Mineral Of The Month: Zinc

Zinc is a bluish-silvery metal that is mined in about 40 countries. Zinc is found everywhere in daily life; in every cell of the animal body (it’s the second most abundant trace mineral after iron), it is estimated to comprise 0.004% of the Earth’s crust, it’s found in the food we eat and in the products we use (sunblock, cars, airplanes, cosmetics, surgical tools etc.).

The element name is believed to come from the German word “zinke,” which means “pointed”. This is most likely in reference to the needle-like appearance of zinc crystals. Andreas Marggraf is credited with isolating the element zinc in 1746 however, it is believed to have been discovered by Indian metallurgists before 1000 BCE (Helmenstine, 2021).

Zinc is Essential for Animals
Zinc is what is known as a trace mineral as it is required in small amounts in the animal body. Zinc has been found in every tissue of the animal body and is a co-factor in over 200 enzymes in metabolism. Zinc is largely involved in the synthesis and metabolism of proteins, carbohydrates and nucleic acids (Ewing, 2007). Large concentrations of zinc have been found in the skin, hair and wool of animals (McDonald, 2011) and it is essential in bone, cartilage, and hoof formation as well as the health of skin (Kohnke, 1999). Among other physiological functions of zinc are the production, storage and secretion of hormones, involvement in the immune system, wound healing, electrolyte balance and some micro-organisms in the rumen require zinc for growth.

A daily intake of zinc is required by animals as utilisation and secretion can rapidly deplete body stores. Bones are the main place where zinc is deposited however, it is not freely available. Other places of zinc storage is the liver, kidney, mucosal cells of the gut, pancreas and spleen but the capacity for storage is limited, making the available zinc pool in the body small hence deficiency can appear quickly.

What Does Zinc Deficiency Look Like in Animals?
If an animal is not getting enough zinc from its diet to meet requirements the following symptoms may be observed:

  • Reduced growth rates and poor skin condition,
  • Affects the immune system,
  • Poor hair formation and wool problems – sheep can show breaks in the wool,
  • Loss of appetite, reduced feed intake and emaciations,
  • Prolongs healing of wounds,
  • Poor testicular development and impairment of sexual function, reduced conception rate, severely impaired spermatozoan maturation,
  • Thickening of epithelial cells known as parakeratosis,
  • Upset electrolyte balance,
  • Offspring can suffer from malformations and behavioural issues – calves showing bowing of hind legs and stiff joints,
  • In dairy cows, low dietary zinc concentrations are associated with high somatic cell counts in the milk.

The Importance of Zinc for Soil and Plants
Similarly, to animals, having adequate levels of the trace element (only needed in small quantities) zinc is important to plants. Zinc in the plant is associated with iron and manganese in the formation of chlorophyll; it is involved in several enzyme systems and is essential for protein synthesis (Glendinning, 1990). Zinc is a component of auxins (a plant hormone) that play a vital role in the coordination of many growth and behavioural processes in plant life cycles and are essential for plant body development. Zinc also has a regulatory role in the intake and efficient use of water by plants.

The concentration of zinc in plants is where growth is greatest such at the shoot tips where stems are formed, in seeds where it is readily available for the seedling and at nodes where buds form and leaves grow.

What Does Zinc Deficiency Look Like in Plants?
Zinc is not easily moved from old tissue to new tissue, therefore, during periods of shortage deficiency symptoms will appear on the new growth. Deficiency symptoms will vary depending on the plant but typically they are expressed as some varying pattern of chlorosis of the new leaves (often interveinal) and necrotic spots may form on the margins or leaf tips. New leaves will often be smaller in size and often cupped upward/distorted, death of tissue in affected leaf areas and early loss of foliage. The plant may have a rosette appearance due to the internodes shortening, in addition to bud development being poor resulting in reduced flowering and branching (Bloodnick, 2021).

The Fertilizer Handbook (Glendinning, 1990) explains that zinc deficiency can arise from several causes such as:

  1. Natural deficiencies – where the total soil zinc content is low or where there may be plenty of zinc present in soil, but it isn’t available to plants. Clay soils of high magnesium content can also depress zinc availability.
  2. Induced deficiencies – where soil management practices have marked effects on the zinc nutrition in plants. Zinc availability may be compromised by:
    • Over-use of lime
    • Frequent us of large amounts of poultry manure in orchards
    • High levels of phosphorus may result in zinc being unavailable
    • Land forming in irrigation areas may cause zinc deficiency in ‘cut’ areas due to the exposure of the subsoil which is often deficient
    • Soil erosion
    • Crop rotation – zinc deficiencies are more common after crops with high zinc requirement such as maize have been planted.
    • Fallowing – long fallows have aggravated zinc deficiencies possibly due to the build-up of nitrate-nitrogen levels in the soil.
    • Nitrogen fertilisers – by increasing total crop growth, there may be an increase in the plant’s zinc needs beyond the available supply.

How AgSolutions Can Help
An adequate supply of zinc is essential for both plants and animals. As zinc is a trace mineral only small amounts are required, however, deficiency can have a significant impact on production for both plants and animals.

A good place to start in order to determine the zinc status of your land is by getting a soil test done. AgSolutions can assist your operation by taking a soil test and working with you to develop a soil management program. The NatraMin range is formulated to restore bio-activated broad spectrum minerals to your soil including zinc, and is designed to help improve the three aspects of soil fertility – nutritional, biological and structural.

MegaMin Livestock Supplements have a number of blends suitable to assist in providing stock with extra dietary zinc along with other essential macro and trace minerals, which in turn can help to promote production and assist with getting a return on investment.

MegaMin Equine Enhancer has been fortified with organic zinc, biotin, methionine and also contains a prebiotic to accompany the provision of broad spectrum minerals and vitamins designed to promote overall health, while also actively supporting hoof quality coat condition and gut function.

For further information on AgSolutions products contact Head Office on 1800 81 57 57.

Bloodnick, E. (2021, March 2). Role of Zinc in Plant Culture. Retrieved from ProMix: https://www.pthorticulture.com/en/training-center/role-of-zinc-in-plant-culture/

Ewing, W. C. (2007). The Minerals Directory. England: Context.

Glendinning, J. (1990). The Fertilizer Handbook. Morningside: Incitec Ltd.

Helmenstine, A. (2021, February 1st). 10 Interesting and Fun Facts About Zinc. Retrieved from ThoughtCo.: https://www.thoughtco.com/interesting-zinc-element-facts-603359

Kohnke, J. K.-J. (1999). Feeding Horses in Australia. Kingston: Rural Industries Research and Development Corporation.

McDonald, P. E. (2011). Animal Nutrition Seventh Edition. Essex: Pearson Education Limited.