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

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 x 10(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. (c) 2007 Elsevier Inc. All rights reserved