recorded within a replicate within a week, and these measures were taken sequentially within three experimental periods. Ewe lambs (n = 3) were equipped with a vaginal temperature sensor (3 days) and an audio recording device (1 day) to detect prehension events. Cameras documented lamb behavior every 60 seconds. Forage measurements taken with a rising plate meter indicated greater productivity in the honeylocust silvopasture (5020 ± 30 kg · ha⁻¹ ) compared to the open pasture (4930 ± 30 kg · ha⁻¹ ;
P = 0.0281), though forage availability in the black walnut silvopastures (3560 ± 30 kg · ha⁻¹ ) was lower than within the other treatments (
P < 0.0001). There was no difference in animal gains between systems (
P ≥ 0.4813), though gains were highest in the honeylocust silvopastures (25.6 ± 3.4 kg · period⁻¹ ), followed by the gains of the black walnut silvopastures (22.3 ± 3.4 kg · period⁻¹ ), and the gains of the open pastures (22.2 ± 3.4 kg · period- 1 ). Lambs in silvopastures spent more time lying down than animals in the open pastures (
P ≤ 0.01), while lambs in the open spent more than two hours longer each day standing (
P < 0.0001). During the hottest part of the day, ewes in the open pasture were 0.4 °C hotter than ewes in the black walnut silvopastures (
P ≤ 0.0202). Lambs in the black walnut silvopastures grazed more (488 ± 14 minutes · day⁻¹ ) than lambs in the honeylocust silvopastures (438 ± 15 minutes · day⁻¹ ;
P = 0.0192) and the open pastures (417 ± 14 minutes · day⁻¹ ;
P = 0.0009), with no difference between the latter two systems (
P = 0.3073). There was no difference in daily bites taken (
P ≥ 0.7222), though lambs in the silvopastures grazed more frequently than lambs in the open pastures.
In one six week winter grazing study, animal performance in the honeylocust silvopastures was compared with the productivity of lambs grazing the open pastures and the black walnut silvopastures. The objective of this study was to determine the effect of these pods on lamb growth when animals grazed stockpiled tall fescue (Schedonorus arundinaceus). Preand post-graze forage mass was estimated with a double sampling technique using a rising plate meter. Treatment pastures were rotationally stocked with three (walnut) or six lambs per experimental unit depending on forage availability. Fescue grab samples were collected…
Advisors/Committee Members: Fike, John Herschel (committeechair), Munsell, John F. (committee member), Greiner, Scott P. (committee member), Tracy, Benjamin F. (committee member).
Subjects/Keywords: Agroforestry; Silvopasture; Lamb; Sheep; Shade; Behavior
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Pent, G. J. (2017). Lamb performance, behavior, and body temperatures in hardwood silvopasture systems. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/76730
Chicago Manual of Style (16th Edition):
Pent, Gabriel J. “Lamb performance, behavior, and body temperatures in hardwood silvopasture systems.” 2017. Doctoral Dissertation, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/76730.
MLA Handbook (7th Edition):
Pent, Gabriel J. “Lamb performance, behavior, and body temperatures in hardwood silvopasture systems.” 2017. Web. 09 Mar 2021.
Vancouver:
Pent GJ. Lamb performance, behavior, and body temperatures in hardwood silvopasture systems. [Internet] [Doctoral dissertation]. Virginia Tech; 2017. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/76730.
Council of Science Editors:
Pent GJ. Lamb performance, behavior, and body temperatures in hardwood silvopasture systems. [Doctoral Dissertation]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/76730
Virginia Tech
9.
Emenheiser, Joseph Carl.
Economic Pasture-Based Cow-Calf Systems for Appalachia.
Degree: PhD, Animal and Poultry Sciences, 2014, Virginia Tech
URL: http://hdl.handle.net/10919/24787
► Pasture-based beef production is well-suited for the Appalachian region of the United States. This research investigated pasture, beef cattle, and economics components within the cow-calf…
(more)
▼ Pasture-based beef production is well-suited for the Appalachian region of the United States. This research investigated pasture, beef cattle, and economics components within the cow-calf sector of pasture beef production, and presents implications of their interplay for the vitality of the whole system. Samples of forage DM mass and CP, ADF, NDF, and ash contents in each paddock of a rotational stocking system were collected monthly for 4 grazing seasons. Effects of month, stockpiling, hay feeding, temperature, precipitation, and durations of paddock grazing and rest on forage mass and quality measurements were investigated. The system was complex and dynamic; precipitation and rest days in particular showed clear interactions with both month and stockpiling when predicting forage mass and quality. Available DM, TDN, and CP were compared to nutrient density requirements for beef cows to conclude that the system met or exceeded requirements. Six years of production data from a spring-calving cow-calf enterprise that utilized rotational stocking and fall stockpiling were analyzed. Comparisons among 2 cow frame size and 2 calf creep system treatments for production efficiency (total weaning weight per land area), and net returns to the enterprise, were made. Pastures with medium frame cows and designated creep systems had the greatest production efficiency, but also had the highest costs and netted the least returns. Greatest net returns were achieved in large frame, forward creep systems, which had the lowest production efficiency but also the lowest costs. Provided the quality of calves produced is suitable for other phases of the production stream, we conclude that minimizing costs rather than maximizing productive outputs is a better focus for cow-calf enterprises faced with similar decisions among frame size and creep system treatments.
