Abstract

Dairy cows are in negative energy balance in the early postpartum period. It was hypothesised that cows that had not resumed ovulating by 1 week before the planned start of mating (PSM) were in negative energy for a longer period and/or to a greater depth than cycling cows. This case-control study compared the condition score, concentrations of selected blood metabolites and milk production in each of 90 pairs of anoestrous and cycling dairy cows on 8 farms. Anoestrous cows had a lower condition score (0.3 units), a higher urea concentration (0.3 mmol/l) and a lower glucose concentration (0.11 mmol/l) than their cycling pair. There was no difference in milk volume, milk fat, protein or length of lactation between cycling and anoestrous cows. The hypothesis that anoestrous cows are in lower energy balance than cycling cows is supported.

TH, Deane

Proceedings of the New Zealand Society of Animal Production, Volume 53, , 51-54, 1993