Abstract
The aim of this study was to know the relationships between carcass traits and mitochondrial displacement loop (D-loop) variations of Japanese Black cattle in Hiroshima prefecture. The D-loop region of female Japanese Black cattle in Hiroshima prefecture was sequenced and revealed 41 mitochondrial haplotypes defined by 44 polymorphic sites. The haplotypes were classified into six mitochondrial types (types 1 to 6) using the unweighed pair-group method with arithmetic means. The breeding values of carcass weight (CW), longissimus muscle area (LMA), rib thickness (RT), subcutaneous fat thickness (SFT), yield estimate (YE), and beef marbling score (BMS) were compared among the six mitochondrial types by BLUP procedures. Significant differences among mitochondrial types were detected for CW, RT, SFT and YE. Significant differences were observed between mitochondrial types I and V for CW (P < 0.05), between types III and V for RT (P < 0.05), and between types I and V, and II and V for SFT (P < 0.05). Significant differences were also found between types I and III, I and V, II and III, and II and V for YE (P < 0.05). These results suggest that cytoplasmic genetic effects are important sources of variation for carcass traits in Japanese Black cattle.
