Environmental influences on age at first lambing and lambing interval in Yankasa sheep
The effects of different environmental factors on age at first lambing and lambing interval of Yankasa sheep kept at the National Animal Production Research Institute, Shika, were studied. Least-squares means ( ± SE) for age at first lambing and lambing interval were respectively, 597.2 ±12.6 days and 253.1± 2.9 days. Type of birth (P<0.05) and season of birth (P<0.05) were important in influencing age at first lambing while parity (P<0.05), season of previous lambing (P<0.01) and year (P<0.001) influenced lambing interval. Dams born single or in the dry season attained reproductive status earlier than twin-born dams and those born in the other seasons. Lambing intervals were generally longer than expected from a flock where dams were bred to lamb twice in a year. Measures to reduce age at first lambing and lambing intervals to improve productivity are recommended.