IMPROVING DAIRY HERD EFFICIENCY AND WELFARE THROUGH DEVELOPMENT OF NOVEL FEEDING STRATEGIES COMPLEMENTARY TO THE DIURNAL PATTERN OF FEED INT

Feed represents the largest and most variable cost for dairy producers. The goal of nutrition is not to simply minimize feed cost, but to optimize conversion of feed into milk. Improvements in production and efficiency are attributable to advances in genetics, nutrition, and management, but central to improved milk yield is the feeding of highly fermentable feedstuffs. The concentration and rate of digestion of fermentable organic matter is important in determining ruminal environment and the products of fermentation. Highly fermentable diets can result in low ruminal pH that reduces fiber (NDF) digestibility, microbial efficiency, and cow health. However, ruminal fermentation of cows is not constant because of diurnal variation in feed consumption. The diurnal pattern of feed intake and the effect of diet on the pattern of feed intake have not been well characterized. In addition, metabolism is regulated by an internal circadian rhythm and the diurnal pattern of milk synthesis is not well described, but may be uncoupled from the diurnal pattern of intake under some feeding strategies. The research proposed will characterize the diurnal pattern of feed intake and milk synthesis and develop strategies improve dairy efficiency by complementing the natural diurnal pattern.