Many horses are currently looking rather lean, probably due to the combination of the extended winter conditions and the lack of grass. For good doers, laminitics, horses with equine metabolic syndrome and any prone to carrying too much weight, this is good news! Such horses ideally should enter the spring in lean condition.
For horses who have lost too much weight or are going into moderate to hard work and have high energy requirements, you need to know how to adjust the diet to cause weight gain (or maintenance). Weight gain (or maintenance in horses with high energy requirements) relies on provision of enough energy (megajoules, sometimes described as calories) in the diet. For weight gain, you simply need to feed more energy than the horse uses, to cause body fat to be laid down.
First and foremost, consider your horse’s forage and ideally choose the highest energy forage you can source. The more nutrients a horse receives from forage, the healthier for the horse. Early cut hay or haylage fed ad lib would be ideal. Ensure your lean horse always has access to forage, both in the stable and out at pasture. Turning your horse out all day to pasture that contains no grass, without supplementary forage is one way to guarantee weight loss! Ensure there is always a little forage left in the stable in the morning.
After you have ensured ad lib (free choice) forage, add extra energy (calories) with concentrate feed. Useful concentrates include medium to high energy compounds (high digestible fibre, low starch is the best choice), unmolassed sugar beet and oats (but these must be balanced correctly). Gradually increase up to the full recommended amount of your choice of feed, split into (ideally) 3 meals daily. Be sure to weigh unmolassed sugar beet out before you soak it, to ensure you feed enough for weight gain.
On top of this you can add an oil-rich supplement or vegetable oil. If you add linseed oil your horse will benefit from the high levels of the essential omega-3 fatty acid alpha-linolenic acid. Gradually increase up to 300 ml daily for a 500 kg horse, if necessary.
For horses that struggle to maintain weight on an ongoing basis, or show signs of digestive disturbance, add a probiotic supplement to their diet e.g. Yea-Sacc.
Older horses with dental problems need a different approach because they are usually fibre, as well as energy deficient. Most need part, or all, of their forage replaced with high fibre feeds. A combination of high fibre nuts and unmolassed sugar beet can work well, but needs to be fed in large enough quantities to replace forage e.g. 4 kg overnight for a horse who – due to poor chewing ability – is eating only a kilo or two of hay overnight.