A zinc-deficient diet for ruminants: diagnosis and treatment of deficiency.

A zinc deficient diet which is not semi-synthetic was tried on 20 male Limousin X Romanoff three and a half month-old sheep weighing 36 kg on average. This diet was composed of strawy hay sprayed with caramel containing urea and minerals. Compared to hay alone this diet is more appetizing to lambs and more equilibrated as to energy level and soluble nitrogen utilization. The deficiency appeared within a week in zinc plasma and progressed clinically within 100 days. The plasmic free zinc and alkaline phosphatase were not better criteria for the deficiency diagnosis than total plasmic zinc. Supplementing the diet to 50 or even 100 mg Zn/kg DM was insufficient to suppress the deficiency. Zinc injection, by contrast, restored zincemia to normal in ten days. Zinc deficiency treatment by oral route should be reconsidered.