Master of Science, The Ohio State University, 2017, Animal Sciences
Inconsistency of lamb quality in the United States has resulted from the wide-range of production management systems including variation of breed, diet, and animal age at time of harvest (slaughter endpoints), which in turn affects body composition. In the present study, a total of 48 lambs originating from three western U.S. regions (16 lambs; 8 ewes and 8 wethers from each location) and similar breed composition (Suffolk cross), were selected to represent different carcass weight compositions (heavy and light market weights), and age at time of harvest (5 and 12 mo.). Lambs were intended to represent different production systems and US market channels within the lamb category. After harvest, carcass measurements were recorded, then fabricated into wholesale cuts (inside boneless lamb leg, boneless sirloin, rack, and whole boneless shoulder), and the semimembranosus, gluteus medius, longissimus thoracis, and ground shoulder were derived from these cuts (14 d postmortem) to identify differences in meat quality and palatability characteristics. Feeding lambs a high concentrate diet after weaning (HW12), and reaching heavier end weights clearly added excess fat (backfat and body wall), had a larger ribeye, and higher yield grades (P < 0.05), resulting in a lower lean to fat ratio compared with 5 and 12 month light weight lambs. Furthermore, intramuscular fat in the longissimus thoracis was influenced as 12 month lambs possessed higher lipid concentrations than 5 month lambs (P < 0.05), and a sex effect was noted as wether lambs had greater lipid concentrations than ewe lambs (P < 0.05). Additionally, shoulder patty samples possessed higher lipid concentrations in heavy weight lambs (P < 0.05). Color (L*, a*, and b*) values and pH were moderately influenced by age, sex, and body weight, but light weight 12 mo. lambs (LW12) had the lowest L* values (darkest) in the LT muscle (P < 0.01). Lastly, a sex difference was noted as wether lambs possessed higher a* value (redder (open full item for complete abstract)
Committee: Lyda Garcia (Advisor); Francis Fluharty (Committee Member); Stephan Boyles (Committee Member); Steve Moeller (Committee Member)
Subjects: Animal Sciences