Impact of heat stress on physiological parameters and milk composition in murrah buffalo

Abstract:

Anyone who has watched a Murrah buffalo seek shade at midday in July already knows the animal is uncomfortable but the hidden costs of that discomfort extend well beyond behaviour to measurable shifts in blood chemistry, thermoregulation, and milk composition. This research monitored 24 lactating Murrah buffaloes across four Temperature-Humidity Index (THI) classes (comfort <72, mild 72-78, moderate 79-84, severe >84) from April through October 2023 at Marmara Agricultural College, Bursa, Turkey. Respiration rate rose from 18.4 breaths/min at comfort to 61.8 at severe THI, while rectal temperature increased from 38.2 to 39.8°C. Milk yield dropped 29.8% from 8.4 to 5.9 kg/day between comfort and peak stress in June. Milk fat declined from 7.41 to 6.23%, and protein from 4.18 to 3.64% under severe stress. These findings quantify the economic and physiological toll of heat stress on Murrah buffalo and support the adoption of cooling infrastructure in Mediterranean-climate dairy systems.