Abstract

Body condition score (BCS) is an on-farm subjective measurement used to inform feed management decisions in sheep. This study determined the associations of BCS and changes in BCS on production. Ewe BCS was recorded four times annually in a flock of 2534 Romney ewes aged one-five, first bred at eight-months of age. Production was measured as the number of fetuses scanned (NLS), number of lambs weaned (NLW), average weight of lambs weaned (WWT) and total weight of lamb weaned (TLW). Ewe BCS was greatest at lambing and lowest at weaning. At pregnancy scanning (at an average of 75 days of pregnancy), two weeks prior to lambing, and at weaning, BCS ≥4.5 was associated with the lowest NLS and NLW, but the greatest WWT. Ewes with a BCS ≤2.5 at weaning were associated with the greatest TLW, suggesting these ewes had utilised their stored body fat to achieve high milk yields. Ewes that decreased BCS between lambing and weaning produced greater (P<0.05) TLW compared with ewes which maintained or gained BCS indicating their body reserves were acting as a buffer for milk production. The results of the current study showed that there was an effect of BCS on NLS, NLW, WWT and TLW. The change in BCS from scanning to weaning is an important determinate of NLW, WWT and TLW. A further study with more focus on the change in BCS is, therefore, warranted.

IM, Tait, PR Kenyon, DJ Garrick, N Lopez-villalobos, AB Pleasants, and RE Hickson

New Zealand Journal of Animal Science and Production, Volume 79, Palmerston North, 91-94, 2019