Ultrasound Anatomy of the Penis in Normal Bos Taurus Bulls

Abstract

The bull penis is subject to various medical conditions that have the potential to cause permanent damage to the penile tract, and thus devastating financial loss to the owner. Such conditions include: trauma with hematoma formation, abscess formation, vascular shunting, urethral obstruction, and fistula formation. The purpose of this study is to examine and document the sonographic appearance of the penis in a subset of normal Bos taurus bulls extending from the distal bend of the sigmoid flexure through the glans. A second purpose is to provide an anatomical reference correlating ultrasound, computed tomography, magnetic resonance imaging, and gross images. Four locations in the bull penis were chosen: the distal bend of the sigmoid flexure (S), the glans (G), and two equidistant locations in between (A and B). Bulls presenting for breeding soundness examination were recruited and were divided into three age groups: 15-18 months, 22-24 months, and 36 months and older. The hypothesis was that no significant differences (p < 0.5; with a confidence interval of 95%) in the penile measurements of bulls in and between the different age groups, including the measurements between locations A, B, and S, would be found. Following numerous measurements of the bull penis from bulls in three different age groups and at three different locations A, B, and S no significant differences in measurements were found supporting our hypothesis. The data were analyzed using the general linear model (GLM) for analysis of variance (ANOVA) and Scheffe’s test for multiple comparisons. A p value of < 0.05 is considered significant.