TESTICULAR MORPHOLOGY OF HOLSTEIN-FRIESIAN BULL CALVES

AND YOUNG BREEDING BULLS

1Gábor G, 2Szász F, 1Györkös, I, 1Dept. Cattle Breeding, Res. Inst. Anim. Breed. Herceghalom, Hungary, 2 Dept. Gynecology and Obstetrics

University of Vet. Science Budapest, Hungary

ÁTKHERCEGHALOM

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

Number Age (month)

of the animals

• 22 7.9 ± 1.9

• 28 23.9 ± 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/cm2)

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 cm2). 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

MEAN ± SD

Bull calvesN=22

Young bullsN=22

T-test;Probability

Age (month)7.9 ± 1.9 23.9 ± 6.6 <0.001

Scrotal (cm)Circumference 24.7 ± 3.8 36.1 ± 2.5 <0.001

Echotexture,0-63 gray scale 27.3 ± 1.7 22.5 ± 4.2 <0.01

DISCUSSIONThe 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.