Nutrient Differences Among Oat Hulls of Different Varieties

Oat hulls are often used as a fibre source in cattle diets. They generally contain 2 - 4% crude protein, 40-50% ADF and 80-90% NDF. Recent work at the University of Saskatchewan has shown though that there can be significant differences in the ruminal degradability, and therefore feeding value, among oat varieties.

Oat hulls, a by-product of the oat milling industry, constitute up to 25% of the total weight of the oat grain. Due to the high fiber content, the ruminant feed market is the most viable market for these hulls. However, the feeding value of oat hulls for ruminants is greatly affected by the cell wall components, particularly acid detergent lignin (ADL). The present study was conducted to determine the variation in chemical composition and ruminal degradability of oat hulls obtained from dehulling of 10 western Canadian oat varieties. The varieties were chosen because they were among the most common varieties grown in western Canada. They were Calibre, Derby, Triple Crown, AC Assiniboia, AC Juniper, AC Medallion, AC Mustang, AC Preakness, CDC Boyer and CDC Pacer. Chemical composition was analyzed for the ten samples. In situ rumen degradability tests were done on the fibre fractions for AC Assiniboia hulls and Calibre hulls and straw.

The results of this study show that AC Assiniboia oats have a much lower ADL content (1.3%) than the other nine varieties ( 5.4-7.7%). Hulls derived from the AC Assiniboia oat variety have almost double the ruminal fiber degradability of Calibre oat hulls. The economic return for the oat milling industry can be increased by selecting low-lignin hull varieties like AC Assiniboia, which have similar ruminal fiber degradability to Calibre straw.

Source: Thompson et. al. Genotypic differences in chemical composition and ruminal degradability of oat hulls. Can. J. Anim. Sci. 80:377.
Nutrition Update  Volume 12 No.1, May 2001