Abstract

The primary aim of this study was to determine whether the milk production and production worth (PW) of anoestrous (AA) cows differed from that of their cycling (CYC) herd mates. In addition, a pilot survey was carried out to examine between herd factors, which may influence the percentage of cows diagnosed anoestrous. Individual production records were collated from 7786 cows in 26 herds, in which AA cows were identified following veterinary examination seven days before the planned start of mating. Milk production and PW did not differ between AA and CYC cows, after adjusting for herd, age and days in milk (P>0.05). The percentage of cows diagnosed AA varied from 13.4% to 51.5% among herds. Completed questionnaires were obtained from 19 herd owners regarding management factors in these herds. Stocking rates were higher in herds with a low percentage of anoestrous cows (<30%AA) compared with those with a high percentage (≥30%AA; p=0.05), but level of supplementary feeding was higher in herds with a low level of anoestrous (p=0.01). It is concluded that milk production and PW do not differ between AA and CYC cows. Nutritional supplementation after calving may influence the percentage of a herd still anoestrus before the start of mating.

FM, Rhodes, and S Morgan

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 208-210, 1999