If your horse is underweight this expert advice for feeding poor-doers will set you safely on the right path

Need to know how to help a horse to gain weight? Whether it’s through age, type, illness or fussiness, some horses struggle to gain and keep on the pounds – and feeding horses like this can feel like an uphill battle.

Concerned owners should call their vet first to determine any underlying medical issues. It’s also wise to consult a qualified equine nutritionist for help tailoring your horse’s diet for weight gain.

It’s important to be sure your horse needs a significant increase in their body condition. Many horses in the UK are overweight and so your eye may be used to seeing horses that are fat, rather than fit. The glimpse of a rib or two coming into spring is healthy for most horses, so it is worth doing a body condition score check first before starting an active weight-gain programme.

Once you are confident your horse needs to gain weight, it’s not just what’s in the diet that counts. While feeding the best feeds for weight gain will usually have an impact, adjusting meal sizes, changing the types of forage the horse consumes, weighing feeds rather than guessing, and splitting feeds into smaller portions can also help a horse gain weight.

Looking for in-depth advice? Here are some helpful, practical tips from experts to help you tailor a poor-doer’s diet and optimise how you feed to make him gain weight.

How to make a horse gain weight: tips to help poor-doers

1. Consult your vet

“Remember that factors like stress, poor dentition, horse worm burdens or underlying health problems can also affect how well a horse maintains their weight,” says Katie Reeve, equine nutritionist at Dengie. “If your horse is struggling, it is worth contacting your vet.

“Speaking to an equine nutritionist is also helpful as they will be able to provide more tailored advice for your horse’s feed and forage.”

2. Underweight or undermuscled?

Louise Scott, senior nutritionist at D&H, explains that a horse’s muscle tone may give a false impression of their body condition. “Many horses lacking muscle and topline will look poor even if they have a healthy body fat level,” she explains.

“Conversely, some horses with a lack of topline and weak core muscles may have a dropped belly, making them look like an overweight horse even if they are underconditioned,” she continues.

“Take the time to assess topline and muscle tone, as well as rib cover and overall body condition score, before making any adjustments to your horse’s routine.”

She adds: “Calories are key to putting on body fat to support condition, so look for conditioning feeds that have a digestible energy content of 12MJ/kg or higher.”

Louise says that to support muscle development and topline, owners could focus on supplying adequate protein in the diet.

“Look for feeds with ingredients rich in quality protein, such as soya, or with added amino acids.”

3. Deliver more calories

Vanessa Allen, nutrition content manager at Spillers, reminds owners to ensure their poor-doers’ meals are calorie-dense.

“Oil is high in calories, relatively cheap, non-heating and starch- and sugar-free, so may be a useful addition,” she explains.

“With oil, 300ml is equivalent to 1kg of oats. Oil for horses should be introduced gradually, and it is advised to check with a nutrition specialist if you’re feeding more than 100ml per day.”

Katie of Dengie concurs. “If you’re interested in feeding fibre sources that are highly digestible, alfalfa and beet pulp are useful ingredients to look out for,” she says. “Using feeds that are low in sugar and starch is preferable for supporting gut health and helping your horse to get the most out of what you’re putting in.”

4. Investigate different energy source types

Emma Short, senior nutritionist at Baileys, encourages owners to be mindful of different energy source types – both what they are and how they work.

“The calories in quick-release sources are rapidly absorbed and readily available, so may not suit the fizziest types, but do work well for many horses,” she explains.

“Quick-release sources include carefully cooked cereals,” she adds. “They are used in higher-calorie horse feeds for weight gain because they are a highly digestible and concentrated source of extra calories for promoting weight gain.

“The starch they contain can increase acidity levels in the stomach, which may exacerbate gastric discomfort in the horses prone to gastric ulcers, however.”

On the other hand, slow-release energy sources include highly digestible fibres, known as “superfibres”, such as beet pulp, alfalfa and soya bean hulls, and vegetable oils.

“They provide more than twice as many calories as the same weight of cereals,” says Emma, and these are more suited to feeding horses prone to ulcers.

She adds: “Many conditioning and competition feeds now contain energy sources which take longer to digest and absorb into the bloodstream and do not exacerbate excitability, so are ideal for fizzy, stressy horses.”

5. Consider gut health as a whole

Some horses seem to eat well, but don’t gain weight as expected.

“Supporting the whole digestive system, from encouraging saliva production and helping to manage stomach acidity, through to supporting nutrient absorption in the small intestine, can make a real difference,” shares Jane Bansted, customer experience and advocacy manager at NAF.

