+publisher:"University of Arizona" +contributor:("Collier, Robert J")

University of Arizona

1. Ortiz de Janon, Xavier Alejandro. A Comprehensive Analysis of Novel Dairy Cooling Systems, Their Cooling Efficiency and Impact on Lactating Dairy Cow Physiology and Performance .

Degree: 2016, University of Arizona

URL: http://hdl.handle.net/10150/604863

► Cooling systems used to reduce heat stress in dairy operations require high energy, water usage, or both. Steady increases in electricity costs and reduction of… (more)

▼ Cooling systems used to reduce heat stress in dairy operations require high energy, water usage, or both. Steady increases in electricity costs and reduction of water availability and an increase in water usage regulations require evaluation of passive cooling systems to cool cows and reduce use of water and electricity. A series of experiments were conducted to evaluate the use of heat exchangers buried as components in a conductive system for cooling cows. In the first experiment six cows were housed in environmentally controlled rooms with tiestall beds, which were equipped with a heat exchanger and filled with 25 cm of either sand or dried manure. Beds were connected to supply and return lines and individually controlled. Two beds (one per each kind of bedding material) constituted a control group (water off), and the other 4 (2 sand and 2 dried manure) used water at 7°C passing through the heat exchangers (water on). The experiment was divided in 2 periods of 40 d, and each period involved 3 repetitions of 3 different climates (hot and dry, thermo neutral, and hot and humid). Each cow was randomly assigned to a different treatment after each repetition was over. Sand bedding remained cooler than dried manure bedding in all environments and at all levels of cooling (water on or off). Results from this experiment demonstrated that bed temperatures were lower and heat flux higher during the bed treatment with sand and water on. We also detected a reduction in core body temperatures, respiration rates, rectal temperatures, and skin temperatures of those cows during the sand and water on treatment. Feed intake and milk yield numerically increased during the bed treatment with sand and water on for all climates. No major changes were observed in the lying time of cows or the composition of the milk produced. The efficiency of conductive cooling as a heat abatement technique in dairy production is highly correlated with the distance between the cooling system and the skin of the cow and the type of bedding material used. A second experiment was conducted to identify possible improvements in the utilization of conductive cooling for cooling cows. Heat exchangers buried 12.7 cm below the surface as components in a conductive system ware evaluated in this study. Six cows were housed in environmentally controlled rooms with tie-stall beds, which were equipped with a heat exchanger and filled with 12.7 cm of either sand or dried manure. Beds were connected to supply and return lines and individually controlled. Two beds (one per bedding material type) constituted a control group (water OFF), and the other four (two sand and two dried manure) used water at 7°C passing through the heat exchangers (water ON). The experiment was divided into two periods of 40 days and each period involved three repetitions of three different climates hot dry (HD), thermo neutral(TN) and hot humid (HH). Each cow was randomly assigned to a different treatment after each repetition was over. The sand and water on treatment was the most efficient… Advisors/Committee Members: Collier, Robert J (advisor), Collier, Robert J. (committeemember), Cuneo, Peder S. (committeemember), Faulkner, Dan B. (committeemember), Kacira, Murat (committeemember), Limesand, Sean W. (committeemember).

Subjects/Keywords: Dairy Cow; Heat Stress; Animal Sciences; Cooling

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ortiz de Janon, X. A. (2016). A Comprehensive Analysis of Novel Dairy Cooling Systems, Their Cooling Efficiency and Impact on Lactating Dairy Cow Physiology and Performance . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/604863

Chicago Manual of Style (16^th Edition):

Ortiz de Janon, Xavier Alejandro. “A Comprehensive Analysis of Novel Dairy Cooling Systems, Their Cooling Efficiency and Impact on Lactating Dairy Cow Physiology and Performance .” 2016. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/604863.

MLA Handbook (7^th Edition):

Ortiz de Janon, Xavier Alejandro. “A Comprehensive Analysis of Novel Dairy Cooling Systems, Their Cooling Efficiency and Impact on Lactating Dairy Cow Physiology and Performance .” 2016. Web. 07 Mar 2021.

Vancouver:

Ortiz de Janon XA. A Comprehensive Analysis of Novel Dairy Cooling Systems, Their Cooling Efficiency and Impact on Lactating Dairy Cow Physiology and Performance . [Internet] [Doctoral dissertation]. University of Arizona; 2016. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/604863.

Council of Science Editors:

Ortiz de Janon XA. A Comprehensive Analysis of Novel Dairy Cooling Systems, Their Cooling Efficiency and Impact on Lactating Dairy Cow Physiology and Performance . [Doctoral Dissertation]. University of Arizona; 2016. Available from: http://hdl.handle.net/10150/604863

University of Arizona

2. Vander Poel, Matthew Jonathon. Implications of Feed Additives in the Mitigation of Heat Stress in Cattle .

Degree: 2019, University of Arizona

URL: http://hdl.handle.net/10150/633132

► Nutritional supplements have been used to mitigate heat stress in cattle. A series of experiments were conducted under controlled environment conditions in the Animal Research… (more)

