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You searched for +publisher:"University of Arizona" +contributor:("Bilby, Todd R"). Showing records 1 – 2 of 2 total matches.

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University of Arizona

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

Degree: 2012, University of Arizona

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

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

APA (6th 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 (16th 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 05, 2021. http://hdl.handle.net/10150/265340.

MLA Handbook (7th Edition):

Rungruang, Sunthorn. “Evaluation of Dietary Niacin and Supplemental Cooling for Alleviation of Heat Stress in Lactating Dairy Cows .” 2012. Web. 05 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 05]. 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

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

Degree: 2008, University of Arizona

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

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

APA (6th 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 (16th Edition):

Zimbelman, Rosemarie Burgos. “Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle .” 2008. Doctoral Dissertation, University of Arizona. Accessed March 05, 2021. http://hdl.handle.net/10150/195322.

MLA Handbook (7th Edition):

Zimbelman, Rosemarie Burgos. “Management Strategies to Reduce Effects of Thermal Stress on Lactating Dairy Cattle .” 2008. Web. 05 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 05]. 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

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