The objective of this trial was to evaluate the effects of three concentrate protein levels (15, 20 or 25% CP) on measurements of carcass and Longissimus dorsi muscle, weights and yields of cuts, and chemical composition and tenderness of meat of Suffolk lambs in creep feeding. Fifteen single birth lambs were used in this study. Lambs were slaughtered when they reached a final body weight of 28 kg. After slaughter, carcasses were maintained in a refrigerator at 5ºC for 24 hours followed by measurements on the left half carcass done after separation of the commercial cuts. The Longissimus dorsi area was measured to obtain the loin eye area (LEA, cm2). Both left and right loins were frozen; the left was used for determination of chemical composition while the right for a tenderness test ("Warner Bratzler Shear Force"). Different concentrate crude protein levels did not affect carcass measurements as well as measurements on the Longissimus dorsi. However, significant differences among treatments were observed for weight and yield of shoulder clod with the highest values found on the 25% crude protein concentrate. Chemical analyses of Longissimus dorsi showed significant differences across treatments for ether extract, ash, and tenderness. It can be concluded that the diet containing soybean meal must be formulated to yield 25% of crude protein because it reduced the fat content and improved the tenderness of the meat. In addition, it also increased both weight and yield of shoulder clod with no changes on carcass measurements and weight and yields of the remaining cuts.
quality of the meat; sheep; tenderness