▼ Nutritional supplements have been used to mitigate heat stress in cattle. A series of experiments were conducted under controlled environment conditions in the Animal Research Complex (ARC) to evaluate the value of nutritional intervention on mitigation of heat stress (HS) in cattle. Previous research and literature have shown mixed results in terms of performance benefits. In the first study, we evaluated the use of a proprietary yeast cell extract to help mitigate the effects of hyperthermia on growth development by improving metabolic and immune functions. Twelve crossbred Hereford steers (250 ± 100 kg) were randomly assigned to one of two dietary groups: control group (CON) received 56.7 g of placebo/hd/day; the feed additive group (BA) received 56.7 g of BA/hd/day. Steers were randomly assigned to one of two tie stall rooms with 6 steers per room and 3 steers per treatment/room. Rooms were exposed to cyclical daily temperature humidity index (THI) of 70 - 81 and 27 – 39 for HS and the thermoneutral (TN) rooms respectively for a total of 15 days. Average daily water consumption and average daily gain were calculated at the end of the experimental period. Heat stress increased water consumption (P<0.001), respiration rate (P<0.001), and skin temperature (P<0.001) and tended to increase rectal temperature (P<0.06). Supplementation with BA tended to reduce rectal temperatures (P<0.06) in heat stressed cattle. Exposure to heat stress lowered serum glucose (P<0.01) and insulin (P<0.01) while increasing NEFAS (P<0.01) and TAG (P<0.01). Supplementation with BA lowered TAG (P<0.05) and glucose (P<0.05). HS and BA supplementation had no effect on serum cortisol levels. Results of this study suggest that HS exposure for 15 days had performance and metabolic impacts in crossbred Hereford steers. Supplementation with the dietary BA alleviated some of the daily metabolic effects associated with heat exposure. The objective of the second study was to evaluate the effect of feeding a dietary supplement (PMI Nutritional Additives, Arden Hills, MN) on the HS response in multi-parturient dairy cows in mid lactation. Two pens of cows at a commercial dairy were fed either control (CON) or additive (YB) at 113 g/cow per d for two weeks prior to arrival. Study cows (n=12) were balanced in days in milk (DIM), milk production, and parity (111.91±4.85 d, 33.67±0.96 kg/d, and 2.25±0.18). Cows were randomly selected from both groups (6 TRT and 6 CON) and housed in environmentally controlled chambers for 18 d and fed appropriate diet. Cows were subjected to 7 d of TN conditions, 7 d of HS, and 4 d of recovery (REC) under TN conditions. HS increased RT (P<0.0001), RR (P<0.0001), BUN (P<0.0001), insulin (P=0.04), neutrophil (P=0.009), and water intake (P=0.0005). HS decreased lymphocyte (P=0.0008), DMI (P=0.0007), energy corrected milk (ECM, P=0.01), and 4% fat corrected milk (FCM, P=0.02). YB decreased the feed efficiency ratio (P=0.03). YB had no effect on blood parameters. There was a treatment x environment interaction with cows fed YB… Advisors/Committee Members: Diaz, Duarte (advisor), Garcia, Samuel (committeemember), Collier, Robert J. (committeemember).

Subjects/Keywords: Cattle; Cows; Feed additives; Heat Stress; Yeast Culture

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Vander Poel, M. J. (2019). Implications of Feed Additives in the Mitigation of Heat Stress in Cattle . (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/633132

Chicago Manual of Style (16^th Edition):

Vander Poel, Matthew Jonathon. “Implications of Feed Additives in the Mitigation of Heat Stress in Cattle .” 2019. Masters Thesis, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/633132.

MLA Handbook (7^th Edition):

Vander Poel, Matthew Jonathon. “Implications of Feed Additives in the Mitigation of Heat Stress in Cattle .” 2019. Web. 07 Mar 2021.

Vancouver:

Vander Poel MJ. Implications of Feed Additives in the Mitigation of Heat Stress in Cattle . [Internet] [Masters thesis]. University of Arizona; 2019. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/633132.

Council of Science Editors:

Vander Poel MJ. Implications of Feed Additives in the Mitigation of Heat Stress in Cattle . [Masters Thesis]. University of Arizona; 2019. Available from: http://hdl.handle.net/10150/633132

University of Arizona

3. Rungruang, Sunthorn. Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows .

Degree: 2012, University of Arizona

URL: http://hdl.handle.net/10150/265340

► Four studies were conducted to evaluate the effects of supplemental cooling and niacin on heat stress (HS) responses in vivo and in vitro in lactating… (more)

▼ Four studies were conducted to evaluate the effects of supplemental cooling and niacin on heat stress (HS) responses in vivo and in vitro in lactating dairy cows. For experiment one, lactating dairy cows were fed four levels of dietary niacin, NIASHURE® (0,4,8,12 g/d) for 21 d. Heat stress decreased niacin levels in whole blood, red blood cells and plasma as compared to thermoneutral. Water intake, plasma and milk niacin concentrations increased linearly with increasing dietary niacin in HS cattle. In thermoneutral, but not HS cows, niacin increased skin temperature compared to controls suggesting niacin increased skin blood flow and sensible heat loss. In experiment 2, lactating cows were used to evaluate the impact of feed-line soaking (FLS) combined with niacin supplementation. In evaporative cooled barns, FLS reduced body temperatures; however the addition of niacin did not improve heat status of these cows. For experiment 3, 200 lactating dairy cows were used to determine the effects of conductively cooled bedding (CC) compared to feed-line soaking with fans (FLSF). Conductively cooled bedding can reduce skin and vaginal temperatures in cows after nighttime rest. However, FLSF were more effective in decreasing body temperature, as cows had lower heat parameter indices, higher milk yield and longer rest time. For experiment 4, three cell types were used to evaluate niacin in vitro. Niacin induced heat shock proteins (HSP) that protected cells during HS in transformed bovine mammary epithelial cells but not in primary bovine mammary epithelial cells (BMEC) or bovine endometrial cells (BEND). Effect of niacin on HSP may depend on enzymes involved in DNA-binding activity of heat shock factor 1. These results suggest that niacin may be involved in whole body metabolism during heat stress and is cell dependent. We did not find dietary niacin to be commercially efficacious in treating HS in cows. Further research is warranted to improve efficacy of CC and FLSF under high temperature humidity index conditions. Advisors/Committee Members: Collier, Robert J (advisor), Smith, John F. (committeemember), Renquist, Benjamin J. (committeemember), Santos, Jose E. P. (committeemember), Bilby, Todd R. (committeemember), Collier, Robert J. (committeemember).

Subjects/Keywords: Heat stress; Niacin; Animal Sciences; Cooling; Dairy cows

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rungruang, S. (2012). Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/265340

Chicago Manual of Style (16^th Edition):

Rungruang, Sunthorn. “Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows .” 2012. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/265340.

MLA Handbook (7^th Edition):

Rungruang, Sunthorn. “Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows .” 2012. Web. 07 Mar 2021.

