The fat deposition and organoleptic properties of yearling steers serially slaughtered at the end of grazing and after varying lengths of full feed

Sixty yearling steers (30 Angus and 30 Hereford) were grazed on spring and summer permanent pasture for 122 days. The steers were assigned to 6 groups of 10 steers each (5 Angus and 5 Hereford). One group was slaughtered at the end of the grazing period, one after 28 days on full food and one group at 28 day intervals thereafter through 140 days. The feedlot ration which was fed ad libitum consisted of whole shelled corn and a 36% commercial protein supplement.

The carcasses were chilled for 48 hours and ribbed for assessment of quality and quantity indicators. They were broken into wholesale cuts by the procedure of Wellington (1953). Those cuts deemed most logical for fabrication into ground beef were separated into bone, connective tissue and edible portion (lean and fat). Each cut was ground and a representative sample retained for fat determination. All cuts from each carcass were subsequently mixed together and a sample was retained for fat determination.

Along with the percentage extractable fat, the fat thickness (mm) and yield grade for the edible portion of the brisket, chuck, plate, loin flap, flank ribends, foreshank, hind shank and total were determined. Sample steaks were retained from the short loin and shankless round (semimembranosus) and evaluated for juiciness, tenderness, flavor intensity and overall acceptability by a 10-member trained sensory evaluation panel.

Based on samples from Hereford and Angus steer carcasses, these data indicate that the percentage fat in all ground beef cuts and sensory flavor, tenderness and overall acceptability of cooked loin steaks was acceptable after a grain finishing period of 56 to 84 days.