Trace Elements – Sheep & Beef

"The sheep and cattle are just not doing good, even though they seem to be getting plenty of feed- they must be deficient in something!”

Symptoms of the Disease/Condition

As well as energy and protein, sheep and cattle are known to need at least 14 different minerals in order to maintain good health and production. Some are required in relatively large amounts (calcium and phosphorus for bone) while others called trace elements are required in small amounts to increase the rate of the body’s chemical reactions.

In New Zealand the economically important trace element deficiencies are Cobalt (Co), Selenium (Se), Iodine (I), and Copper (Cu)

Despite our small size New Zealand has extremely varied geology and soils from adjacent areas may have very different origins and therefore mineral composition. With our pastoral based grazing systems the minerals available for the animals are determined by the mineral content in the plants ingested which in turn is influenced by the local soil.

As well as soil composition climatic factors such as soil moisture and farming practices such as fertiliser use (molybdenum and lime) and grazing predominant species of plants (summer crops, lucerne) can affect availability of minerals to plants.

In reality, trace element deficiency is not a common issue affecting poor stock performance because many farmers are aware of all the local factors involved with trace element deficiencies and are managing them very well.

In many cases the reason for poor stock performance is simply an inadequate energy intake arising from either a feed shortage or poor quality feed. High worm burdens associated with inadequate worm management practices can depress young stock performance and subclinical facial eczema may impact on the reproductive performance of outwardly normal looking ewes.

The Impact

Trace elements have their greatest impact on the growth of young stock and the reproductive performance of adult stock.

Young animals:

  • Cobalt deficiency impairs growth of lambs.
  • Selenium deficiency causes poor growth and myopathy called white muscle disease in lambs and calves.
  • Iodine deficiency causes goitre in lambs and calves.
  • Copper deficiency is characterized by swayback (enzootic ataxia) and osteochondrosis. Growth rate can be diminished when deficiency is induced by excess molybdenum intake.

Adult animals:

  • Selenium deficiency in ewes increases the incidence of barren ewes, decreases lambing % and increases perinatal mortality.
  • Iodine deficiency in ewes can increase perinatal mortality and decrease lambing %.
  • A molybdenum induced Copper deficiency in cattle can reduce calving %.

Diagnosis of trace element deficiencies depends on:

  1. Describing the problem.
  2. Deducing the likely cause.
  3. Confirming diagnosis with tissue/blood sampling of the animals in question. 

In some cases, concurrent soil or herbage analysis may help interpretation of the results. Production response trials may be indicated when the results are in the “marginal” range.

Management and control

Animal tissue analysis (especially liver reserves) also has a role in prevention of some mineral deficiencies by predicting the likely development of a deficiency. The timing of the test and interpretation of results depends on the period of the year in which the deficiency is most likely to occur.

There is a vast range of treatments and methods of supplementing trace elements to animals directly or via water trough, licks, or topdressing.

Contact your nearest VetEnt clinic to learn more about how to manage trace element deficiencies in your stock and provide the most cost effective treatment or control method available.