Average daily gain and shade use of dairy heifers at different energy concentrate

An experiment was conducted to evaluate the effect of total digestible nutrient (TDN) concentrate feed on body weight gain and length of shade of dairy heifers in the dry season. Four dairy heifers (220±50 kg) of Holstein Friesian were randomly assigned to a Latin Square Design of 4 (treatments) x 4 (replications). Each period was 21 days consisting of 14 days of preliminary observation and 7 days for data collection. Treatments were T1 (TDN concentrate 55%), T2 (TDN concentrate 60%), T3 (TDN concentrate 65%), and T4 (TDN concentrate 70%). The variables measured in this stage were microclimate factors (air temperature, relative humidity, wind speed, and solar radiation), temperature humidity index (THI), feed intake, shade occupation, and body weight gain. The results showed that heifers had heat stress at the microclimate condition indicating that THI values ranged from 77−82. The concentrate treatment at different levels of TDN did not affect dry matter intake. The lowest dry matter intake was found in T4 treatment (7.0 kg/day). Differences in average daily gain (ADG) (P