Vancouver:

Rungruang S. Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows . [Internet] [Doctoral dissertation]. University of Arizona; 2012. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/265340.

Council of Science Editors:

Rungruang S. Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows . [Doctoral Dissertation]. University of Arizona; 2012. Available from: http://hdl.handle.net/10150/265340

University of Arizona

4. Fish, Ronald Dean. Estrus Synchronization of Beef and Dairy Cows .

Degree: 2011, University of Arizona

URL: http://hdl.handle.net/10150/217055

► An estrus synchronization trial was conducted to determine the efficacy of adding an injection of gonadotropin releasing hormone (GnRH) at initiation of the controlled intravaginal… (more)

▼ An estrus synchronization trial was conducted to determine the efficacy of adding an injection of gonadotropin releasing hormone (GnRH) at initiation of the controlled intravaginal drug releasing device (CIDR®) progesterone synchronization protocol in heifers. Nulliparous (n=121) beef heifers were randomly assigned to one of two treatment groups. All heifers received a CIDR® implant at the initiation of the breeding season. Half of the heifers (Select Synch) received an injection of GnRH. Heifers in the Select Synch treatment group had a lower numerical response (76.7% versus 88.3%) to treatment (detected in heat) and an overall lower artificial conception rate (46.0% versus 53.3%), but no statistical difference was detected. Days to conception and artificial insemination conception rates for both groups were similar for all heifers inseminated. Three hundred multiparous Hereford, crossbred and composite beef cows were assigned to one of two breeding groups (Early and Late) based on calving date and randomly assigned to receive an injection of GnRH at the time of CIDR® insertion (Select Synch). The addition of GnRH did not impact the percentage of cows detected in estrus or days to conception. Conception rates were not affected by the addition of GnRH (Select Synch), however cows in the early breeding group were more likely to become pregnant (58% versus 45%) by artificial insemination (P<0.02). An experiment evaluated the efficacy of the CIDR® protocol to synchronize estrus in Arizona Holstein dairy cows (n=696). Cows assigned to the CIDR® protocol (n=337) received a CIDR® insert at the end of the voluntary waiting period (55 days). CIDR®s were removed and an injection of prostaglandin was administered seven days after insertion. There was no difference due to CIDR® treatment in number of services per conception or first service conception rate. CIDR® treatment reduced days to first service, days open at first service, and days open (P<0.02). Warm season had a deleterious effect on number of services, days to first service, first service conception rate and days open (P<0.0001). In summary, estrus synchronization improved postpartum reproductive performance; however, thermal stress continues to be a major barrier to reproductive efficiency. Advisors/Committee Members: Marchello, John A (advisor), Collier, Robert J. (committeemember), Schafer, David W. (committeemember), Marchello, Elaine V. (committeemember), Marchello, John A. (committeemember), Franklin, James K. (committeemember).

Subjects/Keywords: progesterone; Animal Sciences; CIDR; Estrus synchronization

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Fish, R. D. (2011). Estrus Synchronization of Beef and Dairy Cows . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/217055

Chicago Manual of Style (16^th Edition):

Fish, Ronald Dean. “Estrus Synchronization of Beef and Dairy Cows .” 2011. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/217055.

MLA Handbook (7^th Edition):

Fish, Ronald Dean. “Estrus Synchronization of Beef and Dairy Cows .” 2011. Web. 07 Mar 2021.

Vancouver:

Fish RD. Estrus Synchronization of Beef and Dairy Cows . [Internet] [Doctoral dissertation]. University of Arizona; 2011. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/217055.

Council of Science Editors:

Fish RD. Estrus Synchronization of Beef and Dairy Cows . [Doctoral Dissertation]. University of Arizona; 2011. Available from: http://hdl.handle.net/10150/217055

University of Arizona

5. Macko, Antoni Ryszard. Elevated Fetal Plasma Norepinephrine Elicits Perinatal Adaptations in β-Cell Function .

Degree: 2013, University of Arizona

URL: http://hdl.handle.net/10150/311460

► The objective of this dissertation research was to determine the specific actions of chronically elevated catecholamines on; 1.) fetal growth and ß-cell function during the… (more)

▼ The objective of this dissertation research was to determine the specific actions of chronically elevated catecholamines on; 1.) fetal growth and ß-cell function during the third trimester in vivo in an ovine model of placental insufficiency-induced intrauterine growth restriction (PI-IUGR), and 2.) regulation of insulin secretion in vitro utilizing the mouse insulinoma cell line Min6.At 0.7-gestation, fetal weights were not different but PI fetuses had lower (P<0.05) basal blood oxygen content, plasma glucose, IGF-1, and insulin concentrations and greater norepinephrine concentrations (891±211 vs. 292±65 pg/ml; P<0.05) compared to controls. Glucose-stimulated insulin secretion (GSIS) was lower in PI than control fetuses (0.34±0.03 vs. 1.08±0.06 ng/ml; P<0.05). ADR-block increased GSIS in PI fetuses (1.19±0.11) but decreased GSIS in controls (0.86±0.02 ng/ml). Insulin content per islet was not different between PI and control fetuses. We concluded that elevated fetal plasma norepinephrine, in PI fetuses at 0.7 gestation, precedes growth restriction and suppresses insulin concentrations, and ADR-block revealed compensatory β-cells stimulus-secretion responsiveness. Therefore, to determine the effects of chronic hypercatecholamine exposure on fetal growth and β-cell function independent of hypoglycemia and hypoxemia, we performed surgical sham or adrenal demedullation (AD) at 0.65 gestation on control and IUGR fetuses (n= 5 Control-Sham, 5 Control-AD, 5 IUGR-Sham, 5 IUGR-AD fetuses). Studies commenced at 0.9 gestation under ambient conditions and steady-state reversal of arterial pO2 between IUGR and control fetuses. Plasma norepinephrine was 5-fold higher in IUGR-Sham vs. Control-Sham and reduced in IUGR-AD fetuses to concentrations not different from Control-Sham fetuses. Fetal mass was lower in IUGR vs. control fetuses but 92% greater in IUGR-AD compared to IUGR-Sham fetuses. Basal plasma glucose and arterial pO2 were lower in IUGR-Sham vs. Control-Sham, and IUGR-AD vs. Control-AD fetuses. Basal and glucose-stimulated insulin concentrations compared to Control-Sham were lower in IUGR-Sham and IUGR-AD and Control-AD fetuses. Oxygenation improved GSIS in IUGR-Sham and IUGR-AD fetuses. In conclusion, hypoglycemia, hypoxemia and norepinephrine interdependently and differentially regulate aspects of fetal growth and β-cell function in the IUGR fetus. In Min6 cells, we determined that GSIS responsiveness is enhanced and adrenergic receptor α2A is desensitized cells following chronic exposure to epinephrine. Advisors/Committee Members: Limesand, Sean W (advisor), Limesand, Sean W. (committeemember), Collier, Robert J. (committeemember), Henriksen, Erik J. (committeemember), Lynch, Ronald M. (committeemember), Renquist, Benjamin J. (committeemember).

