Artificial raising on milk replacer and finishing diet did not affect the color and oxidative stability of longissimus lumborum muscles from Polypay ram lambs

Authors: MONDAL, KOUSHIK - University Of Kentucky; SUMAN, SURENDRANATH - University Of Kentucky; PURVIS, KATHERINE - University Of Kentucky; RENTRFOW, GREGG - University Of Kentucky; ELY, DONALD - University Of Kentucky; Davis, Brittany; Weinert-Nelson, Jennifer; WANG, YIFEI - The Ohio State University; SALIM, ANA PAULA - University Of Kentucky

Submitted to: Meat and Muscle Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2024
Publication Date: 1/28/2025
Citation: Mondal, K., Suman, S.P., Purvis, K.G., Rentrfow, G., Ely, D.G., Davis, B.E., Weinert-Nelson, J.R., Wang, Y., Salim, A. 2025. Artificial raising on milk replacer and finishing diet did not affect the color and oxidative stability of longissimus lumborum muscles from Polypay ram lambs. Meat and Muscle Biology. 9(1). Article 18343. https://doi.org/10.22175/mmb.18343.
DOI: https://doi.org/10.22175/mmb.18343

Interpretive Summary: The color of fresh lamb is light red, and discoloration is a limiting factor in retail display leading to significant economic losses for the lamb industry. It is well-established that the color of fresh meat can be dependent on pre-harvest diet and management factors; However, no research has evaluated the impact of artificial raising pre-weaning and finishing systems on the color and oxidative stability of fresh lamb meat. The objective of this study was to evaluate the effect of pre-weaning management (artificial with milk replacer vs. tradition ewe-rearing) and finishing diet (high grain vs. high forage) on the color stability and lipid oxidation of lamb loin (longissimus lumborum) muscles during refrigerated storage. Pre-weaning management and finishing diet did not have any impact on carcass characteristics or the color attributes and oxidative stability of loin chops during refrigerated storage over 6 days. According to the USDA National Agriculture Statistics Service, there are 5.07 million sheep in the United States, and the demand for lamb is increasing both Nationally and Internationally. Ewes routinely have multiple births (2+ lambs) necessitating the use of artificial pre-weaning management strategies that could impact both pre- and post-harvest factors, including carcass characteristics and meat quality and stability. The results of this study indicate that milk replacer can be utilized as an artificial pre-weaning management strategy in lamb production without compromising fresh meat color and consequently overall economic value to the sheep industry.

Technical Abstract: 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 days, ram lambs in AR and CR were equally divided and randomly allocated to finishing oin a high-forage (50:50 forage: concentrate) or a high-concentrate (85:15 concentrate: forage) 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 post-mortem) 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 days. Instrumental color, color stability (R630/580), pH, lipid oxidation, and metmyoglobin reducing ability (MRA) were evaluated at the end of storage periods. Pre-weaning management and finishing system had no influence (P > 0.05) on the carcass characteristics, surface redness (a* value), yellowness (b* value), color stability (R630/580), pH, and MRA of LL chops. Color stability (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 compromising fresh lamb color.