COMPARATIVE STUDY OF THE TESTICULAR ECHOTEXTURE (ET) AND TONOMETRY (TM) WITH THE SEMEN PRODUCTION AND THE NON RETURN RATE (NRR) IN BULLS

1 Gábor G, 2 Szász F. 1 Dept. Cattle Breeding, Res. Inst. Anim. Breed. Herceghalom, Hungary, 2 Dept. Gynecology and Obstetrics University of Vet. Science Budapest, Hungary ÁTK HERCEGHALOM

INTRODUCTION

• The morphological examinations of the testis may predict the fertility and semen production results. Selection of breeding bulls should be based on both fertility and semen production. 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.

Ultrasonographic ET of the testes (determined with custom software) was highly correlated (R=-0.5, P<0.005) with seminiferous tubule area (Gábor et al., 1998). A tonometer was developed to measure testis consistency in bulls (Hahn et al., 1969). Gábor et al. (1998) used an electronic (auto freeze function at an exact standard pressure) tonometer for the examination of the bull testis.

OBJECTIVES

• Examination of the testicular echotexture (ET) and testicular tonometry (TM) in two different breed of bulls.

• Comparison of the ET AND/OR TM with the semen production in the two breed.

• Comparison of the ET and the non return rate in the AF breed.

Breed • HF • AF

METHODS

ANIMALS

No.

Age (month) 78 16 16.5 ± 7.2

25.9 ± 4.7

Morphological Measures

  Scrotal Circumference (SC) Testicular tonometry (TM) - By Coulter Scrotal Tape - By Consitest ® electronic tonometer    

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.

• 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.

RESULTS

• Data of the examinations are presented in Table 1.

• Results of the statistical analysis are presented in Table 2.

Table 1: Results of the andrological examinations

Breed Age

(month)

Scrotal circum ference

, (SC, cm)

Echo texture

, (ET, 0 64)

Tono metry

(unit, 1 unit = 0.2 mm)

Total sperm number

, (*10 9 )

Non Return Rate

, (%)

AF 25.9 ± 4.7

40.3 ± 1.7

20.4 ± 1.7

36.3 ± 4.5

6.3 ± 1.7

72.6 ± 2.6

HF 16.5 ± 7.2

33.1 ± 3.2

23.8 ± 3.8

33.9 ± 3.8

4.1 ± 2.0

No data

Legend: AF - Austrian Fleckvieh HF - Holstein Friesian

Table 2: Results of the statistical analysis

Parameters compared

Age vs. SC Age vs. TSN Age vs. ET Age vs. TM TM vs. ET TM vs.TSN

TM vs. NRR ET vs. TSN

Pearson's correlation coefficients Austrian Fleckvieh (r=; P<) Holstein-Friesian n=16

0.47; 0.05

n=78 0.63; 0.001

-0.36; NS

0.42; 0.01

-0.12; NS 0.08 NS -0.25; NS -0.24; NS 0.06 NS 0.05 NS

-0.61; 0.001

0.71 ; 0.001

-0.43; 0.01

0.27; 0.05

No data

-0.29; 0.01

No data ET vs. NRR

0 .

5 1 ; 0 .

0 5

Legend: TSN - total spermatozoa per ejaculation; NRR - non return rate, TM: tonometry; NS: non significant

DISCUSSION

The ET and the electronic tonometry are 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, have a lower echotexture.

content could also play a role.

Amount of blood Additionally, echotexture may be used to predict semen production and/or the non return rate in young bulls.

The significant negative correlation between echotexture and TSN or NRR support this concept.

The examination of the testicular consistency by an electronic tonometer showed a rather close correlation with the age, and ET. Although TM should be typical for an exact age of the bull (r=0.71; P<0.001), and these findings may induce new research ideas, at this stage its usage on practical level is not recommendable.

CONCLUSIONS

• These results suggest association among the ultrasonic recording and total sperm number per ejaculate or the non return rate, and echotexture measurement may have a use in finding older bulls that do not produce normal semen.

• Differences in ultrasonic recordings mainly occur due to age but also the health status of animal.

• 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.

• Although the testicular consistency also showed moderate correlation with the examined parameters, at this moment this experimental method has to be improved.