PSXIV-15 The effects of body condition score on the milk production and energy balance of transition dairy cows

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.