Testicular morphological and ultrasonographic characterization of male gray brocket deers (Mazama gouazoubira) in different reproductive status

ABSTRACT

Background: Gray brocket deer (Mazama gouazoubira) populations have been declining due to human intervention.Yet, only a few studies have assessed ultrasonographic testicular characteristics in cervids. Considering the relevance ofmonitoring testicular size, blood flow, and parenchyma, the present study aims to establish baseline information on scrotalcircumference, testicular volume, and spectral Doppler parameters, to describe differences among adult male gray brocketdeer in different reproductive status, and to correlate ultrasound parameters with testes size measurements.Materials, Methods & Results: Six adult male gray brocket deers were used in the study. Scrotal circumference and testicularvolume were measured. B mode ultrasound images of testes (longitudinal and cross-sectional views) and epididymes weresubjected to computer-assisted analysis, obtaining the numerical pixel values (NPV) and pixel standard deviation (PSD).Using spectral Doppler, supratesticular artery blood flow velocities (peak systolic velocity - PSV, end diastolic velocity -EDV, time-average maximum velocity - TAMAX, resistivity - RI and pulsatility indices - PI) were obtained. Semen wasanalyzed through total motility, vigor, and concentration tests. Three animals were normospermic (F+ group) and threewere oligo/azoospermic (F- group). Groups were compared using were compared using a one-way ANOVA or KruskalWallis followed by Student-Newman-Keuls (SNK) test. Ultrasound parameters were correlated to testes size parametersusing Pearson’s correlation for parametric variables and Spearman’s correlation for non-parametric variables. F+ grouppresented significantly higher scrotal circumference (14.57 ± 1.19 cm), testicular volume (26.18 ± 4.94 cm3), and testescross-sectional NPV (69.88 ± 24.00) and PSD (10.78 ± 3.42) than group F- (NPV 28.26 ± 13.75, PSD 6.70 ± 1.84). Nosignificant differences were observed between the groups regarding...