Sodium, potassium, calcium and magnesium are essential minerals in your horse’s diet. However, in New Zealand, our ever-changing climate can create mineral imbalances in your horse’s pasture, most notably in Autumn and Spring.

In our new series, we examine each of these minerals to highlight their importance in your horse’s diet and minimise potential health problems.

For many horse owners, what appears at first glance to be healthy, nutritious pasture, suitable for horses, is actually numerous grass and legume species that are deficient in some minerals and overloaded with others, leading to harmful health consequences.

Unless your pasture is organically farmed and completely free of fertilisers, your pasture will be imbalanced. Most often, Spring and Autumn grasses are high in potassium and low in sodium, and many New Zealand pastures are simply deficient in calcium and magnesium.

In Part One, we started with sodium. Now, let’s continue with potassium…

Spring Grass and Potassium

Just like sodium, calcium and magnesium, potassium is an important electrolyte that every horse needs. However, excess potassium in pasture, hay and commercial horse feeds can cause major health problems in horses.

In New Zealand, Autumn and Spring in particular bring new grass growth. While potassium and nitrogen are needed by growing plants, high levels lead to mineral imbalances that ultimately affect the animals grazing them, including your horse.

Until recently, much attention has been placed on the high levels of non-structural carbohydrates (NSCs) found in young, growing grass, which can trigger laminitis in at-risk horses. However, potassium also has its problems.

Grass tetany, or grass staggers, has been well documented in cattle and is becomingly increasingly recognised in horses. Symptoms usually appear overnight - ranging from stiffness or lameness in the hind legs, to difficulty getting up and, in some cases, even death.

Diet and Potassium

Climatic conditions have a direct influence on the levels of sodium and potassium in your pasture. Following times of drought-breaking rains, wet weather and frosts, potassium and nitrogen levels spike and excess potassium in the diet must be avoided with care.

If your horse ingests too much potassium nitrate, the body excretes this highly toxic substance, but unfortunately, calcium and magnesium are also lost. Your horse’s diet, therefore, must supply them with calcium and magnesium, without adding more potassium.

There are some common horse feed ingredients, which are high in potassium, including:

• Lucerne hay
• Molasses
• Herbs, including garlic
• High protein horse feeds
• Horse supplements containing potassium

Some horses simply can’t tolerate lucerne hay in their diet, due to the levels of potassium present. Potassium and fluorescing pigments can cause photosensitivity, which may arise as persistent mud fever or sunburn on non-pigmented sections of the skin.

Placide is the number one equine calming supplement in New Zealand. Containing organic, chelated magnesium, Placide works to relax muscles, reduce stress and support your horse’s health for improved performance in less than one week. Click here to find out more.

Disclaimer: This article is not intended as veterinary advice. At Placide, we encourage you to make health care decisions for your horse based on your own research and in partnership with a qualified veterinarian.