Vol. 10, Issue 5, Part B (2025)

Author(s): Lakshmi M, N Geetha, Balusami C, Sabin George, Bindu KA, Chinnu MV, Sachin B Patil and Athira VS

Abstract: The study evaluated the physiological responses of two indigenous goat breeds of Kerala, Attappady Black and Malabari subjected to a restricted two-hour grazing regimen during peak summer months under macro-climatic heat stress. Twelve lactating goats (N=6 per breed) were monitored over 30 days for key physiological indicators: rectal temperature (RT), respiration rate (RR), and pulse rate (PR), recorded at three time points daily (08:00, 12:00, and 16:00 hrs). Concurrently, ambient temperature, relative humidity, and Livestock-Poultry Heat Stress Index (LPHSI) values were recorded to quantify environmental stress levels. Results showed consistently elevated LPHSI values (>84), indicating significant thermal load. Both breeds exhibited increased RR and RT in response to heat stress, particularly during noon observations. Notably, Attappady Black goats demonstrated a significant reduction in RT and a delayed yet adaptive increase in RR by day 30, suggesting physiological acclimatization. No significant differences in PR were observed between or within groups. The findings highlight that Attappady Black goats possess greater adaptive potential to short-duration thermal stress, making them more suitable for climate-resilient goat farming strategies in heat-prone tropical regions.