A total of 694 calving records of 582 N'Dama cows (aged 4-15 years) was classified into three groups for comparison of ability to calve again within 21 months postpartum, and calving interval. The classification was based on body weight changes between 1 and 4 months postpartum, as follows: Group 1 (n = 208), cows that lost more than 5% of their initial postpartum weight during this period; Group 2 (n = 352), cows that maintained body weight during this period; Group 3 (n = 134), cows that gained more than 5% of their initial postpartum weight during this period. Both criteria of reproductive performance differed significantly (P < 0.01) between these body weight change classes. In Group 1, 27.5% of cows calved again within 21 months, compared with 32.9 and 50.0% in Groups 2 and 3, respectively. Where the initial calvings were followed by subsequent parturitions (n = 569), the mean (+/- SE) calving intervals for Groups 1, 2 and 3 were 652 (+/- 15) days, 627 (+/- 11) days and 582 (+/- 18) days, respectively. Analysis of body weights from 4 months before conception to the month of conception showed that 71% of cows were gaining weight at a mean rate of 1.74 kg per month before conception. The magnitude of rate of gain depended on the calendar month (i.e. season) in which the 3 month pre-conception period began. The target body weight for conception in these N'Dama cows is about 220 kg. These results indicate that strategic supplementation of cows during the first 3 months after parturition either to maintain or to gain weight could lead to improved reproductive performance in village-managed animals.
