October 2013 - Finding the right forage for your horse

Fresh or dried forage is the staple food for horses. This article focuses on when and how pasture, hay and other roughages will cover most of your horse’s energy and nutrient needs. The PC-Horse program will help you to formulate rations with a high and healthy proportion of roughage for horses, also in situations with special nutritional challenges as, for example, when your horse is in hard training or needs to lose a large amount of weight.
Our guest author this month is Sara Muhonen. She has a PhD in animal nutrition from the Swedish Agricultural University (SLU). From her private company, Sara conducts research, consults and gives courses in horse nutrition through www.equi-nutrition.com. She also provides a service for matching Swedish forage producers and feed buyers on www.grovfoderborsen.se

No one forage is the same as the next. How well the horse can digest forage depends on the forage´s cell wall content. The cell wall is composed of cellulose fibre, hemicellulose, pectins and cell wall protein. Cell walls can be more or less lignified and the later the stage of maturity of a plant, the more lignified they are and the less digestible. When digestibility decreases the nutritive value of the forage also decreases.

Figure 1 shows the results from a digestibility study where four adjacent leys, seeded and fertilized in the same way, were harvested at four different stages of maturity. The results demonstrate how digestibility of dry matter (DM), the fibre fractions NDF and ADF and crude protein in haylage decreases the later the forage is harvested. This means that the nutritive value of the haylage also decreases; the content of digestible energy and crude protein become lower.

Different horses have different energy and protein requirements. The high performing athlete has high energy requirements and needs forage with high energy density. On the other hand, the pony not performing any hard work has a much lower energy requirement. Broodmares and growing horses have higher protein requirements. Besides meeting the horses’ nutritive requirements we also have to consider the horses’ need for occupation and the health and well being of its digestive system. Freedom of access to hay and haylage works well for most horses. If you have to restrict the allowance of coarse fodder (forage), 1.5 – 2 kg DM/100 kg body weight and day is appropriate. The absolute minimum allowance of coarse fodder is 1 kg DM/100 kg body weight and day.

Feeding a high performing athlete with early harvested forage, we can provide most and, in some cases, all of the energy and protein required. Then only a small amount of concentrate, or even none at all, will be necessary. Such rations will be beneficial for gut health, will prevent behavioural disorders and have a positive impact on the horses’ mental health.

However, a pony doing only light work needs forage of lower energy density, e.g. from a later harvest. Early harvested forage quickly satisfies daily energy requirements and it will be difficult to provide the pony with a sufficient daily intake of dry matter. This would result in less eating and chewing activity and thus increase the risk of behavioural disturbances. Therefore later harvested forage is more suitable for horses with lower energy requirements, those performing only light work, or no work at all.

In conclusion, always ask for the forage analysis and try to find the most suitable forage to match the requirements of your horse. You will then have made a good start on formulating your horse’s daily feed ration.

Sara Muhonen AgrD

Reference: Ragnarsson S & Lindberg JE. 2008. Nutritional value of timothy haylage in Icelandic horses. LivestockScience 113, 202-208. The Author can be contacted for further reference.