Ionophore Toxicity in Baby Calves

Dr. Clell Bagley, D.V.M.
USU Extension Veterinarian

    I provided an article on this subject which was published in the July 2000 issue of the USU Dairy Newsletter. It had three errors in it. I apologize for those and will try to correct and clarify them here.

1. Deccox (decoquinate) is NOT toxic to calves, even at a young age. It is lasalocid (Bovatec) which can be toxic, even at low doses, to calves under seven days of age. Sorry for the mix-up in the listing of these two products.

    Deccox has been fed at up to 8,000 times the label dose to young calves and caused no ill effects. A relatively new form of decoquinate (Deccox-M) is available for use in milk being fed to baby calves. It is appropriate for use as an anticoccidial.

2. The previous article stated that it had not been proven that Deccox would aid in prevention of Cryptosporidiosis. However, there is some evidence that it may be of benefit.
    A trial at The Ohio State University was conducted using Deccox in an experimental challenge of baby calves with crypto. This study showed a significant difference in the number of days with abnormal stools for those calves treated at the 5X and 10X dose levels compared to the control calves. �The result of the trial, although not conclusive, suggests there may be some beneficial clinical response using Deccox with experimental cryptosporidial infections.�

    A similar study in goat kids (in France) concluded: �Decoquinate reduced the severity of cryptosporidiosis in ... The oocyst shedding was decreased in number and in duration. ... This drug is well tolerated by animals and may be recommended in prevention of ruminant cryptosporidiosis, a disease which has very limited treatment options.�

3. Ionophores

    Deccox (decoquinate) and Corid (amprolium) are NOT ionophores. Monensin (Rumensin) and lasalocid (Bovatec) are ionophores. Decoquinate is a quinolone. All (decoquinate, amprolium, monensin, and lasalocid) are anticoccidials.


    Coccidiosis is common in young calves. Deccox-M could be used in even baby calves as a preventive. Since it is classed as a medication (and not a feed additive), Deccox could be prescribed by your veterinarian, on an extra label use basis, as an aid for prevention of crypto.

    Colostrum management, sanitation and nutrition are all still essential factors in the prevention of crypto. ©