Congenital First Pharyngeal Arch Anomaly in a Holstein Friesian Calf

The developmental error of the first pair of pharyngeal arch processes would result in a group of malformations related to the oral cavity. These malformations can be listed as agnathia, micrognathia, brachygnathia, syngnathia, cleft palate, campylognathia, parrot beak, and strophocephalia. Campylognathia is an anomaly in which the lower or upper jaw deviated from the midline. Clinical examination of a newborn female Holstein Friesian calf showed mandibular deviation, inferior and superior cheek teeth deformation, and some other facial malformations. No similar case was detected in the history of the herd. Precise consideration of malformed animals and the extent of involvement of different structures indicates the pattern of malformation, the time of teratogenic effect, and the motive embryonic structures. In the present case, the involvement of derivatives of both maxillary and mandibular processes shows the responsibility of the first pharyngeal arch for mentioned abnormalities. In humans, different types of abnormal development of the first pharyngeal arch have been reported and so, have been classified under the “first visceral arch syndrome”. But according to the infrequency of reports, this classification has not been done in domestic animals.