Advisors/Committee Members: Lewis, Ronald M. (committeechair), Greiner, Scott P. (committee member), Tracy, Benjamin F. (committee member), McCann, Mark A. (committee member), Groover, Gordon E. (committee member), D'Souza, Gerard E. (committee member).
Subjects/Keywords: Appalachia; beef; cow-calf; economics; forage dynamics; production
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Emenheiser, J. C. (2014). Economic Pasture-Based Cow-Calf Systems for Appalachia. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/24787
Chicago Manual of Style (16th Edition):
Emenheiser, Joseph Carl. “Economic Pasture-Based Cow-Calf Systems for Appalachia.” 2014. Doctoral Dissertation, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/24787.
MLA Handbook (7th Edition):
Emenheiser, Joseph Carl. “Economic Pasture-Based Cow-Calf Systems for Appalachia.” 2014. Web. 09 Mar 2021.
Vancouver:
Emenheiser JC. Economic Pasture-Based Cow-Calf Systems for Appalachia. [Internet] [Doctoral dissertation]. Virginia Tech; 2014. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/24787.
Council of Science Editors:
Emenheiser JC. Economic Pasture-Based Cow-Calf Systems for Appalachia. [Doctoral Dissertation]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/24787
Virginia Tech
10.
Smith, Jason Kaleb.
Effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers.
Degree: PhD, Animal and Poultry Sciences, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/56596
► Beef cattle producers continuously search for nutritional management options that provide flexibility to production scenarios. Due to its positive effects on maternal productivity, early weaning…
(more)
▼ Beef cattle producers continuously search for nutritional management options that provide flexibility to production scenarios. Due to its positive effects on maternal productivity, early weaning is one such alternative strategy that has received considerable interest. To better understand the effects of early weaning on calf productivity, an extensive literature review and three experiments were conducted to evaluate the effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers. In experiment I, which included 90 Angus-sired steers from four calving seasons, early weaning followed by a short ad libitum concentrate-feeding and pasture-backgrounding phase reduced finishing residual feed intake (RFI) by 7 % (
P < 0.0001) and increased carcass marbling score (MS) by 10 % (
P < 0.01) when compared to conventionally weaned (CW) contemporaries. Similar effects were observed in experiment II, which included 28 Angus and Simmental-sired steers, as early weaning reduced RFI (
P < 0.01) and increased carcass MS (
P < 0.01). Lung mass of early weaned (EW) steers was greater than their CW contemporaries (
P < 0.05), and was inversely related to RFI (R2 = 0.17;
P < 0.05). Finishing treatments in this experiment included a high corn ration and an alternative low corn ration that iso-calorically replaced 50 % of the DM from corn with dried corn gluten feed. Iso-caloric replacement of corn reduced lung mass (
P < 0.01), and when combined with the observed increase of EW steers suggests that lung development is affected by dietary energy type at various stages of growth. In experiment III, objective analyses of ribeye steaks obtained from steers included in experiment two revealed that early weaning increased cross-sectional muscle fiber area by 28 % (
P < 0.001) and tended to increase (
P = 0.08) Warner-Bratzler shear force by 36 %. Nonetheless, these effects were not great enough to alter un-trained consumer perception of texture (
P ≥ 0.65), juiciness (
P ≥ 0.55), flavor (
P ≥ 0.25) or overall acceptability (
P ≥ 0.34). Collectively, these results indicate that early weaning enhances finishing feed efficiency and carcass marbling without affecting un-trained consumer sensory perception.
Advisors/Committee Members: McCann, Mark A. (committeechair), Hanigan, Mark Daniel (committee member), El-Kadi, Samer Wassim (committee member), Johnson, Sally E. (committee member), Greiner, Scott P. (committee member).
Subjects/Keywords: early weaning; feed efficiency; marbling development
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Smith, J. K. (2015). Effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/56596
Chicago Manual of Style (16th Edition):
Smith, Jason Kaleb. “Effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers.” 2015. Doctoral Dissertation, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/56596.
MLA Handbook (7th Edition):
Smith, Jason Kaleb. “Effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers.” 2015. Web. 09 Mar 2021.
Vancouver:
Smith JK. Effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/56596.
Council of Science Editors:
Smith JK. Effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/56596
11.
Thomsen, Sarah Jane.
Linking Cattle, Forage, and Tree Production in Silvopastures.
