Mature beef cows (n = 83) were slaughtered to measure the influence of body condition score (BCS) on carcass characteristics and subprimal yields. All cows were weighed and assigned BCS, based on a 9-point scale, 24 h before slaughter. Cows were slaughtered, and, after a 48-h chilling period, quality and yield grade data were collected on the left side of each carcass. The right side was quartered, fabricated into primal cuts, and weighed. Each primal cut was further processed into boneless subprimal cuts, minor cuts, lean trim, fat, and bone. Cuts were progressively trimmed to 6.4 and 0 mm of external and visible seam fat. Weights were recorded at all stages of fabrication, and subprimal yields were calculated as a percentage of the chilled carcass weight. Live weight, carcass weight, dressing percentage, fat thickness, longissimus muscle area, muscle:bone ratio, and numerical yield grade increased linearly (P = .0001) and predicted cutability and actual muscle-to-fat ratio decreased linearly (P = .0001) as BCS increased from 2 to 8. Carcasses from BCS-8 cows had the most (P<.05) marbling. The percentage of carcasses grading U.S. Utility, or higher, was 16.7, 20.0, 63.6, 43.3, 73.3, 100.0, and 100.0% for cows assigned a BCS of 2, 3, 4, 5, 6, 7, and 8, respectively. At 6.4 mm of fat trim, carcasses from BCS-5 cows had higher (P<.05) shoulder clod yields than carcasses from cows having a BCS of 6, 7, and 8. Carcasses of BCS-2 cows had lower (P<.05) strip loin yields than carcasses from BCS-3, 4, 5, 6, and 7 cows. Top sirloin butt yields were higher (P<.05) for carcasses of BCS-2, 3, 4, and 5 cows than those of BCS-6, 7, or 8 cows. Carcasses from BCS-7 and 8 cows had lower (P<.05) tenderloin and inside round yields than carcasses of BCS-5, or less, cows. At both fat-trim levels, carcasses from BCS-5 cows had higher (P<.05) eye of round yields than cows assigned BCS of 2, 7, or 8. When subprimal cuts were trimmed to 6.4 mm of visible fat, carcasses from BCS-5 cows had higher (P<.05) total lean product yields than cows assigned a BCS of 2, 4, 7, and 8. Regardless of fat trim, total fat yields increased (P = .0001) and total bone yields decreased (P = .0001) linearly as BCS increased from 2 to 8. Although carcasses from BCS-5 and 6 cows had the highest yields of lean product, cattle producers and packers may benefit most by marketing and(or) purchasing BCS-6 cows because a higher percentage of their carcasses had quality characteristics deemed desirable for fabrication into boneless subprimal cuts.

Mature beef cows (n = 122) representing British and Continental phenotypes were slaughtered to measure the influence of body condition score (BCS) on by-product yield and value. All cows were weighed and assigned BCS, based on a 9-point scale, 24 h before slaughter. By-product weights were obtained during the slaughter process and included blood, feet (with hooves attached), oxlips, tongue, gullet, trachea, cheek meat, head meat, skull, tripe, honeycomb tripe, large and small intestines, spleen, mesenteric fat, weasand meat, kidneys, heart, lungs, and oxtail. By-product yields were calculated as a percentage of the animal's live weight taken 24 h before slaughter. By-product values were computed by multiplying the weight of each piece removed during the slaughter process by the 1997 average price. Live weight increased linearly (P<.001) as BCS increased from 2 to 8, whereas Continental cows were approximately 86 kg heavier (P<.05) at slaughter than British cows. Cows assigned a BCS of 2 or 3 had greater (P<.05) skull, feet, tongue, tripe, honeycomb tripe, trachea, and lung yields than cows assigned a BCS of 4 or higher. On the other hand, BCS-7 and 8 cows had greater (P<.05) weights and yields of large intestines and mesenteric fat than cows given a BCS of 6 or lower. The feet, trachea, lungs, and bone meal from BCS-2 cows had the greatest (P<.05) value, whereas the value of the large intestine, oxtail, and mesenteric fat was highest (P<.05) for BCS-7 and 8 cows. Weight, yield, and value of the skull, head meat, and feet were greater (P<.05) for Continental cows than British cows. Total by-product value was quadratically (P<.001) related to BCS. Cows assigned a BCS of 5 had lower (P<.05) total by-product values than either BCS-2 or BCS-7 and 8 cows. Drop credit for BCS-2 cows was greater (P<.05) than BCS-3, 4, 5, and 6 cows, with cows assigned a BCS of 7 and 8 having intermediate drop credit values. Continental cows tended to have greater (P<.10) total by-product and drop credit values than British cows. Information from this study indicated that the BCS of cows at the time of slaughter had a profound influence on by-product yields and, more importantly, values of by-products that are credited back against the cost of production to the beef cattle producer.