Ovarian function and the establishment and maintenance of pregnancy in dairy cows with and without evidence of postpartum uterine disease

摘要

Uterine disease early postpartum reduces fertilityduring the breeding period. One potential mechanisminvolves the reduced functional capacity of the uterusto support pregnancy. A second potential mechanisminvolves damage to ovarian follicles associated with systemicinflammation. We categorized lactating Holsteincows into healthy (n = 63) and diseased (n = 39) uterusgroups based on the percentage of polymorphonuclearneutrophils in the uterine lumen during the second andthird month postpartum and evaluated the functionalityof their ovaries and their capacity to establish andmaintain pregnancy. Cows were enrolled in a timed artificialinsemination protocol (Presynch Ovsynch) so thatthe first artificial insemination was approximately 75 dpostpartum. Ovarian follicles and corpora lutea werecounted and measured using transrectal ultrasound,ovulatory responses were assessed, and luteal phaseprogesterone concentrations were measured. Pregnancywas detected on d 18, 20, 22, 25, 32, and 45 throughchemical (d 18 to 25) or ultrasonographic methods (d32 and 45). The percentage of cows ovulating duringthe Presynch period; the number, diameter, and ovulatorycapacity of follicles during the Ovsynch period;and plasma progesterone concentrations following ovulationwere similar for healthy and diseased cows. Theinitial period of pregnancy establishment (d 18 to 22)appeared to be unaffected by disease because a similarpercentage of healthy and diseased cows were pregnantduring this period. Embryonic loss occurred in bothhealthy and diseased cows after d 22. Based on a relativelysmall number of pregnancies (n = 30 healthy and n = 17 diseased), the cumulative embryonic loss after d22 was greater in diseased compared with healthy cows.In short, uterine disease as defined in this study didnot affect cyclicity, ovarian follicular growth, or plasmaprogesterone concentrations. Percentages of healthyand diseased cows that were pregnant were similar fromd 18 to 22 after artificial insemination. Greater embryonicloss was observed after d 22 in diseased comparedwith healthy cows, but this observation was based ona small number of pregnancies and should be studiedfurther in larger trials with greater statistical power.