Trace elements are essential for bodily function, growth AND performance. Cases of trace element imbalance (deficiency or toxicity) can result in significant implications for your stock. Performance, profitability, general health and fertility can all be compromised when your sheep consume too little or too much of these essential trace elements. Ensuring your flock consumes an adequate supply of minerals is vital for guaranteeing an optimal level of growth, health, and reproductive capability. Even the most marginal of deficiencies can have significant impacts on the performance of your animals.
What minerals do sheep need?
There are two categories of essential minerals required by your sheep, macrominerals and microminerals. Both types of minerals are essential for the function, health and overall performance of your stock, however, they are needed in different quantities.
Macrominerals
Macrominerals are mineral elements that are needed in large amounts (required at a grams/day rate) for normal bodily function. For sheep they include Calcium, Phosphorous, Potassium, Sodium, Sulphur, Chlorine and Magnesium.
Microminerals
Conversely, microminerals (or trace elements) are just as vital as macrominerals, but as their name suggests are required in much smaller quantities (milligrams or micrograms/day). The essential trace elements include Iron, Zinc, Copper, Molybdenum, Iodine, Manganese, Selenium and Cobalt.
Functions of Trace Elements
Each individual trace element has specific roles or functions within the body, they have been summarised in Table 1, below.
Table 1: Trace element functions for sheep
| Trace Element | Function |
| Cobalt | – A precursor of Vitamin B12 – Rumen micro-organisms convert the cobalt into Vitamin B12 – B12 is vital for the metabolism of energy, red blood cell production and essential for body and wool growth. |
| Copper | – Transportation of iron in the body – Hair and wool pigmentation – Crimp formation in wool – Antioxidant |
| Iodine | – Component of thyroid hormones – Vital for protein metabolism and energy in foetal development |
| Zinc | – DNA and protein synthesis – Wool growth, fibre strength and lustre – Hoof health |
| Selenium | – Activating thyroid hormone which is essential for foetus development and growth, as well as general bodily functions. – Antioxidant – Detoxification of harmful peroxides |
| Iron | – Oxygen carrier through the blood to tissues. – Essential for electron (energy) transport – DNA and RNA synthesis |
| Manganese | – Enzyme activator: initiates and speeds up chemical reactions in the body |
| Molybdenum | – Essential for enzymes and related metabolic functions – Prevents copper toxicosis |
Signs of Deficiency of Trace Elements
How do I know if my flock is deficient?
There are a few ways you can determine if your flock needs trace element supplementation, the easiest and most cost-effective method is visual observation. Signs of deficiency for a particular trace element are summarised in Table 2.
Table 2: Signs of trace element deficiencies in sheep.
| Trace Element | Signs of Deficiency |
| Cobalt | – Reduced appetite, pica (eating unusual and non-food substances), therefore resulting in weight loss – Ill thrift – Reductions in wool growth – Watery eye discharge – Anaemia – Poor reproductive performance – White (fatty) liver disease and photosensitisation – Death (in severe cases of deficiency) |
| Copper | – Swayback in lambs and paralysis or staggering gait – Fragile and breaking bones – Anaemia – Wool depigmentation – Reduced crimp and tensile strength in wool – Reproductive disorders – Diarrhoea |
| Iodine | – Enlarged thyroid gland (goitre), see Figure 1 – Reduced foetal size and poor brain development – Developmental and reproductive disorders – Wool or hair loss – Mortality in lambs in the first few days after birth |
| Zinc | – Reduced appetite and therefore weight loss – Reduced wool growth and crimp loss – Alopecia, parakeratosis (skin thickening), skin lesions – Bone abnormalities – Poor hoof growth |
| Selenium | – Nutritional myopathy (heart muscle lesions) – White Muscle Disease (skeletal muscle lesions) – Increased mortality rates – Ewe infertility – Induced thyroid hormone deficiency |
| Iron | – Anaemia |
| Manganese | – Skeletal deformities – Poor would healing and metabolism |
| Molybdenum | – Young lamb leg and back stiffness (swayback) – Renal lithiasis (kidney stones) – Copper toxicity – Neurological defects and mortality |
Diagnosis
Blood and liver tissue testing can be done by a practicing veterinarian and can confirm your concerns if you are worried about a potential deficiency issue. Plant tissue testing or consultation with an agronomist can be beneficial in understanding the soil type, species of pasture/s being grazed, and fertiliser history. These factors can influence the bioavailability of trace minerals in the pastures grazed by your stock.
Supplementation of Trace Elements
There are several ways that you can supplement trace elements to your flock. The method of choice will be dependent on your enterprise and animal health management program. Rumen boluses, oral administration, injections, free-grazed mineral blocks, top dressing pastures, or water trough supplementation are the most readily available options to combat mineral deficiency. Oral drenching, boluses and injections are the preferred delivery methods as they supply an exact dose to each individual animal. Mineral blocks and water trough supplements may not be as effective, as it can be difficult to ensure each animal consumes the required amount.
Toxicity of Trace Elements
Toxicity occurs when your animals are ingesting too much of a trace element, whether from dietary or supplementary sources, or a combination of both. Toxicity can have damaging implications to sheep health. A common occurrence of this is copper toxicity in certain regions of Australia. Subclinical copper toxicity occurs when your animal is consuming a sufficiently high dietary intake of copper or provided at elevated levels for an extended period. Homeostatic mechanisms then begin to fail, and copper accumulates in the blood, liver and vital tissues, therefore impairing their structure and function. Acute toxicity will occur when continuation of this high level of copper causes physiological failure, significant liver damage, killing cells, and can ultimately result in death.
Copper toxicity can commonly occur in clover pastures or other legume crops, heliotropes and paddocks with lime. In these instances, it can be extremely harmful for excess copper to be supplemented to your flock.
Always consult a veterinarian or animal health advisor before providing excess copper or other mineral supplementation if you suspect your animals have sufficient dietary intake or have diagnosed toxicity.
Vetmec Mineral Mix
Vetmec Mineral Mix is a trace element supplement mixture with a combination of Copper, Cobalt, Zinc and Iodine. The minerals are in a special chelated form that is highly soluble and more readily available to your sheep when compared to other forms of these trace elements. The additive can be mixed with 10L of fresh water or 10L of Vetmec LV (which also includes Selenium), and ensures you are providing essential nutrients for your stock, improving their health, performance, growth and reproductive ability.
Benefits of Vetmec Mineral Mix
Vetmec Mineral Mix is an easy and cost-effective product to aid in the prevention of, or treat trace element deficiencies in your flock. The supplement may also aid in reducing the prevalence of foot abscesses in sheep. Customised mineral mixes are also available, more or less of a particular trace element can be altered to meet the needs of your flock. An example of this can be customising your mix to have higher traces of Iodine, which can prevent goitre from developing in newborn lambs. Call us on 1800 243 683, or send a web enquiry, and speak to our in-house veterinarian or animal health advisors and we can customise for you today!
References
Managing trace element deficiencies in sheep | MLA
Trace mineral deficiencies | Agriculture Victoria
Livestock Factsheet: Mineral deficiencies in livestock | VFF
Animal Nutrition: From theory to practice | VetBooks
Do I need to give selenium of vitamin B12/cobalt to my sheep? | Lisa Warn via Agriculture Victoria
Hession, D.V., Kendall, N.R., Hanrahan, J.P. & Keady, T.W.J. 2022, ‘The effects of oral drenching with Co or vitamin B12, drenching frequency and Co via rumen bolus on plasma vitamin B12 concentration in weaned lambs’, Livestock Science, article no. 105108, https://doi.org/10.1016/j.livsci.2022.105108.