A DOUBLED DUCTUS PAROTIDEUS IN A COW

Kaman J.: A Doubled Ductus Parotideus in a Cow. Acta vet. Brno, 55, 1986: 3-9, A ·description is given of a bilateral, doubled ductus parotideus in a cow. This condition is hitherto unreported. Both the dorsal and ventral branches of the parotid duct were equally and well­ developed, passing in parallel but completely separated until just before their end. They united to form a single ductus parotideus only 2 cm (left side) and 2.5 cm (right side) before their piercing the buccinator muscle. This rare deviation from the normal did not cause functional disturbance. The doubled duct caused only a slight change in the topography of the incisura vasorum facialium region; the author described this finding as a variation. The origin of such a doubled duct was assumed to be embryonic, but the causal factor or factors were not investigated. It is hypothesized that this doubling was a result of doubling of an initial, proximal budding of the primordial gland duct. Developmental variation, ductus parotideus, topography of incisura vasorum faci­ alium, cattle. Saliva is for the most species of great importance for the initial processing of feedstuffs. There is a relationship between the nature of feed and the morphology of salivary glands as discussed by Zhedenov (1958). The structure of the salivary gland is ultimately translated into the chemical and physical composition and volume of saliva. Salivary glands are well-developed in herbivores consuming large amounts of relatively dry feeds. The development and maintenance of the structu­ ral. integrity of the duct of the salivary gland is essential for the normal functioning of these glands. The ductus parotideus of cattle is decribed as a single duct in textbooks of comparative and domesticated animal anatomy (Ellenberger and Baum 1943; Sisson 1947; Zhedenov 1958 and 1965; Schummer et al. 1973; Koch 1970; Najbrt et al. 1980) as well as in the bovine anatomy textbooks (McLeod et al. 1958). No mention is made of variation from this normal morphology for the ductus parotideus in .cattle or in other domesticated animals except for the mention of the occurrence of an additional duct in the dog. In this species it is a short duct which drains an accessory parotid gland and empties directly into the distal aspect of the main duct; it is commonly bilateral (Miller et al. 1979). The problem of anomalous ductus parotideus seems to be quite rare also in gross pathology textbooks (Nieberle and Cohrs 1970; Jubb and Kennedy 1970). Developmental defects may occasionally occur as congenital atresia of the duct in the dog but rarely in the horse and cattle (Zakrzewski 1962 in J oest 1962). The terminology and literature of veterinary teratology has been reviewed (Wiedeking 1969) and of 1085 citations, only one described an abnormal development of the parotid duct, a case of congenital atresia of the left ductus parotideus in a horse (Fowler 1965).