She adds that adding an appropriate gastric supplement or gut balancer could be helpful. “Nourishing the hindgut with prebiotics, probiotics and postbiotics helps maintain a healthy microbial balance, supports efficient fibre digestion, and ultimately allows the horse to get more from the diet they’re already eating.”

6. Consider your forage – and forage alternatives

Emma Short of Baileys says the texture of your forage could hold information about its nutritional value. “Choose soft, leafy forage – hay or haylage should be clean and sweet smelling, but feel it in your hand and look for the least stalky bales.

“The stalkier the grass when it was harvested, the less digestible it is,” she continues. “So, try to find softer hay or haylage, with a higher leaf content, which will also be more nutritious and reduce the amount of additional calories that will need to come from bucket feed.”

If your horse is not a good hay or haylage eater, Emma suggests providing some alternatives, such as one of the best hay replacers. “Adding additional fibre sources in separate buckets alongside his forage to browse on and increase your horse’s overall fibre intake.

“This will supply some extra calories from digestible fibre but will also help ensure that gut health and digestive efficiency are optimised so that the system can make the most of the whole diet.”

7. What is ad lib really?

D&H’s Louise Scott acknowledges that feeding forage ad lib is best, but staying informed is even better. “Giving forage ad lib allows horses to self-regulate how much they want to eat,” she begins.

“However, it is important to be aware of how much you have provided, especially if your horse is underconditioned or your horses share access to forage, so you can notice if your horse is not eating enough or if there are any changes in his eating habits.”

Calculating how much hay to feed a horse depends on a few factors.

“Horses that need to gain condition should ideally receive around 2% of their total bodyweight in forage each day on a dry matter basis,” says Louise. “Dry matter refers to the amount of water in the forage and differs depending on whether you feed hay or haylage.

“Haylage contains more water than hay, so you need to feed more haylage to provide the same dry matter than if you were feeding hay.”

So, how much do you actually need to feed? “For a 500kg horse, 2% is equal to 10kg of forage on a dry matter basis. If you feed hay which is around 85% dry matter, this means feeding 12 kilos of fresh hay each day.”

The table below demonstrates the approximate fresh weight of hay or haylage you would need to feed daily, depending on your horse’s weight. Weighing haynets is easy to do with a handheld luggage scale (like this one on Amazon).

8. Know your bucket feed size

Vanessa suggests being clear on bucket feed weight, too. She adds that it’s good practice to weigh all your horse’s feeds to make sure you’re feeding the correct amount, and know how much your scoop holds.

“Keep meal sizes small, no more than 2kg per meal for a 500kg horse,” she advises.

“Feed three or more meals if you need to feed more than 4kg per day. Horses don’t digest large meals so efficiently; feeding large quantities may cause other issues or simply waste money.

“Smaller meals can be useful for tempting fussy horses – large meals can be overwhelming.”

How to help a horse gain weight quickly

According to H&H veterinary consultant Karen Coumbe, those with concerns about their horse’s weight and body condition are likely to benefit from a second opinion before rushing to feed him up quickly.

“Owners who see their horses every day can find it hard to perceive changes in their horses’ weight in either direction, or simply become used to how the horse looks,” she explains.

In Karen’s experience, the average leisure horse owner’s opinion on body condition differs from the average professional competitor. This depends on many factors, especially discipline, but what really matters is that weight and body condition are appropriate to the individual horse.

“When I’m working with racehorses, you can admire almost every bit of muscle on them,” she continues. “They’re built for speed, so there’s barely an ounce of excess fat there.”

Although the average horse owner does not own a racing thoroughbred, Karen adds that horses generally benefit from being on the leaner side.

However, if you’re worried about a very thin or emaciated horse, consult your vet and/or a professional nutritionist to avoid the dangers of refeeding syndrome.

“Certainly very thin horses are better fed back up slowly,” she says. “When we start to think about getting horses to gain weight quickly, it can be dangerous.”

Karen cautions against an immediately calorie-dense diet, adding an influx of volume and energy to bucket and forage at once. This can unbalance a horse’s fat metabolism, or the ability to break down and store fat, and do far more harm than good.

Abrupt changes to the diet can also contribute to gastrointestinal conditions, such as colic, or inflammatory diseases, such as laminitis. Gradual weight gain, therefore, is safest.

“A golden rule is to work a horse ahead of his feed,” she adds. “This helps avoid problems such as tying up (exertional rhabdomyolysis, or azoturia).

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