Abstract

A grazing trial was conducted in southern North Island hill country during 1994, to determine the influence of pasture allowance during winter on cow/calf performance of 40 twin- (T) and 40 single-calf (S) bearing Friesian-cross beef cows. Groups of T and S cows were grazed at low (L), medium (M) and high (H) pasture allowances for the last 4 months of gestation. Average LW in late autumn was 467 kg, and change up to 4 weeks pre- calving was LS -7.8%, MS -2.4%, HS +1.5%, LT -8.1%, MT -3.0%, HT - 3.5%, suggesting S cows responded to a increased pasture allowance in late gestation, but T only to M and no further to H. Blood serum bOH concentration, which was used as a measure of energy status, was not influenced by allowance treatment, but T (2.2 mmol/l) had higher concentrations than S (0.9). Twinning cows had a shorter gestation length than S cows (277 vs 284 d). Twin calves were lighter at birth (30.9 vs 44.2 kg), had lower perinatal survival (73 vs 96%), and grew more slowly to 4 months of age than single calves (0.76 vs 1.11 kg/d). Our results suggest that

MG, Lambert, BP Devantier, K Betteridge, WH McMillan, and PA Pugh

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 382-385, 1996