Protein-Energy Ratios for Dairy Calves

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Abstract
Seventy-two two-day-old calves were used in an 84-day trial to study the influence of the protein-to-energy ratio in calf starters on the growth of dairy calves. Three protein levels, 14, 16, and 18% and three protein-to-energy ratios (% protein; estimated net energy), 1:46, 1:48, and 1:50 were fed. The protein levels were adjusted through the use of urea and soybean oil meal and the energy levels were adjusted through the incorporation of stabilized animal fat. Ground alfalfa hay was incorporated as 25% of all starters. The starters were made into 3/16-inch pellets. Results of this study showed very little difference in the growth rate of calves fed the 14, 16, or 18% protein calf starters. The ratio of protein to energy appeared to influence growth rates, particularly after the calves were off milk-feeding. As the protein-to-energy ratio increased, the body weight gains of the calves decreased, averaging 1.52, 1.51 and 1.28 lb. per day for the 1:46, 1:48, and 1:50 ratio, respectively. This decrease in growth rate was evident at all protein levels. The average daily gain of the calves fed the ratio of 1:50 was significantly less than the weight gain of calves fed the two other rations. Results of this study indicate that the optimum protein-to-energy ratio would be 1:46 or slightly less.