New treatment for bovine clinical anaplasmosis will become available to veterinarians and cattle producers in May 2020.

April 8, 2020

3 Min Read
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The U.S. Food & Drug Administration's Center for Veterinary Medicine has granted Bayer Animal Health a conditional approval for Baytril 100-CA1 (enrofloxacin) Injectable Solution for the treatment of clinical anaplasmosis in cattle, according to an announcement from Bayer Animal Health.

The product will be available to veterinarians and cattle producers in May 2020, the company said.

“Options to address clinical anaplasmosis in cattle have been limited,” said Sebastian Kuszmierczyk, head of farm animal products in the U.S. for Bayer Animal Health. “This conditional approval allows us to offer the proven efficacy of enrofloxacin as a new treatment for this potentially deadly disease.”

Anaplasmosis is a vector-borne, infectious blood disease usually spread by ticks. The feeding tick transmits the bacteria that infects red blood cells and cause severe anemia, Bayer Animal Health said. The disease is most devastating to cows three years of age and older. While younger animals can become infected, calves less than a year old that are infected usually do not show clinical signs of the disease but will become carriers. Cows infected with the disease that recover will continue to be carriers their entire lives, the company noted.

Much like bovine respiratory disease (BRD), anaplasmosis can be hard to detect. Anemia and weakness are frequently the first clinical signs. Infected cattle will fall behind the rest of the herd and will not eat or drink. Weight loss is rapid. Cattle can become extremely aggressive if they are oxygen deprived due to the severe anemia. Oxygen deprivation can also result in abortions in pregnant cows. Constipation, high fever and labored breathing can also be seen. The most critical period is the first four to nine days after clinical signs appear.

Limited treatment options. Until now, tetracycline antimicrobials, oxytetracycline injectables or chlortetracycline medicated feed were the only drugs used in the U.S. for treatment of acute anaplasmosis, Bayer Animal Health said. In some places, vaccines are also available to increase resistance to anaplasmosis.

“Our recent research has shown that some of the currently available anaplasmosis treatment options may not be as effective as in the past,” said Dr. Kathryn Reif with the department of diagnostic medicine/pathobiology at the Kansas State University College of Veterinary Medicine. “A new treatment option to manage clinical anaplasmosis is a welcome option for veterinarians and producers.”

According to the announcement, Baytril 100-CA1 contains enrofloxacin and is indicated for the treatment of clinical anaplasmosis associated with Anaplasma marginale in replacement dairy heifers under 20 months of age, all classes of beef cattle except beef calves less than two months of age and beef bulls intended for breeding of any age. Not for use in any other class of dairy cattle or in veal calves.

Baytril 100-CA1 is conditionally approved pending a full demonstration of effectiveness, the company said, adding that Baytril 100-CA1 has a reasonable expectation of effectiveness for treatment of clinical anaplasmosis in the conditionally approved classes of cattle when administered for the conditionally approved dosage regimen based on published scientific literature and reports from studies conducted by the sponsor. Enrofloxacin treatment in A. marginale-infected cattle resulted in a decrease in parasitemia and, when evaluated, improvement in clinical variables (hematocrit and rectal temperatures).

Enrofloxacin has been shown to have no adverse effects on cow reproductive performance, pregnancy and lactation and no effect on calf viability and health, Bayer Animal Health said.

Federal law restricts Baytril 100-CA1 to use by or on the order of a licensed veterinarian. Federal law prohibits the extra-label use of this drug in food-producing animals. Cattle intended for human consumption must not be slaughtered within 28 days from the last treatment. This product is not approved for use in female dairy cattle 20 months of age or older including dry dairy cows. Use in these cattle may cause drug residues in milk and/or in calves born to these cows. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal. The effects of enrofloxacin on bull reproductive performance have not been adequately determined.

For more information about Baytril 100-CA1, or to obtain a product label, call Bayer Veterinary Services at 1-800-422-9874 or visit

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