If you’ve ever seen black cows with a tinge of red hair, you may have witnessed a case of copper deficiency. This trace mineral is deficient in the diets of many cattle in Western Canada and is a fairly common condition.
As a trace mineral, copper is important for a variety of essential functions in the body. There are many enzymes that use copper to facilitate important molecular reactions. It also is required for production and maintenance of tissues, including bone and the absorption of iron.
Copper deficiency in cattle has been linked to birth defects. Red blood cells need copper for proper development. Because of this, another condition that can occur with copper deficiency is anemia. Anemic animals have really low red blood cell counts leading to insufficient oxygen delivery to tissues. Low copper can also remove the insulation in the brain and spinal cord, affecting co-ordination.
Hearts of copper-deficient calves have signs of damage from reduced amounts of a copper-dependent antioxidant. Another outcome of copper deficiency is DNA damage and a predisposition to develop diarrhea. Calves that have low copper also tend to grow slower, which can have a significant economic cost.
Cattle consume copper from their diets. However, the levels of copper in grass, alfalfa and other forages reflects the amount of copper in the soil. So if hay or silage crops originate in areas with low copper in the soil, this can lead to low levels in those feeds and ultimately, not enough copper in the animals’ diets.
Copper levels in the body are closely linked to another trace mineral, molybdenum. In areas with high molybdenum in the feed, copper deficiencies can develop because molybdenum reduces the absorption of copper in the intestines.
Testing for copper deficiency involves submitting liver and blood samples to a toxicology laboratory. Blood samples can be collected by your veterinarian and sent for testing.
Additionally, if you have cattle die for any reason, it could be an opportunity to have your veterinarian collect a liver sample for testing. There is general consensus that copper measurements in liver are more accurate than those from blood tests, so testing the actual liver tissue should be done when possible. The test for copper at Prairie Diagnostic Services in Saskatoon also includes other trace minerals: magnesium, manganese, iron, cobalt, zinc, selenium and molybdenum. Because you get information about several trace minerals including copper and molybdenum, it is good value for your dollar. Supplements can be adjusted based on the results.
There is growing interest in measuring trace minerals in hair samples as this is a much less invasive method for gaining a sample compared to harvesting liver. However, this technique is so far only really used in research settings and is not available at local laboratories as part of routine testing.
Appropriate amounts of copper supplementation in pregnant cows can benefit their calves. Cows that are not deficient will transfer some of the mineral to their calf fetuses, where it is stored in the liver. This mineral boost sets them up for several weeks of adequate copper after birth. Supplemental copper can be provided as a mineral mix as well as injectable format.
Cattle require much more copper in their diets than do sheep and goats. This is really important to know because the small ruminants are highly susceptible to copper toxicity. And this most often occurs after they are accidentally fed mineral supplements formulated for cattle.
Trace minerals, including copper can have a profound impact on cattle health. Since copper deficiency is so common in Western Canada, periodic testing of your herd can give valuable feedback on how well supplementation is working and provide baseline information if something changes.