Comparison of growth rates in the tissues of primal cuts of Canadian composites

Beef composites (C) have combined favourable traits of pure breeds. The objective was to compare the growth rates (GR) of muscle (M) and fat (F) in the primal cuts of serially harvested Beefbooster C types (SM = C of small breeds, AH = C of Angus and Hereford and GLC = C with Gelbvieh, Limousin or Charolais terminal sires) from 274 - 456 days (d) of age to determine harvest times that reflect an increase M and a decrease F. Analysis of covariance obtained the slopes (GR/d) for M and F within each cut and C type. In the SM and AH the GR of overall F in all primal cuts exceeded that of M by 24.8 g/d and 4.91g/d respectively, while in GLC the gain of M exceeded that of F by 6.77 g/d. We suggest that the SM and AH could be harvested at least 30 d earlier than GLC thereby increasing the proportion of carcass M and decreasing F.