CHEMICAL CHARACTERIZATION AND RUMINAL NUTRIENT DEGRADABILITY OF HULLED AND HULL-LESS OATS

The objectives of this study were to determine the chemical and rumina l nutrient degradability characteristics of two hulled (Calibre and AC Mustang) and one hull-less (AC Belmont) oat varieties. Ruminal nutrie nt degradability characteristics of the oat varieties were determined relative to barley using one ruminally fistulated cow. Neutral (NDF) a nd 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 A DF content than hulled Calibre. Starch content was higher (P < 0.05) i n 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 simi lar CP content (average 124 g kg(-1)). Estimated digestible energy val ue was highest (P < 0.05) for AC Belmont (16.94 MJ kg(-1)), intermedia te for Calibre (14.18 MJ kg(-1)) and lowest for AC Mustang (13.34 MJ k g(-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 feed s and had the order AC Belmont = barley > Calibre = AC Mustang. It was concluded that oat varieties used in this study varied considerably i n their chemical composition and ruminal degradability. When compared with barley, hulled oats had lower while hull-less oats had higher rum inal degradability. (C) 1998 SCI.