We hypothesized that during restriction, UBF and fetal and placentome
measurements would be less than in adequately fed ewes, but upon realimentation, ewes would have similar UBF as ewes that were never restricted.
Because transplacental infection is possible only when the first placentome
is present (30 days after conception in cattle), the window during which the infection of a bovine fetus might lead to a porencephaly/hydranencephaly-micromyelia-arthrogryposis syndrome ranges from 30 to 150 days after conception.
We recently showed that among the fetuses of pregnant cows that were infected after the establishment of the first placentome, 28% were infected and that an arthrogryposis/ hydranencephaly syndrome follows if transplacental virus transmission occurs before fetuses are immunocompetent (6).
Because the virus can infect the fetus only after the first placentome has developed and because roe deer embryos remain in diapause until January (7), it is unlikely that SBV has contaminated many roe deer fetuses.
After dressing, gravid uterine tissue and fetuses were removed, followed by weighing of each placentome
and amniotic fluid.
Maternal intake did not affect fetal or total placentome mass at day 75 in H or C groups; however, switching H ewes to C at d 50 increased placentome mass at day 75 (2).
Whole placentomes (the part of the placenta where nutrient exchange occurs between the fetus and dam), were collected at day 75 of gestation and separated into fetal cotyledon (COT) and maternal caruncle (CAR) tissues.
On the basis of data from this pertinent subset, we found that -28% of the calves born to cows primo-infected after the first placentome
developed (which permitted the virus to cross the placenta) were indeed infected.
The syncytial plaques eventually cover the caruncular surface and aid in formation of placentomes
On day 75 of pregnancy, placentomes from each ewe were fixed with Carnoy's solution by perfusion of the main vessel supplying the cotyledonary (COT; fetal) tissue.
04) in placentomes of ewes fed moderate diet compared with ewes fed high nutrition level (346 [+ or -] 22 vs.
For each ewe, separate placentomes
were fixed with Carnoy's solution by vascular perfusion of the caruncular (CAR; maternal portion of the placenta), or cotyledonary (COT; the fetal portion of the placenta) tissues.