Degree: MS, Crop and Soil Environmental Sciences, 2019, Virginia Tech
URL: http://hdl.handle.net/10919/91382
► Silvopasture is the intentional integration of trees with forages and livestock. In Blackstone, Virginia a silvopasture management plan was created in a thinned, timber stand…
(more)
▼ Silvopasture is the intentional integration of trees with forages and livestock. In Blackstone,
Virginia a silvopasture management plan was created in a thinned, timber stand seeded with a cool-season forage mixture. Treatment pastures for this study included an open pasture, a thinned pine silvopasture, a thinned hardwood silvopasture, and a cleared and replanted new pine silvopasture. Cattle were introduced in 2017 and rotationally stocked within each pasture according to forage availability. Objectives were to determine the forage availability, forage nutritive value, and the performance of heifers in silvopasture and open pasture systems. Additionally, the new pine silvopasture was grazed to determine the effect of cattle on tree seedlings without protection. Forage availability was lowest in the pine and hardwood silvopastures in both years compared to the open pastures. Nutritive value of forages was most greatly influenced by time rather than tree presence. In 2017, average daily gains of the heifers were greatest in the silvopastures in June. In 2018, average daily gain was lowest among silvopastures later in the summer compared to open pastures and new silvopastures. Internal and external body temperatures of heifers during the afternoon decreased with increasing shade availability with the greatest internal body temperatures occurring in unshaded animals. Silvopastures provide an opportunity to improve the welfare of grazing livestock in the summer, while improving the overall productivity and efficiency of land. Tree seedlings experienced minimal damage by cattle and would continue to produce trees with future economic and shade value. Future research should focus on how to implement silvopasture as part of a holistic grazing and management plan while continuing to evaluate cattle, forage, and tree response to silvopastures over multiple years.
Advisors/Committee Members: Pent, Gabriel J. (committeechair), Fike, John Herschel (committeechair), Greiner, Scott P. (committee member), Hodges, Steven C. (committee member), Munsell, John F. (committee member).
Subjects/Keywords: silvopasture; agroforestry; shade; cattle; tree; forage; heat stress
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Thomsen, S. J. (2019). Linking Cattle, Forage, and Tree Production in Silvopastures. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/91382
Chicago Manual of Style (16th Edition):
Thomsen, Sarah Jane. “Linking Cattle, Forage, and Tree Production in Silvopastures.” 2019. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/91382.
MLA Handbook (7th Edition):
Thomsen, Sarah Jane. “Linking Cattle, Forage, and Tree Production in Silvopastures.” 2019. Web. 09 Mar 2021.
Vancouver:
Thomsen SJ. Linking Cattle, Forage, and Tree Production in Silvopastures. [Internet] [Masters thesis]. Virginia Tech; 2019. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/91382.
Council of Science Editors:
Thomsen SJ. Linking Cattle, Forage, and Tree Production in Silvopastures. [Masters Thesis]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/91382
Virginia Tech
12.
Leachman, Lance Douglas.
Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity.
Degree: MS, Animal and Poultry Sciences, 2010, Virginia Tech
URL: http://hdl.handle.net/10919/77007
► The objective of this study was to characterize genetic relationships between growth and carcass traits measured in commercial feedlot and purebred cattle that would aid…
(more)
▼ The objective of this study was to characterize genetic relationships between growth and carcass traits measured in commercial feedlot and purebred cattle that would aid in determining the effectiveness of combined crossbred and purebred selection (CCPS) strategies for sire selection. Data included 2,183 steers and 418 heifers enrolled in the Tri-County Steer Carcass Futurity (TC). Feedlot traits evaluated were initial body weight at time of delivery (IBW) and final BW at time of harvest (FBW) and carcass backfat thickness at the 12th rib (CFAT), marbling score at the 12th rib (CMAR) and ribeye area at the12th rib (CREA). Purebred data from the American Angus Association (AAA) included records of 139,602 bulls, 130,944 heifers and 6,656 steers for weaning weight (WW); 85,702 bulls, 76,603 heifers and 1,908 steers for yearling weight (YW); and 62,752 bulls and 45,958 heifers for ultrasound measures of backfat thickness at the 12th rib (UFAT), intramuscular fat percentage at the 12th rib (UMAR) and ribeye area at the 12th rib (UREA). The genetic correlations between IBW and WW, FBW and YW, CFAT and UFAT, CMAR and UMAR, and CREA and UREA were 0.01 ° 0.21, 0.43 ° 0.22, 0.66 ° 0.19, 0.65 ° 0.17, and 0.92 ° 0.12, respectively. Regressions of TC traits on corresponding sire EPD resulted in coefficients of 0.23 ° 0.19, 0.57 ° 0.16, 0.67 ° 0.19, 93.3 ° 12.3, and 1.08 ° 0.17 for IBW, FBW, CFAT, CMAR, and CREA, respectively. Three selection indices were evaluated on the basis of relative efficiency of genetic progress toward TC goal traits. The index including AAA records on an individual sire with TC records on his progeny was most effective, thus indicating the benefit of CCPS.
