In terms of performance, we now expect more from our horses than ever before. You won’t see shire horses pulling a plough in the field as you enjoy your country walk and gone are the days when horses were for the exclusive use of the upper classes. 

However, you will see our equine comrades competing at high levels in disciplines spanning endurance riding, to show jumping, to polo. Nowadays, our horses are entwined in our leisure activities. The roles they play are more akin to performance athletes than beasts of burden.

The advancement of equine feeding science has paralleled the evolution of the roles of horses in our society. Gone are the days of a scoop of oats and a bran mash after a day of hunting. Our current understanding of the complex mechanisms involved in nourishing our horses is continuously expanding.

Here we discuss some of the recent developments in our understanding of the critical topic of trace minerals for the health of the equine skeletal system.

The importance of minerals

Think about your car for a moment. The battery is a small but incredibly important component. It provides your vehicle with the spark of energy that it needs in order to start. It makes up a tiny percentage of the car as a whole, but when it has a flat battery, the car is essentially disabled.

Mammalian anatomy is similar in that the body is reliant on certain minerals to permit it to function and carry out processes. Minerals, which are inorganic substances, generate the charge of energy that the body requires in order to execute essential functions including the regulation of blood and body fluids, nerve and enzyme function and the formation of bones.

Calcium, phosphorus, magnesium, sodium, potassium, and chloride are needed in relatively large amounts whereas other minerals such as iron and zinc are required in much smaller quantities, and for this reason they are referred to as trace minerals. Even though they are only required in small amounts, they are just as essential to the well-being of a horse as the other minerals.

Minerals and developmental orthopaedic disease in the horse

Young, growing horses usually up to two years of age, can suffer from Developmental Orthopaedic Disease or DOD. This is an umbrella term for irregularities in the skeletal growth of the horse. It can result in conditions such as physitis, an inflammation of the growth plates of the bone, osteochondrosis which is a disruption to the blood supply of the bone resulting in necrosis, angular limb deformities such as pigeon toes or flexural limb deformities where the tendons are too tight and constrict the normal flexion of the limb. DOD can result in permanent lameness problems to the horse which in turn causes substantial economic losses. Ensuring that the pregnant mare and neonatal foal is fed the correct mineral balance is a major contributing factor in avoiding DOD.

The importance of copper to stud farms

Before the 1980s, it was not known how vital trace minerals and in particular, copper, were in regard to preventing DOD. A pioneering study by researchers at Ohio State University determined that low quantities of dietary copper resulted in higher incidences of DOD.

This study focused on the importance of trace minerals on the prevention of DOD and triggered research worldwide that aimed to determine the link between trace minerals, especially copper and zinc and how bones in the newborn foal developed.

On the basis of these original studies and the countless emulators that followed worldwide, the equine feeding industry has without exception acknowledged the significance and value of fortifying the feed of broodmares and foal feed with trace minerals.  If you take a look at any label on these such foods nowadays, there will by standard, be high levels of copper and zinc listed on the ingredients.

Mineral supplementation

Horses that have a good diet with plenty of green grass or quality hay, and hard feed to make up any energy deficit, should, in theory, have a good intake of the vitamins and minerals that they need. The problem is that our modern soils have been over-cultivated, at the Earth Summit in Rio in 1992 it was confirmed that in some areas of the world, the soil has 85% fewer minerals than 100 years ago. This means that the crops grown in these soils will also have a much lower degree of the full range of minerals. It could be that the food you are feeding your horse does not contain the type or level of mineral that it needs for maximum performance, be that reproduction, grown or sport. Feeding your horse a good, all-round mineral supplement will help to avert the issues that lack of sufficient minerals can cause.