NITROGEN UTILIZATION BY PREGNANT YANKASA SHEEP

Résumé

Series of Nitrogen – balance trials were conducted during the last 6 weeks of gestation using nine adult Yankasa ewes aged about 242 years. The animals were fed a basal Digitaria smutsii hay diet supplemented with compounded concentrate ration ted at three levels of crude protein, viz 8.4, 15.6 and 19.1%. The estimated metabolizable energy concentration in the rations averaged 3.2 MJ/kg DM. Mean daily liveweight gains during the last third of pregnancy which were 125.7, 165.7 and 214.3g for the three treatment groups respectively were significantly (P< 0.05) affected by the level of crude protein fed. Nitrogen retention increased with dietary crude protein levels. There was a curvilinear relationship between N-intake and N-balance per unit of metabolic weight. The results showed that Yankasa ewes required 1.5g DCP/day/W^0.75_kg for maintenance and 7.48g DCP/day/W_kg^0.75 for pregnancy.