The Symptoms of Magnesium Deficiency in Cattle: An Overview

Most farmers are aware of the dangers of a magnesium deficiency in cattle and the impact it can have on health and are careful to monitor for signs of any problems.

However, many won’t necessarily be aware of what causes a magnesium deficiency in cattle, why they need magnesium, how cattle process magnesium and, crucially, what are the most effective ways to prevent or treat a magnesium deficiency in their livestock.

A magnesium deficiency crisis can be devastating to a herd, and a farmers’ livelihood, and in this blog we explore the causes, symptoms and measures you need to consider.

Why Do Cattle Need Magnesium?

Magnesium is an essential element for cattle as it is key for a range of energy-generating reactions and for nerve transmission in the animal. Cattle need a constant supply of magnesium to maintain adequate levels in the blood and this magnesium is then stored in the bones and muscles but is not readily accessible to the animal when needed.

This demand for a constant supply faces significant challenges. Magnesium is absorbed from the diet through the rumen, but it does this poorly with around only 30% of available magnesium picked up.

Plus, magnesium is not hormonally controlled and this means magnesium is also constantly excreted through urine, faeces and milk.

The source of magnesium is primarily from the diet, but magnesium levels in the diet can vary considerably over the course of a year and the cow’s demands for magnesium will also vary at different moments through the seasons and production cycle.

Lactating cows face further challenges as milk production places significant demands on magnesium and, even if the cow is deficient in magnesium, levels in the milk will remain the same.

What Are the Symptoms of Magnesium Deficiency in Cows?

A magnesium deficiency in cattle is known as hypomagnesaemia but farmers will know this better as staggers, tetany, grass staggers or lactation tetany.

It is one of the most feared situations for livestock farmers as, when symptoms arrive, it’s already almost too late to save the animal. But what are the symptoms of the staggers?

As the name suggests, the most common symptom is when the cow becomes unsteady on its feet, but it can also present as tremors, convulsions, muscle spasms, poor coordination, restlessness, being over-excitable or aggressive or, in some cases, you can also see bloating.

In the early stages, you may see a change in behaviour in the cow and it may become difficult to handle.

With all of these symptoms, if you miss the warning signs, it ultimately results in the animal collapsing and then rapid intravenous intervention is required in order to save the animal; this is the only option at this stage and therefore prevention is the key.

The onset of the disease is fast and it’s not uncommon for the animal to be dead before the farmer is aware of a problem. However, if one animal is suffering from hypomagnesaemia, it is likely that the rest of the herd will also be deficient in magnesium and farmers must act quickly to prevent any further deterioration of the herd.

If you find an animal dead, a key sign of hypomagnesaemia being the cause is the ground around the body being churned up from their legs thrashing backwards and forwards while they were on the ground, sometimes with signs of frothing at the mouth.

What Is the Most Common Cause of Magnesium Deficiency?

The big risk period for magnesium deficiency is the change in feeding cycles  from winter housing to spring grazing.

As we’ve said, cattle need a continuous supply of magnesium and, while the grass is growing rapidly in spring, the sward can be deficient in magnesium. This change from winter feed to spring grazing can result in a quick drop in magnesium levels in the blood and it is a key moment to watch out for potential symptoms.

Another key moment when cattle are at risk from hypomagnesaemia is in the Autumn when the inclement weather kicks in. Some even refer to problems at this time as Autumn grass staggers.

This is caused because the bad weather forces the cows to seek shelter and interrupts their feeding, this lack of food and the extra demand the weather is putting on their bodies again puts them at risk of a magnesium deficiency. It is important to provide appropriate shelter and food to prevent this situation.

Finally, higher production cattle are also at increased risk as they obviously face higher demands on their bodies, particularly in lactating animals where milk production needs significant levels of magnesium.

How Do You Test for Magnesium Deficiency in Cattle?

Magnesium levels can be measured with blood tests and, if you have any suspicions about animals suffering from a deficiency, it is worth moving quickly to get tests done.

If a blood test shows magnesium levels are falling, you don’t have long to address the problem. Blood tests can take a few days to get results and, because this disease can move so fast, you are already facing a serious situation and need to act fast to provide supplements.

How Do You Treat Magnesium Deficiency in Cows?

Prevention is always the best treatment for magnesium deficiency and this means providing your cattle with a constant supply of this key mineral.

In instances where you are seeing symptoms of hypomagnesaemia, blood magnesium levels must be restored as quickly as possible, and you need to seek veterinary help to administer an intravenous supply of magnesium.

However, this is a last resort and it is crucial you provide a continuous supply of magnesium for your cattle, particularly around the risk periods. The most effective way to provide this supply is through supplementation and the most effective form of supplementation is with a bolus.

RUMBUL Magnesium Bullets are a bolus that aid the prevention of hypomagnesaemia by providing a predictable and controlled release of magnesium throughout key risk periods. This ensures the farmer can be confident their cattle are getting the magnesium they need at critical moments in the production cycle.

The RUMBUL bolus are a proven method, where the bolus is administered to the animal and it then lies in the reticulum where it will slowly dissolve and eventually disappear completely, providing a continuous and regular supply of magnesium to the animal.

If you would like to know more about magnesium deficiency in cattle or have any questions about supplementation, please do not hesitate to get in touch with our experts at [email protected]