WINTER ANNUAL SMALL-GRAIN FORAGE POTENTIAL - II - QUANTIFICATION OF NUTRITIVE CHARACTERISTICS OF 4 SMALL-GRAIN SPECIES AT 6 GROWTH-STAGES

Four small grain species, barley, oat, rye, and wheat were harvested a t six growth stages to investigate their nutritive quality as a possib le replacement for corn silage. Crude protein (CP), in vitro dry matte r disappearance (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin contents were measured on fresh and ensiled sa mples. The IVDMD, an estimate of forage ruminant digestibility, of all species generally decreased from the vegetative (765-854 g kg(-1)) th rough the milk stage (505-662 g kg(-1)) and then remained unchanged or increased slightly through hard dough with the exception of oats whic h often decreased during later stages of growth. The IVDMD of rye was usually lower than the other species from the milk to hard dough stage . The IVDMD of barley was generally higher than the other species at t he soft and hard dough stages. The NDF, ADF, and lignin fractions usua lly increased from the vegetative to milk stages and remained unchange d or increased slightly through the hard dough stage. The ADF and lign in are negatively associated with forage digestibility while NDF value s are negatively related to dry matter intake. The ADF of rye was gene rally higher than the other species at the milk and soft dough stages. Rye and barley contained more lignin than the other species from the heading through hard dough stage. Crude protein content generally decr eased from the vegetative through milk stages and then leveled off or decreased slightly through the hard dough stage. Crude protein of oats was lower than other species at the vegetative stage, while rye gener ally contained more crude protein than the other species at the vegeta tive and boot stages. These data in combination with forage yield data reported in an associated paper suggest that small grains can offer a nutritious source of animal feed for farmers in the southeastern Unit ed States. Rye tended to stand out among the species at the early stag es of growth (vegetative to boot) as a highly digestible green chop or grazing crop that is also high in protein. Barley and wheat stand out as excellent high yielding, nutritious silage choices at the soft dou gh stage.