Artificial Raising on Milk Replacer and Finishing Diet Did Not Affect Color and Oxidative Stability of Longissimus Lumborum Muscles From Polypay Ram Lambs

Lamb production traits are affected by pre-weaning management (such as artificial raising on milk replacer) and finishing (forage vs. concentrate) strategies. The objective of the current study was to examine the effects of pre-weaning management and finishing systems on the color and oxidative stability of longissimus lumborum (LL) muscles from ram lambs. Polypay ram lambs were raised conventionally with ewes (CR; n = 10) or artificially on milk replacer (AR; n = 10). After weaning at 60 d, ram lambs in AR and CR were equally divided and randomly allocated to finishing on a high-forage (50:50 forage:concentrate; HF) or a high-concentrate (85:15 concentrate:forage; HC) diet until reaching the live weight of 59 kg. The lambs were harvested, and the LL muscles from both sides of the carcasses (24 h postmortem) were fabricated into 2.5-cm-thick chops. Carcass characteristics were evaluated while harvesting and fabricating. The chops were placed on polystyrene trays, overwrapped with oxygen-permeable polyvinyl chloride film, and randomly assigned to refrigerated storage (2°C) in the darkness for either 0, 3, or 6 d. Instrumental color, R630/580, pH, lipid oxidation, and metmyoglobin reducing ability (MRA) were evaluated at the end of each storage period. Pre-weaning management and finishing system (HF and HC) had no influence (P > 0.05) on the carcass characteristics, surface L* (lightness), a* (redness), b* (yellow-ness), R630/580, pH, and MRA of LL chops. The R630/580 and MRA decreased (P < 0.05) during storage in both CR and AR chops, whereas lipid oxidation and yellowness (b* value) increased (P < 0.05) in both CR and AR during storage. These findings suggested that milk replacer could be employed as a practical strategy in lamb production without com-promising fresh lamb color.