Extent of dark-cutting in beef carcasses graded Canada B4.

Recovering value from dark cutting carcasses (Canada B4) was investigated by examining twelve muscles in the loin, fore- and hindquarters of atypical (AT, pH < 5.8), borderline (BD, 5.8 < pH < 6.0) and classic (CL, pH > 6.0) dark cutting carcasses. Subjective and objective colour, purge loss, and colour stability were measured over 4 days of retail display. Forequarter muscles from all dark cutting carcasses were not different from those of normal Canada AA carcasses, suggesting that forequarter muscles may be preferentially harvested for sale through normal retail outlets. None of the adductor, biceps femoris, gluteus medius, and semitendinosus muscles in the AT carcasses were dark and all had retail display colour stability comparable to that of normal steaks, indicating that these muscles in these carcasses are undervalued. Sorting of dark cutting carcasses by longissimus thoracis pH or a* and b* values will allow for value to be recovered from atypical dark cutting carcasses.

Effect of ractopamine and sex on growth, carcass characteristics, processing yield, and meat quality characteristics of crossbred swine.

One hundred twenty-eight 64-kg crossbred barrows and gilts were administered either 0 or 20 ppm of Ractopamine (RAC) in a pelleted corn-soybean meal diet that contained either 17.5 or 19.6% CP. Carcass quality was evaluated after slaughter at 100 kg. Dietary protein levels produced few significant effects; therefore, data were pooled for analysis. Pigs fed RAC exhibited improvement in feed efficiency (P < .01), ADG (P < .01), and number of days to slaughter (P < .01). Pigs fed RAC had 1.8 mm less fat (P < .05) and 3.4 mm more lean (P < .01) at the grading probe site. Gilts had 4.9 mm less fat than barrows at the probe site (P < .01) and also yielded an estimated 4.1% more lean (P < .01). Trimmed loins and bellies of animals fed 20 ppm of RAC were 230 g heavier (P < .05) than those of animals fed the control diet. Trimmed loins from gilts were 260 g heavier (P < .05), whereas barrows produced bellies that were 490 g heavier (P < .05) than those of gilts. The yield of processed ham was greater from both pigs fed RAC (P < .01) and barrows (P < .05). Loins of pigs fed RAC had lower cooking loss (P < .05), greater Warner-Bratzler shear value (P < .05), and higher fragmentation index value (P < .01). Although effects of sex were similar to or greater than the effects of 20 ppm of RAC, these effects were additive.