Considerations for Feeding Starch to High-Yielding Dairy Cows

摘要

There has long been interest in the potential benefits and risks of feeding starch to lactating dairy cows (e.g. Henderson and Reaves, 1954; Armsby, 1922) and there have been numerous reviews published on the utilization of starch by ruminants for production (e.g. Waldo, 1973; Owens et al., 1986; Nocek and Tamminga, 1991; Huntington, 1997; Firkins et al., 2001). In a previous publication for the 31st University of Nottingham Feed Manufacturers Conference the effects of feeding starch to lactating dairy cows on nutrient availability and milk production and composition were reviewed, including the effects of altering site of starch digestion within the digestive tract (Reynolds et al., 1997). In recent years there has continued to be research into effects of starch type and site of starch digestion on production and metabolism of lactating dairy cows (e.g. Reynolds, 2006), along with a pervasive concern over the potential negative effects of sub-acute ruminal acidosis (SARA), the future demand for food for a growing human population, and the ethics of feeding starch to ruminants. Our objective is to revisit key points raised in these previous reviews in light of more recent research, the sustained increase in milk yield and nutrient requirements oflactating dairy cows, and concerns regarding the future role of ruminants in sustainable food production systems.