Published online by Cambridge University Press: 27 February 2018
From the late autumn until the spring, a large proportion of the ruminant livestock in the United Kingdom, dairy cows especially, are housed indoors or sheltered and given rations of hay or silage ad libitum with supplementary feeds to provide additional energy and protein. During this period, feeding costs form the major portion of the total cost of meat and milk production and decisions about the type and quality of the conserved forage and about the amount and composition of the concentrate are of crucial economic importance. Against this background, this paper discusses the utilization of forage crude protein and considers in particular the factors influencing the supply of amino acids absorbed from the animal's gut and the implications of the use of supplementary concentrate feeds.