A strategy to reduce crude protein levels within dairy cow diets without compromising performance, health, welfare or fertility


The combined effects of an increased cost of soyabean meal and recent legislation on the storage and application of cattle manure and slurry has resulted in an increased interest in reducing protein levels in dairy cow diets. Most studies indicate that only around 25% of dietary protein intake is captured and secreted in milk, with the remaining 75% being lost in urine and faeces. This not only represents a potential environmental risk, but is costly in feed use and manure storage. There is a very strong and positive relationship between manure nitrogen output and dietary protein intake, although other factors such as milk yield also have an influence. Therefore, the main factor influencing the excretion of nitrogen from dairy cows is protein intake. This study will identify minimum levels of crude protein in the diet that support high productivity without compromising health, welfare or fertility with further research to develop rationing systems that increase feed conversion efficiency, resulting in reduced GHG emissions and fewer nutrients being lost to the environment.

Project code:
411098 FS2
01 August 2011 - 30 June 2015
AHDB Dairy
Project leader:
University of Nottingham - Research Partnership study, University of Reading, Harper Adams University, SRUC, Royal Veterinary College, Aberystwyth University


The effect of reducing dietary crude protein

About this project

Aims & Objectives
To devise diets that allow dietary crude protein (CP) levels to be reduced below those currently used in commercial practice, without compromising milk yield, milk composition, or herd fertility.