Minerals and vitamins

The requirements for vitamins and minerals are calculated from the NRC (2007) norms (recommended amounts). This norm is revised at irregular intervals, and represents cumulated results and experience from equine nutritional research from around the world. The NRC norm for minerals and vitamins is the accepted norm throughout the world today. Some changes to the NRC norm have been included in the programme following recommendations from among others Professor H. Meyer in Germany and in collaboration between the Nordic horse nutritionists.

It is important to recognise that the NRC-norm is a minimum norm. This means that it is advised to increase the requirements by approximately 25% to secure the provision of sufficient amounts of specific nutrients under practical feeding conditions. In the present computer programme we have already done this transformation from minimum norms to what we have termed "optimum norms" for most nutrients. The requirements for nutrients as given in the programme will be the optimum norm. When the amounts of a particular nutrient provided by the diet is below a certain limit (this value is usually the NRC recommendation), the programme issues a warning, and you are prompted to increase the amounts of the nutrient by changing the diet of the horse. The norms are generally provided as equations where you have to input relevant information about the particular horse you are formulating the diets for. Information usually required is:

• Body weight
• Age and growth rate of young growing horses
• Stage of pregnancy or lactation of reproducing mares
• Training intensity or level of exercise

It is common to subdivide the requirements into

Maintenance requirement: The amount of a nutrient which is required to maintain the body pool of that nutrient. The maintenance requirement for energy is the energy used to keep the cells, tissues and organs of the horse alive and running, to maintain body temperature and keep a constant body weight.

Production requirement: The amount of a nutrient which is used by the horse for production of milk, a foetus, or for carrying out a certain amount of work.

The temperament of the horse will influence the requirement for energy and hence for other nutrients as well. Easily agitated and "excitable" horses have a somewhat higher energy requirement than more docile breeds. Excitable horses will also use more energy when contracting the same work load or training intensity as more docile horses. Thus there is an considerable amount of important room for individuality in the feeding requirements of horses, not only when the composition of the diet is concerned, but also when it comes to calculation of requirements. A good computer programme should provide the possibilities for the necessary individual adaptations.