Performance of a station-managed N'Dama herd in the Gambia

Abstract

Data collected on N'Dama cattle from a Government Station at Yundum, The Gambia were analysed for a range of performance traits recorded during the period 1970 to 1985. Least squares procedures were employed to evaluate the influence of environmental and genetic effects on reproductive and productive performance traits. Mean age (n = 59) and weight (n = 87) at first calving were 48.2 +/- 7.6 (s.d.) months and 235 +/- 35 kg respectively and were significantly (P less than 0.05) affected by year of birth. Calving intervals averaged 634 +/- 32 days (n = 160) but their distribution showed three peaks; 12, 24 and 33 months. Previous year of calving had a significant effect on calving interval (P less than 0.01). Calf mean liveweights at birth, one, three and six months and at weaning (eight months) were 20.1 +/- 3.7, 30.7 +/- 6.0, 51.1 +/- 13.2, 88.9 +/- 25.0 and 110.5 +/- 27.0 kg, respectively. Calf mean daily weight gains to weaning averaged 0.38 +/- 0.14 kg. Liveweights and growth rates were significantly influenced by year of birth (P less than 0.01) and sex of calf (P less than 0.05). Cow mean liveweights at calving and six months after parturition were 272.3 +/- 43.0 and 277.4 +/- 34.2 kg. Calf mortality from birth to weaning was 4.6%. Productivity indices based on an eight-month weaner calf per cow per year, per 100 kg cow per year and per 100 kg of metabolic weight of cow per year were 82.6 +/- 36.5, 30.5 +/- 11.9 and 138.2 +/- 55.4 kg respectively. These levels of productivity were equal or superior to those obtained for N'Dama cattle in similar management situations elsewhere in West Africa and to those of a larger breed under a ranch situation in East Africa.