Abstract
The data for the calving intervals, gestation and postpartum periods of 77 Angoni, 58 Africander, 60 Mashona and 50 Hereford cows was analysed. Involution of the uterus and postpartum ovarian activity was studied in 50 cows. The calving intervals, gestation and postpartum periods (days) were 379.7± 85.8, 285.9 ± 13.2, 79.9±19.2 for the Angoni; 425.7±130.9, 297.5 +±11.5, 66.9 +±20.9, for the Africander; 387.8±140.0, 287.8 ± 9.7, 83.3 ± 27.9 for the Hereford, respectively. The calving interval and the gestation period of the Africander were significantly longer than in the other breeds. Clinical involution of the uterus was complete 30.6 days postpartum. First corpora lutea following silent ovulation were observed 10 to 89 days postpartum with a mean of 40.5 days. Overall calving rates were 83%, 65%, 83% and 54% for Angoni, Africander, Mashona and Hereford, respectively. Copyright © 1971. American Society of Animal Science . Copyright 1971 by American Society of Animal Science.