Abstract: [Objective] To systematically investigate the effects of three different rearing patterns-grazing, semi-confinement, and total confinement-on the growth performance, slaughter performance, meat quality, rumen fermentation parameters, and rumen microbial community of Sonid lambs, providing a reference for optimizing efficient and healthy rearing models for Sonid sheep. [Methods] A total of 60 healthy 3-month-old Sonid lambs were selected and were randomly assigned to three groups: a grazing group （FM）, a semi-confinement group （BS）, and a confinement group （SS）, with 20 lambs per group. The FM group grazed freely without supplementation; the BS group received concentrate supplementation on the basis of daytime free grazing, with 0.3 kg/d of concentrate supplement per lamb in the first week, followed by a weekly increase of 50 g per lamb; the SS group was fed a total mixed ration ad libitum under total confinement conditions. The trial consisted of a 14-day pre-trial and a 60-day formal trial. Growth performance was measured at the beginning and end of the trial. After the trial, 5 lambs were randomly selected from each group to determine slaughter performance, organ indices, meat quality, rumen fermentation parameters, and rumen microbial community. [Results] Regarding growth and slaughter performance, the final body weight, average daily gain, carcass weight, and dressing percentage of the BS and SS groups were extremely significantly higher than those of the FM group （P<0.01）; the final body weight of the SS group was significantly higher than that of the BS group （P<0.05）. For organ indices, the heart index in the BS group and the liver index in the SS group were significantly lower than those in the FM group （P<0.05）. In terms of meat quality, the crude fat content in the SS group was significantly higher than those in the FM group （P<0.05）. For rumen fermentation, compared with the FM group, the pH in the BS and SS groups decreased significantly （P<0.05）, while the ammonia nitrogen content increased significantly （P<0.05）. Microbial community analysis showed that the Shannon index of α-diversity in the FM group was extremely significantly higher than in the BS and SS groups （P<0.01）, and the Chao1 index was significantly higher than in the BS group （P<0.05） and extremely significantly higher than in the SS group （P<0.01）. The relative abundances of Succinivibrio and Succiniclasticum in the SS group increased extremely significantly （P<0.01）. [Conclusion] Under the experimental conditions, compared with traditional grazing, both semi-confinement and total confinement models significantly improved the growth performance, slaughter performance, and rumen fermentation function of Sonid lambs, and significantly altered the rumen microbial community structure. Among them, the total confinement model was most effective in promoting weight gain with no negative impact on the primary edible quality of the mutton. Therefore, total confinement is recommended as an efficient rearing model for Sonid sheep.

Key words: Sonid lambs, rearing method, growth performance, slaughter performance, meat quality, rumen fermentation function