Chemical characterisation and ruminal nutrient degradability of hulled and hull-less oats

The objectives of this study were to determine the chemical and ruminal nutrient degradability characteristics of two hulled (Calibre and AC Mustang) and one hull-less (AC Belmont) oat varieties. Ruminal nutrient degradability characteristics of the oat varieties were determined relative to barley using one ruminally fistulated cow. Neutral (NDF) and acid (ADF) detergent fibre levels were higher (P < 0·05) in hulled than hull-less oats. Hulled AC Mustang had higher (P < 0·05) NDF and ADF content than hulled Calibre. Starch content was higher (P < 0·05) in AC Belmont (590 g kg^?1) than Calibre (457 g kg^?1) and was higher in Calibre than AC Mustang (415 g kg^?1). Crude protein was higher (P < 0·05) in hull-less than hulled oat. Both hulled varieties had similar CP content (average 124 g kg^?1). Estimated digestible energy value was highest (P < 0·05) for AC Belmont (16·94 MJ kg^?1), intermediate for Calibre (14·18 MJ kg^?1) and lowest for AC Mustang (13·34 MJ kg^?1). Ruminal dry matter and NDF degradability were higher (P < 0·05) in hull-less than barley and was higher in barley than hulled oats. Ruminal starch degradability exceeded 900 g kg^?1 for all tested feeds and had the order AC Belmont = barley > Calibre = AC Mustang. It was concluded that oat varieties used in this study varied considerably in their chemical composition and ruminal degradability. When compared with barley, hulled oats had lower while hull-less oats had higher ruminal degradability. © 1998 SCI.