Copper is an important mineral for cattle and one that is often deficient in forages. Copper absorption is negatively affected by other compounds in feed and water such as sulfur and molybdenum. Both of these antagonistic minerals can be found in high quantities in forages and waters in South Dakota, making copper supplementation an important part of a mineral program for beef cattle.
The use of dietary copper by cattle is affected by breed and Simmental cattle appear to be more prone to copper deficiencies than other breeds. Although breed differences in copper use have been recognized for some time, the mechanism by which this occurs has not been known. A paper in the February 2013 issue of the Journal of Animal Science reports on research conducted at North Carolina State University that attempts to answer some questions about why breeds differ in susceptibility to copper deficiency.
The researchers fed pregnant Angus and Simmental cows diets that were either adequate or deficient in copper. They also added molybdenum and sulfur to the copper deficient diets. A number of proteins known to be involved in copper absorption and metabolism were measured. Several proteins in the intestine that affect copper absorption differed between Simmental and Angus cows, suggesting that the increased susceptibility to copper deficiency in Simmental cattle was related to poorer absorption of copper from the gastrointestinal tract. This information can be used in future research to evaluate genetic effects on copper absorption.
Liver copper is often used to diagnose copper deficiencies because it is a better indicator of copper status than blood levels. Simmental cows on the copper deficient diets had lower liver copper levels than Simmental cows fed adequate copper. Copper levels in the liver of their fetuses were also affected by the amount of copper in the diet of the cows. This is important because milk is very low in copper and newborn calves rely on liver stores to meet their copper needs.
We know very little about differences in mineral absorption and use between and within breeds of cattle and this study provides information that will help us to learn more. Adequate copper supplementation of beef cows is important for good growth and reproduction and it is important to be aware that Simmental cattle can be more sensitive to copper deficiencies.
- Fry, R.S., J.W. Spears, K. E. Lloyd, A.T. O’Nan, and M.S. Ashwell. 2013. Effect of dietary copper and breed on gene products involved in copper acquisition, distribution, and use in Angus and Simmental cows and fetuses. J. Anim. Sci. 91:861-871.