Modeling Nutrient Supply to Ruminants: Frost-Damaged Wheat vs. Normal Wheat (Report‪)‬

INTRODUCTION Wheat has an attractive energy and protein content. It is high in starch (ca. 60%). In western Canada, wheat is the primary cereal grain grown for export and as a main ingredient of foods for human consumption. Wheat usually has a high rumen degradation rate (19%/h) (NRC, 2001) and a high effective degradability (700 g/kg DM). This may result in digestive disorders, bloat and acidosis (Orskov et al., 1979; Givens et al., 1993) when feeding wheat-based concentrate diets. In Canada, frost damage to wheat is common. In year 2004 alone, more than 50% of wheat was frost damaged (called "frozen") in Canada, rendering millions of tonnes of wheat to be unsuitable for human consumption (Vern Racz, Director of Prairie Feed Resource Center, personal contact). There is an urgent need for the feed, crop, and livestock industries to fully assess the nutritive value of the frozen wheat, not only chemical characterization but also nutritive characterization in animals. The detailed chemical profile differences between the frost-damaged and normal wheat will be published soon in Yu et al. (2008). So far, little research has been conducted to systematically determine the magnitude of the differences in potential nutrient supply between the frozen wheat and normal wheat.