1 Gabor G, 2 Holzmann A, 1 Gyorkos I,
1 Dept. Cattle Breeding, Res. Inst. Anim. Breed. Herceghalom, Hungary
2 Dept. Gynec. and Obstet. Univ. Vet. Sci. Vienna, Austria

Prediction of the semen production by morphological measures (scrotal circumference, testicular echotexture and tonometry ) in Holstein-Friesian bulls

Examination of the scrotal circumference (SC), testicular tonometry (TM) and testicular echotexture (ET) suggested that SC, TM and ultrasonography may be useful to estimate the sperm output. The objectives were to determine the prediction value of the SC, ultrasonographic ET of the testis, testicular consistency (TM) for the semen production in Holstein-Friesian bulls (n=29, average age, 18.0 mo). The ET was measured with standardized gain and pressure, by a B-mode echograph and a 8 MHz linear transducer. Pixel analysis was performed with custom software just under the tunica albuginea. The average ET of the ultrasonograms were indicated on a 256 gray scale (0=black, 255=white). The consistency of the testis was measured by an electronic (auto-freeze function at a standard pressure) tonometer. Semen was collected by artificial vagina twice a week 8 wks apart and total sperm number per ejaculate was determined (TSN). A self developed computer assisted semen analyzer was used for the examination of the percentage of live sperm cells, linear motility and the mean speed of the spermatozoa. Pearson correlation coefficients were determined for these data (SAS). The SC and the age positively correlated with the TSN (r=0.48 and r=0.40; P<0.01), while ET showed a negative correlation with the live percentage of spermatozoa (r=-0.37; P<0.05). These data suggest that bigger testis size means more spermatozoa production and lower ET (SC vs. ET r=-.48 P<0.01). The lower ET probably means more fluid (or blood) in the testicular parenchyma, and better thermoregulation, which results in more live sperm cells in the ejaculate.