Association between automated body condition score at dry-off and calving and hyperketonemia in Holstein cows

Hyperketonemia is a common metabolic condition in high-producingdairy cows and has been associated with many fresh cow diseases.The objective was to test the association between automated BCS atdry-off and calving and hyperketonemia (HYK) in Holstein cows. Thisretrospective observational study used data collected from 12,042 lactations in 7,626 Holstein cows calving between April 2019 and January2022 in a commercial dairy operation in Colorado. Cows were testedfor hyperketonemia at 6 ± 3 DIM (PortaCheck Inc.) and were considered positive when blood BHB ≥1.2 mmol/L. Scores generated by anautomated BCS camera system (DeLaval, Sweden) at dry-off (BCSd)and calving (BCSc) were selected from multiparous cows (n = 7,681lactations) and subsequently categorized into quartiles (Q1 = 25%lowest BCS; Q4 = 25% greatest BCS). Changes in BCS (ΔBCS) werecalculated from dry-off to calving and assigned into quartile categoriesconsidering Q1 as the 25% of cows with greater loss of BCS. Datawere examined using logistic regression with calving season includedas covariable. The adjusted odds ratios (OR) and 95% CI of HYK bycategories of BCSd, BCSc, and ΔBCS are presented in Table 1. GreaterBCS at dry-off and greater loss of BCS from dry-off to calving wereassociated with greater odds of hyperketonemia. Greater BCS at calvingwas partially associated with the incidence of this metabolic disorder.