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Letters to the Editor: Foundation for the Future plan, copper toxicosis

Published on 29 November 2010

Dear Editor,

I wanted to comment on the article in the Nov. 1 issue entitled, “How much copper are you putting down?” I fully agree that we have to be very careful how much copper is applied to cropland due to the potential agronomic implications.However, I am concerned about the author’s description of copper toxicosis, as the symptoms are a bit broad.

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For lactating dairy cattle, it is fairly typical for liver copper concentrations on a dry weight basis to be around 500 ppm.This is from hundreds of liver biopsies collected from healthy U.S. dairy cattle.

Diagnosis of copper toxicosis should not be based solely on liver copper concentrations.We have seen healthy cows have liver concentrations in excess of 1,000 ppm copper on a dry weight basis, and we have seen cows that have died due to copper toxicosis that have liver copper concentrations less than 700 ppm.The reason why liver copper concentration varies is that a cow suffering from copper toxicosis will start exporting copper from the liver, resulting in the drop in liver copper concentrations. To diagnose copper toxicity, one needs to collect not only the liver but also the kidney and have it analyzed for copper content.

Acute copper toxicosis is rare. In a chronic copper toxicosis, where cows were given or consumed excessive amounts of copper for an extended period of time (from months to, in some cases, years), there is a progressive accumulation of copper in the liver.Copper, both a potent pro-oxidant as well as anti-oxidant, is normally bound to a variety of proteins in the body.As long as the copper is bound to a protein and is not free, the animal is able to perform fairly well. However, release of copper from the proteins due to increased protein turnover or saturation of the proteins then results in interaction of the copper ion with exposed cells in the body.This results in hemolysis (breakdown of red blood cells) and necrosis of liver tissue.

General symptoms producers may observe include jaundice, general discomfort, reddish brown urine, lack of coordination, unable to rise, large drop in milk production, brown mucous membranes and head pressing.Clinical symptoms generally last for one to three days with death occurring in most cows. In herds being fed excessive amounts of copper, one may observe an increase in stillborns or calf deaths in the first few days of life.Lameness is not usually associated with copper toxicosis.

However, even the symptoms described above are general and can be the result of other diseases or toxicities and may not be the result of copper toxicosis. If producers do suspect copper toxicosis, we strongly encourage producers to have full necropsies performed on animals and both liver and kidney tissues collected and analyzed for copper content.

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Mike Socha
Zinpro Dairy Research Team Leader

Dear Editor,

I have read the 63-page NMPF Foundation for the Futureplan, I have read about 2011 RMA -LGM-Dairy, I read about DFA Risk Management tools, and I am still trying to learn about puts, options, hedging and futures contracts. I listen to the National Dairy Producer Organization’s town hall meetings, I read all of your articles about the future of milk pricing and all of the plans out there.

Someone needs to make this more simple. Dairy producers do not need DFA block voting the NMPF plan, most will not survive financially until Farm Bill 2012. Frustrated!

Darlene Wittmeyer
Western New York dairy farmer

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