Trace Mineral Deficiency in Ruminants
Trace elements are elements present in the organism in very small amounts (in the order of ppm). Their recommended daily supplies are in mg/kg of dry matter of the ration (DM). On the opposite, the recommended daily supplies of macro minerals, such as Calcium and Phosphorus are in g/kg DM. We find them in much higher quantities in the tissues. About fifteen elements correspond to these criteria. However, only 8 trace elements are of major importance in animal nutrition: Copper, Zinc, Selenium, Manganese, Iodine, Cobalt and, not to a lesser extent, Iron and Molybdenum.
Essential trace elements are elements meeting the following criteria:
- They are present in all the healthy tissues of an individual,
- Their concentration within the organism do not vary significantly,
- A deficiency of this element leads to enzymatic and cellular dysfunctions which have an impact on the health status of the animal, that is in various species,
- A supply of this element allows to prevent or correct physiological disorders led by deficiency (Chappuis & Poupon 1991).
Microminerals/ trace minerals are nutritional elements required in very less amounts. But they are involved in many intricate functions hence, they need to be supplemented adequately in times of deficiency. Economically important functions of farm animals especially production and reproduction are invariably dependent on various microminerals. This emphasizes the importance of trace mineral research; which is an active area of research currently. Major trace minerals or microminerals in animal body are cobalt (Co), copper (Cu), zinc (Zn), iodine (I), iron (Fe), manganese (Mn), selenium (Se), chromium (Cr) and molybdenum (Mo). They are components of various hormones, enzymes and cofactors. Other functions performed by trace minerals are growth and immunity of animals. All these functions are affected badly in times of deficiency and leads to expression of some classical clinical symptoms. Some symptoms are pathognomonic and aids in immediate diagnosis before laboratory diagnosis. This marks the importance of this article, in which some common trace mineral deficiency and their remedies in farm ruminants are discussed briefly for use at field level. Trace element deficiency may be linked to problems such as retained foetal membranes (Gupta et al., 2005), abortion (Mee, 2004) and weak calf syndrome (Logan et al., 1990). Furthermore, Husband (2006) has recently reported combined selenium and iodine deficiency in a dairy herd with a high incidence of retained foetal membranes, milk fever and vulval discharge. In other cases, differences in the reproductive performance of cattle and sheep have been reported when comparing trace element supplementation strategies (Hemmingway, 2003; Black and French, 2004). Since many of the proposed reasons that trace element status reduces dairy cow fertility involve transition cow health and immunity, the trace element status of dry cows is very important for fertility in the following lactation. The trace elements likely to be of most practical significance are copper (Cu), selenium (Se) and iodine (I) (Rice, 1994). For an accurate diagnosis of Cu status, liver Cu samples obtained by biopsy are preferred to blood values. For Se status, blood, milk or liver Se concentration, as well as glutathione peroxidase (GSPx), give an accurate indication. For the assessment of iodine status, blood samples should be assessed for plasma inorganic iodine (PII) and not thyroxine (T4).
Copper (Cu)
Copper is associated with normal cellular homeostasis, structure and function of skeleton, cardiovascular, nervous and immune system. Cu is essential for the utilization of Fe in the body. Copper is a cofactor of various enzymes including ceruloplasmin. The normal serum/plasma copper level is 0.7–1.1 ppm. The serum Cu is not an indicator of body’s Cu level unless the liver is severely depleted of its copper stores.
Clinical signs
Common deficiency signs are anemia, loss of colour of haircoat, digestive impairment, poor growth performance, lactation and reproduction. Cu is essential for connective tissue formation and therefore its deficiency is associated with gait abnormality namely pigeon toed, stiffened hopping. In lambs, Cu deficiency has been termed as swayback or enzootic ataxia, a central nervous system disorder. Other symptoms of this deficiency are poor fertility, libido and semen quality.
Treatment and control
Injectable copper glycinate is ideal for treatment and prevention of copper deficiency. Copper is supplemented in the sulphate, carbonate or oxide forms. The absorbability is highest for sulphate, followed by carbonates and oxides.
