Dry period and parturient predictors of early lactation hyperketonemia in dairy cattle.

The purpose was to determine important dry and calving period predictors of (1) a cow developing hyperketonemia at any time between 3 and 16 d in milk (DIM) and (2) a cow having hyperketonemia at her first β-hydroxybutyrate (BHBA) test after calving (between 3 and 5 DIM). Cows from 4 freestall dairy herds [2 in New York (NY) and 2 in Wisconsin] were enrolled at 266 d carried calf. Precalving data included body condition score, locomotion score, and blood nonesterified fatty acids (NEFA) concentration; calving-associated data included previous days carried calf, calving ease, calf sex, twins, stillbirth, and parity. Cows were each tested 6 times for hyperketonemia from 3 to 16 DIM on Mondays, Wednesdays, and Fridays using the Precision Xtra meter (Abbott Laboratories, Abbott Park, IL). Hyperketonemia was defined as a blood BHBA concentration of ≥1.2 mmol/L. Multivariable fixed-effects Poisson regression models were developed to predict the probability of a cow developing hyperketonemia between either 3 and 16 DIM or at her first BHBA test. As only the NY herds had precalving NEFA data, each prediction model was developed twice: once with data from all 4 herds (n=1,672) and once with data from only the NY herds (n=544). For the models with data from all 4 herds, increased body condition score group and an interaction between advanced parity and herd were important predictors of hyperketonemia development at any time from 3 to 16 DIM; calf sex (male), herd, and an advanced parity by increased body condition score group interaction were important predictors of hyperketonemia development between 3 and 5 DIM. The 4-herd models had a 64 and 78% predictive concordance for hyperketonemia between 3 and 16 DIM and at first BHBA test, respectively. For the models with data from the NY herds only, increased NEFA, calf sex (male), advanced parity, and herd were found to be important predictors of hyperketonemia development at any time from 3 to 16 DIM; increased NEFA, calf sex (male), decreased calving ease, stillbirth, and advanced parity were important predictors of having hyperketonemia at first BHBA test. The NY models had a 69 and 87% predictive concordance, respectively. These results may help identify at-risk animals and improve dry-cow management strategies before hyperketonemia develops.