A second stallion quarantined in Outagamie County, Wisc., has tested positive for contagious equine metritis (CEM), a treatable reproductive disease of horses.

The National Veterinary Services Laboratories in Ames, Iowa, reported the positive test result Thursday afternoon, Jan. 22. The stallion, a 4-year-old Paint, has been quarantined since Jan. 16, when state animal health authorities learned he had been at a Wisconsin artificial insemination center at the same time as another infected stallion from Outagamie County.

He was one of 18 stallions quarantined because they had been exposed to that earlier reported CEM-positive stallion in Outagamie County. All are located in Wisconsin. In addition, 29 exposed mares are quarantined in Wisconsin because they have been exposed to CEM-positive stallions.

State and federal animal health personnel will examine the newly identified stallion’s breeding records and movement history to trace what mares may have been exposed via natural breeding or artificial insemination, and what stallions may have been exposed via shared artificial insemination equipment