There are guidelines in order to estimate how much Digestible Energy (DE), Protein, Fibre and Oil (macro-nutrients) and how much vitamins and minerals (micro-nutrients) an equine’s ration should deliver. These guidelines depend on a number of factors, including workload, age, breed, temperament, management routine, clinical nutritional considerations (for eg., diagnosed with laminitis, EMS or PPID / Cushings Disease).
However, all equines are individuals and as such, they can vary hugely on the amount of nutrients that they require on a daily basis. Indeed, certain horses seem to be harder to feed than others – either they are consistently underweight or they are just fussy or ‘picky’ eaters.
This article is going to consider how best to manage these ‘poor do-er’s’, and assist with some nutritional hints and tips to keep them at a healthy weight and an ideal Body Condition Score (BCS).
Firstly, before any dietary change, a vet should always check an underweight horse or pony to ensure that the animal is healthy. Any clinical contribution to weight loss needs to be addressed by a veterinarian, as sometimes weight loss can be attributed to a high worm burden, poor teeth or a clinical condition, such as EGUS (Equine Gastric Ulcer Syndrome).
Once it is established that the horse is healthy, then in basic terms, the following should be remembered:-
For weight gain, daily energy intake must be greater than energy expenditure.
There are a number of ways that we can ensure this is the case:-
Encourage slow weight gain over several weeks,
Avoid sudden increases in feed,
Improve quality of forage fed,
Consider introducing some concentrate feed,
Ensure that high fibre content feeds are fed, as opposed to high starch content feeds (cereals),
Consider supplementation with high oil-based feeds,
Appropriate exercise will increase muscle tone and improve body shape, condition and topline,
If the horse or pony is kept outside, provide a rug and/or shelter for warmth, as this will reduce the energy expenditure,
Use a weigh tape or weighbridge to regularly monitor progress.
1. Encourage slow weight gain over several weeks and avoid sudden increases in feed
It is tempting to increase the rations of an underweight equine quickly, in order to see a rapid improvement in body condition. However, we should be mindful that the equine hindgut contains a resident microbial population, whose job it is to ferment all fibre-based feeds, and these microbes do not like sudden change. Ideally, then, we should introduce all new feeds slowly - over a period of 5 – 10 days - and we should aim for weight gain of approx. 1% BW (Bodyweight) / month. For the average 500 kg horse, that equates to approx. 5 kg gain / month.
Remember that to sustain a healthy weight, a horse needs to consume a daily ration of 1 - 3% of their bodyweight each day; and of that, at least 1.5 to 2% needs to be some form of forage (grass, hay, haylage). That equates to 5 – 15 kg of total feed intake for the average 500 kg horse just for maintenance - more will be needed for weight gain.
When feeding for weight gain, we recommend increasing the forage element of your horse’s ration, until their total feed intake reaches at least 2.5% of their desired body weight. In other words, if your horse currently weighs 500 kg and you would like them to weigh 550 kg, then your target would be 2.5% of 550 kg, or 13.75 kg of grass, hay or haylage. (Note:- these are DM (Dry Matter) totals. Haylage is lower in dry matter (DM) than hay, so adjustments will need to be made).
2. Improve quality of forage fed
Ideally, for weight gain, it’s important to feed the highest quality hay or haylage possible; look for leafy, soft and green hay as opposed to stalky, brown hay or haylage. There are huge variances in nutrient content of hay and haylage, so it’s also advisable to get your forage analysed in order to determine exactly what it contains.
Blending some good-quality alfalfa hay / haylage in with your horse’s ration of grass hay / haylage is another way to add nutritional value to your forage. Alfalfa is higher in calories and protein than most grass hays, which makes it an excellent choice to help to add weight to a thin horse. If your horse tends to be wasteful with their hay, they may eat more when offered alfalfa in the form of pellets.
Another effective fibre supplement is beet pulp, which contains the same digestible energy as good quality hay. Beet pulp contains high levels of pectins, which are highly fermentable, and so it is referred to as a ‘highly digestible fibre’ or even, a ‘superfibre’, as the dry matter digestibility is approximately 80%. (Hyslop, et al., 1998) This also helps to make it a great source of slow release energy.
3. Consider introducing some concentrate feed and ensure that high fibre content feeds are fed, as opposed to high starch content feeds (cereals)
Forage may be the cornerstone of any equine ration, but it’s not always high enough in calorie content in order to maximise weight gain, and also, there is a limit to how much a horse will eat in a day. If your horse has been consuming all of the forage that they want, and they still are not gaining weight after several weeks, then, it’s time to add more calories to their ration.