Advisors/Committee Members: Lewis, Ronald M. (committeechair), Greiner, Scott P. (committee member), Notter, David R. (committeecochair).
Subjects/Keywords: weight; feedlot; carcass; selection; cattle
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Leachman, L. D. (2010). Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/77007
Chicago Manual of Style (16th Edition):
Leachman, Lance Douglas. “Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity.” 2010. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/77007.
MLA Handbook (7th Edition):
Leachman, Lance Douglas. “Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity.” 2010. Web. 09 Mar 2021.
Vancouver:
Leachman LD. Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity. [Internet] [Masters thesis]. Virginia Tech; 2010. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/77007.
Council of Science Editors:
Leachman LD. Testing purebred and commercial combined selection in Angus: Tri-County Steer Carcass Futurity. [Masters Thesis]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/77007
Virginia Tech
13.
Rorrer, Rebecca Kathleen.
Veterinary Therapeutic and Biologic Agents in Virginia Sheep Production.
Degree: MS, Veterinary Medical Sciences, 2002, Virginia Tech
URL: http://hdl.handle.net/10919/34574
► Biological and therapeutic agents are used in food animal production to maintain animal health and well being, prevent and treat disease, and to maintain or…
(more)
▼ Biological and therapeutic agents are used in food animal production to maintain animal health and well being, prevent and treat disease, and to maintain or enhance production. Concerns about the use of pharmaceutical agents in food animal production have been raised, especially in relation to food quality and safety. This study addressed the scarcity of information concerning the quantity of pharmaceuticals being used and the reasons for their use in sheep production. Additional goals included determining the sources of information used by shepherds in making treatment decisions and evaluating the economic impact that pharmaceutical usage has on sheep production. Thirty-nine
Virginia sheep producers participated in this study of four months duration from March through September. After completing an initial questionnaire to determine flock and management characteristics, participants were asked to record all treatments with biological and therapeutic agents that occurred within their sheep flocks. A total of 14,310 treatments were recorded for a median of 1.5 treatments per sheep per month. Parasite control and vaccination were the most frequent reasons for treatment (64.9% and 15.2%, respectively) with vitamin/mineral supplementation being the next most common (8.8%). Price information was collected for 13,912 treatment events. An estimated total of 7,523.78 was spent on pharmaceutical treatment over the course of the study. This amounts to a cost of 0.63 per sheep per month of observation. Results of this study will enhance the ability of producers to evaluate treatment decisions, allow comparisons to be made between operations and provide a base of information for future research.
Advisors/Committee Members: Pelzer, Kevin D. (committeechair), Greiner, Scott P. (committee member), Elvinger, Francois C. (committee member).
Subjects/Keywords: pharmaceuticals; biologics; suvey; sheep
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rorrer, R. K. (2002). Veterinary Therapeutic and Biologic Agents in Virginia Sheep Production. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/34574
Chicago Manual of Style (16th Edition):
Rorrer, Rebecca Kathleen. “Veterinary Therapeutic and Biologic Agents in Virginia Sheep Production.” 2002. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/34574.
MLA Handbook (7th Edition):
Rorrer, Rebecca Kathleen. “Veterinary Therapeutic and Biologic Agents in Virginia Sheep Production.” 2002. Web. 09 Mar 2021.
Vancouver:
Rorrer RK. Veterinary Therapeutic and Biologic Agents in Virginia Sheep Production. [Internet] [Masters thesis]. Virginia Tech; 2002. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/34574.
Council of Science Editors:
Rorrer RK. Veterinary Therapeutic and Biologic Agents in Virginia Sheep Production. [Masters Thesis]. Virginia Tech; 2002. Available from: http://hdl.handle.net/10919/34574
Virginia Tech
14.
Emenheiser, Joseph Carl.
Use of ultrasound technology in the genetic improvement of U.S. lamb composition.
Degree: MS, Animal and Poultry Sciences, 2009, Virginia Tech
URL: http://hdl.handle.net/10919/31178
► Ultrasound technology allows in vivo estimation of carcass composition. Successful genetic evaluation of ultrasonic measures depends upon technician certification guidelines and a viable common-endpoint adjustment…
(more)
▼ Ultrasound technology allows in vivo estimation of carcass composition. Successful genetic evaluation of ultrasonic measures depends upon technician certification guidelines and a viable common-endpoint adjustment strategy for field data.
Four technicians and three image interpreters ultrasonically evaluated 172 lambs to determine accuracy and repeatability of loin eye area (LEA), backfat thickness (BF), and body wall thickness (BW) estimations. Correlations between ultrasonic and carcass measurements were 0.66, 0.78, and 0.73 for LEA, BF, and BW, respectively. Performance was similar among technicians and interpreters. Mean bias ranged from -1.30 to -2.66 cm2, -0.12 to -0.17 cm, and 0.14 to -0.03 cm, for LEA, BF, and BW, respectively; prediction standard errors ranged from 1.86 to 2.22 cm2, 0.12 to 0.14 cm, and 0.35 to 0.38 cm, respectively. Repeatability standard errors ranged from 1.61 to 2.45 cm2, 0.07 to 0.11 cm, and 0.36 to 0.42 cm for LEA, BF, and BW, respectively.
