Hyperketolactia occurrence before or after artificial insemination is associated with a decreased pregnancy per artificial insemination in dairy cows

摘要

The reproductive parameters of dairy cattle havecontinuously declined worldwide over the last 50 years.Nutritional imbalances are identified as risk factors forthis decrease of reproductive performance. The presentpaper aims to quantify the decrease in the pregnancyper artificial insemination (P/AI) in the case of highmilk ketones before and after AI. A total of 388,731test-day from the Brittany Milk Recording Program inFrance from 226,429 cow-lactations were provided forthis trial. For each test-day, information about lactationcharacteristics, date of AI, date of the following calving,and acetone and β-hydroxybutyrate (BHB) values wereincluded. Ketones were predicted by Fourier transformmid-infrared spectroscopy using MilkoScan Foss analyzers(Foss, Hillerød, Denmark). Many thresholds wereevaluated to define cows with hyperketolactia. Hyperketolactiastatuses were then categorized into 1 of 4possible classes according to the milk ketone dynamicsfor each AI and each threshold of acetone or BHB values(low-low, high-low, low-high, and high-high) within20 d before and after AI. Similarly, the dynamics ofudder health were characterized by changes in somaticcell counts measured at the same test day as ketonebodies. A logistic regression with a Poisson correctionwas performed to explain the relationship of P/AI with milk ketones and somatic cell count dynamics.Predicted acetone and BHB ranged from −0.51 to 4.92mM (mean = 0.08 mM, SD = 0.10 mM) and −0.62 to5.85 mM (mean = 0.07 mM, SD = 0.1 mM), respectively.Hyperketolactia defined by high acetone levelsbefore AI was not associated with decreased P/AI,but high acetone levels after AI were associated with a>10% reduction in P/AI for all thresholds >0.10 mM.Hyperketolactia, defined by high BHB values before,after, or before and after AI, was associated with a 6 to14% reduction in P/AI compared with cows with lowBHB values. These associations are lower than thosereported in previous trials in which blood ketones wereused. High ketones in advanced lactation are likely tobe the result of various primary disorders (secondaryketosis). Because the present work demonstrated thatthis situation is considered a risk factor for deterioratedreproductive performance, we suggest that high ketonesin early and advanced lactation should be of interest tofarm advisors.