title: Circulating concentrations of bovine pregnancy-associated glycoproteins and late embryonic mortality in lactating dairy herds.
abstract: The objectives of these experiments were as follows: (1) to determine the association between circulating concentrations of pregnancy-associated glycoproteins (PAG) and late embryonic mortality (EM) in lactating dairy cattle following fixed-time artificial insemination (TAI) on d 0 or timed embryo transfer (TET) on d 7, (2) to identify a circulating concentration of PAG on d 31 below which late EM would be likely to occur, and (3) to identify when during gestation (d 31-59) late EM is occurring. Cows were diagnosed pregnant on d 31 of gestation based on presence of a fetal heartbeat and reconfirmed to be pregnant on d 59 of gestation. Late EM occurred when a cow had a viable embryo on d 31 of gestation but not on d 59 following TAI or TET. Only pregnant cows on d 31 were included in the analysis (TAI-maintained, n=413; TAI-EM, n=77; TET-maintained, n=238; TET-EM, n=47). Cows that were pregnant at d 31 of gestation and maintained the pregnancy until d 59 had significantly higher circulating concentrations of PAG at d 31 of gestation compared with cows that experienced late EM between d 31 and 59 of gestation in both TAI and TET. To conduct a more stringent test of the effectiveness of a single circulating PAG concentration (d 31) to predict EM, a receiver-operating characteristic curve was generated to identify a PAG concentration on d 31 that would predict EM with ≥95% accuracy in cows that received TAI or TET. Based on positive and negative predicative value analysis, a circulating concentration of PAG below 1.4 ng/mL (TAI; minimal detectable level 0.28 ng/mL) and 1.85 ng/mL (TET) was 95% accurate in predicting EM (between d 31 and 59) at d 31 of gestation, respectively. Following TET, embryonic loss was tracked by Doppler ultrasound, progesterone, and PAG from d 24 to 59 of gestation, with more than 50% of the loss occurring between d 31 and 38 of gestation. In summary, circulating concentrations of PAG on d 31 of gestation may provide a good marker for predicting EM between d 31 and 59 of gestation, and the data suggest that this model could help predict which cows will undergo late EM.
authors.affiliation: Division of Animal Sciences, University of Missouri, Columbia 65211.
authors.forename: K G
authors.initials: KG
authors.lastname: Pohler
authors.affiliation: Departamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University, Botucatu, São Paulo, Brazil 18168-000.
authors.forename: M H C
authors.initials: MHC
authors.lastname: Pereira
authors.affiliation: Departamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University, Botucatu, São Paulo, Brazil 18168-000.
authors.forename: F R
authors.initials: FR
authors.lastname: Lopes
authors.affiliation: Idexx Laboratories Inc., Westbrook, ME 04092.
authors.forename: J C
authors.initials: JC
authors.lastname: Lawrence
authors.affiliation: Division of Animal Sciences, University of Missouri, Columbia 65211.
authors.forename: D H
authors.initials: DH
authors.lastname: Keisler
authors.affiliation: Division of Animal Sciences, University of Missouri, Columbia 65211.
authors.forename: M F
authors.initials: MF
authors.lastname: Smith
authors.affiliation: Departamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, São Paulo State University, Botucatu, São Paulo, Brazil 18168-000.
authors.forename: J L M
authors.initials: JLM
authors.lastname: Vasconcelos
authors.affiliation: Division of Animal Sciences, University of Missouri, Columbia 65211. Electronic address: greenjo@missouri.edu.
authors.forename: J A
authors.initials: JA
authors.lastname: Green
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D004624:Embryo Transfer / Q000662:veterinary; D005260:Female; D046689:Fetal Mortality; D006023:Glycoproteins / Q000097:blood*; D007315:Insemination, Artificial / Q000662:veterinary; D007774:Lactation; D010298:Parity; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood*; D011374:Progesterone / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D011257:Pregnancy Proteins; D011374:Progesterone
keywords: bovine pregnancy-associated glycoprotein; pregnancy loss