|Leeds, Timothy - Tim|
|Taylor, Joshua - Bret|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2014
Publication Date: 4/28/2014
Publication URL: http://www.journalofanimalscience.org/content/92/7/2861.full?sid=057baf48-ba73-4f56-8efc-5d3e0762cf10
Citation: Mousel, M.R., Notter, D.R., Leeds, T.D., Zerby, H.N., Moeller, S.J., Taylor, J.B., Lewis, G.S. 2014. Evaluation of Columbia, USMARC-Composite, Suffolk, and Texel rams as terminal sires in an extensive rangeland production system: VIII. Quality measures of lamb longissimus dorsi. Journal of Animal Science. 92(7):2861-2868. Interpretive Summary: Modern genetic technologies can be used to enhance the inherent abilities of lambs to convert livestock feed into human foods. Enhancing these inherent abilities would allow producers to conserve feed and natural resources, improve the value of their market lambs, and increase the efficiency of producing human foods. Thus, genetics studies are underway at the USDA, Agricultural Research Service, U.S. Sheep Experiment Station to characterize the effects of sire breed on various aspects of growth and carcass merit of lambs. Recent results from these studies indicate that crossbred lambs produced from Columbia, Composite, Suffolk, and Texel rams have similar loin meat quality, which would be acceptable to consumers. Sheep producers can use this information to select sire breeds to make significant improvements in the efficiency of producing human foods.
Technical Abstract: Quality measures of lamb longissimus dorsi were evaluated in 514 crossbred wether lambs to assess sire breed differences. Wethers were produced over 3 yr from single-sire matings of 22 Columbia, 22 USMARC-Composite (Composite), 21 Suffolk, and 17 Texel rams to adult Rambouillet ewes. Lambs were reared to weaning in an extensive western rangeland production system and finished in a feedlot on a high-energy finishing diet. One of 3 harvest groups were randomly assigned to each lamb and lambs were transported to The Ohio State University abattoir when the mean BW of wethers remaining in the feedlot reached 54.4, 61.2, or 68.0 kg. Following harvest, subjective lean quality scores were assigned and LM pH (immediately after and 24 h after harvest), color (quantified as Minolta a*, b*, and L*), intramuscular fat (IMF), cooking loss percent, and Warner-Bratzler shear force (WBS) were determined. Statistical models included fixed effects of sire breed, year of birth, and harvest group and random effects of sire (nested within sire breed and year) and maternal grandsire. At comparable numbers of days on feed, Texel-sired lambs had greater (P < 0.01) subjective lean quality scores than lambs sired by any other sire breed. Lean quality scores were intermediate for Composite- and Suffolk-sired lambs and lowest for Columbia-sired lambs. Minolta L* values were greater (P < 0.02) for Texel- than Columbia-sired lambs. Texel-sired lambs had a numerically higher (P < 0.10) percentage of cooking loss than Suffolk- and Columbia-sired lambs. No significant (P > 0.08) sire breed effects were detected for LM pH at or 24 h after harvest, Minolta a* and b*, IMF, and WBS. At comparable chilled carcass weight, significant (P < 0.01) sire breed effects were detected only for subjective lean quality score. Texel-sired lambs had greater scores than Columbia- and Suffolk-sired lambs but Composite-sired lambs did not differ from lambs sired by the other 3 sire breeds. Sire-breed effects were not detected (P > 0.15) for LM pH at or 24 h after harvest, Minolta a*, b* and L*, cooking loss percent, IMF, and WBS. The 4 sire breeds evaluated in this study thus produced crossbred lambs that were similar in LM quality measurements.