The Effect of Age of the Calf on the Availability of Nutrients in Vegetable Milk-Replacer Rations

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Abstract
Four male calves were assigned to a 4 x 4 Latin square metabolism experiment to determine the apparent digestibility of 2 vegetable milk replacers, evaporated milk, and raw whole at 10, 18, 26, and 34 days of age. Fecal collections were made by a simplified bag technique. N, Ca, and P balances were determined. Mean coefficients of digestibility of whole milk were: dry matter, 94.8; protein, 90.1; ether extract, 97.8; and NFE, 97.1. Dry matter of evaporated milk 76.8% digested by 10- to 14-day-old calves and 90.0% by 19- to 30-day-old calves. Dry matter of the milk replacers increased from 25.0% for 10- to 14-day-old calves to 75.4% for 26- to 38-day-old calves. The most digestible fraction was the NFE and the least digestible, protein. The protein of the milk replacers was markedly less digestible than that of whole milk or evaporated milk. Protein of whole milk was less digestible by 10- to 14-day-old calves than in subsequent periods; maximum digestion of evaporated milk was not reached until calves were 19-22 days of age. N, Ca, and P retention was greater for the calves fed whole milk than for those fed evaporated milk or milk replacers. N and P balances were low or negative in 10- to 22-day-old-calves fed milk replacers, but older calves had positive balances. Milk replacers were not utilized satisfactorily until the calf was approximately 25 days of age.