Long-term pedigree analysis: An effective tool for managing congenital malformations in cattle

Abstract

Controlling congenital defects is an important aspect of breeding for genetic health; however, whether malformations are caused by genetic or nongenetic factors may not be clear. This study aims to analyse the incidence of aplasia genitalis, atresia ani et recti and hernia cerebralis in the Czech cattle population, analyse the relatedness of affected calves by a relationship matrix, and assess the potential future threat. The sires fathering affected calves were born in the Czech Republic or imported from 1986 to 2001. The cases occurred on farms across the Czech Republic. The pedigree of each case was examined for common maternal and paternal ancestors (inbreeding loops) and for ancestors shared by other cases of the defect. The average relatedness coefficient of each individual was computed based on the relationship matrix. The results of the analysis of pedigrees and of the relationship matrix support the hereditary aetiology. The 13 calves affected by aplasia genitalis had common ancestors in 12 cases. The results indicate hereditary causation with recessive inheritance. In atresia ani et recti, some of the pedigrees of 25 affected calves support hereditary causation, and repeating ancestors were found for 11 calves. Our analysis of 11 hernia cerebralis cases also hints at the genetic background, but not as unequivocally as in other congenital defects studied. A high number of descendants fathered by sires of affected calves constitutes a risk for future. The relationship matrix and pedigree analysis could help in managing genetic health, although the final goal in terms of inherited defects must be the description of causal genes and mutations. Measures to control sires and dams with affected calves should be appropriate under the current knowledge, which include culling or prudent use of breeding with the monitoring of descendants.