As long as we have decent grasslands, all a young horse needs is grass, hay, balanced mineral nutrients and salt, with added protein to compensate what’s missing in their forage. This is all they need to grow into a strong, healthy adult horse. But - there's a way to do it wrong, and a way to do it right.

As we’re now experiencing long, and very dry, summers which parch our grasslands, we need to focus on additional feeding during the summer months with adlib hay. For the young horse this means they’ll naturally lack essential protein for their development, which they would normally get from fresh grass. Hay protein levels are fine for the adult horse, although WBs, TBs and our heavier horses may need a little more daily protein, but for the young growing horse, we need to consider additional protein sources.

For our youngstock it’s not just about the protein quantity, but the quality, and the thing is that there’s quality protein versus questionable protein. Protein depends on the proportion of essential amino acids, i.e. those that the horse does not produce itself but has to absorb from its food. You’ll find all manner of soya variables in feeds these days which is very rich in protein, but for our horses it’s not only an inferior protein but there a whole lot of other reasons why it's not appropriate to feed to our horses - the science is now showing that soya is not the nutritional magic potion of the 21st Century that we all once thought it was. And ... let’s not forget it’s also ecologically questionable.

Proteins are built up in the body from amino acids that are chained together in a very specific order, and if an amino acid is missing, the protein can't be formed. All non-essential amino acids are produced in the gut, but three essential amino acids for horses need to come from feed, specifically lysine, threonine and methionine. Soya falls short here, and all the more so since soya also contains a starch called stachyosis, which can’t be digested in the small intestine.

An ideal source of protein for horses is sainfoin (not alfalfa, for many reasons listed here). It’s the leaf and flowering tops that provide the higher protein, and you’ll find these in sainfoin pellets. Avoid chopped as this is mainly produced from the stalk only, and also the fibre length can’t be chewed properly which can cause dysbiosis in the hindgut.

Sainfoin pellets provide around 15% crude protein content with a high proportion of the three essential amino acids; it's also easily digestible and starch-free. Unlike it’s legume sister, alfalfa, it doesn’t make the body photosensitive and also contains no oxalates (which bind to minerals like calcium, preventing the body from absorbing beneficial nutrients in the digestive tract). It’s also high in tannins which have a stabilising effect on the intestinal environment and promote the utilisation of proteins contained in feed, so the entire feed ration is better utilised overall.

Now to how youngstock grow, and they always grow in spurts. One minute they’ll look like a normal, well-covered if not a little bit overweight, horse, then there’ll be a growth spurt where they’re suddenly 10cm higher at the back than the front, often within a few days, and you can now count all the ribs.

The protein will have built up reserves for the growth spurts which are then quickly used up, so the weight you have fed is then immediately utilised. Within around 6-months that growth increase in the hindquarters is then matched by the fore slowly growing back until the horse looks balanced again, but likely mostly still thin. Then the cycle starts again; the protein in the feed will increase the weight again and just as you start thinking about reducing their feed, the next growth spurt comes.

It's perfectly normal for young horses to be lean to a bit ribby during their early years, but what we should always be mindful of is that over-feeding them protein so they look ‘round’ will put too much pressure on their immature joints and increase the risk of developing OCD (osteochondrosis dissecans). Hence why we should always match protein feed levels to their respective stages of development.

Since sainfoin not only provides protein, but also makes the entire ration more digestible due to the tannins it contains, relatively small amounts are often perfectly sufficient. If you notice that your horse is slower with the next growth spurt, add a little more. If you can no longer see the ribs, then reduce the protein again. Be careful what scoop you use to measure, as with the larger scoops there’s always a temptation to overfeed - the general rule of thumb should be that less is more.

Also, always be mindful of foal 'starter’ feeds, as their composition aims to grow and fatten the young horse quickly, so they look like a ready-made little riding horse far too soon. This not only makes them wrongly look healthier for future purchasers, but above all will encourage too much to be asked of them far too early, with many often backed/broken as 3-yo’s and competing in major sports by the age of 4 while their immature body is still growing. Turbo-grow your young horse and you risk ending their working life far too soon.

What you see with these starter feeds is not healthy growth; their bone structure is still very undeveloped, with the extra bodyweight too heavy for their joints which risks early posture issues. It's only by the age of 5/6 that the last growth plates become fixed and rigid, although their muscle still continues to develop. Finally, at around 8yo, they’re all grown up.

Giving our young horses the necessary time to grow and develop is absolutely essential, otherwise it’s the horse that pays the price. Broken tendons/pasterns, chronic navicular disease, kissing spines, inexplicable lameness, chronic musculoskeletal disorders, stress-related stomach ulcers, refusal to perform, burnout - all issues that could so be avoided if young horses were given more time to grow up.

The take-home message is, don’t fatten your young horse during their early years. To finish as we started, all they need is grass, hay, balanced mineral nutrients and salt, with added protein to compensate what’s missing in their forage when needed. This is all a young horse needs to grow into a strong, vibrant, healthy adult horse.