Choanal atresia is the lack of a connection between the nose and the mouth. Normally, the nasal passages lead back into the pharynx which connects to the opening of the trachea which then leads into the lungs. The area where the nasal passages meet the pharynx at the end of the hard palate is called the choanae. Atresia is the absence of a normal opening. Therefore, choanal atresia is the lack of a normal opening at the choanae. The normal opening is absent because the bone or membrane present during embryonic development fails to break down . A study conducted at Oregon State University concluded that this defect is heritable, but it has not been definitively proven yet, and there remains a great deal of debate within the alpaca community. Some advocate the most conservative strategy of removing both parents of a cria with choanal atresia and not just breeding to different animals. Continuing to breed alpacas who are suspected carriers of choanal atresia may only serve to increase the incidence of the choanal atresia genes (if it is heritable) in the population.More »