Changes in ultrasonic measurements were evaluated using seven serial scans on 24 growing Suffolk ram lambs. All equations had similar goodness of fit. Equations were tested on other populations, including similarly-managed rams across breeds and years and ewe lambs fed for slower gain. Correlations between predicted and actual measures ranged from 0.78 to 0.87 for BF and 0.66 to 0.93 for LEA in winter-born rams, were only slightly lower in fall-born rams, and ranged from 0.72 to 0.74 for BF and 0.54 to 0.76 for LEA in ewe lambs. Of the equations tested, linear and allometric forms appear best for general use.
Advisors/Committee Members: Notter, David R. (committeechair), Greiner, Scott P. (committee member), Lewis, Ronald M. (committee member).
Subjects/Keywords: endpoint adjustment; growth; ultrasound; composition; carcass; lamb
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Emenheiser, J. C. (2009). Use of ultrasound technology in the genetic improvement of U.S. lamb composition. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31178
Chicago Manual of Style (16th Edition):
Emenheiser, Joseph Carl. “Use of ultrasound technology in the genetic improvement of U.S. lamb composition.” 2009. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/31178.
MLA Handbook (7th Edition):
Emenheiser, Joseph Carl. “Use of ultrasound technology in the genetic improvement of U.S. lamb composition.” 2009. Web. 09 Mar 2021.
Vancouver:
Emenheiser JC. Use of ultrasound technology in the genetic improvement of U.S. lamb composition. [Internet] [Masters thesis]. Virginia Tech; 2009. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/31178.
Council of Science Editors:
Emenheiser JC. Use of ultrasound technology in the genetic improvement of U.S. lamb composition. [Masters Thesis]. Virginia Tech; 2009. Available from: http://hdl.handle.net/10919/31178
Virginia Tech
15.
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
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
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 March 09, 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. 09 Mar 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 Mar 09].
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
16.
Liles, Amanda Gail.
The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers.
Degree: MS, Animal and Poultry Sciences, 2008, Virginia Tech
URL: http://hdl.handle.net/10919/34684
► Recent efforts have improved synchronization systems that facilitate timed insemination in beef cattle. However, synchronization systems utilizing a single fixed-time artificial insemination (FTAI) frequently result…
(more)
▼ Recent efforts have improved synchronization systems that facilitate timed insemination in beef cattle. However, synchronization systems utilizing a single fixed-time artificial insemination (FTAI) frequently result in 25-40% non-pregnant heifers. The purpose of this study was to determine the effectiveness and define economic parameters of a FTAI resynchronization protocol in beef heifers after synchronization using a 5d CO-Synch + CIDR system. Estrus was synchronized in crossbred heifers (n=176) using 5 d CO-Synch + CIDR with FTAI at 72 h. After the initial AI, open heifers received either resynchronization (RS) or natural service (NS) return service treatments. The RS treatment was diagnosed for pregnancy 29 d after the initial AI, and all open heifers were resynchronized using the 5 d CO-Synch + CIDR with FTAI at 72 h. Heifers diagnosed pregnant following initial AI received no further treatment. Heifers in the NS treatment were exposed to fertile bulls from d 14 to d 66 following initial AI. Return to estrus data were collected using the Heat Watch Estrus Alert System. Total AI pregnancies tended to be higher (
P=0.07) for RS (69.7%) than NS (56.5%) heifers. Overall pregnancy rate was greater for NS (89.4%) than for RS (69.7%) at the end of the breeding season (
P < 0.01). The cost of RS was 128.63 and for NS was 82.50 per pregnancy. The expected average calf value per heifer exposed was 195.84 for RS treatment and 357.62 for NS treatment. This difference was attributed to the increased number of open heifers in the RS treatment. The resynchronization of estrus after the initial FTAI yielded a limited number of pregnancies in the breeding season in this study. However, the resynchronization program also cost more per pregnancy. Further investigation into resynchronization should focus on both biological and economic impacts.
Advisors/Committee Members: Greiner, Scott P. (committeechair), Barnes, Michael A. (committee member), Beal, Wilfred E. (committee member), Hall, John B. (committee member).
Subjects/Keywords: Beef; Heifer; Reproduction; Resynchronization; Economics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Liles, A. G. (2008). The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/34684
Chicago Manual of Style (16th Edition):
Liles, Amanda Gail. “The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers.” 2008. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/34684.
MLA Handbook (7th Edition):
Liles, Amanda Gail. “The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers.” 2008. Web. 09 Mar 2021.
Vancouver:
Liles AG. The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers. [Internet] [Masters thesis]. Virginia Tech; 2008. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/34684.