Subjects/Keywords: Fetal; Metabolism; Norepinephrine; β-Cell; Physiological Sciences; Endocrinology

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Macko, A. R. (2013). Elevated Fetal Plasma Norepinephrine Elicits Perinatal Adaptations in β-Cell Function . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/311460

Chicago Manual of Style (16^th Edition):

Macko, Antoni Ryszard. “Elevated Fetal Plasma Norepinephrine Elicits Perinatal Adaptations in β-Cell Function .” 2013. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/311460.

MLA Handbook (7^th Edition):

Macko, Antoni Ryszard. “Elevated Fetal Plasma Norepinephrine Elicits Perinatal Adaptations in β-Cell Function .” 2013. Web. 07 Mar 2021.

Vancouver:

Macko AR. Elevated Fetal Plasma Norepinephrine Elicits Perinatal Adaptations in β-Cell Function . [Internet] [Doctoral dissertation]. University of Arizona; 2013. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/311460.

Council of Science Editors:

Macko AR. Elevated Fetal Plasma Norepinephrine Elicits Perinatal Adaptations in β-Cell Function . [Doctoral Dissertation]. University of Arizona; 2013. Available from: http://hdl.handle.net/10150/311460

6. Hall, Laun William. The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress .

Degree: 2014, University of Arizona

URL: http://hdl.handle.net/10150/333473

► This dissertation evaluated nutritional approaches such as the addition of betaine, prebiotics, probiotics, transitional metabolic substrates, and β-mercaptoacetate (MAA; a compound which inhibits β-oxidation) to… (more)

▼ This dissertation evaluated nutritional approaches such as the addition of betaine, prebiotics, probiotics, transitional metabolic substrates, and β-mercaptoacetate (MAA; a compound which inhibits β-oxidation) to the diet of lactating dairy cows to determine their impact on physiological, metabolic, hormonal and production responses during thermal stress. The first objective was to evaluate the use of an organic osmolyte, betaine to reduce the impact of heat stress (HS). Cows were fed either 0 (control; CON), 57 mg/kg BW (mid) or 114 mg/kg (high; HI) body weight (BW) betaine and subjected to thermoneutral (TN) and HS conditions. There was an increase in milk yield during TN with HI betaine over controls (P< 0.01), but the advantage was lost during HS. Plasma glucose increased during HS in HI dose cows compared to control (P < 0.01) as did plasma insulin (P = 0.01). Betaine increased milk production during TN and plasma glucose in HS, but did not improve the HS response. Objective two evaluated the use of a probiotic or direct fed microbial (DFM), Calsporin (Bacillus subtilus C-3102) to decrease the effects of HS in dairy cows. We hypothesized that feeding Calsporin prior to and during HS would reduce pathogenic strains of bacteria, maintain commensal microbes, and improve ruminal anaerobic fermentation resulting in improved milk yield (MY). Milk yield was numerically increased (1.26 kg, P = 0.11) in cows fed Calsporin during TN but was reduced under HS (-2.67 kg, P < 0.01) and milk protein content was decreased (P = 0.05). The DFM tended to decrease somatic cell count (SCC) across periods (P = 0.07). Calsporin addition to the diet did not affect respiration rates and was associated with higher rectal temperature at 1800 in HS (P = 0.02). The expression of heat shock protein 27 (HSP27) was decreased with Calsporin treatment (P = 0.03) and in both HS and TN. The fecal microbial count did not change with the exception of the Calsporin strain in treated animals (P < 0.01). The third objective was to feed OmniGen-AF (OG) to dairy cows before and during thermal stress. We hypothesized that feeding OG to HS dairy cows will improve the immune response, and decrease production losses associated with HS. Cows fed OG maintained lower SCC compared to control (P < 0.01) during the recovery period. We did not detect differences between groups in serum calcium while serum non-esterified fatty acid (NEFA) concentrations (P = 0.10) tended to be greater in OG fed cows across the Agricultural Research Center (ARC) portion including HS. Serum Adrenocorticotropic hormone (ACTH) levels were greater in OG cows (P<0.0001) across all sample days. Feeding OG reduced the HS response including serum Cortisol. The final study measured the effects of the metabolic substrate β-hydroxybutyrate (BHB) during HS on feed intake and metabolites. Under TN conditions the cows received a bolus dose of BHB and dry matter intake (DMI) and metabolites were measured. The second part of this study used a bolus of MAA to limit the up-stream production of… Advisors/Committee Members: Collier, Robert J (advisor), Renquist, Benjamin (committeemember), Long, Nathan M. (committeemember), Cuneo, Peder (committeemember), Limesand, Sean (committeemember).

Subjects/Keywords: Betaine; Dairy cows; Heat stress; Mercaptoacetate; OmniGen-AF; Animal Sciences; Beta-hydroxybutyrate

…for the first two days of HS in the environmental rooms at the University of Arizona… …during TN during the betaine study in the environmental rooms at the University of Arizona. Red…

13 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hall, L. W. (2014). The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/333473

Chicago Manual of Style (16^th Edition):

Hall, Laun William. “The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress .” 2014. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/333473.

