Somatic cell count as a selection criterion for mastitis resistance in dairy cattle

摘要: Abstract The purpose of this study was to investigate whether it is possible increase the resistance clinical mastitis by selecting for bulls siring daughters whose milk has a low somatic cell count. Data from animal disease recording scheme, including all veterinary treatments mastitis, were used in analysis. A total 1462 progeny tested Swedish Red and White (SRB), 911 Friesian (SLB), with nearly 750 000 effective daughters, included. Effects alternative selection criteria on response studied using index theory. Correlations between relative breeding values count 0.45 SRB 0.41 SLB bulls. Corresponding genetic correlations indirectly estimated be 0.79 0.71. relationships found linear. It concluded that improve Due higher heritability based more efficient than directly when only small groups (less 100 daughters) available. However, combination both measures about 20% former alone. There no significant differences differing their proportion Holstein-Friesian genes.