Council of Science Editors:
Liles AG. The effects of resynchronization of estrus using the 5 d CO-Synch + CIDR system in beef heifers. [Masters Thesis]. Virginia Tech; 2008. Available from: http://hdl.handle.net/10919/34684
Virginia Tech
17.
Vanimisetti, Hima Bindu.
Genetics of resistance to Haemonchus contortus infections in sheep.
Degree: MS, Animal and Poultry Sciences, 2003, Virginia Tech
URL: http://hdl.handle.net/10919/31414
► Genetic control of resistance to H. contortus was assessed in 198 ewes and 386 lambs of 50% Dorset, 25% Rambouillet and 25% Finnsheep breeding in…
(more)
▼ Genetic control of resistance to H. contortus was assessed in 198 ewes and 386 lambs of 50% Dorset, 25% Rambouillet and 25% Finnsheep breeding in fall and spring over 2 yr. After deworming, lambs that were approximately 120 d old and ewes that had weaned their lambs at 60 d and dried off were individually dosed with approximately 10,000 infective larvae. After infection, body weight (BW), fecal egg counts (FEC) and packed cell volume (PCV) were measured weekly for 7 wk in lambs and fortnightly for eleven wk in ewes. Summary traits were defined as initial PCV, mean BW (MBW) across all times, and means for FEC, log-transformed FEC (MLFEC), and PCV (MPCV) at wk 3 to 7 post-infection for lambs and wk 3 to 11 post-infection for ewes.
No consistent seasonal variation in FEC was observed. Younger ewes were more susceptible to infection than older ewes. Sex differences in FEC were not observed in lambs.
Heritabilities for summary traits were estimated from a REML analysis that included fixed effects of year and season plus effects of either sex (for lambs) or age category (for ewes). Heritability estimates for MBW, MPCV, and MLFEC were 0.74, 0.57, and 0.27 respectively (all
P < 0.01), in lambs, and 0.24 (
P < 0.1), 0.25 (
P < 0.05) and 0.55 (
P < 0.01), respectively, in ewes. Across-year repeatability estimates in ewes for MBW, MPCV, and MLFEC were 0.83, 0.54 and 0.56, respectively (all
P < 0.01). Resistance was antagonistically associated with estimated breeding values for growth in ewes but not in lambs. Fertility and prolificacy in ewes were not related to resistance.
Breed differences in resistance to H. contortus were also evaluated in 4 to 6-mo-old crossbred Dorset and Dorper, straightbred Katahdin, and Barbados Blackbelly x St. Croix lambs. Dorpers were not more resistant than Dorsets but appeared to cope better, with higher PCV and similar BW during infection compared to Dorsets. Katahdin and Barbados Blackbelly x St. Croix lambs were more resistant with lower FEC.
Advisors/Committee Members: Notter, David R. (committeechair), Greiner, Scott P. (committee member), Zajac, Anne M. (committee member), Lewis, Ronald M. (committee member).
Subjects/Keywords: Resistance; Haemonchus contortus; Sheep; Heritability
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Vanimisetti, H. B. (2003). Genetics of resistance to Haemonchus contortus infections in sheep. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31414
Chicago Manual of Style (16th Edition):
Vanimisetti, Hima Bindu. “Genetics of resistance to Haemonchus contortus infections in sheep.” 2003. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/31414.
MLA Handbook (7th Edition):
Vanimisetti, Hima Bindu. “Genetics of resistance to Haemonchus contortus infections in sheep.” 2003. Web. 09 Mar 2021.
Vancouver:
Vanimisetti HB. Genetics of resistance to Haemonchus contortus infections in sheep. [Internet] [Masters thesis]. Virginia Tech; 2003. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/31414.
Council of Science Editors:
Vanimisetti HB. Genetics of resistance to Haemonchus contortus infections in sheep. [Masters Thesis]. Virginia Tech; 2003. Available from: http://hdl.handle.net/10919/31414
Virginia Tech
18.
Borg, Randy Charles.
Phenotypic and genetic evaluation of fitness characteristics in sheep under a range environment.
Degree: PhD, Animal and Poultry Sciences, 2007, Virginia Tech
URL: http://hdl.handle.net/10919/27383
► The objectives of this dissertation were to evaluate genetic and environmental relationships between lamb and ewe traits including body weight, fleece weight and quality, prolificacy,…
(more)
▼ The objectives of this dissertation were to evaluate genetic and environmental relationships between lamb and ewe traits including body weight, fleece weight and quality, prolificacy, body condition, ewe stayability and lamb survival. Average heritability estimates for lamb birth weight (BWT), weaning weight (WW), maternal weaning weight, yearling body weight, fleece weight, spinning count and staple length were 0.19, 0.09, 0.08, 0.35, 0.38, 0.25, and 0.31 respectively. Heritability estimates for adult traits averaged 0.43 for body weight (AW), 0.13 for body condition (AC), and 0.12 for number of lambs born per ewe lambing (NLB). Correlations between direct additive AW and direct additive and maternal lamb weights ranged from 0.21 to 0.96 (
P < 0.05) and 0.29 to 0.53 (
P < 0.05), respectively, with residual correlations ranging from 0.05 to 0.95. Correlations of lamb traits with adult body condition and NLB were generally not different from zero; genetic and residual correlations ranged from -0.52 to 0.69 and -.39 to 0.31, respectively.
