What is a balanced diet?
You’ve probably read about the importance of feeding a balanced diet to your horse on numerous occasions, but what does it mean in practice? In simple terms, a balanced diet is one that contains the nutrients required by an individual according to their specific requirements for work, life stage or reproductive status. Where things get a little more complicated is establishing what those requirements are in the first place and then, working out the contribution each part of the diet is making! Let’s start with working out what the requirements are.
How much of a nutrient does a horse need?
In the UK, the National Research Council’s Nutrient Requirements of Horses tends to be the reference text used as a basis to determining a horse’s nutrient requirements. This text originates in North America and was last published in 2007, so when a nutritionist is formulating a horse feed or supplement, they will also review more recently published research that may indicate a higher or possibly lower level of a particular nutrient is advocated for a certain situation.
It is important to consider at this stage that there are ranges within which a nutrient level can be consumed without causing a problem such as a deficiency or toxicity. The graph shows how there is an optimal level and then a range around optimal before a toxicity or deficiency situation is reached. As long as levels of each nutrient are in that range then the horse’s diet can be considered balanced as it is impossible to achieve optimal levels for every nutrient all at the same time, especially given how the nutritional value of pasture varies throughout the year.
The optimal range varies for each nutrient; selenium, for example, is the mineral with the narrowest above optimal range before causing a toxicity issue. Acute toxicity issues in horses are rare but the potential for a chronic issue exists. It is not unheard of for 3 or more feeds and supplements containing selenium to be fed at the same time which may be enough to cause a chronic toxicity.
Another interesting area that often causes confusion is that of fibre versus forage. Fibre is the nutrient that forages are generally abundant in relative to other feed materials. However, you may be surprised to know that a fibre requirement for horses has not been established, instead, advice is that forage should make up at least 1.5% of a horse’s bodyweight per day. It could therefore be argued that a balanced diet for horses is also dependent on this minimum amount of forage being fed each day, although it is important to note that a horse’s diet isn’t unbalanced if more than 1.5% of forage is fed!
How do we know what each feed ingredient is contributing?
When formulating a horse feed a nutritionist will have reference values for the levels of nutrients found in commonly used ingredients. Some ingredients are more consistent in their nutrient levels than others and because there is a legal requirement for a feed to be within a certain range of what is declared on the bag or tub, equine nutritionists will typically use more of the most consistent ingredients. Regularly testing feed materials as well as the finished feeds allows equine nutritionists to adjust formulations or declarations accordingly.
The complicating factor for both nutritionists and horse owners is the contribution that forage is making to the horse’s requirements. The nutritionist has to take into account the contribution from forage when formulating a feed or supplement as it is the total intake of nutrients from the whole horse’s diet that determines whether the diet is balanced. As you can imagine, there are a number of variables for nutritionists to consider including how much is fed and how good a quality the forage is.
For the vast majority of horses this works fine as the very definition of average is that it represents the most individuals in a population. However, a more nuanced approach may be required for extreme situations, such as the very good doer on restricted forage rations to promote weight loss or the elite performance horse who may be competing in exceptionally hot and humid conditions. In these situations, seeking out feeds and supplements designed specifically for those types of horses is likely to mean that the nutritionist has taken into account additional factors and designed the formulation to reflect them.
The key point for the horse owner is that none of these products will do the job they are intended for if they aren’t used correctly. It is really important that the horse’s weight is known and the amount outlined on the pack for the size of horse is used to ensure the diet is balanced. If you find that you are needing to feed significantly more or less than the recommendation then it probably means you’ve got the wrong feed for your horse and the diet is not likely to be balanced.
How do I know if my horse’s diet is balanced?
A diet can be balanced on paper but the proof is in the horse; if they look well, are the correct weight and are able to perform the level of work required, then it is a good indication the diet is balanced. If the horse isn’t right, then an adjustment may be required even if the diet appears to be balanced – remember that nutrition is the science, feeding is the art! This is most likely in situations where a horse has a disease or underlying health issue and it is important that the whole diet is assessed. Analysing the forage is usually helpful as it is likely to be making up at least half of the ration and so will be having a significant impact on the total ration. Most horse feed companies can arrange a forage analysis for you for which they may charge or your forage supplier may be able to provide you with some detailed analytical information. The nature of the problem will determine which analysis information is going to be most relevant and helpful and your vet or equine nutritionist can advise you on this.
In the case of a particular nutrient shortfall, a nutritionist may advise supplementing with an individual nutrient. Care should be taken in doing this as minerals, in particular, compete with one another for absorption sites in the gut and so increasing one may drastically reduce the uptake of another which can cause further issues. Animals are also usually efficient at regulating uptake of nutrients from the body – increasing consumption doesn’t necessarily mean more will be absorbed, especially if the body doesn’t think it needs it and so can be a waste of money.
In general, nutrients from plant material are absorbed more efficiently by the digestive tract than inorganic (mined sources). For example, alfalfa and sugar beet are both abundant in calcium which is more bio-available than that from limestone flour. A study by Swanhall et al (2019) also showed that calcium source had a significant effect on calcium digestibility with calcium from marine origins being better absorbed than that from limestone flour. An added benefit was that the marine origin calcium was also less negatively affected by the use of ulcer medications containing omeprazole.
So, the take away messages about feeding your horse a balanced diet are:
- Feeds and supplements are designed to be fed at a certain weight according to the horse’s bodyweight – if you need to feed more or less then you probably have the wrong feed
- Minerals interact with one another and compete for absorption sites – take care if supplementing one mineral in isolation as it will impact on others
- Forage makes up at least half of most horses’ rations and so often has a significant impact on whether the diet is balanced – analysis is particularly useful if a horse has a disease or underlying condition
- There are many variables impacting the nutrients levels in forages – the rest of the diet may need to be adjusted to reflect the changes seen in forages throughout the year
If you would like advice on the balancing your horse’s ration, call our Feedline on 01621 841188 or click here to complete our Feed Advice Form.