Carrier frequency of recessive disorders affected on embryonic loss and calf mortality in Japanese Holsteins

Abstract

We estimated carrier frequencies of five haplotypes on recessive disorders (HH1, HH2, HH3, HH4, HH5) which cause embryonic lethal genetic defects, and a haplotype of cholesterol deficiency (HCD) which causes calf mortality by using 43,053 genotyped animals. In addition, impacts of the HH1 to HH5 on conception rate were investigated by implementing analysis of variance which included the interaction of genotype for service-sire and sire of cow as fixed effect. Although carrier frequency of HH1 tended to decrease over the years, the value remained at 4% and was higher than HH2 and HH4 in recent years. The recent carrier frequency of HH3 slightly increased in only females and it of HH5 remained at 3 to 4%. The carrier frequency of HCD had been decreasing since 2012. The interaction of genotype for carrier service sire and carrier sire of cow on conception rate had significant negative in only HH1 (P<0.001) and was also likely to be negative in HH2 to HH4. These results of HH1 to HH5 suggested the necessities of monitoring the carriers and avoidance of their carrier mating.