The safest way to increase the digestible energy in your horse’s ration is to bolster the fat content. Many people are inclined to reach for cereal-dense feeds, such as barley rings or bran, in order to aid weight gain. However, these carbohydrate-loaded cereal-based feeds are high in starch. High starch diets are not recommended as they can lead to unwanted excitable behaviour, as well as acidosis of the hindgut, EGUS (Equine Gastric Ulcer Syndrome) and they can exacerbate wide fluctuations in blood glucose and insulin levels.
4. Consider supplementation with high oil-based feeds
Oil is a high-energy feed, and when it is metabolised in the equine gastro-intestinal tract, it delivers 2.5 times more energy than any other food source (carbohydrate, protein, etc.) on a like-for-like basis (Pilliner & Davies, 2004).
One of the simplest ways to add oil to your horse’s ration is to simply ‘top dress’ the ration with a liquid form of oil, for eg., soya oil, vegetable oil or linseed oil. However, it is important to note that not all oils are the same and specifically, they contain varied levels of Omega 3 and Omega 6 fatty acids. High levels of Omega 6 in fats and oils promote inflammatory responses, whilst Omega 3 fatty acids don’t. It is therefore considered desirable to have twice as much Omega 3 fatty acids in the ration, in comparison to Omega 6 fatty acids. The oil with the highest amount of Omega 3 fatty acids is linseed oil (with 53g per 100 ml of oil). (Marlin, 2017)
As with any other dietary change, oil needs to be introduced slowly. Too much, too fast, and your horse will develop diarrhoea and steatorrhea (fatty stools) - manure will have an oily sheen from undigested oils passing through the gastro-intestinal tract. In addition, we need to be mindful that feeding oil increases the horse’s use of Vitamin E so that, when we increase oil levels fed, we should also increase Vitamin E levels – at a rate of 1 IU per ml of oil (Marlin, 2017)
It is also worth noting that when feeding oil in a liquid form, it makes no contribution to the micronutrient or protein requirements of the equine. In other words, it simply provides additional calories or DE (digestible energy) but is nutrient-lacking.
However, when feeding additional oil in a ‘solid’ form, for example, rice bran, micronised linseed meal or soybean meal, macro-nutrients as well as additional DE, are metabolised. For example, micronised linseed meal is incredibly high in protein (approx. 23%), as well as being very low in both starch and sugar (4% and 5% respectively). It is therefore, a useful inclusion in a ration of a ‘poor do-er’ that also has a clinical nutritional disease, such as laminitis or PPID / Cushings Disease.
It is now becoming very common to use oils or high oil containing feeds, in the diets of many performance horses as well as for those needing to gain weight. Typically, oil is a frequent addition alongside low energy feeds, as it allows us to put a greater emphasis on fibre-based energy sources, thus, delivering an overall ration with reduced reliance on starch levels.
5. Appropriate exercise will increase muscle tone and improve body shape, condition and topline
Exercise, alongside a ration delivering a horse’s daily crude protein requirement, will aid condition and body muscle development. Condition cannot be achieved by feeding alone.
it is also worth noting that feeding more protein in a ration will not lead to more muscle development. A recent study concluded that, ‘exercising horses fed 160% of their crude protein requirement showed increased water intake, nitrogen excretion, and urine volume compared to exercising horses that received the recommended crude protein requirement. Carrying additional water weight can hamper overall performance.’ (KER, 2020)
Horses typically gain muscle throughout their bodies, not in one specific region. With a proper, balanced, feeding regime and regular exercise, your horse should develop condition.
6. If the horse or pony is kept outside, provide a rug and/or shelter for warmth, as this will reduce the energy expenditure
An underweight horse or pony will benefit from a rug as this will prevent them increasing their metabolic rate and using more energy to keep warm, leading to further weight loss. In addition, older or ill horses, typically have more difficulty regulating their body heat meaning the use of an appropriate rug will benefit them in the colder weather. Some older horses may also have difficulty maintaining their weight and experience an arthritic flare up from the cold and damp, which reduces movement and reduces the creation of body heat.
7. Use a weigh tape or weighbridge to regularly monitor progress
The basic concept behind fattening up a thin horse is fairly simple: Feed them more calories or DE (Digestible Energy).
Sometimes it can be hard to judge progress, so it helps to regularly keep a log and monitor their weight, in order to accurately gauge progress made. Finally, remember, if you have trouble maintaining the horse at their ideal weight, please don’t hesitate to consult an independent equine nutritionist.
