Nutrition is an important part of equine health and welfare. A balanced diet contains sufficient amounts of energy, proteins, vitamins and minerals, each of which has an important function in the body. An appropriate diet is therefore important to meet these daily requirements. But how do you ensure that your horse's diet meets its daily nutritional needs?
The Daily Nutritional Requirements of the Horse
Each horse requires a specific daily energy, protein, vitamins, and minerals intake. The horse's needs depend on several factors (Figure 1). The level of exercise is one of the factors that affects the horse's daily nutritional requirements. A horse that exercises lightly requires less nutrients for body maintenance, compared to a horse that exercises intensively 1. Age also affects the requirements of the horse 2. Younger horses have a higher requirement for proteins and minerals, important for body and muscle growth, than a fully grown adult horse. It is important to regularly check if the horse's ration meets its needs, as these factors may change.
Figure 1: The factors that affect the horse's requirements
Body Condition Score (BCS)
The horse's nutrient requirements are calculated based on the horse's (desired) body weight. Therefore, body weight is also an important factor influencing the horse's daily requirements 3. Using the body condition score (BCS), the horse's body weight is estimated and monitored. The BCS indicates whether the diet contains sufficient energy and can therefore be used to measure the energy intake. If the BCS is low, the horse is not getting enough energy from the diet. A high score indicates that the diet contains too much energy, leading to the storage of excess fat in the body. It is therefore important to monitor body weight through the BCS and adjust the diet when necessary. For more information on body weight, the BCS and rations, check out the blog ‘Managing and Maintaining Horse Body Weight’.
The Foundation of the Diet: Roughage.
The foundation of the diet is roughage. Horses are naturally grazing animals and graze between 14 to 16 hours a day 4. Therefore, the horse must have access to sufficient roughage throughout the day to perform the natural behaviour. Roughage is important for the health of the digestive system, especially the hindgut. It is essential for stomach health that a horse should not be denied access to roughage for more than 4 to 6 hours 5. Leaving the horse without access to roughage for too long can result in the development of gastric ulcers (See blog: Equine Gastric Ulcers: Causes, Treatment, Prevention and the Role of Nutrition). Besides, about 60-70% of the daily energy intake is provided by the fermentation of roughage in the hindgut. The rule of thumb is to provide at least 1.5% of the horse's body weight in kilograms of roughage. For a 600kg horse, this means he or she should get at least 9 kg of roughage per day. There are different types of roughage and the quality and amount of nutrients it contains varies by type or pack of roughage. Roughage often does not contain enough vitamins and minerals to meet the horse's requirements, which is why concentrates and supplements are used in addition to roughage. A forage analysis also gives more insight into the amount of nutrients it contains, allowing you to more precisely formulate a diet based on the horse's requirements.
Different Types of Feed
There are different types of feed to choose from to formulate a diet. Forage includes hay, silage, alfalfa and grass, for example. The choice of roughage for your horse depends on several factors. The main difference between hay and silage is the time it takes for the grass to dry after being cut. Silage is also packed in plastic. The dry matter content of hay is also higher than that of silage. Therefore, if your horse is sensitive to respirable dust, it is better to choose silage. Grass is a type of roughage that horses mainly have access to during the spring and summer. Grass contains more nutrients compared to the other types of roughage. However, it can also contain more sugar (fructan), making it unsuitable for some horses. Managing grass intake and taking into account the fructan content in grass is therefore important (Regulating and Managing the Horse’s Grass Intake).
There are also different types of concentrates such as muesli and pellets. The nutrient differences between concentrates is dependent on the feeding objective and the intensity of the exercise. Some concentrates are specifically formulated for leisure horses and therefore contain less energy, proteins, vitamins and minerals. There are also concentrates intended for sport horses, which contain more nutrients to meet their specific requirements. Concentrates are also produced for pregnant or lactating mares, as well as for young growing foals.
Supplements are added to the horse's diet to support the body by providing nutrients that the diet does not contain, or not enough, to provide the body with additional support. There are different types of supplements, each offering a different kind of support to the horse. For example, a vitamin and mineral supplement can be added to supplement a roughage based diet because it does not contain enough vitamins and minerals to meet the horse's requirements. These supplements do not contain extra energy, making them suitable for horses that do not exercise much and get enough energy and protein through the roughage. Other supplements support the horse's tendons and joints, digestive system, hooves or immune system.
Why is an Appropriate Diet Important?
The nutrients in a horse's diet each serve an important function in the body. Energy is required for body maintenance, various metabolic processes and is used as fuel during exercise. Proteins are important for body growth and a healthy and strong muscle mass. Vitamins and minerals each also have an important function in the body. A certain amount of these nutrients is required for them to perform their function in the body. Too little or too much of these nutrients can therefore affect the horse's health. Every individual horse is different and has different nutritional requirements which also makes it important to formulate an appropriate and fitting diet for each horse.
If you find it difficult to formulate a fitting diet or you are not sure whether the current diet meets your horse's needs, ask a nutritionist for advice and help you formulate a well-balanced diet.
References
1. Ellis, A.D. (2013) Chapter 5 - Energy systems and requirements. In: Geor, R.J., Harris, P.A., & Coenen, M., (Eds.). Equine Applied and Clinical Nutrition. Saunders Elsevier: China.
2. Siciliano, P.D. (2002) Nutrition and feeding of the geriatric horse. Veterinary Clinics of North America: Equine Practice, 18(3):491-508.
3. Dunnett, C.E. (2013) Chapter 23 - Ration evaluation and formulation. In: Geor, R.J., Harris, P.A., & Coenen, M., (Eds.). Equine Applied and Clinical Nutrition. Saunders Elsevier: China.
4. Krishona, L., Siciliano, P.D., Sheaffer, C.C., McIntosh, B., Swinkler, A.M., Williams, C.A. (2017) A Review of Equine Grazing Research Methodologies. Journal of Equine Veterinary Science, 51:92-104.
5. Luthersson, N., Nielsen, K.H., Harris, P., Parkin, T.D.H. (2009) Risk factors associated with equine gastric ulceration syndrome (EGUS) in 201 horses in Denmark. Equine Veterinary Journal, 41(7):625-630.
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