title: Pregnancy rates and metabolic profiles in cattle treated with propylene glycol prior to embryo transfer.
abstract: The objective of this study was to determine the effect of a sustained propylene glycol administration to recipients of frozen/thawed in vivo derived bovine embryos. Heifers were treated with oral propylene glycol for the last 20 days before embryo transfer (n = 142), and untreated as controls (n = 133). Progesterone, insulin, insulin-like growth factor-I, glucose, urea and triglyceride were analysed in blood on Day 0 and Day 7 of the estrous cycle corresponding to embryo transfer. The heifers were selected as recipients when showing progesterone levels <2.0 ng/ml (Day 0) and >2.5 ng/ml (Day 7), according to corpus luteum quality on Day 7 by technicians unaware of animals treated. Within treated animals, significantly more recipients were selected, and increased progesterone, corpus luteum quality, pregnancy and calving rates were recorded. Day 7 progesterone concentrations were higher in heifers treated and transferred. Propylene glycol increased insulin and insulin-like-growth factor-I, but glucose, urea and triglyceride did not vary. Furthermore, insulin-like-growth factor-I, glucose and triglyceride increased at estrous time, but urea decreased and insulin remained unaltered. Together with the sustained gain in pregnancy rates throughout the experiment (2 years), other evidences suggested that the observed effects did not rely on nutritional deficiency. Thus, propylene glycol improved pregnancy rates after embryo-transfer, and progesterone, insulin and insulin-like-growth factor-I are probably involved in this effect.
authors.affiliation: Area de Genética y Reproducción, Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Camino de los Claveles 604, Gijón 33203, Spain.
authors.forename: Carlos Olegario
authors.initials: CO
authors.lastname: Hidalgo
authors.forename: Enrique
authors.initials: E
authors.lastname: Gómez
authors.forename: Lupicinio
authors.initials: L
authors.lastname: Prieto
authors.forename: Paloma
authors.initials: P
authors.lastname: Duque
authors.forename: Félix
authors.initials: F
authors.lastname: Goyache
authors.forename: Lina
authors.initials: L
authors.lastname: Fernández
authors.forename: Itziar
authors.initials: I
authors.lastname: Fernández
authors.forename: Nieves
authors.initials: N
authors.lastname: Facal
authors.forename: Carmen
authors.initials: C
authors.lastname: Díez
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002417:Cattle / Q000097:blood*; D015925:Cryopreservation / Q000662:veterinary; D004624:Embryo Transfer / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000502:physiology; D004971:Estrus; D005260:Female; D006358:Hot Temperature; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011374:Progesterone / Q000097:blood; D019946:Propylene Glycol / Q000008:administration & dosage*; D014280:Triglycerides / Q000097:blood; D014508:Urea / Q000097:blood
chemical_list: D001786:Blood Glucose; D007328:Insulin; D014280:Triglycerides; D011374:Progesterone; D007334:Insulin-Like Growth Factor I; D019946:Propylene Glycol; D014508:Urea