Life Sciences Commons^™

Effects Of Acute Heat And Oxidative Stress On The Hepatic Expression Of Orexin And Its Related Receptors, Stephanie Khaldi

Graduate Theses and Dissertations

It is widely known that orexin A and B peptides as well as their receptors are expressed in the hypothalamus and distributed throughout the central nervous system, but there have been few studies regarding its presences in other parts of the body. There is now evidence that orexin (ORX) and its receptors (ORXR1/2) are present in the avian liver; however, their regulation under different environmental conditions is still unknown. In the current study, we sought to determine the effects of heat and oxidative stress using hydrogen peroxide (H2O2) and 4-hydroxynonenal (4-HNE) on the hepatic expression of ORX and ORXR1/2 in …

Effect Of Varying Rumen Degradable And Undegradable Protein On Milk Production And Nitrogen Efficiency In Lactating Dairy Cows Under Summer Conditions, Jeffrey D. Kaufman

Masters Theses

The objective is to determine the effect of reducing nitrogen input through feeding low rumen degradable protein (RDP) and rumen undegradable protein (RUP) proportions on milk production, nitrogen efficiency and metabolism in heat-stressed cows. Forty-eight mid-lactating, Holstein cows were assigned to treatments using a randomized block design in a 2x2 factorial arrangement of treatments (n = 12/treatment). Treatments included two levels of RDP (10 and 8%) and two levels of RUP (8 and 6%). From d 1 to 21, a common diet (10% RDP-8% RUP) was fed to cows followed with their respective treatment diets fed from d 22 to …

The Effect Of Heat Stress And Essential Amino Acids On Production And Metabolism Of Lactating Dairy Cattle, Kimberly Rose Kassube

Masters Theses

Heat stress (HS) causes decreases in production of lactating cattle that is only partially explained by decreases in intake. Evidence suggests that changes in energy and protein metabolism occur to cope with the impact of HS. The objective of this thesis was to determine if the effect of jugular infusion of essential amino acids (AA) ameliorated the negative effects of HS in milk production and metabolism. Twelve multiparous lactating Holstein cows were used in a crossover design to evaluate the effect of thermoneutral (THN) and HS environments along with the absence (CTL) …

Cooled Perch Effects On Performance And Well-Being Traits In Caged White Leghorn Hens, J Y. Hu, P Y. Hester, M M. Makagon, G Vezzoli, R S. Gates, Y Xiong, H W. Cheng

Department of Animal Science: Faculty Publications

We assessed the effects of chilled water cooling perches on hen performance and physiological and behavioral parameters under “natural” high temperatures during the 2013 summer with a 4-hour acute heating episode. White Leghorns at 16 wk of age (N = 162) were randomly assigned to 18 cages (n = 9) arranged into 3 units. Each unit was assigned to one of the 3 treatments through 32 wk of age: 1) cooled perches, 2) air perches, and 3) no perches. Chilled water (10◦C) was circulated through the cooled perches when cage ambient temperature exceeded 25^◦C. At the age of …

Distinct Cardiac Responses To Heat Stress Between Two Broiler Lines Identified By Transcriptome Analysis, Jibin Zhang, Carl J. Schmidt, Susan J. Lamont

Jibin Zhang

Circulating Metabolic And Reproductive Hormone Changes In Laying Hens Kept Under Various Heat-Combating Systems, Muhammad Safdar Anjum, Mansur Abdullah Sandhu, Zia Ur-Rahman, Anum Safdar

Turkish Journal of Veterinary & Animal Sciences

The objective of the present study was to observe the circulating metabolic, reproductive, and stress hormones in laying hen performance under different heat-combating systems (HCSs). A total of 500 White Leghorn pullets at 24 weeks of age were subjected to four HCSs, i.e. desert cooling (DC), water sprinkling (WS), time limit feeding (TLF), and ascorbic acid (AA) supplementation, at environmental temperatures from 32.30 to 40.80 °C with 76.40% relative humidity. Blood was collected before heat stress, at peak stress, and after heat stress to collect plasma. The results of the 24-week stress period showed significantly less circulating T3, T4, estrogen, …

Comparative Efficacy Of Antioxidant Retinol, Melatonin, And Zinc During In Vitro Maturation Of Bovine Oocytes Under Induced Heat Stress, Jafrin Ara Ahmed, Devojyoti Dutta, Nawab Nashiruddullah

Turkish Journal of Veterinary & Animal Sciences

Both A and B grade cumulus-oocyte complexes (COCs) aspirated from cattle ovaries at slaughter were matured in vitro under normal (38.5 °C) and elevated temperatures (41 °C). Maturation competence based on cumulus expansion, COC diameter, and nuclear maturation were compared with and without antioxidant supplementation incorporating 7.5 µM retinol, 1 nM melatonin, and 1.5 µg/mL zinc chloride in an oocyte maturation medium. Heat stress significantly reduced cumulus expansion by approximately 20%, while only retinol could bring a significant (P ≤ 0.05) increase. Heat stress also decreased expansion of A (approximately 50%) and B (approximately 40%) grade COC diameter. All antioxidants …

Evaluation Of Weather Information From On-Farm And Meteorological Stations To Assess Heat Stress In Dairy Cows In Southwest Kansas, A. Scanavez, L. Rocha, B. E. Voelz, L. Hulbert, L. Mendonca

Kansas Agricultural Experiment Station Research Reports

Heat stress represents a challenge for the dairy industry. In order for producers to implement appropriate management practices, it is crucial for researchers to assess the extent of heat stress to which cows are exposed during the summer. Temperaturehumidity index (THI) may be used to determine the severity of heat stress that cows are exposed to during the summer. The objective of this study was to evaluate climate conditions by calculating THI using information from: 1) an official meteorological station, 2) loggers at the pen-level, and 3) loggers at the cow-level from a commercial dairy located in southwest Kansas. Temperature-humidity …