Effect of quality of forage on availability of trace elements and some major elements.

The effect of forage quality on copper, zinc, manganese, calcium, phosphorus and magnesium availability were studied. Six growing lambs (25 kg) received successively frozen grass (Italian Rye Grass, first cycle at earing stage) and the same plant as hay dried after a very wet period in two balance trials. Copper and zinc digestibility and retention dropped more significantly with poor hay than with grass. Manganese availability was not modified by forage quality but by its content. There was a drop in calcium and phosphorus retention and no change in Mg digestibility when lambs were fed with hay.