title: Effect of a CIDR insert and flunixin meglumine, administered at the time of embryo transfer, on pregnancy rate and resynchronization of estrus in beef cattle.
abstract: The objectives of this study were to evaluate the effects of flunixin meglumine (FM), an inhibitor of PGF(2alpha) synthesis, and insertion of an intravaginal progesterone-releasing device (CIDR), on pregnancy rates in beef cattle embryo transfer (ET) recipients, and to examine the effect of a CIDR after embryo transfer on the synchrony of the return to estrus in non-pregnant recipients. Cows (n=622) and heifers (n=90) at three locations were assigned randomly to one of four groups in a 2x2 factorial arrangement of treatments with FM administration (500 mg i.m.) 2-12 min prior to ET, and insertion of a CIDR (1.38 g progesterone) immediately following ET as main effects. Fresh or frozen embryos (Stage=4 or 5; Grade=1 or 2) were transferred on Days 6-9 of the estrous cycle and CIDR devices were removed 13 days after ET. Recipients at Location 2 only were observed for signs of return to estrus. Recipients that returned to estrus at Location 2 were either bred by AI or received an embryo 7 days after estrus. Following the initial ET, there was an FMxlocation interaction on pregnancy rate (P<0.01; Location 1, 89% versus 57%; Location 2, 69% versus 64%; Location 3, 64% versus 67% for FM versus no FM, respectively). Pregnancy rates of embryo recipients were not affected by CIDR administration (P>0.05; 65% with CIDR, 70% without CIDR), however, the timing of the return to estrus was more synchronous (P<0.01) for recipients given a CIDR. Pregnancy rate of recipients bred following a return to estrus did not differ between cows receiving or not receiving a CIDR for resynchronization (P>0.13). Effects of FM on pregnancy rate were location dependent and CIDR insertion at ET improved synchrony of the return to estrus.
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0306, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Purcell
authors.forename: W E
authors.initials: WE
authors.lastname: Beal
authors.forename: K R
authors.initials: KR
authors.lastname: Gray
mesh_terms: D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle / Q000502:physiology*; D003002:Clonixin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D015925:Cryopreservation / Q000662:veterinary; D015237:Dinoprost / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D004624:Embryo Transfer / Q000662:veterinary*; D004973:Estrus Synchronization; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D007774:Lactation; D011247:Pregnancy; D011374:Progesterone / Q000008:administration & dosage*
chemical_list: D011374:Progesterone; C014558:flunixin meglumine; D015237:Dinoprost; D003002:Clonixin