Utility Nav


Trace element deficiencies

Chris Gregory BVSc MRCVS, Molecare Veterinary Services

Diagnosis of mineral deficiencies at animal level can be relatively non-specific, especially if the scenario is complicated or even exacerbated by other problems with similar signs e.g. parasite burdens, pneumonia, poor forage quality.

Trace element (or micro ‘mineral’) deficiencies classically come down to four usual suspects:

  1. Copper
  2. Cobalt
  3. Selenium (Vitamin E)
  4. Iodine

Deficiencies in one or more of the above elements can be broken down into two categories:

Primary Deficiency – A straight lack of the mineral in the soil/grass/forage.

Secondary Deficiency – The mineral is present at acceptable levels but locked up, or made unavailable to the animal by another antagonist (e.g. sulphur, molybdenum and iron).


Diagnosis of mineral deficiencies will likely involve some combination of clinical observation of stock, soil/forage analysis, blood sampling and eventual response to supplementation.

Some of the classic signs of deficiency are summarised below (Table 1), although whilst they can be useful indicators of a problem, they should not be relied on for specific diagnosis.

Routine soil/forage analyses will flag mineral levels as standard parameters, and will also give an estimation of how available the mineral is relative to other antagonists. This type of analysis is a good first port of call but may or may not correlate with clinical signs in stock.

Blood sampling can be useful in certain cases to confirm a suspected deficiency at any one point in time. However, it will not take into account dietary variations over time or natural daily fluctuations.


Once a deficiency is highlighted, supplementation trial is most likely the next step. There are many methods of supplementing the animal, e.g., mineralised blends/concentrated feed, oral drenches, slow release oral boluses, external treatments and injectable preparations. All have their benefits and drawbacks and should be tailored to fit in with farm management practices and requirements.

Care should be exercised as dose rates are nominally based on predicted daily requirements. Over-supplementation is uncommon but does occur, mainly with respect to multiple copper sources. Response to supplementation should be monitored closely, e.g., growth rates and clinical improvement.


Mineral Risks Generalised Signs
Copper Most commonly occurs as a secondary deficiency on pastures high in antagonists, e.g., Molybdenum (‘teart pastures’), sulphur and iron

  1. Care must be taken not to over-supplement, copper toxicity is common where multiple sources of mineral are fed cumulatively.
Poor growth rates in young stock at grazingDiscolouration of the skin around the eyes ‘spectacled appearance’

Thin poor quality coat

(NB. High levels of Molybdenum can cause scours and chronic anaemia)

Selenium (Vitamin E) Deficiency more common in home grown cereals/root crops Still-born/weak new-bornsAt first turn-out: sudden death, muscle stiffness, struggle to breath

Poor immune responses

Cobalt Almost exclusively a primary deficiency in regions where soil is low in cobalt Reduced intakes/feed conversion efficiencyChronic anaemia

Thin skin and poor hair coat

Iodine Primary deficiency in low iodine soilsLow selenium can cause secondary iodine deficiency Goitre’s (swelling on the neck) in new-bornsWeak or still-born +/- patchy hair loss and puffy skin

Retained placenta

Milk drop

Table 1: Common clinical signs of trace element deficiencies

Comments are closed.