Effects of parity order, age at first calving and season of calving on productive performance of Friesian crossbred cattle in Sudan

الملخص

This study was carried out to determine the effects of parity orders, season of calving and age at first calving on total milk yield (TMY) and lactation length (LL) in a herd of Friesian crossbred cattle in Sudan. Data obtained from records from 2002 to 2011. The average TMY and LL were 3988.2 ± 36.2 kg and 355.8 ± 2.4 days, respectively. The TMY and LL were significantly (P ≤ 0.01) affected by parity orders. Highest TMY reported at 6^th parity and longest lactation was recorded at 4^th parity. Moreover, season of calving was significantly (P ≤0.01) affected on TMY and LL. In addition higher average values for TMY and LL were obtained in wet summer. The age at first calving had a significant (P≤ 0.01) effect on TMY, while heifers calved in late age were significantly (P ≤ 0.01) higher in milk yield than heifers calved in medium and early age.