O – Orthopaedic disorders and their effect on how to feed the young horse

Growth disorders are something that every horse owner wants to avoid. There are many things that can be done to help prevent developmental orthopaedic disease (DOD); nutrition is one of the pieces of the puzzle.

Genetics

DOD is a descriptive term which covers an array of joint and bone disorders seen in growing horses. This includes osteochondrosis dessicans (OCD; defective bone and cartilage at the joint surface), epiphysitis (enlarged, painful growth plates) and also flexure and angular limb deformities.

The cause of DOD is multi-factorial and genetics play a big role. Horses with a genetic predisposition for a large mature size (eg Warmbloods) often develop skeletal problems regardless of how well they are fed and managed as youngsters.

So, it is important to realise that it is not always the keeper’s fault if DOD occurs. Management and nutrition, however, are the two things that we can do something about to help alleviate any genetic predisposition.

Good bones

It was once thought that high protein diets were the cause of DOD but research has well and truly dispelled this myth. It has been shown that feeding high energy diets with an imbalance of nutrients is the most common cause.

Diets for young horses must be formulated with great care. Nutrients such as protein, calcium, phosphorus and other minerals and vitamins must be provided in the correct amounts relative to each other and in balance with the amount of energy fed.

This is because growing horses fed high energy diets with nutrient imbalances may grow faster than their bones can develop, leading to DOD. Quality protein is crucial to help prevent the development of DOD.

Bone consists of protein and mineral components. The protein (osteoid) makes up 20% of mature bone. The mineral components are primarily calcium and phosphorus.

Protein forms the framework on which these minerals are deposited and so is an essential part of the young horse’s diet, especially as it is also crucial for muscle development, healthy hooves and coat condition.

Steady growth

Consistency of growth is just as important as the rate of growth. In fact, research has shown that it may even be more important. In a trial where feed was restricted in foals for four months and then uncontrolled; 65% of them developed deformities.

None of the control horses, who were maintained at a consistently moderate growth rate, had any problems. Sudden changes in growth rate must therefore be avoided.

This can be quite tricky when it comes to the spring flush of grass, so make sure that you keep an eye on your youngsters growth rate and condition score (never allow your foal or yearling to become obese), and adjust the energy content of their feed accordingly. Remember that it is energy and not protein that makes horses fat.

Exercise is

good for them

Environment is the third essential bone building factor. Foals and all youngsters should be turned out as much as possible in as large a space as possible. This is because bone strength and development also requires exercise. Animals that are shut in during the crucial first two years will have lower bone strength compared to their outdoor counterparts and this can lead to future lameness problems when it comes to bringing them in to work.

Forced exercise, however, (eg lunging in circles etc) is not good for the developing skeleton and should be avoided.

Key nutrition

We have ascertained that for healthy skeletal development the young horse requires minerals (particularly calcium and phosphorus), vitamins, trace elements and protein.

Energy is required for growth but should be adjusted, according to grass/forage quality, climate and paddock size (amount of exercise), to maintain consistent but moderate growth. When feeding youngsters it is always worth feeding a compounded feed to ensure that there are no deficiencies.

Proprietary feeds will be balanced for all the important nutrients and, therefore, takes away any guess work. Most feeds formulated for non-Thoroughbreds are of the concentrate type (a specialised balancer), to provide all the protein, minerals etc in a balanced form that the youngster requires without excessive amounts of energy.

These include Suregrow (pellet) and Mare and Youngstock mix from Dodson and Horrell. This type of product is great for good doer types as energy can be adjusted accordingly by using forages (including grazing), oil or beet pulp.

There are also many other proprietary ‘stud’ balancers available and feeds specifically targeted towards thoroughbreds who are likely to be in training by two years old.

Be sure to select the feed appropriate for your situation, advice is available so please do seek it out if you are in doubt.

Cereals and starch

There is some indication that excessive starch (ie from cereals) fed to youngsters can lead to problems with insulin resistance in later life and may also have a link to DOD in those breeds predisposed to it.

So the use of cereals (oats, barley) should be kept to a minimum and only used if absolutely necessary. Care must also be taken that the feed is not made unbalanced as a result of using cereals (only use with a balancer).

Cereals are high in phosphorous which means that the calcium:phosphorous ratio in your diet could become unbalanced, resulting in DOD.

Key components

Keeping an eye on the following key components will help to prevent any growth issues;

1, Provide appropriate energy levels for a steady growth curve – with no spurts

2, Provide feed with well balanced protein to build bone frame and structure

3, Provide feed with balanced minerals and trace elements for bone mineralisation and structural soundness

4, Provide as much turnout as possible and in as big a space as as you can to build bone strength

Seek advice

Finally, always seek advice if you are unsure. Specially formulated compound feeds are the safest and most appropriate way to feed your youngster. For non-Thoroughbred types, an appropriate balancer will fulfil requirements without providing too much energy.