Abstract
The causes or triggers for the development of muscular abnormality including steatosis or muscular dystrophy are not fully understood in Japanese Black cattle. Investigations into the gender and bodyweight revealed that the muscular abnormality in cows (4.5%) was higher than that in steers (2.8%). In addition, the muscular abnormality was found to be higher in cows with a bodyweight of less than 600kg. However, no such trend was found in steers. Regarding the sites of affected muscles, the muscles trapezius was most affected in steers, while it was muscles longissimus in cows. In terms of beef carcass traits (grades 3 to 5), the muscular abnormality in steers was most apparent in grade 3 or below. However, in cows, the muscular abnormality was higher in grade 5 (8.0%) than in grade 3 and below (2.8%) and 4 (3.5%). These results suggest that gender, bodyweight as well as beef carcass traits may influence on the development of muscular abnormality in Japanese Black cattle.
