USDA Issues Rule on Importing Horses from CEM-Affected Countries

The USDA Animal and Plant Health Inspection Service (APHIS) is making final its interim rule regarding the importation of horses from countries affected with contagious equine metritis (CEM).

"These certification and testing requirements, in addition to our existing import regulations, will strengthen protections for horses in the United States," said John R. Clifford, DVM, USDA's chief veterinary officer and deputy administrator for APHIS' Veterinary Services program.

APHIS took this action after reviewing probable causes of CEM outbreaks in the United States. This review identified the need to strengthen testing protocol for horses arriving from CEM-affected countries, and the final rule includes changes based on comments received on the interim rule issued in March 2011.

APHIS will now have additional entry requirements for imported horses based on age. Yearlings and weanlings must not have been bred to other horses, either through artificial insemination or live breeding, from the time they were tested for CEM until export. Test mares, imported mares, and imported stallions above a certain age are now required to undergo an additional CEM test that will help improve the accuracy of final test results. These actions outlined in the final rule will provide additional safeguards against the introduction of CEM through the importation of affected horses.

CEM is a transmissible, exotic venereal disease in horses. It usually results in infertility in mares and, on rare occasions, can cause mares to spontaneously abort. Infected stallions exhibit no clinical signs but can carry the CEM bacteria for years. CEM is commonly transmitted during sexual intercourse but can also be transmitted indirectly through artificial insemination or contact with contaminated hands or objects. It can be treated with disinfectants and antibiotics.

The final rule can be found by visiting

The final rule was published in the Feb. 12 edition of the Federal Register and became effective upon publication.

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