Growth and carcass characteristics of lambs grazing cowpea, sudangrass or fed in drylot

Abstract

A trial was conducted (1990–1993) to compare growth and carcass characteristics of lambs grazing cowpea with those lambs grazing sudangrass or fed corn/soybean meal or corn/whole cottonseed in drylot. The trial was conducted in the Midwest region of the USA from the end of July (mid summer) until the middle of October (fall) of each year. Each trial consisted of 48 lambs that were divided equally into 12 lambs per treatment. Total gain of lambs grazing cowpea was 14.2 ± 0.45 kg which was greater ( P < 0.05) than that of lambs grazing sudangrass (6.0 ± 0.41 kg), fed a 16% CP corn/soybean meal ration (11.1 ± 0.42 kg), or fed a 16% CP corn/whole cottonseed ration (10.4 ± 0.42 kg). Lambs grazing cowpea had greater ( P < 0.05) carcass weight (22.5 ± 0.44 kg), dressing percentage (50.0 ± 0.54) and larger loineye area (17.2 ± 0.44 cm 2) than lambs grazing sudangrass (15.5 ± 0.44 kg, 41.3 ± 0.54%, 13.9 ± 0.44 cm 2), fed corn/soybean meal (20.6 ± 0.44 kg, 47.7 ± 0.54%, 14.8 ± 0.44 cm 2), or fed corn/whole cottonseed (19.1 ± 0.44 kg, 43.7 ± 0.54%, 14.4 ±0.44cm 2). Lambs grazing cowpea did not differ ( P > 0.05) from drylot lambs in backfat, retail cuts, kidney-pelvic fat percentage, live weight, and yield grade. In conclusion, cowpea can be used as an alternative feed source for finishing lambs during the summer months and early fall in the Midwest region of the USA.