Increasing efficiency of dietary nitrogen use in Dairy systems

Aims & Objectives To determine the long term impact on health and productivity of feeding dairy cows diets lower in protein concentration than currently used by UK dairy farms. Effects of reduced protein consumption on milk production and composition, fertility, body condition, and health will be measured in cows of high and low genetic merit for milk solids yield fed maize- or grass-based diets. Expected Outcomes Improved understanding of the long-term effects of reduced dietary protein on milk production, nitrogen excretion and environmental pollution Improved understanding of the effect of lower protein diets on milk production, fertility and health of high genetic merit cows fed maize or grass based diets. Improved understanding of reduction in dietary protein concentration on growth rate of dairy heifers, nitrogen excretion in urine and faeces and performance in subsequent lactations Development of models to measure economic impacts of changes in protein feeding strategies Practical recommendations for protein rationing of dairy cattle