Livestock undergo various kinds of stress such as physical, nutritional, chemical, psychological and thermal stress. Among all thermal stress is most concerning now a day in the ever changing climatic scenario. Thermal stress redistributes the body resources including protein and energy at t he cost of decreased growth, reproduction, production and health. Goats (Capra hircus) are relatively resistant to harsh environmental conditions. Thermal stress stimulates sort of complex responses which are fundamentals in the preservation of cell survival. Physiological responses to thermal stress are rectal temperature, respiration rate, heart rate, skin temperature; hormonal changes in terms of thyroxin, tri-iodothyronine, cortisol, electrolyte concentration; hematological responses like hemoglobin level and packed cell volume. Biochemical responses include changes in antioxidants level, plasma or serum enzymes and metabolites like blood glucose, total cholesterol level. At molecular level changes in gene expression of heat shock proteins and many other proteins ensure protections. Altogether these physiological, biochemical and molecular responses makes the goats to survive in harsh environment.
Key words: Goat, Thermal stress, thyroxin, serum enzymes, heat shock proteins