MLA Handbook (7^th Edition):

Hall, Laun William. “The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress .” 2014. Web. 07 Mar 2021.

Vancouver:

Hall LW. The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress . [Internet] [Doctoral dissertation]. University of Arizona; 2014. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/333473.

Council of Science Editors:

Hall LW. The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress . [Doctoral Dissertation]. University of Arizona; 2014. Available from: http://hdl.handle.net/10150/333473

7. Chen, Xiaochuan. Chronic Norepinephrine Suppression Induces a Compensatory B-Cell Adaptation that Enhances Insulin Secretion after Alleviation of the Catecholamine Inhibition in Fetal Sheep .

Degree: 2012, University of Arizona

URL: http://hdl.handle.net/10150/238671

► Placental insufficiency-induced intrauterine growth restriction (IUGR) increases risk of mortality and morbidity in newborn infants and domestic animals. IUGR fetuses are typically exposed to prolonged… (more)

▼ Placental insufficiency-induced intrauterine growth restriction (IUGR) increases risk of mortality and morbidity in newborn infants and domestic animals. IUGR fetuses are typically exposed to prolonged hypoxemia, hypoglycemia, and hypercatecholaminemia, which results in perinatal pancreatic β-cell dysfunction. Recent evidence indicates that chronic exposure to norepinephrine in utero suppresses insulin secretion through α2-adrenergic receptors (ARs), but if the adrenergic actions are blocked compensatory hyper insulin secretion response is observed in the IUGR sheep fetus. In the current studies, we demonstrate that chronic NE exposure alone can produce the compensatory enhancement of β-cell responsiveness following termination of a chronic NE infusion. In the fetus NE was continuously infused at 1-4 μg/min for seven days starting at 131 days of gestational age (term = 145 days). During treatment, NE infused fetuses had higher (P < 0.05) plasma NE concentrations and lower (P < 0.01) insulin concentrations than vehicle infused control fetuses. Glucose stimulated insulin secretion (GSIS), which measures β-cell function, prior to NE treatment was not different between treatments. However, insulin concentrations during hyperglycemic steady state period of GSIS studies and area under the curve of glucose-potentiated arginine-induced insulin secretion were higher (P < 0.01) than control values and this augmentation was confirmed at 3 hours, 24 hours, and five days in NE-infused fetuses after discontinuing the infusion. Pancreatic islets isolated within 10 hours post NE infusion had lower (P < 0.05) mRNA expression of α1D (58%), α2A (43%), α2C (42%), α1 (67%) adrenergic receptors (ARs), and uncoupling protein 2 (40%) compared to islets from controls. Isolated islets from NE-infused fetuses 5 days after NE treatment had lower (P < 0.05) inhibitory responsiveness from NE and a greater (P < 0.05) maximal insulin release with glucose simulation in static incubations compared to controls. These findings show that following chronic NE exposure insulin secretion responsiveness was augmented and was coupled with desensitized adrenergic signaling. Moreover, this compensatory β-cell enhancement persists for days indicating chronic NE exposure permanently alters β-cell responsiveness. Advisors/Committee Members: Limesand, Sean W (advisor), Allen, Ronald E. (committeemember), Collier, Robert J. (committeemember), Griffin, Kurt J. (committeemember), Lynch, Ronald M. (committeemember), Limesand, Sean W. (committeemember).

Subjects/Keywords: Metabolism; Pancreas; Pregnancy; Type 2 Diabetes; Animal Sciences; Adrenergic receptor; Fetal programming

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chen, X. (2012). Chronic Norepinephrine Suppression Induces a Compensatory B-Cell Adaptation that Enhances Insulin Secretion after Alleviation of the Catecholamine Inhibition in Fetal Sheep . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/238671

Chicago Manual of Style (16^th Edition):

Chen, Xiaochuan. “Chronic Norepinephrine Suppression Induces a Compensatory B-Cell Adaptation that Enhances Insulin Secretion after Alleviation of the Catecholamine Inhibition in Fetal Sheep .” 2012. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/238671.

MLA Handbook (7^th Edition):

Chen, Xiaochuan. “Chronic Norepinephrine Suppression Induces a Compensatory B-Cell Adaptation that Enhances Insulin Secretion after Alleviation of the Catecholamine Inhibition in Fetal Sheep .” 2012. Web. 07 Mar 2021.

Vancouver:

Chen X. Chronic Norepinephrine Suppression Induces a Compensatory B-Cell Adaptation that Enhances Insulin Secretion after Alleviation of the Catecholamine Inhibition in Fetal Sheep . [Internet] [Doctoral dissertation]. University of Arizona; 2012. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/238671.

Council of Science Editors:

Chen X. Chronic Norepinephrine Suppression Induces a Compensatory B-Cell Adaptation that Enhances Insulin Secretion after Alleviation of the Catecholamine Inhibition in Fetal Sheep . [Doctoral Dissertation]. University of Arizona; 2012. Available from: http://hdl.handle.net/10150/238671

University of Arizona

8. Zerai, Desale Berhe. Halophytes for Bioremediation of Salt Affected Lands .

Degree: 2007, University of Arizona

URL: http://hdl.handle.net/10150/195274

► The area of secondarily salinized lands is increasing at a faster rate over time. Many irrigation districts around the world are shrinking as a result… (more)

Subjects/Keywords: Salinity; Bioremediation; Halophytes; Salt; Allenrolfea occidentalis; Salicornia bigelovii

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zerai, D. B. (2007). Halophytes for Bioremediation of Salt Affected Lands . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/195274

Chicago Manual of Style (16^th Edition):

Zerai, Desale Berhe. “Halophytes for Bioremediation of Salt Affected Lands .” 2007. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/195274.

MLA Handbook (7^th Edition):

Zerai, Desale Berhe. “Halophytes for Bioremediation of Salt Affected Lands .” 2007. Web. 07 Mar 2021.

