Article
Physiological Changes during Thermal Stress in Buffalo Rachana Sharma1, Subrat Kumar Dash1 and Gurpreet Singh2 1
Assistant Professor, 2Associate Professor, Department of Veterinary Physiology and Biochemistry College of veterinary Science, Rampura Phul Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana
One of the greatest challenges facing producers and livestock around the world is heat stress. Heat stress strongly affects animal bioenergetics, with adverse effects on the performance and well-being of livestock. Heat stress is one of the most important stressors in hot regions of the world and adaptation to heat stress requires the physiological integration of many organs and systems viz. endocrine, cardio respiratory and immune system. Buffalo are more vulnerable to suffer heat stress when exposed to radiation and access to a wallow or cooling shower. They are less tolerant of heat and cold extremes than cattle of different breeds. Despite the buffalo's body temperature being lower than that of the cows, its black skin absorbs too much heat and the density of sweat glands in its skin is only one-sixth that of the cow's skin. Buffalo are at greater risk of heat stress due to sweat glands, dark color and sparse hair on the surface of the body. Moreover the sweat glands of buffalo skin have a low blood supply. The number of sweat glands per unit area of skin is about one third of that of cattle and the thickness of corneal layer and epidermis is about double that of cattle. This suggests that buffalo like to wallow in the water when temperatures and humidity are high. There is general agreement throughout the literature that buffalo are insufficiently heat tolerant and reports indicate that milk yield, growth and fertility are all reduced during periods of high ambient temperature. Heat
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stress represents one of the most factors for impairment of infertility in tropical and subtropical countries and need effective applicable strategy to beat the harmful effects of heat stress. Regulation of blood heat during this way affect feed intake, reproduction, and milk production. When animals are exposed to stress for long duration (chronic stress), they try to acclimatize in the adverse condition. Acceleration involves phenotypic responses to environmental changes, which are reflected in hormonal signals, and also changes in target tissue response to hormonal stimuli. The time required for accretion varies according to the type of tissue, and changes in metabolism in response to heat stress over a few days to several weeks, for example. Alterations in physiological responses to thermal stress was found to be within 24-48 h within the Egyptian buffaloes to permit acclimatization of the animal against severe condition under artificial condition at 40°C and 25°C. In Asia high environmental temperature, hot humid summer and dr y seasons, has led to low and inconsistent availability of feed and n u t r i e n t s t h ro u g h o u t t h e y e a r ; therefore, producing adverse effect on rumen metabolism as well as production performance of buffalo. However, many technologies are required to improve milk production of dairy cattle in the tropics. Many studies are wiped out attempting to enhance dairy productivity by management strategies in high environmental
temperatures. Environmental modification is that the commonest to scale back the impacts of heat for increase milk production, for instance water spray with fans or evaporative cooling system. Experimental evidence has indicated that for maintaining proper homeothermy, the buffalo should be provided with a wall or shower during the summer months and drafts from the cold should be avoided during the winter months. Buffalo is well suited to hot and humid climates and muddy terrain, but they exhibit signs of major distress when exposed to direct solar radiation or working in the sun during hot weather. This is often because buffalo bodies absorb radiation to their dark skin and sparse coat or hair, and additionally thereto they possess a less efficient evaporative cooling system thanks to their rather poor sweating ability. Exposure to buffalo at high ambient temperatures leads to drastic changes in biological functions, including depression in feed intake, efficiency, and utilization, disturbances in the m e t a b o l i s m o f w a t e r, p r o t e i n , energy, and minerals, changes in enzymatic responses, hormonal secretions, and blood contains metabolites. Studies conducted to improve management using the cooling system and feed management have helped reduce some of the negative effects of heat stress on buffalo production, however, productivity during the summer continues to decline.
Dairy Planner | Vol. 18 | No. 1 | January 2021
