Controlled Parturition in Cattle

Abstract
Parturition was artificially induced in 294 cows (Angus, Hereford, Holstein, Brown Swiss and their crosses) by treatment with dexamethasone or flumethasone. An additional 10 cows calved before administration of a corticoid treatment was performed. The 20 mg dosage of dexamethasone caused parturition within 72 hr. in 159 of 189 cows. All higher dosages of dexamethasone (30, 50 or 60 mg) and the 7.5 mg dosage of flumethasone caused parturition within 72 hr. in all animals treated. Placental retention occurred in 159 of the 294 treated cows and none of the 10 untreated cows. Intramuscular treatment of cows with a retained placenta with 4 million units penicillin and 5 g streptomycin resulted in good post-partum recovery and subsequent normal fertility. Mean services per conception was 1.23 for retained placenta animals and 1.35 for animals that did not retain the placenta. The calving interval was 365 days following the induced parturition. There was a significant correlation (r=.271, P<0.01) of birth weight with day of pregnancy at parturition over all breeds. Within individual breeds, only the cross-bred females failed to show a similar correlation. The average increase in calf birth weight per day of gestation length ranged from 1.20 lb. (.545 kg) for Angus females to 0.28 lb. (.129 kg) for cross-bred females and averaged 0.94 lb./day, (.428 kg/ day) for all animals. These data were based on calving at days 267 to 285 of gestation. One may expect some reduction in birth weight but since good calf survival is difficult if parturition occurs more than 1 to 2 weeks early, this would mean that a reduction of 8.8 to 13.2 lb. (4 to 6 kg) would be the most that could be anticipated on the basis of this study.

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