Recent research into the nutrition of the horse

The majority of recent experiments in equine nutrition relates to the metabolism of protein, non-protein nitrogen, carbohydrate, calcium and phosphorus. An understanding of the significance of the nitrogen cycle is emerging in which there is a two-way movement of compounds across the wall of the G.I. tract. Some quantitative estimates of the role of microflora in this process have been made for comparison with similar processes in ruminants. However, the pathway by which the microflora contributes to the nitrogen economy and the extent to which this occurs is not established in the horse. It is well established that both glucose and volatile fatty acids are common substrates in tissue metabolism; but in contrast to evidence in the ruminant the ratio of starch to fibre in the diet does not affect the efficiency fo fibre digestibility. This, and similar observations, are explicable in terms of the anatomy of the G.I. tract of the horse. There is a scarcity of information on the secretion of digestive enzymes by the horse and on the relationship between intestinal function and certain digestive upsets. Furthermore, there is an urgent need for accurate clinical evidence for the significance of calcium and phosphorus nutrition to the development of leg abnormalities in horses. The irrelevance, for diagnosing purposes, of estimates of serum Ca and P is concluded, especially where no other relevant information is available. Haematological procedures, of diagnostic value in this respect, are available for use at least in controlled clinical conditions.