Estimates of non-genetic effects and genetic parameters for semen traits in Piemontese bulls

Male reproductive performances are often ignored in cattle breeding programmes, although semen traits might be used to improve bull soundness. Effects of genetic and environmental factors on production quality were estimated 693 Piemontese bulls with the aim providing first estimates parameters for this breed. Volume concentrations individual ejaculates (up three per each test-day), volume, concentration, total number spermatozoa post-thawing progressive motility within test-day pooled available 19 060 ejaculates. Bulls reached maximum amount daily after their third year age, concentration rapidly increasing until 23 months then slowly decreasing. Semen volume was at its highest when collection days least 15 apart, whereas interval 6 days. Heritability generally moderate (0.14–0.26), low (0.08). Estimates correlation among volumes high positive (?0.79), as correlations (?0.46). Genetic varied from ?0.47 (with a 95% posterior density ranging ?0.65 ?0.23) ?0.32 ?0.55 ?0.09). Progressive unrelated other traits, but moderately positively correlated second The magnitude heritabilities showed that selection is possible. However, unfavourable relationship between must taken into account if future programme established.