Government surveillance data has revealed that winter trace element deficiencies remain one of the most frequent health issues in UK sheep flocks, prompting fresh warnings for farmers as ewes enter the most nutritionally demanding stage of gestation.
Figures from the Sheep Disease Surveillance Dashboard, produced by APHA and SRUC, show that between 2015 and 2024 selenium deficiency was the second most common diagnosis in sheep submissions between October and December, with cobalt and vitamin B12 deficiency — or pine — ranking fourth.
These shortages are a recurring winter challenge due to declining forage quality, variable soils and increased metabolic pressure during late pregnancy.
Nia Williams, technical manager at Nettex, said failing to correct deficiencies can have serious consequences as lambing approaches. “In the last six weeks of pregnancy, around 75% of foetal development takes place, putting extra pressure on the ewe,” she said.
“That means providing a correctly balanced diet — not just in terms of energy and protein but also trace elements — is vital.” She warned that shortages of selenium or vitamin E can contribute to abortions, stillbirths, weak lambs and poor early vigour.
Selenium availability in forage depends on how efficiently the element is digested and on soil conditions that influence plant uptake. Digestibility can vary widely, while well-aerated, alkaline soils tend to support greater absorption than compacted or waterlogged ground.
Rumenco technical services manager, Dr Alison Bond, said these factors should inform winter grazing plans. “If your ewes are grazing areas prone to compaction, the ability of the forage to absorb certain trace elements such as selenium may be reduced — and this should be factored into nutrition plans,” she said.
Williams cautioned that over-supplementation carries its own risks. “The safety margin for selenium is narrower than for many other elements,” she noted, advising producers to take blood samples from a small group of ewes and conduct a full forage analysis before deciding on supplementation.
Cobalt and vitamin B12 deficiency is similarly linked to low-cobalt soils and may be complicated by worm burdens that cause diarrhoea and interfere with B12 absorption.
“Rumen microbes use cobalt to produce vitamin B12, which is then absorbed by the sheep,” Williams explained. “Vitamin B12 is essential for fibre digestion and energy metabolism, so ewes that are deficient won’t be able to make the most of the diet available to them.” Farmers often first spot the issue as poor thrift, dull coats or ewes failing to hold condition despite adequate feed.
A range of targeted products is available to help protect ewes and unborn lambs. Williams said the priority is “knowing what’s going on within your flock and targeting supplementation where it’s needed”, whether through a bolus, conditioning drench or a combined cobalt, selenium and B12 drench.
Dr Bond added that mineralised feed blocks or molassed buckets may support energy requirements but again warned that farmers “must take caution not to over-supplement.”
Reviewing forage analysis, conducting blood testing and planning supplementation strategically will help safeguard ewe condition and support lamb viability through the winter.
