Ultrasonographic study of age-related changes on the size of prostate and testicles in healthy German Shepherd dogs

Introduction and aim. In last decades, dog life expectancy has increased and now the overall median age at death is 11 years approximately (1). This can be attributed to different factors, including better management and nutrition, improved owner education and veterinary care. Therefore, an increasing demand for understanding changes due to ageing in dogs has aroused. In males, prostate and testicle dimensions are positively correlated with body weight (2-6) and their size change along life. Prostate gland increases in weight due to normal growth and it may develop benign prostatic hyperplasia (BPH) in dogs over 5 years (7). A senile involution of the gland might also occurs in aged dogs (2). The size of the testicles increases only during juvenile period within puberty (8). The study of size changes of these organs, could contribute to set reference values for their asymptomatic non pathological ageing. For this purpose, in the present study the ultrasonographic age-related changes of prostatic and testicular dimensions in an homogeneous group of healthy German Shepherd dogs were evaluated. Materials and methods. Fifty-nine intact German Shepherd dogs aged between 1 and 12 years (mean body weight 33.1 ± 4.5 kg) healthy, with normal physical examination, no history of genital disorders, no previous hormonal treatments and normal echotexture of prostate and testicles were included in this study. Length (L), width (W) and height (H) of the prostate and testicles were determined by ultrasonographic examination (8C-RS 6-10MHz probe, Vivid i, GE Medical Systems Israel Ltd, Tirat Carmel, Israel). Prostatic and testicular volume was estimated using the ellipsoid formula L x W x H x 0.523 (9). Data were analyzed by non-linear fit followed by ANOVA and significance was set at p<0.05. Results. Overall size of the prostate progressively increased with age (Fig. 1; p<0.0001). The average dimensions of right and left testicles showed a significant age-related tendency to increase within 6 years of age with a subsequent significant decrease (Fig. 2; p<0.0001). Conclusions. The availability of reference values for prostatic and testicular age-related size changes in different breeds could help practitioners to evaluate whether dimensions of these organs may be responsible or predictive of clinical signs.References.1) Adams et al. JSAP, 2010;51,512–24. 2) O’Shea. J Comp Pathol, 1962;72:321-31. 3) Woodal et al. JSAP, 1988; 29:543-7. 4) Eilts et al. Theriogenology, 1993;40:819-28. 5) Ruel et al., Vet Radiol Ultrasound, 1998;39:212-6. 6) Atalan et al., JSAP 1999;40:119-22. 7) Johnston et al. Canine and Feline Theriogenology, 2001; WB Saunders, Philadelphia. 8) James and Heywood. Toxicology, 1979;12:273-9. 9) Gouletsou et al. Anim Reprod Sci, 2008;108:1-12.