TESTICULAR MORPHOLOGY OF HOLSTEIN-FRIESIAN BULL CALVES AND YOUNG BREEDING BULLS 1 Gábor G, 2 Szász F, 1 Györkös, I, 1 Dept. Cattle Breeding, Res. Inst. Anim. Breed. Herceghalom, Hungary, 2 Dept. Gynecology and Obstetrics University of Vet. Science Budapest, Hungary

INTRODUCTION Generally a prediction of testes volume is use in morphological examination of testes. The size and length of testes and scrotal circumference are used to predict volume of the testes. Among the first trials using echography for examination of testes the normal bull testis was found to be homogeneous and moderately echogenic. A considerable variation has been found in testicular ultrasonic image intensity (pixel units) with age of bull calves. Changes in echotexture in peripubertal bulls (Chandolia, 1996) suggested that ultrasonography may be useful for prediction of sperm production.

OBJECTIVES Examination of the testicular echotexture (ET) in different ages of bulls. Comparison ET with the scrotal size.

METHODS ANIMALS NumberAge (month) of the animals ± ± 6.6

 Morphological Measure  Scrotal Circumference (SC) - By Coulter Scrotal Tape Image Analysis by Testigabsas Software Echotexture - see Picture 1  Used a Scanner 450 with a 7.5 MHz Linear Transducer  Gain was held constant  Images were saved on a IBM notebook  Controlled pressure between scrotal skin and the probe (0.76 kg/cm 2 )

Figure 1: Evaluation of the echotexture (ET) by Testigabsas software in young bull. The ultrasonic images of left and right testes are aligned and recorded on the left panel. After making a distance-calibration an examination area (box) was created (6.5 x 1.0 cm, area: 6.5 cm 2 ). The box was moved to the surface of the testicular tissue just under the scrotal skin and fat (white area). The average gray level (termed ET) and a histogram of the different gray levels (right panel) of the examined area were presented immediately. The bar below the histogram is of gray levels with zero on the left (dark) and 64 on the right (light). All of the nominal values were saved into a data file.

Figure 2: Evaluation of the echotexture (ET) by Testigabsas software in bull calf.

RESULTS Data of the examinations are presented in Table 1.

Table 1: Results of the andrological examinations

DISCUSSION The ET is a new morphological measure of the testicles. A lower echotexture suggests a greater seminiferous tubule lumenal space and fluid content within the examined area of the testicular parenchyma. This study supports this concept in that older bulls, expected to have greater seminiferous tubule activity and bigger testis, have a lower echotexture. Amount of blood content could also play a role. Additionally, echotexture may be used to predict semen production and/or the non return rate in young bulls.

CONCLUSIONS These studies show that there is a negative correlation between the ultrasonic recording of the testis and the age of the bulls. Significant differences were found between the age groups. The bigger testis usually (normally) associates with lower echotexture. Our other studies showed that an echotexture measurement may be useful in prediction of semen quality or the non return rate in young bulls which are still in the maturation process. Echotexture measurement may have a use in finding older bulls that do not produce normal semen but this awaits further study.