Feeding Horses and Ponies Prone to Laminitis: Part 2

As we continue our discussion on equine laminitis, we invite you to read Part 1 of this article series.

The Importance of Forage

Second to water, forage is the most important component of the horse’s diet. It’s also the largest source of ‘sugar’ and the hardest element of the diet for owners to control!

Furthermore, forage accounts for a significant portion—and in some cases 100%—of daily energy or ‘calorie’ intake.

Did you know that a 250-kg (550-pound) pony living out 24/7 can consume enough (calories) to fuel a racehorse? And they might take in almost 2 kg (4.4 pounds) of simple sugars per day from grass alone!

Minimum Forage Intake

For most leisure horses and ponies, total daily forage intake should not be restricted to less than:

1.5% of current bodyweight on a dry matter basis if they are overweight or very prone to weight gain.
2% bodyweight on a dry matter basis if they are at a healthy weight.

Some very overweight horses and ponies (or those that are genuinely weight loss resistant) might need a greater level of restriction. Keep in mind that more restriction should be done for the shortest time possible and under the supervision of a veterinarian and/or experienced nutritionist.

The term ‘dry matter’ often causes confusion, but it’s important.

Essentially, all forage—including dry hay—contains water. The water doesn’t count toward your horse’s forage intake.

The term ‘as fed’ is used to describe the amount of forage you weigh out, while ‘dry matter’ describes what you weigh out minus the water.

If you don’t increase the amount of forage you weigh out to account for the water content, you might end up restricting your horse’s intake too severely. This is especially true if you’re feeding soaked hay (see below) or the horse doesn’t have access to grazing.

How Much Hay to Weigh

The table below can be used as a practical guide to help you decide on how much hay to weigh out if you intend to feed it dry. Of course, every horse is an individual. The amount of forage you should feed will depend on many factors. Those include the calorie content of the animal’s current forage and how much of it is eaten (including grass). Your horse’s current body condition and how sensitive they are to changes in diet are also important.

Desired dry matter intake	As fed feeding rate for dry hay* (the amount that needs to be weighed out and eaten)
Desired dry matter intake	% bodyweight	Kilos per day 500kg horse Pounds per day 1,100-pound horse
1.5% bodyweight	1.8	9kg/4 lb
2% bodyweight	2.4	12kg/24 lb

*based on no grazing and a dry matter of 85%

Calculating Percent Bodyweight

If math wasn’t your favourite subject at school and calculating percentages feels daunting, the following example might help:

Bodyweight in kilos divided by 100 x 1.8 = 1.8% of bodyweight (kg)
500 divided by 100 x 1.8 = 9
1.8% of bodyweight for a 500kg = 9kg

Counting Droppings

In practice, calculating forage requirements and intake can be challenging, especially if you don’t know your horse/pony’s exact weight or if they have access to grazing. Although it might lead to a few raised eyebrows, counting droppings might be a more a practical way of monitoring forage intake.

If your horse/pony needs to lose weight, aim to reduce the number of droppings by a third initially. Never reduce the number by more than half.

Soaking Hay to Reduce the ‘Sugar’ Content

Soaking hay helps to reduce the water-soluble carbohydrate (WSC) or ‘sugar’ content. Losses due to soaking are highly variable, which means soaking alone doesn’t guarantee suitability for laminitics.

If your horse/pony is prone to laminitis, ideally have your forage analysed and feed soaked hay as a back-up. It’s important to check the lab/company you use will test your hay for water soluble carbohydrate or WSC + starch and what method they use.

Wet chemistry is the most accurate method of analysis, although ‘NIR’ might be a suitable alternative if the machine is regularly calibrated and the lab is very experienced with equine NIR. Speak to a nutritionist for more advice.

As a guide, soak hay for 1-3 hours in warm/hot weather (ambient temperature 16°C/61°F and above) and 6-12 hours in cold weather.
Use fresh water for every soak.
Make sure the hay is fully submerged in the water.
In hot weather, ideally soak your hay out of direct sunlight.
Soaking results in a loss of some vitamins, minerals, and soluble protein.
Dispose of the soaking water down an appropriate drain.

Steaming has little effect on WSC levels. Although not a practical solution for all owners, soaking followed by steaming in a commercial steamer is useful. It helps achieve the best of both worlds if you are trying to reduce the level of ‘sugar’ in your hay and improve hygienic quality. Note that homemade steamers might act as an incubator for bacteria and are not recommended.

Did you know that due to the loss of nutrients into the water, your haynet will contain less ‘hay’ after soaking? In fact, a net of hay weighing 8kg/18 pounds might contain approximately 7kg/15 pounds of dry matter or ‘actual hay’ before soaking and 5.5kg/12 pounds after soaking!

As a guide, increase the amount of hay you soak by 20% to compensate.

Grazing Tips for Horses Prone to Laminitis

Here are some grazing tips for those equids at risk of laminitis.

Restrict or remove grazing. Horses and ponies at very high risk of laminitis might need to be removed from grazing completely. This might be especially true during spring and autumn.
Beware of binge eating! Turning out for short periods might be counterproductive. Ponies can consume almost 1% of their bodyweight (dry matter) in only 3 hours. This can equate to two-thirds of the total daily forage allowance for those on a weight loss diet!
Consider using a grazing muzzle. Grazing muzzles have been shown to reduce grass intake by approximately 80% in ponies turned out for three hours, regardless of the season. However, some horses and ponies might simply eat more once their muzzles have been removed to compensate. Therefore, consider stabling or non-grass turn out for remainder of the day.
If available, consider non-grass turnout for those at very high risk or at certain times of year. This can be a useful way of encouraging voluntary exercise and providing time for socialisation.
Try turning out at times and in places where WSC/NSC levels are likely to be at their lowest. For example, this could be early in the morning, in shady areas, or on cloudy days.
Avoid turning out on pasture exposed to bright sunlight in conjunction with cold temperatures For example, don’t turn these animals out on sunny, frosty mornings.
Avoid turning out on recently cut hay stubble.
Where possible, avoid pastures with grasses likely to a have high water-soluble carbohydrate level content. For example, avoid predominantly rye grass pastures.
Seek specific advice from your nutrition team.