Abstract
Our objective was to evaluate the effects of body condition score (BCS) on the milk production and energy balance of transition dairy cows. Seventy-five multiparous dairy cows were separated into four groups according to the BCS, HH (4.25 ± 0.23 and 3.35 ± 0.19 BCS, pre and postpartum, respectively, n = 17), HM (4.14 ± 0.15 and 2.92 ± 0.24, n = 19), MM (3.10 ± 0.21 and 2.78 ± 0.17, n = 23), ML (2.88 ± 0.23 and 2.46 ± 0.19, n = 16). The milk yield, rumen pH, etc., data were collected and analyzed using a one-way ANOVA model in SAS (SAS version 9.4, SAS Institute Inc., Cary, NC, USA). The ML group had a higher milk yield and total solid yield than the MM group (P < 0.05), while the HH and HM groups had no difference with other groups. The HM and ML groups had a higher milk fat content than the MM group (P < 0.05), while the HH group had no difference with other groups. Milk protein content in the HH group was higher than the ML group (P < 0.05). The milk lactose, total solids, urea content in these groups had no difference. The ML group had a higher milk acetone content than the HH group (P < 0.05). The BCS change in the HH and HM groups was higher than the MM and ML groups, and that in the ML group was higher than the MM group (P < 0.05). The rumen pH had no difference within these groups. These findings collectively indicated the prepartum dairy cow with middle BCS would have a more efficient body fat utilization and a better milk production performance. Furthermore, reducing body fat loss is necessary to avoid the negative energy balance.
Short communication: Genetic relationships among daily energy balance, feed intake, body condition score, and fat to protein ratio of milk in dairy cows
