Dr. Stephanie Wood, PhD Equine Nutrition, PgDip,
BSc (Hons), RNutr (Animal), R.Anim.Tech
Feeding horses seems to have become a complicated business. An internet search with the term ‘how to feed my horse’ produced over 140 million results, showing how there is now a vast amount of information available to owners and carers of horses. Not all of those search results will be relevant, but if we also add in information provided in magazines, videos, from equine feed and supplement producers, from animal welfare charities, vets, instructors, farriers and the multitude of social media groups dedicated to the topic of equine health, nutrition and management, it is easy to see why people can become confused and overwhelmed by the task of feeding their horse. Many of these sources provide correct information that is based on sound scientific research and practical experience, however some information, particularly that from unverified sources, contains inaccuracies and recommends inappropriate feeds or rations. This short article outlines the key points to consider when deciding what to feed your horse and in what quantities.
Two terms that are often used when discussing equine nutrition are diet and ration. Diet refers to the feedstuffs the animal is eating. Grass, hay, oats, sugar beet, competition mix, and supplements are all examples of feedstuffs. The feeds consumed supply the nutrients that the horse needs to sustain life and perform any additional activities, such as heal, grow, reproduce, or perform exercise. The level of nutrients within feeds and the availability of those nutrients to the horse, varies depending on the feed type, the nutrient profile, the combination of feeds fed, and the form in which feeds are given. For example, forages are generally higher in structural carbohydrates (fibre) and lower in soluble carbohydrates (starch and sugars) and protein, compared to cereal grains, and processing feedstuffs (cooking, crushing, grinding) generally makes them more digestible than if they were fed in their natural form. The term ration refers to the amount of feed given to the horse, in total and of each individual feedstuff. Some horses may be fed a forage only diet meaning that the total ration is also provided as forage, whereas others may have a diet that comprises of forage, concentrate feed and a supplement. The total ration for these horses is the total amount of feed consumed on a daily basis, made up of the individual rations (amounts) for each feed type. When deciding what to feed your horse, the feeds selected (diet) and the amounts fed (ration) need to be considered in combination to ensure their nutrient requirements are met.
Outlined below are some of the steps to take when developing your horse’s diet and ration.
IDENTIFY THE OVERALL AIM OF THE FEEDING PROGRAMME
As mentioned above, it is important to know the aim of your horse’s feeding programme. This could be as simple as keeping everything the same, or it could be more complicated with the aim of improving a specific health issue or reducing your horse’s body weight whilst ensuring they have enough energy to perform more demanding exercise. Identifying the aim of feeding programmes is what makes them individual to each horse and leads to an endless answer to the initial question of ‘how to feed my horse’. This is what makes the subject of nutrition so challenging, as there is no single diet and ration that will work for all horses. There are however general principles that support the horse’s physical and behavioural wellbeing which are outlined below. Taking the time to identify what you want to achieve through the feeding programme will help to keep you focused on the overall aim as you examine your horse’s more specific requirements.
Figure 1. Feeding programmes should be individual to each horse, tailored to their specific requirements.
CONSIDER YOUR HORSE'S PHYSIOLOGICAL AND BEHAVIOURAL REQUIREMENTS
Equids have a gastrointestinal tract (GIT) developed to process large amounts of plant material that is of relatively low nutritional value. The article Your horse’s gut: gastrointestinal structure and function describes in detail the equine GIT structure, the importance of chewing and feeding fibrous feedstuffs, and some of the consequences of feeding cereal grains in large amounts. When developing equine feeding programmes, it is important to account for GIT structure and the processes involved in the breakdown of ingested food. The trickle feeding strategy of equids also needs to be considered, as this has consequences on GIT health and behaviour. Grazing and chewing are appetitive behaviours in equids, meaning that all equids have a natural desire to perform these behaviours to satisfy a bodily need (Roberts et al., 2017). If these behaviours cannot be performed due to not having access to grass or forage (low forage diet or restricted eating time), other behaviours replace the desired behaviour as the horse is still motivated to perform such behaviour. This can lead to undesirable behaviours such as crib biting, windsucking and wood chewing which then become habitual behaviours, making them extremely difficult to correct even when access to forage or grazing permits normal behaviour (Roberts et al., 2017). As such, reducing the likelihood of such behaviours developing in the first instance is preferred, through management and feeding practices that enable grazing and chewing for most of the day. For equids that are underweight or who maintain a healthy weight easily, feeding forages ad libitum is an easy way to satisfy this physiological and behavioural requirement for trickle feeding. Additional feedstuffs to supply protein, vitamins and minerals, can then be added in measured amounts to satisfy requirements. Equids that are overweight or gain weight easily can be more challenging unless the right feedstuffs are selected. Horses should eat between 2% and 2.5% of their body weight per day on a dry matter (DM) basis (NRC, 2007), although many can consume much higher amounts than this. For a 425kg horse this equates to 8.5kg of DM each day. An overweight body condition shows that energy is being consumed in excess, therefore the balance in these situations is feeding enough food to satisfy the daily DM requirement, without feeding excess energy. Selection of appropriate feedstuffs holds the key. If feedstuffs that are low in energy are selected, then enough can be fed to allow trickle feeding. Low energy chaffs or chopped straw are just two examples of potential feeds for such situations, but these must still be fed in appropriate amounts to prevent excess intakes. This is just one example of how diet and ration must both be considered when deciding your horse’s feeding programme.
