Meat quality in goats as influenced by dietary protein and energy levels,and postmortem aging

The objectives of this study were to determine effects of different dietary treatments and postmortem aging on meat quality characteristics in goats. Twenty castrated dairy goats (BW = 30.7 ± 6.80 kg, age 10 months) were subjected to one of four dietary treatments for 82 days (treatment): (i) 2.5 Mcal/kg DM DE and 12% CP, (ii) 2.5 Mcal/kg DM DE and 18% CP, (iii) 2.9 Mcal/kg DM DE and 12% CP, or (iv) 2.9 Mcal/kg DM DE and 18% CP. At the end of the feeding trial, the animals were slaughtered to evaluate meat quality. Longissimus muscle pH and temperature were measured at 0, 3, 6, 9, 12, 15, 18, and 24 h postmortem (time). Sarcomere length (1.65 μm), total collagen (4.17 mg/g), and heated calpastatin (44.7 units) measured at 24 h postmortem were not influenced by treatment (P > 0.05). Warner–Bratzler shear force values, collagen solubility, and cooking losses of loin/rib chops (2.5 cm thick) aged for 1, 3, or 6 days postmortem were not influenced by treatment (P > 0.05) or aging time (P > 0.05). Postmortem sampling time affected muscle pH and temperature decline (P < 0.01), but there was no effect of treatment. There was a trend toward a treatment × time interaction (P < 0.06) in muscle pH. Temperature and pH declines followed cubic (P < 0.01) and linear (P < 0.01) trends, respectively. Average muscle temperature declined rapidly and reached 14.5 ± 2.0 °C at 3 h postmortem, while the pH was still high (6.60 ± 0.087). In conclusion, diet did not influence meat quality characteristics, and shear force values of chevon did not decrease due to postmortem aging. Rapid heat dissipation from goat carcasses during too rapid chilling may have caused cold shortening of muscles resulting in meat that did not respond to aging.