Body Temperature In Zebu Animals

Indian livestock breeds are well adapted to topography, flora and prevailing climatic in different agro-climatic zones. Zebu breeds are smaller in size and possess lower body weight as compared to the temperate cattle breeds. Their body structure is small barrel shaped along with slender legs and augmented with unique parts like hump and dewlap. The head is held high in most zebu breeds. These breeds, which were developed for draught purpose, are well known for their ability capacity to run and swiftly move even under moist soils due to their long legs with articulate joints. The balanced fore and hind body quarters are result of small size and low volume of internal organs, which help them in propelling body and moving forward with loads at

Metabolism of livestock species is affected by ambient temperature rise and humidity levels. The magnitude of response depends upon species, breed and physical environment factors. The rectal temperature has been considered as an index of thermal balance of animal. The increase in body temperature of animals may be to an extent of 1-2 °C during normal diurnal variations and 4-5 °C during thermal exposure/work in heat. Increase in body temperature over a hot day has been considered a test of adaptability and gross deviation has been attributed to poor adaptation (Rhoad, 1944). Various other physiological processes like respiratory rate and body temperature have also been used in scoring heat tolerance/adaptability (Benezra, 1954). The necessity of heat loss to maintain thermal balance particularly during hot humid conditions force thermal distressed animals (Taurine breeds crossbreds and buffaloes) to employ open mouth panting with tongue protruded out to complement heat elimination

The ability of Sahiwal cattle to increase evaporative cooling at higher temperatures without increasing their respiratory frequency much is an important factor in establishing the heat tolerance superiority of the Sahiwal compared with the heat tolerance of Sahiwal-Holstein crossbreds (Aggarwal and Upadhyay, 1997). Zebu cattle breeds of India have special adaptive mechanisms to deal with extra heat loads of tropical climate. The mechanisms that facilitate easy transfer of heat from body without much loss of moisture are unique in Zebu and other tropical livestock species in addition to mechanisms that conserve energy for body maintenance at high temperatures. Adaptive mechanisms to deal with heat gain and loss are coat colour, length of hair coat, skin pigmentation, number of sweat glands and their secretion. The small body size with low energy requirement for maintenance and capacity to use poor quality feeds and fodders make them superior to many breeds of livestock in efficiency of feed conversion. The water recycling and economy in these animals is much more that give them higher capacity to dehydrate and withstand higher thermal