Location: Meat Safety and QualityTitle: Sire variation in the severity of the ham halo condition
Submitted to: Meat and Muscle Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2020
Publication Date: 9/1/2020
Citation: King, D.A., Shackelford, S.D., Nonneman, D., Rohrer, G.A., Wheeler, T.L. 2020. Sire variation in the severity of the ham halo condition. Meat and Muscle Biology. 4(1):20, 1-15. https://doi.org/10.22175/mmb.9743.
Interpretive Summary: The Halo condition is characterized by a band of very pale tissue on the superficial portion of ham muscles. This results in inconsistent cured color development in ham products, which is discriminated against by consumers. This condition exists in virtually all ham muscles, but the severity of the condition varies across animals. Swine companies would like to reduce or eliminate the condition through genetic selection. The present experiment was conducted to determine the extent to which variation in the severity of the halo condition is genetically regulated. The results indicate that sire effects have large effects on the halo condition. Moreover, genetic selection could be accomplished by selecting for increased myoglobin content or by selecting for improved lean color of the halo affected portion of the ham.
Technical Abstract: A study was conducted to examine genetic variation in the ham halo condition. The distal portion of the biceps femoris was sampled by taking cores (2.54-cm diameter) from progeny (n = 1,016) from a Duroc meat quality–focused line. Commission Internationale de l´Éclairage (CIE; “International Commission on Illumination”) color-space values (L*, a*, and b*) and myoglobin concentration were measured on the halo (“Halo”) and inside (“Inside”) portion of each core. The Halo portion of the biceps femoris had greater L* and b* and lesser a* and myoglobin content (all P < 0.001) than the Inside portion. Sires with 11 or more progeny were compared. The sire × muscle-location interaction affected (P < 0.001), L*, a*, and myoglobin concentration. Sire progeny groups differed for each trait in both portions of the muscle, but differences in the Halo portion of the muscle were not mirrored in the Inside portion of the muscle. Similarly, sire group affected the magnitude of the difference in L* (P = 1.4 × 10-4) and a* (P = 9.0 × 10-6) between the Halo and Inside portions of the muscle and tended (P = 0.08) to affect myoglobin content. However, the largest sire-group differences were not necessarily seen in the sires with the highest means for these attributes. Thus, selecting for myoglobin concentration, L*, or a* content in the Halo portion of the biceps femoris muscle would be an effective strategy for reducing the severity of the ham halo condition.