Srivastava A, Yadav P, Mahajan A, Anand M, Yadav S, Madan A K, Yadav B
Department of Veterinary Physiology, College of Veterinary Science and Animal Husbandry, Veterinary University, Mathura, 281001, UP, India.
Department of Veterinary Physiology, College of Veterinary Science and Animal Husbandry, Veterinary University, Mathura, 281001, UP, India.
J Therm Biol. 2021 Feb;96:102845. doi: 10.1016/j.jtherbio.2021.102845. Epub 2021 Jan 12.
The present study was attempted to identify an appropriate THI model and threshold THI for goats of semi-arid regions of India. Sixty non-pregnant goats each from Jamunapari and Barbari breeds were selected for the study. The study was conducted from last week of February to first week of June, during which average THI ranged between 53 and 92. Pulse rate (PR), respiration rate (RR) and rectal temperature (RT) were recorded at 1430 h on alternate days from six goats of each breed randomly during the experiment. Nine THI models were used to calculate THI. An appropriate THI model was predicted on the basis of correlation between THIs calculated from each model and physiological responses. The data of physiological parameters were linked to the THI calculated from identified THI model and threshold THI for each parameter was determined using segmented regression analysis (SegReg Software). The THI models; THI{(1.8 × Tdb+32)-[(0.55-0.0055 × RH) × (1.8 × Tdb-26.8)]} and THI{(0.8 × Tdb)+[(RH/100) × (Tdb-14.4)]+46.4)} were found to be equally appropriate for assessing environmental heat stress. Threshold THIs with respect to PR, RR and RT in Jamunapari goat were 71.78, 75.14 and 85.94, respectively and in Barbari goats, threshold THIs for PR and RR were 79.48 and 84.40, respectively. A threshold THI could not be identified for RT in Barbari goats. It can be concluded that THI and THI were the appropriate THI models for measuring environmental heat stress in goats. Results suggested that PR is the first physiological parameter which alters after the onset of heat stress and is followed by changes in RR and RT. On the basis of differential threshold THIs, it can be concluded that Barbari is better adapted than Jamunapari goats in semi-arid regions of India.
本研究旨在为印度半干旱地区的山羊确定合适的温湿度指数（THI）模型及阈值THI。从Jamunapari和Barbari品种中各选取60只非妊娠母羊用于本研究。研究于2月最后一周至6月第一周进行，在此期间平均THI在53至92之间。在实验期间，每隔一天的1430时，从每个品种的6只山羊中随机记录脉搏率（PR）、呼吸率（RR）和直肠温度（RT）。使用9种THI模型计算THI。根据每个模型计算出的THI与生理反应之间的相关性预测合适的THI模型。将生理参数数据与根据确定的THI模型计算出的THI相关联，并使用分段回归分析（SegReg软件）确定每个参数的阈值THI。发现THI模型THI{(1.8×干球温度+32)-[(0.55 - 0.0055×相对湿度)×(1.8×干球温度 - 26.8)]}和THI{(0.8×干球温度)+[(相对湿度/100)×(干球温度 - 14.4)] + 46.4}同样适合评估环境热应激。Jamunapari山羊的PR、RR和RT的阈值THI分别为71.78、75.14和85.94，Barbari山羊的PR和RR的阈值THI分别为79.48和84.40。在Barbari山羊中未确定RT的阈值THI。可以得出结论，THI和THI是测量山羊环境热应激的合适THI模型。结果表明，PR是热应激开始后第一个发生变化的生理参数，随后是RR和RT的变化。基于不同的阈值THI，可以得出结论，在印度半干旱地区，Barbari山羊比Jamunapari山羊适应性更强。
