Vol. 10, Issue 1, Part E (2025)

Author(s): Arunasalam Singaravadivelan, Ambazamkandi Prasad, Chinnappan Balusami, Subramaniakaimal Harikumar, Vakayil Beena, Villan Lonappan Gleeja, Veerasamy Sejian and Patil Bakkesh Sachin

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<0.05). Murrah buffalo and crossbred cattle exhibited higher respiratory rate (mean RR = 80±5 breaths/min) and heart rate (mean HR = 110±8 beats/min) values after exposure, with p-values < 0.001. In contrast, Vechur maintained relatively stable physiological responses, even under stress, with lower rectal temperature and RR, all showing significant differences (p<0.05) compared to the other breeds. The findings reveal Vechur cattle's superior heat tolerance, establishing them as an ideal breed for sustainable dairy farming in hot climates.

DOI: 10.22271/veterinary.2025.v10.i1e.2037