CONSIDERATIONS IN THE NUTRITIONAL MODIFICATION OF MILK-COMPOSITION

The trend to determine milk value on the basis of its components, is b ecoming global, with increasing emphasis being placed on its protein c ontent (Murphy and O'Mara, 1993). A milk market based on fat appears t o be shrinking, Consequently there is a need to increase milk protein content using a combination of nutrition, management and genetics. Nut ritional modification to accomplish this must consider impact on the e nvironment, society and animal welfare, as well as economics, Opportun ities for doing so may include the development of RPAA products, lipid supplements and improvements in forage digestibility and quality of s tored forages, Ability to formulate diets that will change milk compos ition in a predicted direction requires research to improve the predic tion of effects of diet on quantity and balance of absorbed amino acid s, ruminal fermentation and DMI, Dynamic, predictive models will be us eful in the development of practical diets to optimize yield of milk a nd its components.