Effect of Supplemental Chromium, Vitamin E and Selenium on Biochemical and Physiological Parameters of Holstein Friesian Calves under Heat Stress.

Background: Heat stress has been a major concern in tropical, sub-tropical and arid areas affecting the performance of farm animals. Along with vitamin E and Selenium, chromium is gaining importance in combating heat stress. Methods: Twenty-four calves of 7-8 months old with an average body weight of 172.79±4.39 kg were distributed randomly into four dietary treatment groups (T0, T1, T2 and T3). The calves of control group (T0) were fed on basal diet i.e. total mixed ration (TMR). The basal diet of T1, T2 and T3 on per kg DM basis were supplemented vitamin E (500 IU) + selenium (0.3 mg), chromium propionate (0.5 mg) and chromium propionate (0.5 mg) + vitamin E (500 IU) + selenium (0.3 mg), respectively. Ambient air temperature and humidity were measured for calculation of THI. Blood samples were collected fortnightly and the rectal temperature (RT), respiration rate (RR) and pulse rate (PR) of all the experimental animals were recorded twice daily to study the biochemical and physiological parameters. Result: Supplementation of chromium along with vitamin E and selenium decreased significantly (P<0.05) the cortisol levels and increased the albumin concentration. Chromium supplemented groups (T2 and T3) showed greater (P<0.05) increase in mean total protein concentration. A significant reduction in RT was observed in all the supplemented groups compared to control. Whereas, the PR and RR differed significantly in T3 group compared to control. [ABSTRACT FROM AUTHOR]