CORRELATION BETWEEN THE TESTICULAR ECHOTEXTURE AND THE SEMEN PRODUCTION IN 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. Post (1987) and Wekerle (1989) suggested that blood testosterone concentrations following GnRH treatment could be useful in identifying bulls with adequate reproductive potential. 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 two different breed of bulls. Comparison the semen production of the Holstein- Friesian (HF) and the Austrian Fleckvieh bulls (AF). To predict the total number of spermatozoa in two breeds of young bulls. Comparison of the ET and the non return rate in the AF breed.

METHODS ANIMALS BreedNo.Age (month) HF ± 6.6 AF ± 4.7

 Morphological Measures  Scrotal Circumference (SC) - By Coulter Scrotal Tape  Scrotal Length and Width - By digital camera 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 ) Testis Size - see Picture 2  Obtain a digital-image with a digital camera

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.

Figure 2: Evaluation of the scrotal size by Testigabsas software. At time of taking the digital image, a grid of known dimensions was projected, from a fixed distance, onto the scrotum to use as a distance calibrator. The software was used to draw a vertical and horizontal line, beginning and ending at estimated testicular margins. The length of the lines were determined by a calibrator within the software. The width and length of testis is presented as 14.4 and 15.7 cm respectively in this picture.

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

Table 2: Results of the statistical analysis

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, 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. The significant negative correlation between echotexture and TSN or NRR support this concept. The examination of the digital images showed a rather close correlation with the SC, and may useful for the evaluation of the scrotal size. The difference between the two breeds realized only in the scrotal size. Probably this difference caused the lower correlation between the scrotal size and the semen output.

CONCLUSIONS These studies show that there is an association among the ultrasonic recording and total sperm number per ejaculate or the non return rate. Differences in these recordings occur due to age 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. Echotexture measurement may have a use in finding older bulls that do not produce normal semen but this awaits further study.