Effect of desert steppe grazing on slaughtering performance and meat quality of Tan sheep

To investigate the effect of desert steppe grazing on the Tan lamb, 39 Tan lambs were randomly divided into three groups: grazing (GZ), time-limited grazing with supplement (TG), the stall-fed (SF). Then, slaughtering performance and meat quality were measured. The final body weight, carcass weight, dressing percentage, pure meat percentage, and meat-bone ratio were significantly better in the SF group than in the TG group (P < 0.05). Moreover, the slaughtering performance was significantly better in the TG group than in the GZ group, except for the pure meat percentage and meat-bone ratio. There were no significant differences in meat color, pH, shear force, and drip loss, but SF group was lower in cooking loss (P < 0.05). The content of meat polyunsaturated fatty acids (C18 ꞉ 3n3, C20 ꞉ 5n3, C22 ꞉ 6n3, C18 ꞉ 2n6, C20 ꞉ 3n6, and C20 ꞉ 4n6) of Tan lambs in the GZ and TG groups was significantly higher than that in the SF group (P < 0.05); the GZ and TG groups had a significantly lower n-6/n-3 ratio in the muscles than the SF group (P < 0.05). These results suggest that grazing in the desert steppe can increase the content of unsaturated fatty acid in muscle, and have an adverse effect on cooking loss and the slaughtering performance of Tan sheep. Time-limited grazing with supplement feeding modes can improve the slaughtering performance, while preserving the fatty acid composition of Tan sheep.