Liquid supplementation of grazing cows and calves

One hundred and one Angus cows (average weight 614 kg) and their bull calve s (average weight 213 kg) grazing improved summer pastures were used to det ermine cow and calf intake of liquid supplement, and its effect on forage i ntake and performance. Forty-seven pairs had access to a 410 g CP/kg DM mol asses-based liquid supplement in an open feeder and 54 pairs were not suppl emented. The study was conducted in southwestern Montana from July 28 to Oc tober 3, 1997. Cows consumed significantly more supplement (0.3 kg/day) tha n calves (0.1 kg/day) but both consumed 0.5 g/kg bodyweight per day. Supple mented cows gained 0.12 kg/day more (p<0.05) than unsupplemented cows; howe ver, there was no difference (p>0.10) in body condition score change. Avera ge daily gain by supplemented calves was 30% greater (p<0.01) than average daily gain by unsupplemented calves. Forage intake (g/kg body weight) by bo th supplemented cows and calves was 64% greater (p<0.01) than forage intake by unsupplemented cows and calves. There was no difference (p>0.10) in mil k intake between supplemented and unsupplemented calves. There was no diffe rence (p>0.10) in time spent at the supplement feeder between cows and calv es, averaging 5.0 min/day. Time at the feeder was lowest for 7-year-old cow s, intermediate for 6- and 8-year-old cows, and highest for 9-year-old cows (p<0.10). There was no difference (p>0.10) in supplement feeding bouts/day between age groups of cows. Calf liquid supplement intake (g/kg body weigh t) and time spent at the supplement feeder were similar to intake and time spent at the feeder by cows. Liquid supplementation increased forage intake and average daily gain by cows and calves grazing improved forages in late summer. The cost for additional weight gained by the supplemented calves w as US$ 0.33/kg and October cattle prices in Montana were US$ 1.64/kg. Liqui d supplementation was cost effective under the conditions of this study. (C ) 1999 Elsevier Science B.V. All rights reserved.