  Factors affecting plasma progesterone in the early fetal period in high producing dairy cows.; ; et al in Theriogenology (2008), 69(4), 426-32 The aim of the present study was to determine whether certain animal- or management related factors could affect plasma progesterone concentrations on Day 42 of gestation in high producing dairy cows ... [more ▼] The aim of the present study was to determine whether certain animal- or management related factors could affect plasma progesterone concentrations on Day 42 of gestation in high producing dairy cows. Factors affecting early fetal loss were also analyzed. The study population was comprised of 199 pregnant cows classified as having high (> or =9 ng/ml) or low (<9 ng/ml) plasma progesterone concentrations. Through logistic regression procedures it was determined that, based on the odds ratio, cows with two or more corpora lutea were three times more likely to have high progesterone concentrations than cows with a single corpus luteum. Low producing cows during the warm season were 2.86 times more likely to have high progesterone concentrations than the remaining cows. Primiparous cows with high concentrations (>4 ng/ml) of pregnancy associated glycoprotein-1 (PAG-1) were 2.73 times more likely to have high progesterone concentrations than the remaining cows. Of the 199 pregnancies, 25 (12.6%) suffered early fetal loss: 22/136 (16.2%) during the warm season and 3/63 (4.8%) during the cool season, all in cows without additional corpora lutea. Based upon the odds ratio, cows without an additional corpus luteum were 3.67 times more likely to suffer fetal loss during the warm season than during the cool season. Our results indicate that milk production, the presence of two or more corpora lutea and plasma PAG-1 concentrations can affect plasma progesterone concentrations at the onset of the fetal period. The presence of an additional corpus luteum strongly diminished the risk of early fetal loss during the warm period. [less ▲] Detailed reference viewed: 20 (1 ULg)Plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations during gestation in Neospora-infected dairy cows.; ; et al in Theriogenology (2007), 67(3), 502-8 The aim of this study was to determine whether plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations in pregnancy are affected by persistent Neospora caninum infection in dairy cows. The data ... [more ▼] The aim of this study was to determine whether plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations in pregnancy are affected by persistent Neospora caninum infection in dairy cows. The data analyzed were derived from 22 multiparous cows: 16 N. caninum-seropositive and 6 N. caninum-seronegative animals (used as controls). Three of the 16 seropositive cows aborted during the study period and the corresponding data were analyzed separately. Pregnancy diagnoses were performed on day 40 post-insemination by transrectal ultrasound, and by palpation per rectum on days 90, 120, 150, 180 and 210. Blood samples were collected from each animal immediately before each pregnancy diagnosis, and then at parturition or at the time of abortion detection. Plasma was tested for antibodies against N. caninum and PAG-1 concentrations were determined by radioimmunoassay. In non-aborting animals, the effects of neosporosis (seropositive versus seronegative), N. caninum antibody levels, semen providing bull, sex of the newborn, and day of gestation on PAG-1 concentrations were evaluated by GLM repeated measures analysis of variance. The effect of the gestation period (first half versus second half) on the N. caninum antibody titer was established by the Student's t-test in seropositive cows. A significant positive effect of gestation day on PAG-1 concentrations was observed (d.f.=6; F=12.6; P<0.0001). For all cows, PAG-1 concentrations increased steadily during the course of gestation, with peak concentrations recorded at parturition. Neosporosis (P=0.493), N. caninum antibody levels (P=0.921), sex of the newborn (P=0.856) and semen providing bull (P=0.087) had no effect on plasma PAG-1 concentration. There was a significant 52% increase (P<0.0001) in N. caninum antibody titers during the second half of gestation compared to the first half. The fates of the three aborting cows were abortion on gestation day 215 in one, and fetus mummification diagnosed on gestation days 180 and 210, respectively, in the remaining two cows. A luteolytic dose of prostaglandin was applied 30 days after mummification diagnosis in these last two cows, and fetus expulsion was detected on days 215 and 250, respectively. Two of the aborted fetuses were submitted to laboratory analysis and the presence of N. caninum was confirmed by specific PCR. In the cows with a mummified fetus, PAG-1 concentrations were low or undetectable when the diagnosis was made. These findings suggest that N. caninum infection has no effect on placental function in chronically infected, cows not suffering abortion, while PAG-1 measurements in aborting animals provide a useful indication of feto-placental status. [less ▲] Detailed reference viewed: 17 (1 ULg) |
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