Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal132 001, India
Online published on 5 January, 2012.
Eight cross-bred calves (3.5m, 5.17 kg) were fed concentrate mixture and green maize supplemented with 30 g mineral mixture daily. A metabolism trial was conducted at 6 m of age. The daily feed intake and retentions (mg/kg B.wt.) were 13.05 and 1.98 for Fe, and 0.65 and 0.52 for Cu, respectively. The percentage excretion in faeces and urine were 84.50 and 034 for Fe, and 57.47 and 1.77 for Cu, respectively. The mineral balances were positive in all the animals. The experiment suggested that the feaces was the main route for Fe and Cu excretion. Fe and Cu requirments of cross-bred calves determined by multiple regression equation were 393.84 and 20.40 ppm, respectively.
