Résumé:
This study fit into a doctoral project .
A meta-analysis including 37 different models from 14 papers was conducted to evaluate the
effect of elevated non-esterified fatty acids (NEFAs) and β-hydroxylbutyrate (BHBA) on the
variables pregnancy rate at first AI (FSCR), estrous cyclicity (EC), time to pregnancy.
The available studies provided approximately 23 382 cows with sufficient data for analysis.
For each outcome, the odds ratio (OR), relative risk (RR) or hazard ratio (HR) was presented
for various moderators to reduce heterogeneity among the studies.
Over all the studies analyzed, elevated NEFAs and BHBA had effect on FSCR (OR = 0.592), EC
(OR=0.879), days to pregnancy (HR= 0.771). The results showed that 2 main categories of
moderators had a significant effect on the adjusted risk. First, the adjustment made by
defining type and time of test [High post-partum BHBA (BHB-post) and high post-partum
NEFAs (NEFA-post)] for PR/AI. Second, frequency of testing [High BHBA or NEFAs in one fixed
time (one) and High BHBA or NEFAs in either of the first 2 wk. postpartum (either) for EC.
