Copper (Cu) is an important trace element for both animals and plants, optimising health and supporting reproductive performance, bone growth, neuro-muscular function, bone and cartilage growth in stock. In plants, copper is needed for photosynthesis, transpiration and nitrogen fixation.
Many areas of New Zealand have low or deficient copper levels in soil and pasture, and according to a DINZ deer survey it’s suggested about 80% of deer farmers supplement their herds with copper. Copper deficiency can be found in a range of soils in multiple regions of NZ, the main problem areas are soils on coastal sands, leached sandy soils, marine silts, some river silts, peat soils, podzols, pumice soils and limestone soils with high pH.
In addition, copper can be affected by the levels of other trace elements, leading to induced copper deficiency or marginality at peak demand. The absorption and utilisation of copper in animals can also be affected by molybdenum, sulphur, iron and zinc levels; including fertiliser influences and plat types. In some situations, an imbalance in supply of these elements can induce a copper deficiency.
You may suspect copper deficiency if you have soil types and pasture types that would predispose you to marginal or deficient states and production measures appear to be poor, e.g. difficulty achieving target growth rates, poor coats, higher disease rates, poor reproductive parameters or poor velvet growth.
In deer herds affected clinically typically only a proportion of animals show signs of deficiency. The main clinical signs are swayback in older deer with incoordination in the gait and apparent loss of balance [enzootic ataxia], and abnormal bone development, deformities and fractures in young deer [osteochondrosis].
Copper is involved in melanin production – which in turn is responsible for coat colour, deficiencies can lead to faded looking coats.
Except in severe deficiencies signs and consequences can be difficult to assess but it is likely that some effects on growth, immune response and reproductive capability could be expected as copper impacts collagen and bone formation, formation of red blood cells, synthesis of proteins and enzymes and white blood cell function..
Be aware that the lowest levels are usually seen in the late winter and early spring and tend to be highest in late summer and early autumn. Crops can affect levels and availability with legumes having higher copper and fodder beet being lower and increasing soil intake leading to antagonistic reductions in copper absorption.
Most primary copper deficiency is due to low soil levels associated with sandy, pumice and peaty soils. Highly alkaline soils and liming reduce the availability of copper.
Secondary copper deficiency is associated with antagonists reducing copper absorption – usually present in the soil, elements like molbydenum and sulphur can be particularly influential.
Copper supplementation needs to consider all the predisposing factors mentioned above and the periods when animals have greater requirements for trace elements, such as late pregnancy and lactation and especially in growing animals, such as young hinds.
DINZ warns about the risks of unnecessary supplementation and care to avoid overdosing, especially in the young. Crucial to this is working with your veterinarian to understand the copper levels in your stock at these key times, and to test at the critical periods in different stock types both before and after supplementation to ensure you are getting optimal benefit.
Timing – will depend on your farm management but utilising samples at the deer slaughter plant is an efficient method; but you must consider whether the timing means the levels would likely be high or low on your property at that time of year. Liver sampling hinds pre-mating in autumn will give a good indication of “high” levels, and blood samples from weaners at this time would be indicative too. Given that levels will likely be lowest from July to September this is a good time to gauge your “worst-case” situation.
Along with the test results you should discuss the form of supplementation and timing, and where copper is likely to impact on your production system. Copper crosses the placenta well and hinds pass high levels into the fawn in the final 2 months of pregnancy so supplementing the hinds pre-fawning [6-8 weeks] will ensure good protective levels in the fawns.
In marginal areas, or if you wish to optimise the performance of animals, a product like Multimin® + Cu may well be a good choice to supplement copper at critical periods and has the benefit of offering Selenium, Manganese and Zinc as well – all of which provide benefits for reproduction and immunity. This can be important to help support vaccination and a strong antibody response. It is also beneficial in the last trimester of pregnancy where the high demands of the fawn’s growth could triple the trace element requirements. Impact of these elements on velvet production are not well documented but it is likely, given the nature of the velvet/antler growth cycle that copper and zinc could be influential and may be beneficially supplemented; particularly in young stags.