Abstract

The aim of this study was to describe the effect of cow body condition score (BCS) on pregnancy rate, inter-calving interval, wean-ing rate and birth and weaning weights of calves. Measurements of BCS in a herd of mixed age (2-10 years), predominantly Angus, beef cows were recorded annually four times between November 2012 and March 2015, at joining/rebreeding (November), wean-ing/pregnancy diagnosis (PD, March), winter (June) and calving (August). Year influenced BCS (P<0.05) and BCS was greatest at weaning 2014. Two-year-old cows had greater BCS (P<0.05) than three-year-old and the mixed age cows. Pregnancy rate was no different (P>0.05) between BCS at calving, joining and PD. Cows that increased BCS from joining to PD had lower pregnancy rate than cows that maintained or decreased BCS during this period, although it is unclear whether this association reflects an influence of BCS on pregnancy rate, or whether the BCS change was a result of differing pregnancy status. Greater BCS at joining was associated with lower calf birth weights. Body condition score at each event was not associated with inter-calving interval or calf weaning weight. Further research is still required to determine the optimum BCS at each stage of the production cycle.

IM, Tait, ST Morris, PR Kenyon, DJ Garrick, AB Pleasants, and RE Hickson

Proceedings of the New Zealand Society of Animal Production, Volume 77, Rotorua, 23-28, 2017