In the first experiment, 132 Jersey calves were assigned to one of three diets on three farms. Diet 20/20, 28/25, and 28/20 were milk replacers (MR) consisting of 20%, 28%, and 28% CP, and 20%, 25%, and 20% fat, respectively. Diet 20/20 was reconstituted at 10% DM solids, whereas diets 28/25 and 28/20 were reconstituted at 12.5% DM solids. Body weight, body length, hip height, wither height, heart girth, and hip width were measured weekly. An initial plasma sample was analyzed for IgG concentration to test for passive immunity. Calves remained on study for 8 wk.
Body weight gain, ADG, total weight gain, and stature measurements were greatest for calves fed 28/25 and lowest for calves fed diet 20/20, whereas calves fed 28/20 were intermediate.
In the second experiment, 70 calves were assigned to one of two treatments. Calves included purebred Holsteins, Jerseys, and crossbred reciprocals. Calves were assigned to diet 20/20, which was reconstituted to 10% DM solids or diet 28/20, which was reconstituted to 13% DM solids. Body weight, body length, hip and wither heights, heart girth, and hip width were measured weekly. Plasma samples were collected weekly for analysis of PUN, glucose, and total proteins. Body weight gain, ADG, and total weight gain were greatest for calves fed 28/20 and least for calves fed diet 20/20. Therefore, feeding calves a 20/20 MR at 10-15% of their BW results in lower BW gain, ADG, total weight gain, and stature measurements.
