Hi everyone, I am struggling with the commands for analyzing the following data (sample)

Study animal Treat CH4yield CH4W
51 1 1 -21.39 0.78
51 1 1 -21.39 0.78
[more data]
;
Proc sort;
by animal;
Proc mixed data = Pepeta COVTEST;
Class Treat study;
by animal;
Model CH4yield = Treat;
Random study study*Treat;
Weight CH4W;
Lsmeans treat/ pdiff stderr ADJUST= Tukey;
Run;