This is also the time to consider specific health issues your horse has as these can influence what feeds can be fed, what feeds need to be avoided, and the form of feeds. Dental health greatly influences the types of feeds that can be grasped and chewed, and so must be considered (see The importance of regular dental care). The most nutritious feed is no good if it cannot be chewed to a small enough size to be swallowed. Horses affected by certain health issues such as insulin resistance or polysaccharide storage myopathy (PSSM) benefit from diets that are low in starch and sugar (Naylor, 2015; Durham et al., 2019), whilst those with respiratory issues benefit from low-dust forages, meaning that hay often requires soaking or steaming (Invester et al., 2014; Moore-Colyer et al., 2016). Consideration of these factors combined with the overall feeding aim enables suitable feedstuffs to be identified.
EVALUATE THE SETTING AND FACILITIES YOU HAVE AVAILABLE
An often overlooked consideration when developing feeding programmes is the setup of the facilities where the horses live, the management routines to be followed and access to the desired feedstuffs. If your own commitments or the horse’s routine only permit twice a day feeding, then there needs to be consideration of how to prolong eating time to enable trickle feeding for the period between feeds. Similarly, if hay needs to be soaked or steamed to remove dust yet there is no water supply or temperatures are below freezing, feeding haylage may be more practical. Being able to source your preferred feedstuffs is also important to ensure a consistent diet can be fed. If the local feed merchant is your only option for purchasing feed, and they only stock certain brands, then selecting a feed from that range will ensure continued supply. Alternatively, if you live in an area where feed can be delivered then ordering online increases the range of feedstuffs you can choose from. What is important is that the diet can remain consistent as sudden dietary changes can cause digestive upset.
KNOW YOUR BUDGET
Continuing the theme of consistency, it is important to select feedstuffs that you can continue feeding for a prolonged period of time. This means they need to be within your budget. Bulk buying is generally cheaper so long as the feed can be stored correctly and it can be fed before it goes out of date. Changing feed brands, even between feeds with the same or similar name, can cause digestive upset as the microbial population within the GIT has not had time to adapt to differences in the ingredients and formulations of feeds that may initially appear the same.
ASSESS YOUR HORSE'S BODY WEIGHT AND FAT STORES
At this point, the aim of the feeding programme, the horse’s individual requirements and how the feeds are going to be fed should all have been identified. It is now important to assess the horse’s body weight and fat stores. You may already have identified if they need to gain, maintain, or lose weight, however it is important to record body weight and fat stores so changes in these parameters can be monitored over time, and the feeding programme adjusted accordingly. Accurately measuring body weight can be achieved with access to a weigh scale which many owners do not have. Alternatively, an equine weigh tape provides an estimate of body weight. The accuracy of weigh-tapes varies depending on the frame of the horse, often underestimating body weight. Despite these inaccuracies, weigh-tapes provide a better alternative than a best guess and are useful in identifying increases and decreases in body weight. Knowing your horse’s body weight enables the amount of feed (ration) to be calculated correctly as all feeding recommendations are based on body weight.
Knowing if a change in fat stores is needed enables feeds with an appropriate energy content to be selected. Remembering that horses should consume 2% - 2.5% of their body weight per day as DM, for horses that need to gain weight, offering more energy dense feeds enables them to consume enough energy within their daily appetite. Simply offering more of a lower energy feed does not result in weight gain as they are physically unable to eat enough to gain weight. Similarly, feeding a high energy feed to overweight horses leads to weight gain as they eat to satisfy their DM requirements, or the amount they can eat must be severely restricted to limit energy intake, but with a negative effect on their GIT health and behaviour. Selecting feeds that are designed for the purpose of the feeding programme is a good place to begin as these allow you to feed the manufacturer’s recommend daily amount, which for feeds containing vitamins and minerals, will also provide the correct amounts of these nutrients to balance the diet. If you are unsure about which feeds are most suitable, contact a nutrition professional who will support you in selecting the most appropriate feeds for your horse.
