Copper deficiency
Low copper levels can limit growth rates, reproductive performance and lactation.
How does copper deficiency affect an animal?
In cattle, copper deficiency can cause reduced growth rates in young cattle, diarrhoea, bone defects, lightening of the coat colour especially around the eyes, anaemia and possibly reduced milk production and poor reproductive performance.
Young deer suffer reduced growth rates and adult deer develop a condition called ‘swayback' where they lose coordination of their hind end. Lambs can also suffer from swayback. Copper deficiency in sheep will also lead to weak bones, wool abnormalities and possibly reduced fertility.
The classic signs of copper deficiency are not as common these days and most of the time we are aiming to achieve levels that optimise production.
What causes copper deficiency?
The reason for inadequate copper levels is usually due to interfering minerals in the soil/pasture and not low levels of copper in the diet per se. Minerals that reduce the absorption of copper (antagonists) include molybdenum, sulphur, iron and zinc. Antagonists have a large influence on the amount of copper that must be present in the diet to maintain optimal levels.
When do copper levels normally drop?
Copper levels tend to fall over the winter and are often at their lowest heading into the spring. The reasons for this are:
- Pasture molybdenum levels increase in water-logged soils
- During the winter the amount of soil, and hence iron, ingested by animals increases (it can be up to 10% of the diet if grazing short muddy pastures, if silage has a lot of soil contamination or if the water table is high)
- Copper requirements are higher during the late winter/early spring due to the demands of the developing foetus and early lactation
Autumn is a good time of the year to test trace element levels.
Why is liver-testing better than blood-testing for copper?
Liver samples are preferred to blood samples for assessing copper status. The liver is the major storage site of copper in the body. Think of the liver as being like a water tank slowly feeding a trough (the blood). The trough remains full until the tank is empty and then the trough level also falls. Blood-testing will identify clinical deficiency but does not give any indication of the level of copper reserves in the liver. Generally we are not looking for clinical deficiency but want to know whether there is enough copper reserve to get through the next period of time and how effective the supplementation programme has been.
Liver samples can be collected from animals going to the works. Simply call us in advance to organise the form that must accompany the animals. Alternatively, we can come out and perform a simple procedure on live animals to collect liver samples. If necessary, we can take blood samples, but as mentioned, this does not give us an accurate indication if copper levels will limit productivity in the upcoming season.
It is best to test mixed-age animals as copper levels are depleted during pregnancy and lactation. These animals are likely to have the lowest levels in the herd so will give the best indication of the optimal level of copper supplementation.
How can copper be supplemented?
There are a variety of ways to supplement including copper boluses, injections or copper added to the water supply.
It is vital to measure copper levels and not treat without diagnosis as copper can be toxic, and indeed fatal if overdosed.
Now is a good time to test, as levels will drop over winter and are at their lowest in the pasture in spring when the demands of late pregnancy and lactation are at their greatest. Speak to your vet about testing and supplementing on your farm to minimise performance losses from low copper levels.
