Probably the most well known, and most feared, of all camelid defects is a congenital abnormality of the respiratory system called Choanal Atresia. Crias born with this defect will have respiratory difficulty from birth as they are unable to breathe when their mouth is closed therefore causing them difficulty to nurse and breathe at the same time.
Normally air is allowed to pass from the nasal passageways to the throat where it proceeds down the trachea to the lungs. With coanal atresia, an embryonic membrane fails to rupture during fetal development creating an obstruction between the nasal cavity and the throat. The obstruction may be only on one side of the nose or on both sides of the nose resulting in either a partial or complete coanal atresia. Since camelids are obligate nasal breathers, many of these crias die soon after birth. Surgical repair may be possible if the abnormality is not severe, but often euthanasia is recommended.
A partial CA cria may go undetected for quite a while, but a full CA cria will exhibit some symptoms. The nostrils of a cria with CA normally will flare with each breath and he will seem less active than your other normal crias. You may notice him gasping for air or appearing to have trouble breathing or out of breath. A CA cria must breathe through its mouth and therefore can not nurse without sucking milk into its lungs. This then results in pneumonia often causing death. One way to determine whether the cria is able to breathe through its nose is to hold the mouth and one mostril tightly closed and notice if the remaining open nostril is able to fog up a mirror. Then repeat the procedure with the other nostril closed. A blocked nasal passage will not be able to produce fog on a mirror.
Since coanal atresia has been found to be hereditary, if the cria should survive, it is, without a doubt, recommended that this offspring be removed from the breeding pool. However, as of this time, research studies have not been able to determine exactly what requirements are necessary for this defect to surface within our camelid breeding programs. Threrefore, it becomes a very difficult decision for the unfortunate breeder of a CA cria whether to immediately cull both the parents of the affected offspring or whether to allow them to breed again with different pairings. Perhaps another CA cria will result. Or perhaps they each will go on to produce many perfectly healthy offspring in years to come. Research just doesn't provide us with enough information at this time to make the decision for us.
If repeated occurances of CA appear in one animal's lineage, that animal should be removed from the breeding pool in order not to pass on this unfortunate defect. However, opinions vary to just how far back related animals should be culled. A discussion of thoughts, opinions, and experiences pertaining to coanal atresia appears at CA Discussion. We invite you to share your thoughts with other camelid breeders also.
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