Pharmacological intervention in swine reproduction
Roy N. Kirkwood, DVM, PhD
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If gilts are known to be cyclic, the options to control estrusare breed-and-abort or feeding allyl trenbolone (Regumate(R)).For breed and abort, terminate pregnancy 25-30 days postbreedingwith two injections of prostaglandin F2[alpha] (PGF2[alpha]),6-8 hours apart. Gilts should return to estrus within 4-6 dayswith normal fertility. When feeding allyl trenbolone, you mustensure individual feeding so that gilts receive at least 15 mg(Regumate(R)) per day. There is probably no problem with overdosing,but underdosing (<13 mg per day) may cause cystic follicles.If gilts are known to be prepubertal, gonadotropin (PG600(R))works well. If inducing estrus with gonadotropin, breed at theinduced estrus but expect some possible depression in reproductiveperformance. If the gilts' cyclic status is unknown, gonadotropincan be used but there may be risks. If gilts are having silentheats, cystic follicles may form and the gilts will become infertile--treatfor 14-18 days with allyl trenbolone followed by gonadotropinat withdrawal. Gonadotropin also works well after weaning of thefirst litter.Injection can be administered on the day of, or theday after, weaning. For farrowing induction, determine gestationlength on each farm and do not inject PGF2[alpha] morethan 2 days before due date. Inject a half-dose of PGF2[alpha]intravulvally at the beginning and end of the day (split-dose).Do not use oxytocin unless at least one pig has been born or continualsupervision is practiced.
Keywords: reproduction, pharmacology
Cite as: Kirkwood RN. Pharmacological intervention in swine reproduction. J Swine Health Prod 1999;7(1):29-35.
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