FORAGE FIRST, THEN ADD IN ADDITIONAL NUTRIENTS
Forage should be the main feedstuff in every horse’s feeding programme, regardless of whether they are a top-level performance horse or retired and living leisurely in a field. As previously explained, forage provides fibre which is needed for healthy GIT function, particularly hindgut function, and to satisfy the need to chew. Fermentation of fibre also provides slow-release energy, enabling some horses to meet their energy requirements from a forage only diet. The process of fermentation also produces considerable heat which the horse can use to help maintain body temperature during periods of cold weather. Providing as much of your horse’s daily ration as forage is advised, with additional feedstuffs added in to compliment the forage. Such additions include a vitamin and mineral supply as the level of these nutrients varies in grass and reduces after grass has been cut and dried to produce preserved forages (Richards et al., 2021) (see Forage options for horses). Options for supplying vitamins and minerals include vitamin and mineral supplements, balancers (vitamins and minerals plus a protein source), chaffs containing a vitamin and mineral pellet, and concentrate feeds. The amount of additional energy and protein your horse needs should guide your choice of vitamin and mineral supply. If your horse requires more energy than the forage can supply, you could select a concentrate feed to provide the energy, protein, vitamins and minerals. In contrast, for horses able to meet their energy requirements from forage, then a balancer or vitamin and mineral supplement would be more suitable as these provide very small amounts of energy. For horses sensitive to cereal grains but requiring more energy, oil, or a high-fat feed such as linseed, can be added to the diet alongside the forage and vitamin and mineral supplement.
Supplements for specific purposes can also be added at this stage. The need for supplements should have been identified when considering your horse’s physiological and behavioural requirements. Suitable supplements designed for that specific purpose can then be selected. There are now options to combine individual supplements in tailor-made, bespoke formulations calculated to your horse’s specific requirements. Such options simplify feeding, which is helpful for those short on time or based on livery yards where others are responsible for making up and giving feeds to your horse. What is important for all supplements is that they are fed for a specific reason and not because other horses have them in their diet. This ensures the supplement can have the effect it was developed to have and prevent unnecessary feedstuffs being included in the feeding programme.
SUMMARY
Deciding what to feed your horse can seem daunting and is made even more challenging by the vast amount of information on the subject and the extensive number of feedstuffs on the market. Ensuring you identify the key aims and requirements of the feeding programme is essential to enable correct feeds to be selected. Manufacturers of quality equine feeds and supplements provide guidance on the amounts that should be fed, although there is still a requirement to assess your horse regularly to determine if the feeding programme is suitable and if any changes are needed. Speaking to a qualified equine nutritionist, preferably one registered with the Association for Nutrition (able to use the title RNutr Animal), is advised as they will help guide your choice of feeds and supplement and calculate the correct ration for your horse.
REFERENCES
Durham, A.E., Frank, N., McGowan, C.M., Menzies-Gow, N.J., Roelfsema, E., Vervuert, I., Feige, K., Fey, K. (2019). ECEIM consensus statement on equine metabolic syndrome. Journal of Veterinary Internal Medicine, 33: 335-349.
Invester, K.M., Couëtil, L.L., & Zimmerman, N.J. (2014). Investigating the Link between Particulate Exposure and Airway Inflammation in the Horse. Journal of Veterinary Internal Medicine, 28: 1653-1665.
Moore-Colyer, M.J.S., Taylor, J.L.E., & James, R. (2016). The effect of Steaming and Soaking on the Respirable Particle, Bacteria, Mould, and Nutrient Content in Hay for Horses. Journal of Equine Veterinary Science, 39: 62-68.
Naylor, R.J. (2015). Polysaccharide storage myopathy – the story so far. Equine Veterinary Journal, 27(8): 414-419.
NRC (2007). Nutrient Requirements of Horses, 6th Ed. The National Academies Press, Washington, USA.
Richards, N., Nielsen, B.D., & Finno, C.J. (2021). Nutritional and Non-nutritional Aspects of Forage. Veterinary Clinics of North America: Equine Practice, 37(1): 43-61.
Roberts, K., Hemmings, A.J., McBride, S.D., & Parker, M.O. (2017). Casual factors of oral versus locomotor stereotypy in the horse. Journal of Veterinary Behaviour, 20: 37-43.