Sugar is a hot topic when it comes to the equine diet. There are many questions and much confusion about how much sugar a horse may be fed, which feeds are high in sugar and how sugar can affect equine metabolism. In this blog post, Cavalor experts Caroline Loos (Head of Research and Development) and Fien Demeyere (Feed Expert) answer frequently asked questions concerning sugar and equine nutrition.
#1 Where does all that sugar come from?
It’s generally known that concentrate feed contains sugar. But did you know that, in most cases, the biggest source of sugar is forage? Concentrates actually have the highest sugar content per kilogramme, but horses eat much more forage than concentrates in a day. On average, concentrates contain between 500 and 1,000 grammes of sugar (2 to 4 kg of concentrates per day) while forage contains between 1,000 and 1,500 grammes (10 to 12 kg per day).
#2 Is there a connection between sugar sensitivity and sweet itch?
Sugar sensitivity is often associated with sweet itch. But what’s the connection? There is no proven direct relationship between sugar consumption and the insects that cause sweet itch. However, we regularly see horses that are sensitive to sugar often suffering from sweet itch. It may be that horses that react to sugar (such as horses with sensitive bowels or metabolic issues) in many cases also have underlying problems involving the immune system. With such horses, too much sugar – for example from grazing on a lush, grassy pasture – can lead to an overly sensitive immune system. This, in turn, may lead to their having stronger reactions to other stimuli, such as insect bites. There is no direct connection between sugar and the insects responsible for sweet itch, but it’s possible that sensitivity to sugar plays a role in immune response as well as susceptibility to these pesky mosquitoes.
#3 Is it possible to tell, by looking, if a horse is insulin resistant?
There’s a common misconception that an overweight horse will always be insulin resistant. But that’s not always the case, because body weight can be misleading. Studies actually show that overweight horses are not always insulin resistant. In fact, some insulin resistant horses are quite thin. That’s why it’s always important to get a diagnosis from a vet. Testing involves measuring the basal glucose level in the blood. A more precise diagnosis can be obtained through a more dynamic test. Here, insulin response is examined after administering sugar. In short, you shouldn’t automatically assume that an overweight horse has an insulin problem. Always consult your vet before making any changes to the horse’s care and feeding.
#4 How can I make sure that a horse with a metabolic disorder is getting enough protein and other important nutrients from a low-sugar feed ration?
We often see that overweight horses or horses with metabolic disorders are given a smaller portion of concentrate feed as a supplement to forage, or sometimes no supplemental feed at all. But this may mean that the horse isn’t getting enough important nutrients like protein, vitamins and minerals. The best solution is to choose a concentrate feed that’s low in sugar and starch so that the horse gets its daily requirement of protein, vitamins and minerals.
Another option is to use a balancer. This is a product that is high in bioavailable protein and contains all the important vitamins and minerals the horse needs. Balancers are highly concentrated, which means that they can be fed to the horse in small quantities each day to cover the horse’s total nutritional requirements. This way you can be sure that your horse isn’t getting too much sugar, but nevertheless all the important nutrients to stay healthy.
#5 Is it true that dry hay contains less sugar?
Not necessarily. Hay quality depends on several factors, e.g. the hay’s handling and storing, and how long it has been stored. More information is needed to determine whether a dry hay’s sugar content, for example through a forage analysis. If the hay is high-structure, it’s more likely that it contains little sugar. Other factors, like fertilisation, cutting period, grass maturity and grass type should be considered when determining hay quality. Haylage generally contains less sugar than hay does, as some of the sugar is fermented by bacteria during storage. Studies show, however, that horses eat haylage faster than they eat hay; the sugar is absorbed more quickly, which can raise insulin levels. Caution should be exercised when feeding haylage to sugar-sensitive horses.
#6 When is the best time for a forage analysis?
A forage analysis can provide information on the forage’s nutritional value; the sugar content of hay is especially important for sugar-sensitive horses because forage makes up such a large portion of the feed ration. However, an analysis is advisable only if you buy a large quantity of hay at one time and feed that hay to your horse over a longer period. The best time to carry out a forage analysis is at the start of winter, so that you can adjust the feed rations and quantities accordingly. The feed’s nutrient values change gradually during storage. These changes depend on the conditions under which the hay was processed and stored. Therefore, it is recommended that another analysis be carried out after four months/in mid-winter to determine whether the feed still contains adequate nutrients.
#7 Is it OK for an overweight horse to eat straw?
It’s perfectly fine for an overweight horse to eat straw. Just keep in mind that straw has little nutritional value and so should not be used as a complete feed. It’s better to mix straw with hay. Straw can replace between 10% and 25% of the daily hay ration. For overweight horses and good doers, straw can be a sensible supplement to their feed ration, providing them with extra structure and filling them up so that they don’t consume too many calories.
#8 Is short-cut grass better for a sugar-sensitive horse?
The taller the grass, the less sugar it contains. So a horse can eat more grass in a lush field without necessarily consuming more sugar. But a word of caution: very short grass may contain considerably more sugar, because the plants react to the “stress” of overgrazing by storing more sugar. So it’s important to know that a pasture with very short grass is not always safer. Good pasture management is essential for reducing a horse’s sugar consumption. Make sure that your pasture stays healthy by encouraging growth, for example by putting the horses in another area when the grass gets too short, and by mowing it before it gets too long.