Trace Elements in Cattle


Copper is required in the body for growth, bone development, skin and hair pigment, immunity and red blood cell production. It is usually present in feed in adequate amounts, but molybdenum, sulphur, iron, and zinc all compete with it for uptake into the body, and high levels of these compounds can cause secondary deficiency.  


Signs of copper deficiency are ill thrift, sometimes with rough, reddened coats, anaemia, immune suppression and bone disease. Sudden death may occur in adult animals that have been deficient for some time.


Copper levels fall over winter, so autumn is the best time to test animals so that supplementation can be put in place before animals become deficient. 



Selenium acts as an antioxidant in the body, as an important part of the immune system. 


Ill thrift, anaemia, poor milk yield, subfertility, abortions and stillborn calves can result from Se deficiency. In calves, white muscle disease is seen. 


Selenium is not stored in the body, so measuring blood selenium is recommended to check if cattle are currently receiving enough selenium. 


Selenium is the most toxic trace element, so care needs to be taken to not overdose cattle. As a general rule, only one method of selenium supplementation should be used on farm to avoid toxicity. 



The next 3 diseases are similar in appearance and all fall into the blood poisoning category which is typified by sudden death followed by rapid post death deterioration, bloody discharge from nose & bloating.

Blackleg: This is usually associated with dirty wounds, grazing muddy winter feed crops, after lambing & using dirty vaccination needles.

Malignant oedema: Lesions very similar to blackleg.

Black disease: Usually associated with liver fluke infection.  

Cobalt / Vitamin B12
Cobalt is a trace element which is converted into vitamin B12 by microbes in the rumen. Vitamin B12 is essential for energy production and appetite in cattle. Cobalt is consumed in soil and plant matter, and the amount of cobalt in the soil varies markedly across NZ, with volcanic soils being most deficient.
Signs of cobalt/B12 deficiency start as decreased appetite, progressing to ill thrift, poor fertility, diarrhoea, rough hair coat and watery eyes. Weight loss on excellent feed is often noted. Young animals are most susceptible. Death can occur if severe. 

Iodine is required for the production of thyroid hormones, which control metabolic rate in the body. Low iodine levels can poor growth rates and milk production, anoestrus and poor heat expression, poor conception rates, abortions, and retained foetal membranes. Oestrus expression is the most important of these seen on dairy farms. Goitre can occur in calves – large thyroid glands in the neck.
Iodine deficiencies can occur due to primary soil deficiencies of iodine, or due to goitrogens (iodine binding compounds) in feed. Brassica crops and white clover contain high amounts of goitrogens.