This study aimed to determine the thermoneutral zone (TNZ) in Sahiwal zebu calves under controlled environmental conditions. The experiment was conducted in the psychrometric chamber in two phases on six calves aged 8 to 11 months and weighing 120 to 150 Kg at the beginning of the experiment. In the first phase, to determine the upper critical temperature (UCT), calves were kept for six hours per day over 10 consecutive days at six different increasing temperature ranges from 24 to 39 °C with corresponding temperature humidity indexes (THIs) between 67 and 93. In the second phase, the same calves were exposed to decreasing temperatures (24 °C to 9 °C) to determine the lower critical temperature (LCT). On the 10th day of each temperature exposure, physiological parameters were recorded, and blood sampling was done. Using segmented regression analysis (SegReg standard version software), the breakpoints in linear regressions for different parameters with respect to exposure temperatures and THI in both phases were separately determined and considered to be the critical temperatures and threshold THIs, respectively. The LCT and UCT were arranged on a temperature scale. The temperature range between the highest LCT and the lowest UCT with respect to different studied parameters was considered as the thermoneutral zone (TNZ). The highest LCT was observed for granulocyte % at 18.15 °C, whereas the lowest UCT was observed at 30.10 °C (THI: 82.35). It was found that the LCT and UCT varied with respect to different physiological parameters. A subset of parameters displayed identifiable LCT and UCT values, while some did not exhibit clear breakpoints. The respiration rate (RR), rectal temperature (RT), total leukocyte count (TLC), granulocyte%, aspartate amino-transferase (AST), Alanine amino-transferase (ALT), cortisol, IL6, and HSP90 were the sensitive parameters for both cold stress and heat stress, whereas pulse rate (PR), triglyceride, and urea were only sensitive to cold stress, and erythrocytic parameters and lymphocyte % were sensitive only to heat stress. Based on heat stress responses, the UCT for zebu calves was identified at approximately 30.10 °C (THI: 82.35), whereas based on cold stress responses, the LCT for zebu calves was identified at approximately 18.15 °C. Thus, the TNZ for zebu calves can be proposed to be between 18.15 and 30.10 °C. These findings can inform climate-adaptive housing and management strategies for improving calf welfare and productivity in subtropical environments.

The world population is growing at an unprecedented rate, and so is the requirement for food. To keep up with this demand, the agricultural industry has adopted a more industrialized approach to food production. However, this has led to the emergence of new diseases and increased mortality in animals, which can have a devastating impact on the industry. It is essential to ensure the health and welfare of animals to maintain sustainable food production. The importance of animal health in food production is complimentary to the risks associated with animal diseases, and the measures that can be taken to mitigate these risks. From vaccination programs to biosecurity measures, we will explore the best practices to ensure the safety and sustainability of our food supply chain.

Background: The present investigation was envisaged to find out the impact of extreme hot environmental temperature period (ETP) on marker enzymes of carbohydrate metabolism in male and female non-descript sheep of various age groups i.e. 4 to 13 months from arid tracts of Rajasthan. Glucose-6-phosphate dehydrogenase (G-6-PDH) and malate dehydrogenase (MDH) marker enzymes of carbohydrate metabolism were considered for study. Methods: During the period October 2016-June 2017 blood samples were collected to harvest sera for spectrophotometric method from 240 healthy animals selected from private slaughter house during moderate and extreme hot environmental temperature periods (ETPs). The mean values of markers attained during moderate ETP were reckoned as the control. It was 10.00 ± 0.10 UL-1 and 42.00±1.00 respectively. Conclusion: The mean value of MDH was significantly (p≤0.05) higher while G-6-PDH significantly (p≤0.05) lowers during extreme hot temperature in comparison to moderate period. Therefore, it could be concluded that variations in enzyme markers were associated with changes in environmental temperatures. Probably ETP were able to produce a profound effect on carbohydrate metabolism in sheep. Therfore it can be suggested that during the period of extreme temperature balanced ration must be provided to the animal along with proper management to decrease the severity of temperature impact.