Morphology and morphometry of in vivo- and in vitro-produced bovine concepti from early pregnancy to term and association with high birth weights.
This study was designed to characterize conceptus development based on pre- and postnatal measurements of in vivo- and in vitro-derived bovine pregnancies. In vivo-produced embryos were obtained after superovulation, whereas in vitro-produced embryos were derived from established procedures for bovine IVM, IVF and IVC. Blastocysts were transferred to recipients to obtain pregnancies of single (in vivo/singleton or in vitro/singleton groups) or twin fetuses (in vitro/twins group). Ultrasonographic examinations were performed weekly, from Day 30 of gestation through term. Videotaped images were digitized, and still-frames were used for the measurement of conceptus traits. Calves and fetal membranes (FM) were examined and measured upon delivery. In vitro-produced fetuses were smaller than in vivo controls (P < 0.05) during early pregnancy (Day 37 to Day 58), but in vitro/singletons presented significantly higher weights at birth than in vivo/control and in vitro/twin calves (P < 0.05). From late first trimester of pregnancy (Day 72 to Day 93), placentomes surrounding in vitro-derived singleton fetuses were longer and thinner than controls (P < 0.05). At term, the presence of giant cotyledons in the fetal membranes in the in vitro group was associated with a larger cotyledonary surface area in the fetal horn (P < 0.05). The biphasic growth pattern seen in in vitro-produced pregnancies was characterized by conceptus growth retardation during early pregnancy, followed by changes in the development of the placental tissue. Resulting high birth weights may be a consequence of aberrant placental development due to the disruption of the placental restraint on fetal growth toward the end of pregnancy.
Bertolini
Marcelo
M
Department of Animal Science, University of California, Davis 95616, USA.
Mason
Jeffrey B
JB
Beam
Stephen W
SW
Carneiro
Gustavo F
GF
Sween
Matthew L
ML
Kominek
Daniel J
DJ
Moyer
Alice L
AL
Famula
Thomas R
TR
Sainz
Roberto D
RD
Anderson
Gary B
GB
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001522:Behavior, Animal; D001724:Birth Weight; D002417:Cattle / Q000196:embryology*; D002418:Cattle Diseases / Q000453:epidemiology; D018568:Crown-Rump Length; D046508:Culture Techniques; D004624:Embryo Transfer / Q000662:veterinary; D005314:Embryonic and Fetal Development; D005321:Extraembryonic Membranes / Q000033:anatomy & histology; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D005313:Fetal Death / Q000453:epidemiology / Q000662:veterinary; D005317:Fetal Growth Retardation / Q000453:epidemiology / Q000662:veterinary; D005865:Gestational Age; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D013480:Superovulation; D014427:Twins; D016216:Ultrasonography, Prenatal / Q000662:veterinary