Abstract
Daily growth (DG) records and carcass sales figures of castrated Japanese Black cattle were compared with their blood component values at every growth stage. Cattle were divided into slow, average, and rapid growth groups. As to sales figures for carcass by DG, the rapid growth group attained the best results in both weight gain and price. The blood component values fluctuated significantly depending on the growth stage. The value of vitamin A in rapid growth group was significantly lower in stages 4 (22-25 months of age) and 5 (26-30 months age) compared to that in slow growth group. The level of total cholesterol and phospholipids in rapid growth group was significantly higher in stages 3 (18-21 months age) and 4 (22-25 months age) compared to slow and average growth groups. Since blood component values varied depending on DG or growth stage it was suggested that the weight gain varied by animal. Therefore we concluded production efficiencybecomes possible can be improved by classifying the natural characteristics of each animal cattle.
