Comparison between Individual and Pooled Samples of Non-esterified Fatty Acids (NEPA) and B-hydroxybutyrate (BHBA) in Transition Dairy Cows to Determine Herd Alarm Level Status

Abstract

As energy demands surpass dry matter intake during the transition period, elevated non-esterified fatty acids (NEFA) and B-hydroxybutyrate (BHBA) concentrations can be used as markers of the extent of negative energy balance both at the individual cow and herd level. Previous studies have demonstrated that there is a threshold above which elevated NEFA and BHBA concentrations are associated with increased risk of disease and decreased reproductive and milk production performance in individual cows. Recently, the herd alarm level, i.e., the proportion of sampled animals with metabolite concentrations above the threshold which was associated with detrimental herd-level outcomes, was determined. The objective of this study was to compare the interpretation of the proportion of individual samples above the metabolite threshold versus pooled samples to evaluate the herd alarm level status.