Effects of caesarean section, retained placenta and vaginal or uterine prolapse on subsequent fertility in beef cattle.

Data collected at the Livestock and Range Research Station, Miles City, Montana, on 13,296 calving from the years 1963 through 1977 were used to evaluate subsequent reproductive performance of dams experiencing caesarean section, retained placenta or vaginal or uterine prolapse. A total of 121 caesarean sections (.9% of all calvings) was performed from 1963 through 1977, with the highest incidence reported among first-calf 2- and 3-year-old dams. Fall pregnancy rate among the 105 dams that had caesarean deliveries was 52.4%, which was 26.6% lower (p less than .01) than the herd average. Fetal membranes were retained after 49 natural parturitions. Pregnancy rates among dams retaining fetal membranes were not significantly altered (82.2 vs 79.4%). A total of 153 calvings was associated with prolapse of the reproductive tract, including 124 (81.0%) vaginal prolapses and 29 (19.0%) uterine prolapses. Subsequent pregnancy rate of all dams experiencing prolapse was lower (p less than .01) than the herd average. Pregnancy rates following prolapse among primiparous and multiparous dams were 28.0 and 57.9%, respectively. These data indicate that caesarean section and vaginal or uterine prolapse result in significant reductions in subsequent pregnancy rates of affected dams, with no detrimental effect on dams retaining fetal membranes.