Feeds and Feeding for Obesity and Easy Keeper Horses
Advances in nutrition and pasture management over the last decade have led to improvement in animal husbandry. People are better educated in dental care, worming and ration formulation which enables a horse to become fat and stay that way. The source of the problem comes in many different varieties and most are through no ill intent of the owner. One major problem comes when the change of seasons occurs and the horse is exposed to large amounts of "carb loaded" grasses, and the owner continues to feed the horse its normal amount of hard feed typically high in non structural carbohydreates (NSC's). This means the horse is eating more energy than its burning and this leads to weight gain, ie horses are being overfed and underworked. Over the past two or three years many studies have been performed on the link between obesity and laminitis and a range of other metabolic disorders such as insulin resistance.
The Stance Equine Feeding System outlines several low NSC feeds.
Obesity and Insulin Resistance
If a horse is insulin resistant, the cells within the body that depend on insulin for glucose uptake (skeletal muscle cells) are starved for energy, or the glucose they should be getting from metabolism of food. Not all obese horses develop insulin resistance and not all insulin resistant horses are obese. It is simply that the occurrence of insulin resistance is higher in cases where the horse is overweight.
Recent studies have been trying to determine the order of sequence in relation to obesity and insulin resistance. Do horses develop insulin resistance because they are overweight or do horses become overweight due to the occurrence of insulin resistance? Do vascular changes occur due to obesity which then causes laminitis? These questions are important if horse owners are to be educated in avoiding these metabolic conditions through overfeeding and obesity. One of the unfortunate developments of horses who are obese and have reduced sensitivity to insulin is that they tend to be next in line to develop laminitis or founder.
Obesity and Laminitis
Keratinocyte glucose starvation resulting from the lack or failure to move glucose within the body, weakens the link between keratinocytes and lamellar basement membrane which attaches the coffin bone to the hoof wall. Situations associated with the cause of keratinocyte starvation, such as IR, increase the risk dramatically of laminitis. Obese horses also tend to suffer from vasoconstriction which would also predispose a horse to laminitis as the equine hoof in particular is extremely sensitive to any vasoconstrictors.The biggest indicator that obesity is the cause of insulin resistance and as a result, laminitis is that weight loss in overweight horses has been shown to increase the sensitivity.
Obesity is the cause of so many disorders that is essential that horse owners are educated of the implications of over feeding with high sugar and starch (high NSC) feeds. A major misconception is that a fat horse is a healthy horse. This is especially detrimental to ponies as they retain weight better than horses and can quickly turn from "plump" to unhealthy. Adipose tissue within the body produces substances called adipokines. These substances are known to have negative effects on the body;
- Over feeding high (>12%) NSC feeds
- Lipid and glucose homeostasis
- Blood pressure
- Feeding Behaviour
Luckily in order to treat obesity it takes diet management (feeding low NSC feeds) and an exercise routine which can be managed at home. Gradually the horse will regain fitness, lose the weight and reduce the occurrence of metabolic disorders.