Each of the sires other than AD has daughters that yield 10 units more (on average) than
daughters of sire AD. The same principle can be applied to construct other meaningful estimable functions (we could have for example zeroed out the some levels of herd). Furthermore, treating sire effects as fixed is equivalent to omitting the G-1 matrix from the mixed model equations of the previous example.
The LHS of the MME equations obtained by R looks like this: