Breeding soundness examination of Chianina, Marchigiana, and Romagnola yearling bulls in performance tests over a 10-year period.

ABSTRACT

The objectives of the present study were (i) to establish the mean value of scrotal circumference (SC), sperm motility, concentration and morphology at 13+/-1 months of age for Chianina, Marchigiana, and Romagnola breeds and (ii) to assign Italian beef bulls at the end of a growth performance test to a potential breeder category by applying the guidelines of the Society for Theriogenology in 1993 (SFT93). Of 1,315 bulls, 869 were not given the breeding soundness examination for the following reasons not passing the growth performance test (n=445), no training for semen collection (n=404), and presence of genital abnormalities (n=20). Testicular length and diameter and SC exhibited a logarithmic trend over time, with an R(2) value of 0.963, 0.979, and 0.978 (P<0.001), respectively. The SC of Romagnola (33.82+/-2.47 cm) was higher than those of Chianina (33.28+/-2.65 cm, P<0.001) and Marchigiana (33.05+/-2.20 cm, P<0.001). Sperm concentration in Romagnola (875.89+/-416.13x10(6)cells/mL) was higher than those in Chianina (751.63+/-444.45 x 10(6)cells/mL, P<0.05) and Marchigiana (862.57+/-421.87 x 10(6) cells/mL). Progressive sperm motility was 61.30+/-11.24%, 62.18+/-11.17%, and 58.48+/-14.40% in Romagnola, Marchigiana, and Chianina, respectively. Total spermatozoal abnormalities were higher in Chianina (23.35+/-15.41%). Sperm concentration was positively related to testicular length (P<0.01), diameter (P<0.001), and SC (P<0.001). Satisfactory breeders presented high sperm motility compared with deferred and unsatisfactory ones, whereas unsatisfactory breeders had a higher number of abnormal spermatozoa. By applying the SFT93 guidelines, we showed that 74.72%, 78.01%, and 80.16% of Chianina, Marchigiana, and Romagnola bulls, respectively, have been classified as satisfactory potential breeders.