If the mare can not be used, an alternative donor that is Aa and Qa negative may be used. This donor profile is most commonly seen in Quarter Horses, Morgans, and Standardbreds and is less likely in Thoroughbreds and Arabians, but ideally the donor should be blood typed prior to use rather than using breed as the sole method of identification. In mule foals, female donors that have been previously bred to a jack should not be used.
If a mare cannot be employed, an alternative donor with the Aa and Qa negative blood type may be utilized. This particular blood type profile is most frequently observed in Quarter Horses, Morgans, and Standardbreds; however, it is less likely to occur in Thoroughbreds and Arabians; prior typing of the donor is recommended over breed identification alone.