Mature ewes usually have twins, occasionally producing triplets or quadruplets. Rams are aggressive breeders, generally fertile year round, and can settle a large number of ewes in the first cycle of exposure. The Katahdin ewe shows a strong, protective mothering instinct, usually lambs without assistance, and has ample milk for her lambs. Rejection of lambs is rare. Lambs produce a high quality, well-muscled carcass that is naturally lean and consistently offers a very mild flavor.
Lambs are comparable to other medium-sized maternal breeds in growth and cutability.
The hair coat of the Katahdin varies in length and texture among individuals and can be any color or color combination. It generally consists of coarse outer hairfibers and an undercoat of fine wooly fibers that becomes very thick and longer if cold weather sets in and day length decreases. This undercoat and some hair naturally sheds as temperature and day length increase seasonally, leaving a shorter, smooth summer coat. While some uses may be found for the shed fiber, it is generally not harvested. It usually takes at least 3 generations, depending on the type of wool sheep parentage, to obtain a lamb with a shedding hair coat and other purebred characteristics.