Effects of calving month, pasture conditions and management on the growth of Holstein-Friesian x Ankole crossbred calves in a semi-arid rangeland

Daily weight gain of crossbred calves was studied in relation to seasonal changes in pasture quality and quantity, and management routines. A total of 171 and 56 calves were monitored up to the ages of 6 and 9 months, respectively, on ten farms in a semi-arid region of Uganda. Daily weight gains of calves were 288, 315 and 442 g/day at ages 0-2, 2-6 and 6-9 months, respectively. Average live weights of calves at ages 6 and 9 months were around 90 and 120 kg, respectively. Daily weight gain of calves at ages 6-9 months increased by 81 g for each additional percentage of crude protein in pasture (p < 0.05). At ages 0-2 (p < 0.05) and 0-6 (p < 0.05) months, crosses with > 75 % Holstein-Friesian (HF) had 30 and 60 g lower daily weight gain, respectively, than crosses with 75 % HF and 25 % Ankole. Birth month (August-January) and the number of days with low pasture quantity (< 800 kg dry matter (DM)/ha) had no significant effect on calf weight gain. A significantly higher weight gain was obtained for calves with the opportunity to suckle twice daily, compared with once. This indicates that suckling is beneficial for calves in semi-arid environments where seasonal pasture shortage regularly occurs.