Vancouver:

Zerai DB. Halophytes for Bioremediation of Salt Affected Lands . [Internet] [Doctoral dissertation]. University of Arizona; 2007. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/195274.

Council of Science Editors:

Zerai DB. Halophytes for Bioremediation of Salt Affected Lands . [Doctoral Dissertation]. University of Arizona; 2007. Available from: http://hdl.handle.net/10150/195274

University of Arizona

9. Moore, Chel Earl. CONTROLLED MILK FAT DEPRESSION AS A MANAGEMENT TOOL TO IMPROVE ENERGY BALANCE IN LACTATING DAIRY CATTLE .

Degree: 2005, University of Arizona

URL: http://hdl.handle.net/10150/194107

► Research conducted for this dissertation had three goals; 1) determine if CLA can induce milk fat depression immediately postpartum, 2) determine if CLA can alter… (more)

▼ Research conducted for this dissertation had three goals; 1) determine if CLA can induce milk fat depression immediately postpartum, 2) determine if CLA can alter energy availability, 3) determine the mechanism behind the mammary gland's decreased sensitivity to CLA immediately postpartum. The first study provides strong evidence indicating CLA can decrease milk fat synthesis immediately postpartum, but the dose required is approximately 3x greater than in established lactation. This trial also provided evidence that CLA can alter energy status, as CLA decreased days to EBAL nadir by nearly 5 days. This is relevant as recovery of EBAL from its lowest point provides an important signal for initiating ovarian activity and days to nadir is highly correlated with days to first ovulation. Study two was designed to determine if CLA induced milk fat depression could improve energy status during heat stress. Rumen-inert CLA reduced milk fat synthesis, and was able to improve energy availability, but did not increase milk yield or yield of other milk components. Although production was unchanged in this study, the study did provide further evidence that rumen-inert CLA can alter energy availability. Study three utilized intravenous infusion of CLA in cows in mid and early lactation to determine the mechanism for the mammary gland's decreased sensitivity in early lactation. It is postulated that increased fatty acid oxidation and subsequent enhanced levels of circulating NEFA present during the transition period competitively prevent adequate CLA uptake by the mammary gland. In the current study, trans-10, cis-12 CLA concentration in milk was not different between early and established lactation, while milk fat yield was drastically reduced on d 4 and 5 of trans-10, cis-12 CLA infusion in mid lactation cows, but unaltered in early lactation. Further, NEFA levels were nearly 3 fold higher in early lactation than in mid lactation, providing further evidence that increased circulating NEFAs in early lactation are unlikely to be the source of the mammary gland's decreased sensitivity during this time. Do to the variation in gene expression observed in this trial, we were unable to make any definitive conclusions as to the sensitivity of the expression of genes involved in milk lipid synthesis to CLA in early vs. mid lactation. Advisors/Committee Members: Baumgard, Lance H. (committeemember), Collier, Robert J. (committeemember), Duff, Glenn C. (committeemember).

Subjects/Keywords: Dairy; Milk Fat Depression; Conjugated Linoleic Acid

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Moore, C. E. (2005). CONTROLLED MILK FAT DEPRESSION AS A MANAGEMENT TOOL TO IMPROVE ENERGY BALANCE IN LACTATING DAIRY CATTLE . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/194107

Chicago Manual of Style (16^th Edition):

Moore, Chel Earl. “CONTROLLED MILK FAT DEPRESSION AS A MANAGEMENT TOOL TO IMPROVE ENERGY BALANCE IN LACTATING DAIRY CATTLE .” 2005. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/194107.

MLA Handbook (7^th Edition):

Moore, Chel Earl. “CONTROLLED MILK FAT DEPRESSION AS A MANAGEMENT TOOL TO IMPROVE ENERGY BALANCE IN LACTATING DAIRY CATTLE .” 2005. Web. 07 Mar 2021.

Vancouver:

Moore CE. CONTROLLED MILK FAT DEPRESSION AS A MANAGEMENT TOOL TO IMPROVE ENERGY BALANCE IN LACTATING DAIRY CATTLE . [Internet] [Doctoral dissertation]. University of Arizona; 2005. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/194107.

Council of Science Editors:

Moore CE. CONTROLLED MILK FAT DEPRESSION AS A MANAGEMENT TOOL TO IMPROVE ENERGY BALANCE IN LACTATING DAIRY CATTLE . [Doctoral Dissertation]. University of Arizona; 2005. Available from: http://hdl.handle.net/10150/194107

University of Arizona

10. Puthenparampil Alex, Abraham. Effects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cows .

Degree: 2009, University of Arizona

URL: http://hdl.handle.net/10150/193425

► Six primiparous Holstein cows were assigned to a half udder design (n=6) 40 days prior to parturition. Beginning at parturition, one udder half was milked… (more)

Subjects/Keywords: Bovine lactation; Milking frequency; Udder half experiment

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Puthenparampil Alex, A. (2009). Effects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cows . (Masters Thesis). University of Arizona. Retrieved from http://hdl.handle.net/10150/193425

Chicago Manual of Style (16^th Edition):

Puthenparampil Alex, Abraham. “Effects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cows .” 2009. Masters Thesis, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/193425.

MLA Handbook (7^th Edition):

Puthenparampil Alex, Abraham. “Effects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cows .” 2009. Web. 07 Mar 2021.

Vancouver:

Puthenparampil Alex A. Effects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cows . [Internet] [Masters thesis]. University of Arizona; 2009. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/193425.

