The effect of proportion of whole or rolled oats in steer rations on their digestibility

Abstract

In a cross-over design, digestibility (D) of organic matter (OM), crude fibre (CF) and starch (S) was examined for steer rations containing hay plus 33 to 74% of whole or rolled oats at constant total DM. The DOM and DCF varied with proportion of grain in the ration, but did not differ with form of grain. The DS did not vary with proportion of grain, but was lower with whole than with rolled grain (93.8 cf 98.2%). The variation in the DOM was slight, with the highest value at about 60% grain. The DCF was highest at about 50% grain, and declined rapidly with a higher proportion of grain. The DOM of hay fed to reserve steers was 54.1%. By difference, the DOM of the oats at the lowest and highest proportion of grain was 78.1 and 67.0%, respectively. The results refute the hypothesis that proportion of grain in the diet may influence the relative digestibility, by beef cattle, of whole and rolled oats. However, they do suggest a detriment to animal performance if the ration exceeds an oats content of about 50-60%.