An experiment was carried out to findout the effect of mechanical and chemical control of heat stress on physiological reactions and blood parameters in crossbred Jersey cows during summer and south west monsoon. Eighteen early lactating crossbred Jersey cows were selected and put into three groups of six each and randomly allotted into three treatments such as housing in covered shed (T1), housing in covered shed with water spray (T2), and housing in covered shed with electrolyte supplementation (T3). Water spraying and electrolyte supplementation had a highly significant (P<0.01) effect to reduce the diurnal rise of physiological respcmses such as rectal temperature, respiration rate and pulse rate. Different seasons had a significant (P<0.05) effect on physiological responses. Water spraying (57.54 ± 2.2794 mg/dl) and electrolyte supplementation (45.63 ± 1.8477 mg/dl) had a highly significant (P<0.01) effect on the elevated blood glucose level. Significantly (P<0.01) lower (1.06 ± 0.063 ng/ml) and higher (61.68 ± 2.1634 ng/ml) level of triiodothyronine (T3) and thyroxine (T4) was observed in water sprayed group than non-sprayed groups. The mean serum electrolytes concentration was reported to be highly significant (P<0.01) in electrolyte supplemented group.
