Morphological and morphometric characterization of the preputial ostium, internal preputial leaflet, and free part of the penises of Aberdeen Angus and Nellore bulls

ABSTRACT The morphological characteristics of the external genitalia of the bull may contribute to the etiopathogenesis of preputial diseases that trigger the impotence coeundi and losses in farms. The goal of this study was to establish morphometric parameters of the preputial ostium, the internal preputial leaflet (IPL), the free part and glans of the penis; describe the histological characteristics of the IPL; perform a count of the preputial sebaceous glands and compare these variables between 24-month-old Aberdeen Angus and Nellore bulls. At the slaughterhouse, 20 preputial pieces were collected from each breed. A device composed of base, rod, ring, and funnel was designed to hold each suspended and distended part. The IPL, the free part of the penis and the glans were measured. The ostium diameter was measured, and the radius, perimeter, and area of the preputial ostium were calculated. Samples were collected from the dorsal and ventral regions and from the cranial, medial, and caudal portions of the IPL. By electronic and optical microscopy, IPL characterization and sebaceous gland counts were performed. Analysis of variance was performed using the F test at 5%. It was concluded that Nellore bulls have a more extensive IPL and free part of the penis and more preputial sebaceous glands than Aberdeen Angus bulls. In both breeds, there are more glands in the ventral region of the ostium.