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 ± 416.13 × 10 6 cells/mL) was higher than those in Chianina (751.63 ± 444.45 × 10 6 cells/mL, P < 0.05) and Marchigiana (862.57 ± 421.87 × 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.