Effect of dietary chromium, vitamin E and selenium supplementation on growth performance and cost economics of Holstein Friesian calves under heat stress

Abstract

A study was conducted in Holstein Friesian calves with an average body weight 172.79 ±4.39 kg and aged 7-8 months for a period of 90 days during the months of peak summer (April 15-July 15). Calves were distributed randomly into four dietary treatment groups of six animals each considering their body weights. The treatment groups were T0 (control), T1, T2 and T3. The calves of control group were fed total mixed ration (TMR). Other treatment groups were fed with TMR supplemented with chromium propionate @ 0.5mg/kg DM (T1); vitamin E @ 500 IU/animal/day and selenium @ 0.3 mg/kg DM (T2) and chromium propionte @ 0.5 mg/kg DM, vitamin E @ 500 IU/animal/day and selenium @ 0.3 mg/kg DM (T3). The mean THI values were 75.10±0.42 in the morning and 80.01 ±0.64 in the afternoon indicating that the animals were under mild to moderate heat stress. High THI was found in the month of May with a THI value 83.48±1.41 in the afternoon. Dry matter intake (kg/d), DMI per 100 kg BW and per kg BW 0.75 were comparable among the calves fed different experimental rations. DMI per kg weight gain was significantly (P<0.05) lesser in T3 calves. Weight gain and the average daily gain were significantly (P<0.05) higher with supplemented rations compared to control ration. Supplemented rations were found to be economic. However chromium fed rations proved to be more profitable