Ewe stayability was analyzed as overall stayability (STAYn|2) which indicated the presence or absence of a ewe at n yrs of age, given that she was present at 2 yrs of age, and marginal stayability (STAYn|1-n) recording the presences of a ewe at n yrs of age, given that she was in the flock the previous year. Additive variance in ewe stayability was only found in stayability at 5 and 6 yr of age (
P < 0.05). Heritability estimates for STAY5|4 and STAY6|2 from multiple trait analyses with other traits averaged 0.08 and 0.10, respectively. Phenotypic correlations between STAY and all other traits were near zero, ranging from -0.04 to 0.03. The estimated correlations between additive effects on STAY5|4 and STAY6|2 and additive maternal effects on WW were positive (both 0.46;
P < 0.05). Genetic correlations between STAY5|4 and WW, adult weight, and NLB were 0.06, 0.13 and -0.06 (
P > 0.10), respectively. However, genetic correlations between STAY6|2 and WW, adult weight, and NLB were negative (-0.17, -0.32 (
P < 0.05) and -0.03, respectively). Significant genetic variation was thus present in stayability, with nonzero genetic correlations present between STAY, maternal milk, WW, and adult weight.
Survival analysis was performed using a proportional hazards model to measure the probability of lamb death before weaning. Lamb survival was recorded as the day of age at death. Records were censored if a live lamb was artificially removed from their litter before death. Fixed effects on survival included ewe age, litter size, sex, and linear and quadratic BWT. Average age of death was 13.7 d. Censoring of records before weaning occurred in 12.9% of the total lambs born. Risk ratios indicated lambs from yearlings and ewes older than 5 yr had the greater risk of death, as did triplet and quadruplet lambs. Linear and quadratic BWT effects on lamb survival were found (
P < 0.05) and accounted for most of the litter size effects in large litters. The influence of informative…
Advisors/Committee Members: Notter, David R. (committeechair), Lewis, Ronald M. (committee member), Kott, Rodney W. (committee member), Greiner, Scott P. (committee member).
Subjects/Keywords: stayability; heritability; survival analysis; sheep; ewe size
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Borg, R. C. (2007). Phenotypic and genetic evaluation of fitness characteristics in sheep under a range environment. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27383
Chicago Manual of Style (16th Edition):
Borg, Randy Charles. “Phenotypic and genetic evaluation of fitness characteristics in sheep under a range environment.” 2007. Doctoral Dissertation, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/27383.
MLA Handbook (7th Edition):
Borg, Randy Charles. “Phenotypic and genetic evaluation of fitness characteristics in sheep under a range environment.” 2007. Web. 09 Mar 2021.
Vancouver:
Borg RC. Phenotypic and genetic evaluation of fitness characteristics in sheep under a range environment. [Internet] [Doctoral dissertation]. Virginia Tech; 2007. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/27383.
Council of Science Editors:
Borg RC. Phenotypic and genetic evaluation of fitness characteristics in sheep under a range environment. [Doctoral Dissertation]. Virginia Tech; 2007. Available from: http://hdl.handle.net/10919/27383
Virginia Tech
19.
Wuenschel, Jeffrey Carl Jr.
Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids.
Degree: MS, Animal and Poultry Sciences, 2006, Virginia Tech
URL: http://hdl.handle.net/10919/34958
► The objective of this study was to determine the effects of dietary supplementation of eicosapentanoic (EPA) and docosahexanoic acids (DHA) on reproduction in beef females.…
(more)
▼ The objective of this study was to determine the effects of dietary supplementation of eicosapentanoic (EPA) and docosahexanoic acids (DHA) on reproduction in beef females. In experiment 1, cows (n = 31) were individually fed rumen protected fish meal (FM) or no fish meal (C) supplements. Estrus was synchronized and ovulation induced on d 37. Ovarian follicular growth and diameter were determined by ultrasound on d 35 and d 37. Serum progesterone (P4) profiles were analyzed on d 37 through d 52. On d 52 cows were cannulated, primed with estradiol-17β at -240 min, and stimulated to release PGF2α by oxytocin injection at 0 min with blood sampled every 15 min from -30 min to 240 min. Supplement type did not affect (
P > 0.05) follicular diameter, follicular growth or P4 concentrations. In cows fed FM, prostaglandin metabolite (PGFM) concentrations tended (
P ≤ 0.10) to be reduced at 0, 30, and 60 min. In experiment 2, crossbred heifers (n = 214) received FM or C concentrates with corn silage from 30 d before estrous synchronization until 14 d after artificial insemination (AI). Serum fatty acid profiles were determined in five heifers from each group . Estrus detection and AI were conducted from d 37 through d 39. Dietary treatment increased (
P < 0.05) EPA and DHA concentrations. Dietary treatment did not affect estrus response or AI conception rates and pregnancy rate. Supplementation of FM increased EPA and DHA concentrations but did not affect reproductive factors.
