title: Embryonic loss from 30 to 60 days post breeding and the effect of palpation per rectum on pregnancy.
abstract: This study was conducted over a 12-mo period to determine the rate of bovine embryo death between 30 and 60 d of gestation. In addition, palpation per rectum as a means of pregnancy detection was evaluated as a possible cause of embryo death. Estrus was synchronized in Holstein heifers (n = 1358), weighing > or = 385 kg, with a single intramuscular injection of 25 mg prostaglandin F(2alpha). Estrus was primarily detected by the absence of paint marks on the tailhead. The heifers were artificially inseminated with semen from 5 Holstein sires. Blood was collected between 30 and 45 d after breeding, and sera were evaluated for the presence of bovine pregnancy-specific protein B (bPSPB) by RIA to determine pregnancy. Palpation for fetal membrane slip was conducted by an experienced technician in approximately one-half of the inseminated heifers. To determine embryonic survival, a second blood sample was collected at approximately 60 d from 862 heifers that were determined to be pregnant at the first blood sampling. Embryonic loss averaged 5.3% during the interval between the initial detection of pregnancy at 30 to 45 d and the subsequent detection of pregnancy at 60 d of gestation. Embryo loss in heifers that were palpated was 6.5% compared with that of 4.3% in the control heifers (X(2): P = 0.145). These findings establish that there was substantial loss of embryos between 30 and 60 d post breeding but that embryo loss was not affected by palpation per rectum.
authors.affiliation: Department of Animal and Veterinary Science, University of Idaho, Moscow, ID 83844, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Alexander
authors.forename: M S
authors.initials: MS
authors.lastname: Johnson
authors.forename: R O
authors.initials: RO
authors.lastname: Guardia
authors.forename: W L
authors.initials: WL
authors.lastname: Van de Graaf
authors.forename: P L
authors.initials: PL
authors.lastname: Senger
authors.forename: R G
authors.initials: RG
authors.lastname: Sasser