Assessment of heat tolerance in Murrah buffalo, crossbred and Vechur cattle using the dairy search index

Abstract

This study aimed to evaluate the heat tolerance of Murrah buffalo, crossbred and Vechur cattle using the Dairy Search Index (DSI). The research was conducted at the Climate Controlled Research Complex, Kerala, India. A total of 18 calves (6-12 months old), with six calves from each breed, were exposed to 42 °C and 50-55% relative humidity for 21 days, for six hours daily. Vechur exhibited the lowest DSI values across all time points (e.g., DSI = 1.5±0.2), indicating superior heat tolerance compared to Murrah (DSI = 2.3±0.3) and crossbred cattle (DSI = 2.7±0.4). Statistical analysis revealed significant differences in DSI values among the breeds (p