LOSS IN DIGESTIBLE NUTRIENTS WHEN ENSILED BARLEY IS FED WHOLE

Abstract

Two experiments were conducted to determine the proportion of whole and milled ensiled barley which passed through the digestive tract of cattle. Four three-year-old Holstein steers were used in a 4 × 4 Latin square design. Six kg/day of whole barley or barley milled through a hammermill with a 1.3-cm diameter screen was fed either as the sole ration or with 2 kg/day of long hay. Milling the barley resulted in a 25 to 30% increase in the digestion coefficients for dry matter, organic matter and energy. The whole barley kernels recovered from the feces were similar to the barley as fed in chemical composition and in vitro dry matter digestibility. Feeding hay did not increase the digestion of barley in spite of increased rumination. Whole barley recovered from the feces was only 15% of that consumed by four yearling heifers in a switch-back experiment. The barley recovered was lower in in vitro dry matter digestibility than the barley as fed. It was concluded that the younger animals chewed the whole barley more efficiently than the three-year-old steers. The loss of potentially digestible dry matter, organic matter and energy, when ensiled barley was fed whole as compared with milled, ranged from 10 to 30%. It was concluded that ensiled barley should not be fed whole to cattle.