Short Communication: Differential Endocrine and Antioxidant Responses To Heat Stress Among Native and Crossbred Cattle.

Abstract: The present study was undertaken to evaluate the comparative effect of in-vivo heat stress on native and crossbred cattle based on specific hormone responses and antioxidant enzyme activities. Eighteen healthy cattle aged between 4 to 5 years were selected and divided into three equal groups (n= 6) with consideration of breed as Sahiwal, Tharparkar, and crossbred (Hariana× Holstein Friesian / Brown Swiss / Jersey). The temperature humidity index (THI) was calculated using temperature and relative humidity (RH) daily throughout the experimental period. Blood sampling was done during summer and winter seasons and the serum was used for the estimation of hormones like triiodothyronine, thyroxine, and cortisol. The enzymatic antioxidant activity of catalase, superoxide dismutase, glutathione peroxidase, and total antioxidant capacity were also recorded. THI values indicated that the animals under thermal stress in summer but thermoneutral in winter. During heat stress, significant higher levels of T3 and T4 were observed in native cattle than the crossbred cattle. A significantly higher (p