Percent and Solubility of Protein in Complete Feeds for Holstein Calves to Age 12 Weeks

Abstract

In study of the influence of amount and solubility of dietary protein on calf performance, five male and three female Holstein calves were assigned at birth to each of six diets in a 3×2 factorial design. Formulations were for three percents of crude protein in dry complete feeds, each at relatively high and low protein solubilities. Analyzed percent protein in dry matter and percent soluble nitrogen in the six feeds were: 1) 13.0, 31.3; 2) 12.6, 20.1; 3) 14.0, 21.2; 4) 15.3, 14.2; 5) 17.6, 18.0; and 6) 18.1, 12.8. Calves were fed their assigned diets for ad libitum intake from 1 to 12 wk. Fermented colostrum diluted 1:2 with water was fed at 5% of initial body weight twice daily for 4 wk, then once daily to 5 wk. Average daily dry matter intakes and average daily gains were 1.36, .53; 1.24, .43; 1.46, .53; 1.61, .62; 1.64, .64; and 1.52, .62kg for diets 1 to 6. Feed intake and growth were reduced at the lowest dietary protein percentages. There was little effect of nitrogen solubility, except for a protein solubility interaction on weight gain. This was expressed inconsistently on only the low and medium protein diets. Digestibilities measured during wk 13 were similar. Efficiency of nitrogen utilization was reduced as dietary protein increased.