Nutritional Needs and Body Condition in Weanling Horses

There are two nutrition resources for feeding horses of all ages: the National Research Council (NRC) and German Society of Nutrition Physiology (GIE). Both organizations attempt to provide sound nutritional information, yet in some instances differ widely in their recommendations.

For example, “adequate energy intake in the growing horse” differs markedly between the two guidelines. The GIE recommends supplying 74 MJ (megajoules, a measure of energy) of digestible energy (DE) per day from the seventh to twelfth month of age, whereas the NRC recommends 78 MJ of DE/day in the seventh month and 94 MJ DE/day at 12 months.

Why does this matter? Because in foals, inappropriate growth and development—as in too fast and intensive growth—can be detrimental on the musculoskeletal system. The combination of conflicting guidelines and potential lifelong consequences leaves owners unsure of how to feed foals and weanlings to achieve a moderate growth rate.

To determine the best feeding level to achieve a “moderate growth rate,” German researchers* fed two groups of freshly weaned Warmblood foals (31 foals total). The first group was fed haylage, oats, and foal-starter feed. The first group received 74 MJ of digestible energy/day (based on GIE guidelines), and the second group of foals was fed 88 MJ DE/day.

Researchers discovered that both diets caused foals in the study to grow too rapidly, exceeding the desired “moderate growth intensity,” as determined by various measurements, including body condition score (BCS). After two months, the foals’ energy supply was therefore decreased to 80% of the GIE recommendations. The body weights of all foals gradually approached the GIE recommended values for Warmbloods.

The study authors concluded that both sets of recommendations, particularly protein intake, exceed the requirements of Warmblood foals and that one way to easily assess if a foal is being fed excessively is through BCS recording. The BCS of included foals reliably matched the recommended growth curve.

*Mack, J.K., H.P. Remler, E. Senckenbert, et al. 2014. No effect of moderate or high concentrate allowance on growth parameters in weanling Warmblood foals fed late-cut haylage as forage. Journal of Animal Physiology and Animal Nutrition 98:886-893.