Abstract

Body condition scoring is an efficient on-farm visual-assessment tool used to describe the energy reserves of animals. Cow body condition score (BCS) at crucial time points throughout the year is likely to influence reproductive performance. The aim of this experiment was to examine the influence of BCS before calving, before mating and at weaning on reproductive performance of mature beef cows. Percentage of cows conceiving to a single artificial insemination (AI) at a synchronised oestrus and pregnancy rate after 49 days of mating were determined for a total of 2,683 individual cows. Cows with a greater than average BCS had greater pregnancy rate to AI than did those with low BCS (P<0.001). The percentage of animals conceiving to AI was on average 54.8% but was lower at 42.5% for pre-mating BCS 4.5 or greater at 64.5% for BCS 9.0 (P<0.001). Cows had greater overall pregnancy rate after 49 days of mating with greater BCS; ranging from 88.3%, 75.7% and 79.7% for BCS 4.5 before calving, before mating and at weaning, respectively, to 93.5%, 93.3% and 93.3% for BCS 8.0 at the same time points. Increasing BCS up to 7 is likely to improve overall pregnancy rate, and most benefit tends to come from improving BCS in lower-conditioned cows to achieve high pregnancy results. Keywords: beef cows; BCS; reproductive performance; pregnancy rate; artificial insemination

F, Weik, JA Archer, ST Morris, DJ Garrick, and RE Hickson

New Zealand Journal of Animal Science and Production, Volume 80, Online, 14-20, 2020