Age-related changes in scrotal circumference of Hungarian Simmental bulls in self-performance test.

Between 1989 and 1992, investigations were carried out on a total of 164 young Hungarian Simmental bulls of different age at central performance testing stations and on farms (field test) to measure the scrotal circumference of bulls and describe its relationships with age and body weight. An age-related increase was found in average scrotal circumference in the populations studied. Average scrotal circumference of Hungarian Simmental bulls was 17.86 cm at 5 months of age and 37.06-37.72 cm at 13-14 months of age. The coefficient of correlation between age and scrotal circumference was between r = 0.31 and r = 0.40, while that between scrotal circumference and body weight varied between r = 0.35 and r = 0.59. The partial regression coefficients for age and body weight showed values of r = 0.003-0.063 and r = 0.017-0.032, respectively. The multiple coefficient of correlation was between R = 0.47 and R = 0.59.