THE EFFECT OF DIETARY-PROTEIN ON REPRODUCTION IN THE MARE .1. THE COMPOSITION AND EVALUATION OF THE DIGESTIBILITY OF DIETARY-PROTEIN FROM DIFFERENT SOURCES

Four rations that differed in their crude protein and essential amino- acid content were compiled. Digestibility of the crude protein and ess ential amino-acid contents were determined biologically in a feeding t rial using 4 Anglo-Arab stallions. Their respective daily diets were: Diet 1:2 kg cubes, 5 kg tef hay (Eragrostis tef); Diet 2: 2 kg cubes, 5 kg lucerne hay (Medicago sativa); Diet 3: 2 kg cubes, 5 kg tef hay, 200 g fishmeal; Diet 4: 2 kg cubes, 5 kg lucerne hay, 200 g fishmeal. The concentrations of the amino-acids threonine, iso-leucine, leucine and arginine were increased in the total ration when lucerne hay repla ced the tef hay while fishmeal supplementation increased the methionin e and lysine contents, which provided a wide range of concentrations o f digestible amino-adds in each of the 4 rations.