The Role of Trace Elements in Cattle

When we think of a balanced diet, we typically think energy, fibre, fat and protein, and the trace elements (TE) often go under the radar. However, TE’s play many vital roles in the day-to-day functions of the body and are essential in every cattle diet. Below covers the roles of the five main trace elements required in New Zealand, and what signs to look out for when spotting deficiencies.

Cobalt

Cobalt is the first of the main five important TEs. The main significance of cobalt is its interaction with the rumen bugs to produce Vitamin B-12. Vitamin B-12 is involved in processes such as protein synthesis and carbohydrate and fat metabolism. If cattle are deficient in cobalt, and therefore Vitamin B-12, energy metabolism is impacted. Early signs of cobalt deficiency include poor growth rates and weight loss, whilst more serious signs include anaemia, and increased occurrences of infection.  Young animals tend to be more susceptible to cobalt deficiency, as they have less reserves in their liver, however all stock classes can be impacted.   

Copper

Copper is involved in processes such as bone and connective tissue health and development, and detoxification processes. Loss of hair colouration are the eyes is typically the first sign of a copper deficiency.  More server signs include scours, amenia, poor growth, fragile bones (increases bone breakages), and poor reproduction. These animals are typically more susceptible to infection also as immune function is often impacted. Due to copper being stored in the liver, and blood levels fluctuating depending on the animal’s state, blood tests may not accurately represent the copper levels of an animal, therefore liver biopsies are the preferred method for checking for deficiencies. 

Iodine

Iodine is required for the synthesis of the thyroid hormones, which are subsequently involved in energy metabolism. The amount of thyroid hormone produced, and therefore iodine required, varies with animal status, however requirements are typically higher during peak lactation, or in cold weather for example, when energy demand is higher. 
Signs of iodine deficiency are often not visible, however enlarged thyroid glands and reduced fertility are examples of what may be seen. Additionally, if a cow is pregnant, and the deficiency is server, she will divert iodine away from her foetus, into her own thyroid hormone production as a priority, therefore risking the health of the foetus. 

Selenium

Selenium is primarily recognised for its role in immunity, and as an antioxidant.  Short term or mild deficiencies of selenium have been related to poor growth and diarrhoea in all stock classes. In breeding cows specifically, additional signs such as increased occurrences of retained foetal membranes, metritis and udder swelling and mastitis are also common. White muscle disease is also caused by selenium deficiency. 

Zinc

Finally, Zinc. Zinc is involved in many molecular level processes in the body, and is active a large range of different enzymes related to metabolism, hormones, and immunity. Cattle deficient in Zinc have a reduced feed intake and growth rate, over time, they can also develop poor hoof health, and skin issues, due to zincs role in keratinization.
 
Overall, keeping the TE levels at an optimum rate in your cattle ensures they continue to perform at their best. Deficiencies can be hard to identify and can potentially take a large toll on the production and performance of cattle under the radar. Knowing the TE status of cattle is critical to maintain their health and longevity.