Fish Meal or Cottonseed Meal as Supplemental Protein for Growing Holstein Steers

Twenty-three Holstein steers of 195 kg mean live weight were individually fed a complete mixed diet composed primarily of ground corn grain with either 140 g cottonseed meal or 90 g cottonseed meal plus 30 g menhaden fish meal/kg diet as the source of supplemental protein. Thirteen steers were slaughtered at 454 kg and 10 at 544 kg live weight. Steers slaughtered at 544 kg gained weight more slowly with consequent 18.2% increase in dry matter required per unit gain compared with steers slaughtered at 454 kg live weight. Steers fed the fish meal diet gained 1.34 kg/d and consumed 7.36 kg dry matter daily while steers fed the cottonseed meal diet gained 1.17 kg/d and consumed 7.40 kg dry matter daily. Dry matter consumed per unit gain was 12.6% less for steers fed fish meal diet than for steers fed cottonseed meal diet.