INFLUENCE OF MINERAL YEAST SUPPLEMENTATION ON GROWTH PERFORMANCE AND DIGESTION IN BEEF STEERS GRAZING STAR GRASS (Cynodon plectostachius) PASTURES

Organic yeast minerals have higher bioavailability than inorganic sources, which are conventionally used as a supplement for cattle grazing tropical grasses. The objective of this study was to evaluate the influence of mineral-yeast mixture supplementation (chromium, selenium and zinc) on growth performance and digestion in beef steers grazing star grass (Cynodon plectostachius) pastures. For 120 d, daily doses of 0, 15 and 30 g of mineral-yeast mixture into a 1 kg supplement (as fed) were randomly assigned to 30 Brahman x Brown Swiss steers (325 +/- 11 kg initial body weight; BW) grazing star grass. The experimental design was completely randomized with three treatments and 10 experimental units (steers). Final BW, total gain, average daily gain and total feed intake increased linearly, as the amount of mineral-yeast mixture increased. Feed conversion was not affected by the mineral-yeast supplementation. Dry matter digestion and neutral detergent fibre digestion increased linearly as the amount of mineral-yeast mixture increased. The mineral-yeast mixture at daily doses of 30 g improved growth performance and digestion in steers grazing star grass pastures. Mineral supplementation with organic sources could improve cattle production under grazing tropical systems.