It has been found that administering 25-hydroxy vitamin D3 to ruminants helps to eliminate or at least reduce the need for supplemental inorganic P in the diets while maintaining milk production or growth performance. Furthermore, the excretion of P with the manure will be reduced and thus a positive effect on the environment will be achieved. Thus one aspect of this invention is a method of promoting phosphorus utilization in ruminants, comprising administering a sufficient amount of 25-hydroxy vitamin D3 to the animal, preferably as a feed additive. Another aspect of the invention relates to the use of a 25-hydroxy vitamin D3 for promoting or improving phosphorous utilization in ruminants and for reducing the excretion of P via faeces and urine.
