Annual variations in resistive index (RI) of testicular artery, volume measurements and testosterone levels in bucks

Abstract

The gonads of animals with sexual seasonality should change their metabolic requests throughout the year. In this study, we registered the variations of testicular volumes and serum testosterone levels in three Sarda bucks (Capra Hircus) and characterized the blood flow in the testicular artery by Doppler Ultrasonography, in order to shed light onto the type of relation between these parameters. After a 12-month study we observed that testicular volumes and testosterone levels show a typical seasonal variation with a maximum volume of testicular parenchyma recorded in September (116.06±25.22 ml) while testosterone reached its peak in December (620.43±192.87 ng/ dl). Blood supply and resistivity seem to follow the changes in the parenchyma according to the functional activity, and the lowest resistivity values were observed in September (0.73± 0.02). An inverse U-shape best describes the relationship between testicular volume and testosterone levels (p<0.05). This is the first report showing the changes in the blood supply to the testicular parenchyma of the buck throughout the year.

Testicular Morphological and Ultrasonographic Characterization of Male Gray Brocket Deers (Mazama gouazoubira) in Different Reproductive Status

“…These different results may be due to different locations of the evaluated vessel, species and techniques. It is known that many factors can influence vascular changes, including age [38], ambient temperature, seasonality [41,44], pathological conditions [34,43], and anaesthesia [8]. Thus, they may have influenced the spectral Doppler parameter's variability in the supratesticular artery of gray brocket deer.…”

New Approaches to Assess Fertility in Domestic Animals: Relationship between Arterial Blood Flow to the Testicles and Seminal Quality

“…Doppler ultrasonography has become the method of choice to evaluate blood supply of various organs. It is one of the simplest and most precise techniques for estimating blood flow, as it combines data concerning the anatomy and dynamic flow parameters [ 12 ]. Doppler effect was first described in 1842 by the Austrian physicist Christian Johann Doppler.…”

“…Pozor and McDonnel (2004) concluded it is possible to characterize the testicular artery by ultrasonography and the importance of its measurement in two locations due to its convoluted course [ 20 ]. Following these results, more research was performed in other animal species, establishing physiological parameters of the testicular artery using CD and SD at different locations in stallions [ 20 , 21 , 22 ], jackass [ 23 ], dogs [ 21 , 24 , 25 ], felines [ 26 ], bull [ 27 , 28 , 29 ], rams [ 30 , 31 , 32 , 33 , 34 ], bucks [ 9 , 12 ] and camelids [ 35 ].…”

“…The testicles require a stable blood supply for its function and maturation [ 36 ]. CD and SD of the blood flow towards the testicular parenchyma could reflect the functional changes occurring in the different reproductive periods [ 12 ].…”

“…These changes have also been noticed in ultrasonography. In goats, the testicular volume increased during the summer months reaching its highest values in September [ 12 ]. Similarly, in rams the mean testicular pixel intensity reached its lowest values during the winter and increased gradually reaching its highest values during summer [ 57 ].…”