With lambing finished for another year, it is time now to focus on maximising returns from this year’s lamb crop. Ill thrift in growing lambs caused by trace element deficiencies (TED) is costly due to increased feeding, medicine and veterinary costs and higher mortality rates. Therefore monitoring growing lambs over the next few weeks and months is key to reducing the potential impact of such deficiencies. It is important to note that TEDs also can cause production losses in adult animals and if issues are highlighted in the lamb crop investigation of other groups may be warranted.

The signs of trace element deficiencies in sheep are often gradual in onset, and therefore problems can be overlooked until groups of poorly grown lambs are identified in late summer. The nutritional stress of weaning can initiate these deficiencies, and levels can diminish to low, and therefore performance limiting, levels within weeks. The symptoms of TED are non-specific and parasitic disease can be a compounding factor in ill thrift so further investigation is always warranted where lambs are not growing as well as expected.

TED can be very localised, mainly due to variations in pasture caused by soil type and pH, drainage and fertiliser applications. In addition, pasture mineral levels can vary greatly year on year. Last year at Armac we diagnosed cobalt and selenium deficiencies in several flocks which had never had an issue in previous years.


The trace elements of concern are copper, cobalt, selenium and iodine. There are numerous symptoms which include ill thrift, watery eyes, anaemia, poor wool growth and diarrhoea. Deficiencies of different trace elements can give similar symptoms, highlighting the importance of further investigation.

For a detailed table explaining the symptoms and the possible corresponding mineral deficiency, head to the QMS website.


Regular weighing of lambs and recording of growth rates if possible is an excellent tool in identifying poor doing lambs, allowing problems to be identified quickly. If a concern is raised your vet should be notified and investigation initiated. This could involve:

Examination of the animals to assess clinical signs and to rule out conditions such as under-nutrition, lameness and pneumonia

Worm egg counts to assess if parasitic disease is contributing to the problem

Blood samples on a small proportion of the group

Post mortem examinations


Once TED is diagnosed, the next hurdle is identifying the most cost effective method of supplementation. This will depend on various factors, such as how often it is practical to handle lambs, whether they are destined for slaughter or breeding and which trace elements are to be supplemented. The timing of treatment should coincide with the period of perceived risk, which may begin at weaning for lambs and pre-tupping for adult animals. If supplementation is initiated it is worth sampling animals every 1-2 years to ensure it is still appropriate. Various methods of supplementation are available and your vet can give advice on these, which include: drenches, mineral blocks, injections, bolus and pasture treatment.

In conclusion, the key aspects to TED management are early detection, exact identification of the problem and cost effective supplementation. Seeking veterinary advice each step of the way is essential in reducing losses due to these preventable deficiencies.