Structures of the Bovine Vomeronasal Complex and Its Relationships to the Palate: Tongue Manipulation

Abstract

The rostral part of the bovine vomeronasal complex was examined to determine its relationships to structures of the palate which are compressed by the tongue during investigative sexual behavior. The rostral vomeronasal cartilage (VNC) is C-shaped and contains the incisive duct (ID). The hilus of the cartilage is directed medially, approximately 0.5 cm dorsal to the palate. Just caudal to the origin of the vomeronasal duct, the VCN lies approximately 1 cm above the palate with a ventrally oriented hilus containing the ID. Further caudally, the hilus is directed laterally, toward the nasal cavity. Palatal mucosa occupies the intervomeronasal, cartilaginous area below the nasal septum and caudal to the incisive papilla. This mucosa and the ID appear to be compressed by the bull’s everted tongue, forcing fluid samples into the vomeronasal system.

The bovine vomeronasal organ.

“…The macroscopic appearance of the bovine vomeronasal organ is similar to that described by JACOBS et al (1981). Contrary to the brief statement by MINETT (1925), the entire rostral portion is surfaced by non-neurosensory epithelium.…”

“…The bovine utilizes a vomeronasal organ for sensing sex-related odors (ESTES,1972;PALEOLOGOU, 1977;JACOBS et al, 1981;KLEMM et al, 1984). As only a brief report by KRATZING (1972) is available on the ultrastructure of the bovine vomeronasal organ, the present study was initiated to characterize it in the neonatal calf.…”

Vomeronasal organ and its associated structures in the opossumMonodelphis domestica

“…The dental gap also enables the unimpeded flow of moisture in the reverse direction, i.e., out of the nasopalatine canals and onto the rhinarial nuzzling pad. The opossum's nasopalatine ducts are covered with an elaborate incisive papilla compared to other species with oral access to the VNO (e.g., bovine, Jacobs et al, 1981). The very thin ''wings'' seal the whole upper palate and may help regulate the pressure in the VN system in addition to the vasculature.…”

“…Poran et al (1993a) proposed that several specialized structures may be significant for nuzzling behavior: (1) the opossum's tongue may play a role especially before and after the nuzzling bout when licking of the snout is evident. The importance of the tongue in vomeronasal investigation was demonstrated in bovine species, which, like the opossum, employ the oral route for vomeronasal uptake of social odors (Jacobs et al, 1981); (2) two ventral rhinarial grooves on either side of the median philtrum that terminate at the margins of the extensive, winged incisive papilla. Maier (1980) noted the importance of the median philtrum for the channeling of odor solutes; (3) a very large serous vomeronasal gland draining into the VNO lumen at its caudal end; Poran et al, (1993a) proposed that the fluid involved in nuzzling is at least in part composed of secretions from this gland; (4) a dual venous sinus system.…”

The West Indian Manatee <i>(Trichechus manatus) </i>Lacks a Vomeronasal Organ

“…Ad ditionally, there was no nasopalatine duct in any of the manatees examined. In ter restrial mammals, chemicals reach the vomeronasal organ dissolved in a watery mucus, either through the nose or via the nasopalatine duct from the mouth [Estes, 1972;Jacobs et al, 1981;Mackay-Sim and Rose, 1986;Meredith et al, 1980;Wysocki et al, 1980]. Thus, the lack of a naso palatine duct in the manatee provides in direct support for the absence of a vomer onasal organ.…”