Abstract
Data on the reproductive performance of Kenana cattle at Um Banein Livestock Research Station in Sudan are analysed for 1958-1980. There was a marked seasonality in calf births, most cows calving in December and January and fewest July-September. Age at first calving (least-squares mean) was 1535 days, ranging from 1248 days over 1966-1968 to 1990 days for 1971-1972. Calving interval averaged 534 days, decreasing from 621 days 1964-1967 to 463 days 1976-1980: it was about 460 days in young cows but increased to 630 days following seventh and subsequent parturitions. Cows produced an average of 4.02 calves during their lifetimes. Changes in management and variations in stocking rates probably account for most of the observed differences in performance.
