Relationships of dietary and ruminal characteristics to carcass traits in Wagyu steers [Bostaurus]
1996
Naruse, M. (Aichi-ken. Agricultural Research Center, Nagakute (Japan)) | Kajikawa, H. | Morita, H. | Hashiba, K. | Maruyama, S. | Morimoto, H. | Miura, Y. | Fujita, K. | Fuke, T. | Amari, M. | Masaki, S. | Ozutsumi, K. | Abe, A.
Correlations among characteristics of diets, ruminal fermentation and carcasses were investigated using 134 Wagyu (Japanese Black cattle) steers fed for 484 days on the average to determine primarily if the fat deposition in the longissimus muscle is affected by dietary and ruminal factors. Fat content in the longissimus muscle, subcutaneous (s.c.) fat thickness and rib-eye area were positively correlated to dry matter intake (DMI). The DMI decreased as the neutral detergent fiber (NDF) content in diets decreased under 31% of NDF on DM basis. Feed efficiency (gain/DMI), however, was positively correlated to nitrogen cell wall free extract (NCWFE) and total digestible nutrients (TDN) content in diets and to the propionate: acetate ratio in the rumen. Characteristics in the rumen (i.e., the ratio of each volatile fatty acid (VFA) and protozoa number) had no correlation to any of the carcass traits (i.e., fat content in the longissimus muscle, marbling score, rib-eye area and s.c. fat thickness). These results suggest that feeding a high amount of concentrate to Wagyu steers would impair the DMI, which leads to a lower deposition of fat in the longissimus muscle, whereas it may improve the feed efficiency
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