Boosting sheep fertility and protecting unborn lambs

Bolus progression of dissolution
Bolus progression of dissolution

As tupping approaches it is vital for farmers that their sheep are in optimum condition to maximise their chances of a successful breeding season. Many factors contribute to fertility but an often underestimated consideration is the role of trace element nutrition.

Trace element deficiencies and toxicities can have a direct impact on an animal’s ability to cycle properly, to conceive and to maintain the pregnancy, so ensuring your animals have a healthy trace element status could mean the difference between a successful and an unsuccessful breeding season.

Trace Elements & Fertility

Some elements which are directly related to fertility are copper, iodine, cobalt and selenium.


Copper deficiency in forages causes problems in its own right in the UK.

This is exacerbated in many areas, by high levels of molybdenum, sulphur and iron in grass pastures, which leads to the suppression of key copper-containing fertility enzymes. As a result, copper supplementation is often necessary for normal reproductive health, general health and weight gain.

Cobalt plays a vital role in weight gain and fertility but as the body has no capacity to store cobalt and with many UK pastures being deficient- ongoing cobalt supplementation is required.

Selenium is another critical element. A good supply of selenium is not only necessary to prevent white muscle disease in lambs, but is also essential for ewes to dispel their placentas post-lambing and have good fertility into the breeding season.

Additionally, in many areas of the UK, grass and forages are often low in iodine which can lead to sub-fertility in ewes and lack of libido in rams.

It is clear that fertility of animals suffering from molybdenum toxicity, or deficiencies in cobalt, selenium, iodine or copper, is often impaired. Where these deficiencies and toxicities occur, it is vital that they are addressed through high quality trace element supplementation. It is also vital that farmers understand that not all forms of trace element supplementation are equal. Many farmers use a particular bolus or supplementation method just because they ‘always have’. However, as tupping approaches, they may need to reconsider this approach and speak to their animal health advisor or vet about products which are scientifically proven to give results.

A Scientific Approach To Supplementation

Throughout the UK, vets and nutritionist advisors are recommending the Bimeda CoseIcure and Cosecure range of soluble glass boluses. These boluses have been shown in independent trials to significantly improve fertility in ruminants.

They use a unique soluble glass technology, which delivers exactly the same amount of trace elements every single day for up to six months (CoseIcure) and eight months (Cosecure). Unlike some boluses, there are no ‘peaks’ and ‘troughs’ of supplementation. They contain a unique ionic copper which is active at the same pH as the rumen, and therefore readily-available in the rumen. Rumen-available copper is vital to prevent thiomolybdate toxicity (also known as ‘copper lock’ or ‘secondary copper deficiency’) which impairs fertility. Many other boluses contain copper oxide, which is only available in the abomasum and is not rumen-available.

A Single Bolus For Convenience

Cosecure delivers copper, cobalt and selenium. CoseIcure delivers all of these elements, with additional iodine. As all these elements are included in a single bolus they offer convenience to farmers.

Placental Transfer of Elements to Lambs

An additional benefit of the Cosecure and CoseIcure boluses is that they contribute to the healthy development of the unborn lamb; through the placental transfer of trace elements. For all farmers looking to give their lambs the best start to life, the bolus range is a quality and highly scientific offering.

Copper Toxicity

Before using any form of trace element supplementation it is vital that farmers understand their animals’ trace element status. Providing trace elements that are not required is potentially dangerous. For example, certain breeds of sheep, housed sheep, and sheep in certain areas of the UK can be susceptible to copper toxicity, and excess copper supplementation could be potentially lethal. Always speak to your vet to understand your sheep’s trace element status before undertaking any form of trace element supplementation.

Zinc Supplementation

For animals which have zinc deficiencies (as evidenced, for example, by flock lameness issues and forage and blood analysis) the Bimeda Zincosel boluses, which deliver zinc, cobalt and selenium, are a popular choice.

Zincosel boluses are suitable in breeds which are susceptible to copper toxicity and are used as an aid to fertility, as well as to improve hoof health and boost immunity in zinc, cobalt and selenium deficient flocks. Like the Cosecure/CoseIcure copper boluses, Zincosel boluses will also contribute to the healthy development of the unborn lamb, through the placental transfer of trace elements.

For more information on the bolus range, contact your animal health advisor, stockist or vet.

Bimeda can be contacted directly on 01248 725 400. See for more information on the bolus range.