Why are trace elements important ?
Trace elements are essential components of an animal’s diet required for a range of metabolic and physiological processes. Severe deficiency of one element can cause a clinical condition (e.g. Selenium and White muscle disease/muscular dystrophy; Copper and Swayback etc.). More often, the effect of a deficit is insidious, causing ill health and a loss of productivity, without obvious clinical symptoms. Marginal deficiencies affect variable numbers of sheep from year-to-year. They are hard to predict and identify, but routine supplementation can be incorporated into the flock health plan. The principle of trace element nutrition should be one of prevention, rather than a response to evidence of a deficiency.
What role do trace elements & vitamins play in sheep nutrition?
COBALT (Co) is required by sheep for the production of vitamin B12.
A deficiency results in listlessness, loss of appetite (pine) poor fleece condition, reproductive failure and anaemia. Sheep are particularly sensitive to cobalt deficiency and lambs, without supplementation, will experience a ‘check’ in growth mid-season which can have major economic implications for farmers.
COPPER (Cu) is a component of red blood cells and is involved in enzyme systems, i.e. haemoglobin synthesis. It is necessary for the pigmentation of wool and hair. Copper is a very important trace element. A deficiency causes retarded growth, loss of appetite, anaemia and scours. Wool may grow straight and straggly; hair tends to fade and is often shed particularly round the eyes. Milk yield is lowered and fertility affected.
A deficiency results in swayback in sheep. However, it is well known that some breeds of sheep (particularly continental breeds) are susceptible to copper toxicity and it is very important to be aware of this when discussing supplementation programmes with farmers.
IODINE (I) is incorporated into the hormones produced by the thyroid gland. Thyroid hormones exert control over energy metabolism, physical and mental growth, endocrine glands and the circulatory system.
A deficiency can result in birth of weak or dead young and infertility. A typical symptom is a swollen neck or goitre. The thyroid gland of lambs is formed early on in the pregnancy so it is important to ensure the ewe receives supplementation over this period
MANGANESE (Mn) is essential for the correct formation of bone and the development and function of the reproductive system – it is mainly associated with enzyme systems.
A deficiency results in poor growth, leg deformities, poor fertility and abortion.
SELENIUM (Se) promotes growth by improving the correct functioning of muscle and organs such as the liver. Selenium improves fertility and can reduce post-natal losses, particularly in sheep. The anti-oxidant function of selenium means that it is considered closely with Vitamin E.
A deficiency causes muscle weakness, i.e. white muscle disease in lambs and retained placentas in adults. Poor fertility is also associated with selenium deficiency.
ZINC (Zn) is involved in the growth of body cells, formation of skin, hair, bone and cartilage.
A deficiency results in poor growth, lowered appetite, poor feed conversion and delayed wound healing.
