Effect of uterine size on fertility of lactating dairy cows

摘要: There are multiple reasons for reduced fertility in lactating dairy cows. We hypothesized that one cause of could be the overall size reproductive tract, particularly uterus, given well-established uterine functions many aspects process. Thus, objectives this study were to evaluate variability primiparous and multiparous cows analyze whether there was an association between fertility, within a parity. Lactating Holstein (n = 704) synchronized receive timed artificial insemination (TAI) on Day 81 ± 3 lactation by using Double-Ovsynch protocol (GnRH-7d-PGF-3d-GnRH-7d-GnRH-7d-PGF-56h-GnRH-16h-TAI). At time last injection PGF, diameter determined at greater curvature ultrasound, length rectal palpation, volume calculated from these two measurements. Blood samples also taken measure progesterone assure synchronization all used final analysis (n = 616; primiparous, n = 289; multiparous, n = 327). Primiparous had percentage pregnant/AI (P/AI) compared (49.8% vs. 39.1% 67 days pregnancy diagnosis, P = 0.009). Diameter, length, uterus larger than (P < 0.001). For cows, smaller became pregnant not TAI with similar tendency observed Logistic regression quartile showed as increased, decreased P/AI either or is negative association between associated