The age of first calving is 3.5 years in Upper Casamance and is slightly lower in Lower and Middle Casamance. The calving interval is 16 to 17 months in Middle and Upper Casamance and roughly 19 months in Lower Casamance with 80% of calving taking place in the last six months of the year. The abortion rate is 10 to 20%, which leaves an average calving rate of 56%.