A comparison of serum metabolic profiles of dairy cows that maintained or lost body condition score 15 days before calving

Abstract Text: Body condition score is an indirect measure of energy balance. Energy balance prior to calving may affect production and health in the following lactation. Energy restriction prior to calving has recently been advocated as an nutritional strategy which may result in BCS loss before calving.  The objective of this study was to determine if loss of BCS 15 d prior to calving had an impact on the NEFA and calcium at wk -1 and wk 0 relative to calving and β-hydroxy butyrate (BHBA) and haptoglobin at wk 0 and wk +1 relative to calving from 93 Holstein-Friesian cows. On d -15 to d 0 relative to calving BCS was assessed (1 = emaciated, 5 = obese). Cows were divided into two groups; those that did not lose BCS between d -15 and d 0 (MAINT, n=50) and those that lost BCS from d -15 to d 0 (LOSS, n=43). The fixed effects of BCS group, parity, wk and their interactions and a random effect of cow were analysed for using PROC MIXED of SAS. Before calving LOSS cows tended to have higher NEFA concentrations than MAINT cows (0.88±0.05 v 0.78±0.04 mmol/L, P = 0.10) and a group by wk interaction was also found (P < 0.01), with an increase of 0.69 ± 0.09 mmol/L for LOSS and an increase of 0.59 ± 0.07 mmol/L for MAINT from wk -1 to 0. There was no difference in calcium concentrations between the LOSS and MAINT cows (2.21 ± 0.02 v 2.23 ± 0.02 mmol/L) however a group by wk effect (P < 0.01) was found with a decrease from wk -1 to wk 0 of 0.32 ± 0.04 and 0.25 ± 0.03 mmol/L for LOSS and MAINT respectively. After calving LOSS cows were found to have higher concentrations of BHBA than MAINT cows (0.72±0.04 v 0.57±0.04 µmol/L, P < 0.05). A group by wk interaction (P < 0.05) was found for BHBA with an increase of 0.19 ± 0.07 µmol/L for LOSS and an increase of 0.02± 0.07 µmol/L for MAINT cows from wk 0 to 1. There was no difference found for haptoglobin between the LOSS and MAINT cows (115.41 ± 1.45 v 114.71 ± 1.29 ng/mL, P > 0.05. In conclusion, LOSS cows tended to have significantly higher NEFA before calving and had a higher BHBA after calving with little effect on serum concentrations of calcium or haptoglobin. 

Keywords: Haptoglobin, NEFA, β-hydroxy butyrate