Production of semen by young bulls at the end of performance test
1993
Petac, D. (Veterinary Faculty, Ljubljana (Slovenia)) | Brecelj, M. (Kmetijski veterinarski zavod, Nova Gorica (Slovenia)) | Kosec, M. | Mrkun, J. (Veterinary Faculty, Ljubljana (Slovenia))
42 young bulls were tested on semen quality since 44 weeks of age. At the time the mean weight of bulls was 358,9 +- 27,7 kg and stand at the wither 120,3 +- 3,9 cm. According to their original weight bulls were assigned to two groups: below and above the average. At the end of performance test (52nd week) the lighter ones were also significantly lighter (364,5 +- 36,8 kg: 439,9 +- 24,6 kg, P 0,005) and smaller (120 +- 6 cm: 126 +- 4 cm, P 0,05). Between first and second group of bulls significant differences were noticed at the end of performance test in sperm concentration (0,6 +-0,2: 1,3 +- 0,3 x 10** (6), P 0,005), in total sperm number per ejaculation (1,63 +- 1,29: 3,20 + 1,61 x 10** (9), P 0,025) and m "swirl" (1,9 +- 0,7: 3,5 +- 1,0, P 0,005). In the view of the other biological properties of semen there were not significant differences between groups. At the end of performance test only 22,2% of animals correspond to the minimal condition for sperm quality of breeding bulls. We suppose that at this time the selection on reproductive ability in not realistic
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