Home » All Posts » Farm animal » Trace elements in sheep: Checking and supplementing for smallholders

It’s unlikely for any sheep keepers, however small-scale, never to have come across lick buckets or other ways to supplement sheep with minerals, trace elements and vitamins. Often asked about, often the cause (or the scapegoat) of various illnesses and predicaments, what are these minerals/vitamins/trace elements? Why are they needed and why do sheep need topping up? How can we check if anything is needed and lastly, how could we do it?

Without taking the pleasure of the full discussion off the hands of your farm vets, this article will try and give you a whistlestop tour of the answers to the above questions.

Table of contents

What are trace elements, and why are they needed?

By trace elements (or minerals) we tend to refer to a large group of micronutrients that could be inorganic such as Calcium, or of organic nature such as the vitamins. They are called micronutrients because they form a very small part of the diet. (Macronutrients being needed in much larger quantities – carbohydrates, proteins, fibre etc). Under the umbrella term of micronutrients, there are macro and microminerals (also referred to as trace elements), plus vitamins and other molecules. The fact these terms are often used interchangeably, and that when it comes to testing of microminerals often we need to rely on other organic parameters, may explain why for many the topic remains a mystery. 

In brief, micronutrients are needed for the correct functions of organs, systems and cells

They are not the building blocks as such (like protein); but without them the “construction process” cannot be completed or it may malfunction. For example, some enzymes and vitamins require a metal ion to become an active form and carry out its job.

There are three main macro minerals (Calcium, Magnesium and Phosphorus), and their daily requirements are higher than other minerals; usually forage provides them in sufficient quantities. However, it is always a good idea to have the forage analysed, especially if destined to animals under high metabolic stress such as ewes at the end of pregnancy.   

Microminerals are usually metals such as Copper, Zinc, Iron, Cobalt, Manganese (etc – many are needed, rarely in large amounts which is why they are called trace elements). Most of the time they are required for the correct synthesis of vitamins, enzymes and generally aid metabolism.

There are many types of vitamin, all doing different jobs around the organism

The main distinction is between water soluble vitamins (such as those of the B group) and non-water soluble ones (such as Vit. A-D-E). Many of these can be synthesised in the rumen, therefore the sheep can rely on this steady supply. For a pet sheep that is (quite possibly) a bit overweight and under no metabolic stress, no supplementation is usually needed. Other groups of animals, though, such as ewes in a commercial flock and rapidly growing lambs, are better supplemented. This is because the requirements may be higher than the forage and the rumen can supply.

Ruminants are lucky in many ways as their body is so amazingly adapted via the rumen microflora to provide them with almost all they need to function correctly. As long as the rumen and the bugs in there are fed and happy, the sheep is happy. 

Why do sheep need topping up?

Well, firstly, not all sheep do need topping up on trace elements/vitamins! If they present no symptoms and their growth or reproductive performance is as good as expected, is it unlikely they would need any specific treatment. If any kind of symptom is present, you should discuss your concerns with your vet and mention trace elements if you think a deficiency may be involved.

Usually, sheep that need topping up fall into one or both of these categories; intensive commercial flocks with big, fleshy lambs needing to keep up with growth rates; and/or very extensive hill flocks that by nature are more resilient to deficiencies but may be grazing very poor ground and having a hard job of rearing lambs. 

Copper needs special attention

Before supplementing, it is always best to check its status because it is easy to overdo it and cause toxicity. Some breeds of sheep like Texel, Blueface Leicester, Suffolk, Charollais and North Ronaldsay are known to have higher susceptibility to copper toxicity. Others like Merino appear to have a higher tolerance. Always check with your vet before making any final decision.

How do we test for deficiencies?

The scope of this article is beyond trying to diagnose deficiencies and describing symptoms. We’ll leave all that fun to your vet! However, if you have never tested for trace elements and suspect there may be a reason for an acute or chronic poor performance or other symptom; the best way to check is to run some blood samples. Your vet will ask you a detailed history to decide which trace elements are best targeted in the test to make it the most cost efficient. Usually, the most commonly tested for trace elements combination is copper, selenium, cobalt, iodine. 

And how can they be supplemented?

There are 4 main ways to supplement these micronutrients (5 if we count compound feed). Bearing in mind that there isn’t a perfect delivery method, nor any product that contains everything. Not all products are indicated to each flock. As always when it comes to animals, there is no “one size fits all”.

Each delivery method has its pros and cons; briefly:

Boluses

These are the longest lasting, with some brands claiming up to 8 months of constant slow release, and as you administer it to each animal, you know it should be covered. Price/sheep/day once calculated is often lower than expected and can be lower than some other products. The downside is that they usually only provide 3-4 trace elements, most commonly cobalt, copper, selenium and iodine, and none of the macro minerals. Plus they can be tricky to administer so a good technique is essential.

Drench

These are the easiest to administer (hopefully!). Most sheep need dosing for worms periodically so keepers are used to doing it. In fact some wormers contain a small amount of trace elements. (Beware – usually not sufficient to cover deficiencies and we should NOT dose with wormers when burdens are low just to cover for trace elements). You gave them the dose, so you know they got it! Usually drenches are the cheapest way to supplement individual animals; though some fancier brands claiming longer lasting duration and dozens of nutrients can be dear. Of course, the downside is that many mineral drenches don’t last more than a few weeks. And in cases of severe deficiencies they may require repeat administrations.

Injections

Injectable supplements will have to be prescribed by your vet, require handling needles and confidence in administration; the duration of effect can be weeks to months and they tend to cover either vitamins or mineral trace elements. 

Lick buckets

Usually, these are used to supplement macro- and micro-minerals, as well as vitamins in situations where help in maintaining optimal levels is needed but the animals are not critically deficient. As they are fed ad-lib and free access, nobody knows how much of the lick actually goes into each sheep; this is a big downside. With some heavily molassed types, often the majority of it will be consumed by a minority of the group (due to bullying, age difference, plain greed, etc). Lick buckets tend to be given as an energy or other macronutrient top up, which just happens to have minerals and vitamins added. In cases of deficiencies (even asymptomatic ones), lick buckets will not be sufficient to guarantee the whole group will be sufficiently topped up.

You should always ask your vet for guidance on what to use; they may not give you a brand name but should be able to help you navigate the needs of your flock (on the back of test results) and identify the most efficient way to cover any deficiency.

Further reading:

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