Abstract
The relationship between changes of body condition score (BCS) during the pre and postpartum periods and reproductive performance was investigated in 158 cows in 31 herds. Cows were scored on a five-point scale (1=too thin to 5=obese in 0.25 increments) beginning at ?? 20 days before calving and then every 30 days until pregnancy was confirmed by rectal examination. Prepartum BCS was classified in three degrees (low : ?? 3.00, moderate : 3.25-3.75, high : ?? 4.00). Cows with higher BCS before calving tended to have a significant decrease of more than 1.25 points in postpartum BCS (p<0.05). Cows losing ?? 1.25 postpartum BCS points had significantly more days until first service and a longer open period (p<0.05) compared with cows losing 0-1.0 point. Cows with decreased pre and postinsemination BCS had significantly lower conception rates than cows with increased BCS (p<0.05). Therefore, these data suggest that high prepartum BCS decreases postpartum BCS and reproductive performance in dairy cows. They also suggest that decreased BCS pre and post insemination may lower the conception rate.
