Published online by Cambridge University Press: 02 September 2010
An on-farm study was conducted over a 12-year period (1979 through 1990) at four locations in the subhumid zone of Nigeria to estimate levels of performance of Bunaji cattle and to examine factors affecting productivity in these production systems. Average weight at birth, at 9 months and at 12 months were 19·6 kg, 76·2 kg and 93·1 kg, respectively. Average daily gain between birth and 9 months was 211 g/day. The corresponding figure between 9 months and 12 months was 176 g/day. Cumulative calf mortality at 9 months and at 12 months were proportionately 0·14 and 0·15, respectively. Mean age at first calving was 62·5 months while interval between consecutive calvings averaged 22·5 months. Mean daily milk offtake was 510 ml. Mean length of offtake period varied substantially between locations ranging from 339 days in Kurmin Biri to 425 days in Madauchi. Lactation milk offtake was estimated at between 200 and 260 I. Peri-urban Madauchi had the highest daily milk offtake, the longest milk extraction period but the poorest calf growth and survival rates. Locations with low milk offtake had superior calf performance both in terms of growth and survival. Calves born in late wet and early dry seasons had superior growth and survival rates. Most calvings occurred in the dry season mainly because of the effect of season on conception rates. There was a tendency towards improved productivity on a per-animal basis over the years. This ivas so for age at first calving, calving interval, calf survival and milk offtake. Improved reproductive performance provided opportunity for higher offtakes. However, growth between 9 months and 12 months and weight at 12 months declined during the study period.