Effects of Supplementation Strategies on Performance of Early-Weaned Calves Raised on Pastures

Abstract

ABSTRACT The objective of these experiments was to investigate the effects of supplementation and grazing strategies on the performance of early-weaned calves grazing cool-season and warm-season grasses in Florida. In Exp. 1, 40 calves were early-weaned (92 ± 15 d of age) and randomly allocated to 8 ryegrass (Lolium multiflorum) pastures (January to May) and then moved onto 8 stargrass (Cynodon nlemfuensis) pastures (May to August). Two supplement treatments (1.0% BW) were randomly allotted to pastures (4 pastures/treatment), consisting of 1) soybean hulls, or 2) a blend of soybean hulls and cottonseed meal (80:20). Supplement treatment did not impact ADG during ryegrass grazing; however, calves grazing stargrass and receiving supplemental soybean hulls + cottonseed meal had greater ADG than calves receiving soybean hulls alone. In Exp. 2, 24 early-weaned calves (89 ± 20 d of age) were randomly assigned 1 of 2 management treatments from January to April (3 pastures/treatment and 4 calves/pasture). Treatments consisted of 1) bahiagrass (Paspalum notatum) + 2.0% BW supplementation, or 2) ryegrass + 1.0% BW supplementation. Supplements were an 80:20 blend of soybean hulls and cottonseed meal. Herbage mass and allowance were similar among treatments, but ryegrass had greater nutritive value than both the bahiagrass and supplement. Consequently, calves grazing ryegrass had greater ADG. In conclusion, the addition of cottonseed meal to a soybean hull supplement increased performance of early-weaned calves grazing summer warm-season grasses, but not while grazing winter ryegrass. In addition, early-weaned calves grazing warm-season grasses during the winter had decreased performance when compared with calves grazing ryegrass, despite increased supplementation.