Cattle suffering from calving difficulty have been reported to have pregnancy rates decreased by 16% and to calve 13 days later at the next calving. Results from a recent study (Doornbos, et al., 1984; Montana) showed that heifers receiving assistance in early stage 2 of parturition returned to heat earlier in the post-calving period and had higher pregnancy rates than heifers receiving traditionally accepted obstetric assistance. In this study heifers were either assisted when the fetal membranes (water bag) appeared (EARLY) or were allowed to progress normally and assisted only if calving was not completed within two hours of the appearance of the water bag (LATE).
Heifers that were allowed to endure a prolonged labor had a 20% lower rate of cycling at the start of the next breeding season. In addition, the rebreeding percentage was 17% lower than the counterparts that were given assistance in the first hour of labor.
Prolonged deliveries of baby calves (in excess of 1 to 1.5 hours) often result in weakened calves and reduced rebreeding performance in young cows!