Jennifer Little BSc Hons MSc RNutr PgCert
Equinutrition
Independent Equine Nutritionist

The transformation from a young horse into a performance horse involves a multitude of changes and adaptations in their education and physiology. The health of a young horse at the point of starting exercise training is of significant importance for long term health and performance. As per normal, nutrition is just one facet of a young horses overall health, but it is a significant factor.

Frequently during the initial stages of training the main focus is to limit a young horses mental stress. To encourage a ‘level headedness’, conducive to learning, the diet of a young horses is commonly kept stripped back and minimal. While this nutritional approach is potentially suitable for the horse (and all those involved in the backing and training process), it is often less than optimal in relation to micro-nutrients associated with muscle support.

Now, while there isn’t anything that we can add to a feed bucket which magically turns into muscle. There are several ways in which diet can support muscle health in a young horse. Firstly it should ensure free access to clean water, secondly that a minimum of 2% body weight per day, or ad lib, of fibre, depending on body condition is provided. Fibre sources can include grass, hay, haylage, chaffs or fibre beets. At initial levels of work fibre sources can usually provide sufficient levels of fibre, total protein and even some vitamins and minerals. But, alone it is unlikely to be able to provide all the vitamins, minerals, and essential amino acid for muscle development at the levels required for a young horse. To ensures their diet is complete a suitable concentrated feed, such as a balancer is also required. Helping the horses metabolic pathways to convert the work being done into improved muscle mass and health.

Even with a correct diet, appropriate exercise is required for muscle development and strengthening. Exercise results in micro-injuries to the myofibres within muscle tissue. This is actually necessary to stimulate a post exercise inflammatory response, enabling muscle cells to develop and strengthen.

After exercise both pro and anti-inflammatory mediators are released, including cytokines, acute phase proteins, and stress hormones. Inflammatory responses are commonly considered as negative or detrimental. However, this is not necessarily the case. Initially following exercise the release of pro inflammatory mediators provide a protective response, triggering cell adaptation. It is by this process that muscles adapt, develop, and strengthen. This required inflammatory response can and does become detrimental to muscle development and the overall health of the horse, if it is left unchecked. A inflammation response that is either excessive or prolonged can result in heat, swelling, cell damage, and poor performance [1]. Post exercise the secondary phase is a release of anti-inflammatory mediators, which act to resolve the inflammatory response.

For young horses balancing these two post exercise responses, and mitigating the negative implications of inflammation, is pivotal to maintaining the quality of life and performance longevity [1]. One addition to a balanced diet and controlled exercise program, known to be beneficial is the supplementation of Saccharomyces cerevisiae.

This is a specific live, yeast, probiotic, with a proven, beneficial ability to function within a horses hindgut. S.cerevisia and its metabolites, have the ability to enhance sub-maximal exercise performance, and moderate the inflammatory response [2;3]. It has the potential to prevent the post exercise inflammatory response from becoming excessive or prolonged, while still allowing the initial process of muscle adaptation to occur unhindered.

In young horses supplementation of S.Cerevisiae for as little as 8 weeks, has been shown to improve their response to exercise, when compared to young horses undergoing the same training and on the same diet. S. cerevisiae supplementation reduced lactic acid formation and exercise heart rates, improved blood glucose, haemoglobin and packed cell volume, improved post exercise recovery rates, control the levels of certain stress hormones (Cortisol), and prevent excessive inflammation [1;3;4]. The exact mechanisms by which this specific yeast achieves this in not yet fully understood. But, mechanisms to improve the performance of young horses and their longevity is an area of increasing focus and interest in related research [5].

References

1. Valigura, H.C., Leatherwood, J.L., Martinez, R.E., Northon, S.A., White-Springer, S.H. Dietary supplementation of Saccharomyces cerevisiae fermentation product attenuates exercise-induced stress markers in young horses. Exercise Physiology. Journal of Animal Science, 2021, Vol. 99, No.8, 1-11
2. Evans, M., Reeves, S., Robinson, L.E. 2012. A dried yeast fermentate prevents and reduces inflammation in two separate experimental immune models, Evid. Based Complement. Alternat. Med. 2012: 973041. doi:10.1155/2012/973041
3. Wickler, S.J. 2002. Effect of diamond V XP yeast culture on sub-maximal exercise performance of Arabian horses. California State Polytechnic and University. EQ007-s. (Research Summary). Cedar Rapids, IA: Diamond V Mills, Inc
4. Glade, M., Campbell-Taylor, M. 1990 Effects of dietary yeast culture supplementation during conditioning period on equine physiology.J. Equine. Vet. Sci. 10(6): 434-443. doi:10.1016/SO737-0806(06)80140-1
5. Horohov,D., Sinatra, S., Chopra, R., Jankowitz, A., Bloomer, B., Bloomer, R. 2012. The effect of exercise and nutritional supplementation on pro inflammatory cytokines expression in young racehorses during training. J. Equine Vet. Sci. 32 (12): 805-815. doi:10.1016/j.jevs.2012.03.017