BACKGROUND Preterm birth is a leading cause of perinatal mortality, yet the evolutionary history of this obstetrical syndrome is largely unknown in nonhuman primate species. METHODOLOGY/PRINCIPAL FINDINGS We examined the length of gestation during pregnancies that occurred in a captive chimpanzee colony by inspecting veterinary and behavioral records spanning a total of thirty years. Upon exa...

Data on the Red Angus, Angus and Hereford herds of Pioneer Hi-Bred International, Inc., Des Moines, Iowa, collected from 1968 to 1976, were analyzed for relationships among gestation length, birth weight, prenatal gain (birth weight adjusted for gestation length), growth traits and age at first calving. A total of 5,691 calf records, 1,783 listing gestation length, were included in the study. P...

The experiment involved observations of 2,514 Holstein-Friesian cows to determine the effects of environmental factors (cow's age, calving season, weight and sex of calves, housing system) and genetic factors on gestation length in dairy cattle and the correlation between gestation length and other reproductive traits (calving ease, stillbirth rates and placental expulsion). Genetic parameters ...

The aim of this study was to determine the predictive value of cervical length as a risk factor for spontaneous pre-term birth in twin gestations. A retrospective chart review was carried out on patients with twin pregnancies referred to our multiples' clinic. Cervical length was measured by transvaginal ultrasonography. Patients with an indicated pre-term delivery or intervention were excluded...

The length of gestation in Andalusian, or Spanish Purebred (SPB) and Arabian (AB) mares reared in Spain was analysed, based on 766 spontaneous full-term deliveries appertaining to 141 mares of SPB breed and 72 mares of AB breed in 31 breeding seasons. The data were obtained from the Yeguada Militar de Jerez de la Frontera stud farm in Cádiz, Spain. The mean length of gestation was of 336.8+/-0....

Records of gestation length (71,461) for Simmental cattle were distributed with mean 284.3 d and standard deviation 5.52 d. Gestation length was found to increase with percent Simmental and was 1.9 d longer for calves born to mature dams than for those born to heifer dams. Bull calves experienced gestation lengths 1.5 d longer than heifer calves. Sire, maternal grandsire, residual and total var...

objective of the present study was to determine calving parameters in eighteen large dairy herds of holstein friesian in tabriz. data analysis showed that the mean gestations length were 276.69 ± 6.29, 279.54 ± 8.55 and 271.38 ± 7.34 days in multipara cows and twining pregnancy respectively. percent of premature birth were 24.14% in twining (28 cases out of in 116 births), 9.61% in heifers (114...