Influence of BHB concentration in blood on fatty acid content in the milk of high-yielding cows

The objective of this study was to determine the effect of increased concentration of BHBA in the blood in high-yielding cows on fatty acid concentrations in milk fat in first month of lactation. The milk fatty acid profiles of cows classified as healthy (n = 33) or as cows with increased concentration of BHBA (iBHBA) (n = 9) based on a blood plasma beta-hydroxybutyrate threshold concentration of 1.2 mmol/l were compared. The increased concentration of BHBA decreased milk yield (by 1176 kg on average in 305-days of lactation) had a negative effect on the milk fatty acid profile and the health benefits delivered by fatty acids. Increased concentration of BHBA contributed to a decrease in the conjugated linoleic acid (CLA) content of milk fat, a less desirable n-6/n-3 ratio, and an increase in the concentrations of unsaturated fatty acids, in particular oleic acid.