Zinc (Zn)
Normal serum Zn range is 80-120 mg/dl in cattle and sheep. Around 200 enzymes in the system are Zn dependent and the therefore it is involved in all major biochemical pathways. Among many functions performed by Zn, most important are protein, DNA and RNA synthesis. Zn is essential to prevent oxidative damage to the membranes. Various hormones are dependent on Zn.
Clinical signs
The clinical signs of Zn deficiency are poor growth, poor reproductive performance and immunity. The classical sign of Zn deficiency in animals is inappetence. In farm animals, impaired keratin formation associated with Zn deficiency is called as parakeratosis. Serum Zn level is a good indicator of body’s Zn status.
Treatment and control
Zinc should be supplemented @50 mg/kg dry matter. For cattle zinc sulphate 2-4g daily as an oral supplement is recommended. Intraruminal pellets are also found effective in small ruminants.
Iron (Fe)
Iron is the major component of haemoglobin and myoglobin. The rest of the Fe is present in liver, spleen, metalloenzymes etc. Fe is major structural component of cytochromes and are involved in cellular oxidation. Iron deficiency is common in young animals since milk is a poor source of iron. Piglets are mostly affected by Fe deficiency anaemia and turns fatal.
Clinical signs
In piglets, major clinical signs manifested are dyspnea, lethargy, palor, puffed up appearance, sudden death or unthriftiness. Poor immunity leads to secondary bacterial infections also. Still birth is common if sows are Fe deficient. The Fe deficiency anaemia is hypochromic microcytic type.
Treatment and control
Iron supplementation orally and parenterally are sufficient. Organic iron preparations are administered parenterally @0.5-1g/week. Orally Iron sulfate or Iron gluconate @2-4g daily for 2 weeks. As a preventive measure, piglets are given Iron @15mg/day orally until weaning.
Selenium (Se)
Se is the element involved in cellular antioxidant defence system. The functions performed by Se are thyroid function and spermatogenesis. Major source of Se is plants. Normal blood Se level is 0.8 ppm.
Clinical signs
Se deficiency is reflected by impaired growth processes, reproduction and immunity. The clinical manifestations of Se deficiency are white muscle disease (a highly fatal disease in young calves and lambs) and myopathy leading to calcification.
Treatment and control
Combined Se and α-tocopherol is used in the treatment of Se deficiency. For calves and lambs a mixture of 3mg Se (Sodium or Potassium selenite) and 150IU/ml DL- α-tocopherol acetate given i.m @2ml/45Kg BW. It can be used in prophylaxis as well. Single treatment is sufficient. The dietary requirement of Se for ruminants and non-ruminants is 0.1mg/kg DM. Dietary, parenteral or pasture top-dressing of Se @10g/ha is recommended. The dose for parenteral injection is 0.055 mg Se/kg BW. A slow-release S.C inj. of Barium selenate is available for farm animals. Avoid high sulphate diets to increase availability of Se.
Iodine (I)
Thyroid is main storage site for Iodine and its deficiency is associated with impaired functioning of thyroid gland. Iodine deficiency can be primary or secondary. Primary deficiency is present when soil is deficient in I and secondary deficiency is precipitated by feeding of plants containing goitrogens namely, raw soyabean, beet pulp, corn, sweet potato, white clover etc. Estimation of iodine level in blood and milk are reliable indicators of the thyroxine status of the animal. Iodine concentrations in blood, serum, plasma or milk are of diagnostic value.
Clinical signs
Iodine deficiency lead to birth of goitrogenic calves. While in herds poor fertility and high abortion rate.
Treatment and control
Treatment is not undertaken in farm animals because of high case fatality rate. As a preventive measure, pregnant cattle are supplemented with Iodine @0.8-1mg/kg DM and nonpregnant cattle are supplemented @ 0.1-0.3mg/kg DM. Iodine can be supplemented in salt or mineral mixture i.e Potassium Iodate @ 200mg/kg salt. Weekly application of tincture of Iodine (4ml cattle; 2 ml pig or sheep) inside of flank; administration of long-acting injectable Iodine (Iodized oil) @390mg; Iodine slow-release device in forestomach are other preventive measures.
DR SP DIWAKER,IVRI