Council of Science Editors:

Puthenparampil Alex A. Effects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cows . [Masters Thesis]. University of Arizona; 2009. Available from: http://hdl.handle.net/10150/193425

University of Arizona

11. Hernandez, Laura L. Characterization of the Bovine Mammary Gland Serotonergic System .

Degree: 2007, University of Arizona

URL: http://hdl.handle.net/10150/196049

► Previous research indicates the presence of a feedback inhibitor of lactation (FIL) in milk (Peaker and Wilde, 1996). Recently, tryptophan hydroxylase I (TPH1), the rate-limiting… (more)

▼ Previous research indicates the presence of a feedback inhibitor of lactation (FIL) in milk (Peaker and Wilde, 1996). Recently, tryptophan hydroxylase I (TPH1), the rate-limiting enzyme in serotonin (5-HT) biosynthesis, was identified in the mouse mammary gland and to be regulated by prolactin (PRL). Furthermore, 5-HT was present in rodent milk and addition of 5-HT to in vitro mammary cultures and in vivo administration of 5-HT to lactating mice reduced milk protein synthesis. Studies were conducted to determine the presence of the enzymatic machinery necessary to produce 5-HT in the bovine mammary gland, the presence of specific 5-HT receptors within the bovine mammary gland, the effects of 5-HT and non-selective and selective receptor antagonists on milk protein gene expression in cultures of primary bovine mammary epithelial cells (BMEC), and to determine the effects of intra-mammary infusions of 5-HT and a non-selective 5-HT receptor antagonist on milk production and composition in lactating dairy cows. Tryptophan hydroxylase I, aromatic amino acid decarboxylase (AADC) and the 5-HT reuptake transporter (SERT) were detected in lactating bovine mammary tissue by qRT-PCR and immunohistochemical staining. Additionally, mRNA for the 5-HT 1B, 2A, 2B, 4 and 7 receptors were detected in bovine mammary tissue as well as BMEC by qRT-PCR and in situ hybridization. Tryptophan hydroxylase I mRNA is in BMEC and up-regulated by PRL. Serotonin down-regulates milk protein gene expression but has not apparent effects on apoptosis and methysergide, ritanserin, SB-224289, and pimozide (receptor antagonists) increased milk protein gene expression in BMEC. Intra-mammary 5-HT infusions decreased overall milk yield in late-lactating dairy cows by 11.1%. Intra-mammary infusions of METH increased overall milk yield by 10.9%. In conclusion, the enzymatic machinery for 5-HT biosynthesis and uptake, as well as receptors involved 5-HT signaling are present in the bovine mammary gland. Furthermore, 5-HT appears to be a FIL in the bovine, but further research regarding its cellular mechanism of action and the location of its receptor populations should be conducted. Advisors/Committee Members: Collier, Robert J (advisor), Baumgard, Lance H (advisor), Horseman, Nelson D. (committeemember), Limesand, Kirsten H. (committeemember), Goll, Darrel E. (committeemember).

Subjects/Keywords: Nutritional Sciences

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hernandez, L. L. (2007). Characterization of the Bovine Mammary Gland Serotonergic System . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/196049

Chicago Manual of Style (16^th Edition):

Hernandez, Laura L. “Characterization of the Bovine Mammary Gland Serotonergic System .” 2007. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/196049.

MLA Handbook (7^th Edition):

Hernandez, Laura L. “Characterization of the Bovine Mammary Gland Serotonergic System .” 2007. Web. 07 Mar 2021.

Vancouver:

Hernandez LL. Characterization of the Bovine Mammary Gland Serotonergic System . [Internet] [Doctoral dissertation]. University of Arizona; 2007. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/196049.

Council of Science Editors:

Hernandez LL. Characterization of the Bovine Mammary Gland Serotonergic System . [Doctoral Dissertation]. University of Arizona; 2007. Available from: http://hdl.handle.net/10150/196049

University of Arizona

12. Zimbelman, Rosemarie Burgos. Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle .

Degree: 2008, University of Arizona

URL: http://hdl.handle.net/10150/195322

► Two strategies to reduce impact of heat stress on high producing dairy cows were examined. The first was to recalculate the temperature-humidity index (THI) using… (more)

▼ Two strategies to reduce impact of heat stress on high producing dairy cows were examined. The first was to recalculate the temperature-humidity index (THI) using high producing dairy cows under diurnal summer conditions. This re-evaluation confirmed that current THI values underestimate the severity of heat stress levels. Therefore, cooling of dairy cattle during warm summer months should begin at a THI of 68. Previously, a THI equal to or greater than 72 has been used to define onset of heat stress. This study demonstrated that a THI greater than or equal to 68 is sufficient to increase body heat storage, respiration rate, skin evaporative heat loss, declines in feed intake and milk yield. A second objective involved three studies carried out to evaluate use of niacin in dairy cow rations to improve evaporative heat loss and resistance to heat stress. Niacin is known to cause intense vasodilation in human and lab species. We hypothesized that increasing vasodilation would improve evaporative heat loss in dairy cows. In the first niacin study, supplementation of lactating dairy cows with an encapsulated rumen by-pass form of niacin (NIASHURE™; Balchem Corporation, New Hampton, NY) at a dose of 12 g/d proved effective in alleviating some affects of heat stress during mild thermal stress. We hypothesized that encapsulated niacin would induce vasodilation effects documented in humans and lab animals increasing evaporative heat loss. Past research demonstrated that the possible mechanism for vasodilation affects seen by niacin were most likely due to prostaglandin D secretions. Niacin may act through increased prostaglandin D and E production and secretion by Langerhans cells which then act upon vascular endothelial prostaglandin D receptors to increase vasodilation. No studies have evaluated impact of encapsulated niacin on milk yield and composition during periods of thermal stress under commercial dairy conditions. The objective of the last study was to examine the effects of encapsulated niacin during heat stress on milk production and composition as well as core body temperatures under commercial conditions. Advisors/Committee Members: Collier, Robert J (advisor), Baumgard, Lance H (committeemember), Duff, Glenn C (committeemember), Bilby, Todd R (committeemember), Foster, Billye (committeemember).

Subjects/Keywords: Heat stress; niacin; temperature humidity index; THI

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zimbelman, R. B. (2008). Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle . (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/195322

Chicago Manual of Style (16^th Edition):

Zimbelman, Rosemarie Burgos. “Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle .” 2008. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/195322.

