EFFECTS OF HEAT STRESS ON PHYSIOLOGICAL TRAITS IN SHEEP
Cagrï Kandemir, Nedim Koşum, Turgay Taşkin
Ege University, Faculty of Agriculture, Department of Animal Science, 35100 Bornova, Izmir, Turkiye
cagri.kandemir@ege.edu.tr
Sheep husbandry in tropical and sub-tropical regions tends to breed throughout the year, although the sexual activity is restricted to a certain extent to the summer months. In such areas, a high ambient temperature is the major constraint on animal productivity. This effect is aggravated when heat stress is accompanied by high ambient humidity. Exposure of sheep to elevated temperatures results in a decrease of body weight, average daily gain, growth rate and body total solids. The possible mechanisms involved in inducing the biological changes in heat-stressed sheep could have definite applications. Growth in young animals, the increase in live body weight, is controlled genetically and environmentally. The available nutrients, hormones and enzymes, as well as, elevated ambient temperatures are considered as some of the environmental factors that can influence daily gain. During the early stage of embryonic life, the total cell number and placentome size were greatly reduced and the cell size only slightly decreased by exposure to warm temperatures, compared to thermo-neutral temperatures. This occurred at the time of examining aspects of placental protein and energy metabolism of pregnant ewes during middle and late gestation. The effect of heat is aggravated when heat stress is accompanied with high ambient humidity
Keywords: sheep; heat stress; welfare; milking management
|