Advisors/Committee Members: Hall, John B. (committeechair), Beal, Wilfred E. (committee member), Knowlton, Katharine F. (committee member), Greiner, Scott P. (committee member).
Subjects/Keywords: Prostaglandin; Nutrition; Reproduction; Beef Cattle; Fatty Acids
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wuenschel, J. C. J. (2006). Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/34958
Chicago Manual of Style (16th Edition):
Wuenschel, Jeffrey Carl Jr. “Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids.” 2006. Masters Thesis, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/34958.
MLA Handbook (7th Edition):
Wuenschel, Jeffrey Carl Jr. “Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids.” 2006. Web. 09 Mar 2021.
Vancouver:
Wuenschel JCJ. Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids. [Internet] [Masters thesis]. Virginia Tech; 2006. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/34958.
Council of Science Editors:
Wuenschel JCJ. Effects of Feeding Supplemental Eicosapentanoic Acid and Docosahexanoic Acid to Beef Females on Reproductive Responses and Free Fatty Acids. [Masters Thesis]. Virginia Tech; 2006. Available from: http://hdl.handle.net/10919/34958
Virginia Tech
20.
Bowdridge, Scott Alexander.
Characterizing physiological and genetic differences in the early immune response to Haemonchus contortus in resistant and susceptible sheep.
Degree: PhD, Animal and Poultry Sciences, 2009, Virginia Tech
URL: http://hdl.handle.net/10919/29372
► This dissertation compares immune responses of resistant and susceptible sheep to infection with Haemonchus contortus during the peri-parturient period and larval stage of infection. Identification…
(more)
▼ This dissertation compares immune responses of resistant and susceptible sheep to infection with Haemonchus contortus during the peri-parturient period and larval stage of infection. Identification of immunological events resulting in parasite resistance in St. Croix hair sheep may provide better targets for differential gene expression analysis and eventual discovery of selectable markers for parasite resistance. Antibody levels of hair ewes and composite Dorset x Finnsheep-Rambouillet wool ewes were measured during breeding and again after parturition. Results demonstrated that hair ewes had higher levels immunoglobulin-A after infection and maintained a higher level of circulating antigen-specific antibody when compared to wool ewes. To characterize immune responses to the larval stage of infection, hair and wool lambs were sacrificed at 0, 3, 5, and 7 d after infection with H. contortus. Neutrophil migration to abomasal mucosa and lymph node development were higher in hair sheep than in wool sheep. Gene expression analysis indicated no difference in the abomasal lymph node as both breeds expressed a general T-helper cell type 2 (TH2) response. However, profound differences in TH2 responses were observed in the abomasal mucosa, where hair sheep expressed more IL-4, -13 and -33 than wool sheep. These data thus document the presence of immunological differences between the breeds. Immune responses to larval parasite infection in wool sheep are generally suppressed and may increase the magnitude and duration of infection whereas immune responses to larval infection in hair sheep was more robust and more strongly polarized towards a TH2
Advisors/Committee Members: Notter, David R. (committeechair), Zajac, Anne M. (committee member), Greiner, Scott P. (committee member), Dalloul, Rami A. (committee member), Mullarky, Isis K. (committee member).
Subjects/Keywords: gene expression; immune response; larval infection; Hair sheep
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bowdridge, S. A. (2009). Characterizing physiological and genetic differences in the early immune response to Haemonchus contortus in resistant and susceptible sheep. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/29372
Chicago Manual of Style (16th Edition):
Bowdridge, Scott Alexander. “Characterizing physiological and genetic differences in the early immune response to Haemonchus contortus in resistant and susceptible sheep.” 2009. Doctoral Dissertation, Virginia Tech. Accessed March 09, 2021.
http://hdl.handle.net/10919/29372.
MLA Handbook (7th Edition):
Bowdridge, Scott Alexander. “Characterizing physiological and genetic differences in the early immune response to Haemonchus contortus in resistant and susceptible sheep.” 2009. Web. 09 Mar 2021.
Vancouver:
Bowdridge SA. Characterizing physiological and genetic differences in the early immune response to Haemonchus contortus in resistant and susceptible sheep. [Internet] [Doctoral dissertation]. Virginia Tech; 2009. [cited 2021 Mar 09].
Available from: http://hdl.handle.net/10919/29372.
Council of Science Editors:
Bowdridge SA. Characterizing physiological and genetic differences in the early immune response to Haemonchus contortus in resistant and susceptible sheep. [Doctoral Dissertation]. Virginia Tech; 2009. Available from: http://hdl.handle.net/10919/29372
. 
Open Access Theses and Dissertations