MLA Handbook (7^th Edition):

Zimbelman, Rosemarie Burgos. “Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle .” 2008. Web. 07 Mar 2021.

Vancouver:

Zimbelman RB. Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle . [Internet] [Doctoral dissertation]. University of Arizona; 2008. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/195322.

Council of Science Editors:

Zimbelman RB. Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle . [Doctoral Dissertation]. University of Arizona; 2008. Available from: http://hdl.handle.net/10150/195322

University of Arizona

13. Annen, Ehrin Lea. EVALUATION OF THE EFFECTS OF CONTINUOUS MILKING, BOVINE SOMATOTROPIN, AND PROSTAGLANDIN E2 ON SUBSEQUENT MILK PRODUCTION, MILK COMPOSITION, MAMMARY GENE EXPRESSION, AND MAMMARY CELL TURNOVER IN DAIRY CATTLE.

Degree: 2005, University of Arizona

URL: http://hdl.handle.net/10150/195770

► Previous research has shown that dairy cows require a dry period of at least 40 d for maximal milk yield in the subsequent lactation. Reducing… (more)

▼ Previous research has shown that dairy cows require a dry period of at least 40 d for maximal milk yield in the subsequent lactation. Reducing the dry period requirement could prove beneficial to animal health and dairy profitability if subsequent milk yield was not reduced. Studies were conducted to evaluate the effects of continuous milking (CM) and hormonal treatments on milk yield, mammary epithelial cell (MEC) turnover during late gestation and early lactation, and mammary gene expression in dairy cows. A commercial trial using primiparous and multiparous cows demonstrated equal milk yields in bST-supplemented, CM and 60-d dry (CTL) multiparous cows, but lower milk yields in bST-supplemented CM, primiparous cows treated with bST. Subsequent experiments evaluated mammary development requirements during the dry period in primiparous cows and methods of rescuing milk yield. MEC growth was lower in CM glands during most of late gestation. Maintenance of lactation in CM glands resulted in a marked reduction in the MEC turnover process that occurs in the early dry period. In the last 20 d of gestation, MEC growth remained reduced in CM glands. By the last week of gestation, MEC growth was 50% less in CM tissue vs. CTL tissue. MEC apoptosis was unaffected by CM during the last 20 d of gestation, but a premature decrease in early lactation apoptosis occurred in CM glands at 7 d postpartum. Mammary gene expression demonstrated bax and insulin-like growth factor binding protein 5 are involved in apoptosis and cyclin D1, CCAT/enhancer binding protein-β, and bcl2 are involved in mammary development. Ultrastructure of CM tissue revealed large populations of resting or involuting alveoli by d 20 postpartum, whereas CTL glands had a homogenous population of secretory alveoli. Collectively, these data suggest that a 40-53% reduction in milk yield in CM glands is caused by reductions in MEC renewal and reduced secretory capacity. Treatments (bST, prostaglandin E2) to stimulate milk synthesis or MEC growth in CM primiparous glands were unsuccessful. In conclusion, primiparous cows continue to require a 60-d dry period, but multiparous cows are good candidates for short dry periods, and potentially no dry period. Advisors/Committee Members: Collier, Robert J (advisor), McGuire, Mark A. (committeemember), Baumggard, Lance H. (committeemember), Vicini, John L. (committeemember), Hadsell, Darryl L. (committeemember), Weinert, Ted A. (committeemember).

Subjects/Keywords: continuous milking; mammary epithelial cell

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Annen, E. L. (2005). EVALUATION OF THE EFFECTS OF CONTINUOUS MILKING, BOVINE SOMATOTROPIN, AND PROSTAGLANDIN E2 ON SUBSEQUENT MILK PRODUCTION, MILK COMPOSITION, MAMMARY GENE EXPRESSION, AND MAMMARY CELL TURNOVER IN DAIRY CATTLE. (Doctoral Dissertation). University of Arizona. Retrieved from http://hdl.handle.net/10150/195770

Chicago Manual of Style (16^th Edition):

Annen, Ehrin Lea. “EVALUATION OF THE EFFECTS OF CONTINUOUS MILKING, BOVINE SOMATOTROPIN, AND PROSTAGLANDIN E2 ON SUBSEQUENT MILK PRODUCTION, MILK COMPOSITION, MAMMARY GENE EXPRESSION, AND MAMMARY CELL TURNOVER IN DAIRY CATTLE. ” 2005. Doctoral Dissertation, University of Arizona. Accessed March 07, 2021. http://hdl.handle.net/10150/195770.

MLA Handbook (7^th Edition):

Annen, Ehrin Lea. “EVALUATION OF THE EFFECTS OF CONTINUOUS MILKING, BOVINE SOMATOTROPIN, AND PROSTAGLANDIN E2 ON SUBSEQUENT MILK PRODUCTION, MILK COMPOSITION, MAMMARY GENE EXPRESSION, AND MAMMARY CELL TURNOVER IN DAIRY CATTLE. ” 2005. Web. 07 Mar 2021.

Vancouver:

Annen EL. EVALUATION OF THE EFFECTS OF CONTINUOUS MILKING, BOVINE SOMATOTROPIN, AND PROSTAGLANDIN E2 ON SUBSEQUENT MILK PRODUCTION, MILK COMPOSITION, MAMMARY GENE EXPRESSION, AND MAMMARY CELL TURNOVER IN DAIRY CATTLE. [Internet] [Doctoral dissertation]. University of Arizona; 2005. [cited 2021 Mar 07]. Available from: http://hdl.handle.net/10150/195770.

Council of Science Editors:

Annen EL. EVALUATION OF THE EFFECTS OF CONTINUOUS MILKING, BOVINE SOMATOTROPIN, AND PROSTAGLANDIN E2 ON SUBSEQUENT MILK PRODUCTION, MILK COMPOSITION, MAMMARY GENE EXPRESSION, AND MAMMARY CELL TURNOVER IN DAIRY CATTLE. [Doctoral Dissertation]. University of Arizona; 2005. Available from: http://hdl.handle.net/10150/195770

Open Access Theses and Dissertations