Interrelationships among plasma metabolites, production, and ovarian follicular function in dairy cows

Associations of blood metabolites and production variables with ovarian function and parity, specifically, interval to first ovulation (IFO) and the incidence of ovarian cysts (OC) and multiple ovulation (MOV) at the first ovulation postpartum, were determined in lactating dairy cows. This retrospective study involved data on 169 Holstein cows from 3 studies on the same herd. Blood samples were taken weekly from wk -1 to 4, relative to calving, and transrectal ultrasonography was performed twice weekly from d 7 to 60 postpartum. The overall IFO was 32.6 Âą 1.9 d [mean Âą SEM] and did not differ among lactations. Primiparous cows were at a greater risk of failing to ovulate before d 60 postpartum and cows in the 3rd or greater lactation were at a higher risk for OC and MOV. Blood metabolites and production variables indicating a negative energy balance were associated with cows failing to ovulate before d 35 postpartum, but were not related with OC. Increased DMI and milk yield, particularly in 2nd lactation cows, were associated with a higher incidence of OC. While BHBA and IGF-1 were associated with MOV, the relationship was weak. Reducing negative energy balance is necessary to reduce IFO but may increase the incidence of MOVThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author