Why keeping sugar and starch levels low isn’t only advised for Laminitics…
Owners of metabolic horses and ponies (those with Equine Metabolic Syndrome [EMS], Insulin Dysregulation [ID], Pituitary Pars Intermedia Dysfunction [PPID]) and those prone to laminitis, are well versed in keeping the diet low in sugar and starch. Most will work towards a cut off of 10% combined sugar and starch, often referred to as the Non-Structural Carbohydrate or NSC level, although many try to achieve levels lower still.
The perhaps fortunate owners of those not affected by metabolic issues may let this ruling pass them by, but at Simple System, we feel that no horse has evolved to thrive on a high starch or sugary diet and that keeping NSC levels low for all horses might be a wise decision – with a variety of benefits!
An understanding of digestive physiology explains why horses haven’t evolved to thrive on a high starch diet…
Unlike humans, the horse's saliva does not contain amylase (the enzyme that breaks down starch into sugar molecules), and is the reason bread tastes sweet if you keep chewing it. This means that in the horse, starch is not “pre-digested” before entering the stomach and relies on the stomach acid and enzymes present here to break it down. The horse’s stomach is also small relative to their overall size. This means they have limited physical ability to digest starch but also limited chemical ability too, due to the lack of amylase in their saliva and low levels of amylase in general.
These limitations require starch levels in the diet to be kept low and starchy meals to be kept small, hence the age-old rule of feeding “little and often” but also allowing for breaks between feeding and work. Undigested starch that passes into the hindgut will undergo rapid fermentation, lowering the pH level, disrupting the hindgut microbiome and potentially leading to digestive issues, ranging from general discomfort and gassiness to colic, hindgut dysbiosis or even triggering laminitis.
But surely poor doers need all the help they can get?
Keeping starch intake low for poorer doing horses means you can safely feed generous meals, helping keep your routine simple - negating the need for multiple smaller meals through the day - but still ensuring they get adequate nutrition and physical intake.
We may typically recommend that a poor doing 500kg horse needs at least 3kg (dry weight before soaking) of Lucie Nuts per day, Lucie Nuts being made from nothing but lucerne which is naturally low in sugar and starch. Giving them this all in one go would be no different for them digestively than giving them 3kg of hay – but will likely be a lot more nutritious!
You couldn’t safely feed cereal feeds in these quantities and, due to their limited ability to digest them, often feeding more of a starchy cereal based feed doesn’t successfully promote weight gain.
What about our competition horses – surely they need energy from somewhere …
Feeding competition horses on a low starch diet means you can feed right up until the point you get on board. This helps line the stomach to protect against acid splash and work related ulcers, staves off hunger pangs to improve concentration, and supplies a direct energy source. This is a process we call a target feeding and it allows you to quite literally put fuel in the tank beforehand without compromising the horse digestively. You can also feed immediately after work to aid recovery and with the use of soaked mashes such as SimplyComplete, will also aid rehydration.
Travel is a major risk factor for gastric ulcers, this is unavoidable for many competition horses but by keeping starch levels low in the diet, you are at least controlling and reducing dietary related risk factors.
… and keeping starch low may even benefit their energy metabolism!
During work it is important to keep metabolism off the anaerobic, glucose pathway as this results in the formation of lactic acid and heat in the muscles, too much of which can trigger muscular discomfort or even exertional rhabdomyolysis - a tying-up episode.
If we can instead keep them on aerobic pathways, using free fatty acids as fuel (produced by the breakdown of fibre in the hindgut), lactic acid and heat are less likely to be produced in the muscles and the risk of discomfort is greatly reduced.
Energy released from the breakdown of fibre in the hindgut is also a more slowly released form of energy, we typically refer to Simple System Horse Feeds as being “non-heating” for this very reason. People find their horses have appropriate energy levels but that they sustain them more evenly: avoiding those typically hot first few moments and then the slump in energy which follows. This tends to happen on more conventional feeds where the quickly released energy from molasses and cereal starch is metabolised much faster and burnt through quicker.
Low sugar and starch intake can also benefit growing youngsters…
Growing foals and youngstock are best fed a low sugar and starch diet to reduce the heating effects these fast release energy sources can have, but also to avoid rapid growth and development which can cause joint issues such as Osteochondritis Dissecans (OCD), down the line. Forage fed yearlings on a low starch diet reach the same adult weight on a steadier growth plane and show improved handleability and inquisitiveness.
… and will look after their teeth into adulthood.
High sugar intake from molassed feeds can also negatively affect our horses teeth – just as children are warned by the dentist to not eat too many sweets or drink sugary fizzy drinks, equine dentists are seeing an increasing number of dental caries that are often linked to the feeding of molassed and starchy feeds.
In summary...
Whilst a low sugar and starch diet may be more commonly associated with overweight traditional and native ponies, considering the horses digestive physiology and how these nutrients may affect them energetically, enables us to begin to understand that keeping NSC levels low might be a good idea for all our equines!
If you are concerned about sugar and starch intake in your horse's diet, please contact the Feed Line on 01728 604 008. For a free, comprehensive Feed Plan, tell us about your horse by completing our advice request form here.