Complete rations utilizing hay or corn silage for dairy calves

Thirty-two Holstein and 13 Jersey heifer calves in 1974-1975 and 34 Holstein and 9 Jersey heifer calves in 1975-1976 were individually fed the following rations: (a) 1:1 ratio of hay to grain (16% crude protein), (b) 2:1 ratio of corn silage to grain plus soybean meal, and (c) 4:1 ratio of corn silage, to grain plus soybean meal from birth until 29 weeks of age. The soybean meal was added to make all rations isonitrogenous. Average daily gains (lb) for the Jerseys and Holsteins on each treatment in 1974-1975 were: (a) 1.06, 1.73; (b) 1.12, 1.82; and, (c) 1.02, 1.74 and in 1975-1976 were: (a) 1.06, 1.60; (b) .95, 1.63; and, (c) .97, 1.53. There were no significant differences in height, at withers, length, and paunch circumference in either year. Also, nine Holstein bull calves were used to determine the digestibility and retention of the complete feeds at 4, 17, and 29 weeks. Within an age group, there were no significant differences in dry matter digestibility, acid detergent fiber digestibility, acid detergent lignin digestibility, nitrogen digestibility, and phosphorous and nitrogen retention. Over time dry matter digestibility and calcium and phosphorous retention at four weeks were significantly higher than at 17 or 29 weeks with calcium and phosphorous retention being significantly higher than at 29 weeks. Nitrogen digestibility and retention were significantly higher at four weeks than for later ages. This data suggest that Holstein and Jersey calves may be raised successfully on complete feeds containing corn silage. Also as these heifers become older their rate of gain can be predicted by the amount of digestible dry matter consumed.