Induction of Parturition in Cattle with Long and Short Acting Corticoids and Estradiol Benzoate2

Summary Efficacy of three treatment regimens for parturition induction was investigated in three experiments with the objectives to maximize synchrony of parturition and to minimize the incidence of retained placentas. In Experiment 1, 20 mg of dexamethasone (DEX) was given alone or in combination with 6 mg estradiol benzoate (EB). The additional treatment with EB failed to reduce the incidence of retained placentas. In Experiment II, parturition was induced by injection of 5 mg flumethasone (FLU) or sequential treatment with triamcino- lone acetonide (TA) followed 5 days later by an injection of 5 mg flumethasone. The incidence of placentas retained longer than 24 hr tended to be decreased (59% vs 37%, P = .09) by pretreatment with TA. In Experiment III, treatment with DEX alone was compared with DEX following pretreatment with TA + EB to induce parturition in dairy cows. Triamcinolone acetonide (8 mg) injected 6 days prior to the DEX injection in combination with EB (10 mg) given 6, 4 and 2 days before and 20 mg at the time of DEX treatment tended to reduce frequency of retained placentas in dairy cows (40% vs 78% for cows receiving only DEX and 20% for controls). Pretreatment with either TA or TA + EB 1Contribution from the Missouri Agr. Exp. Sta. Journal Series No. 8219. Approved by the Director. z The authors acknowledge the valuable suggestions of Dr. R. A. S. Welch, New Zealand Ministry of Agri- culture, Ruakura Anim. Res. Sta., Hamilton, New Zea- land, on the use of triamcinolone acetonide to induce parturition in cattle. 3 Present address: Department of Animal Sciences and Industry, Kansas State Univ., Manhattan 66506. 4Present address: Department of Animal Science, Univ. of Illinois, Urbana 61801. SDepartments of Dairy Husbandry, Veterinary Medicine and Surgery and Animal Husbandry. increased the number of cows calving by 72 hr after FLU and DEX (P