Bobbin had his first does of Lapizole on carrot last night, thankfully he ate it all like a very good boy!
The Lapizole leaflet I have says nothing about subsequent yearly or 6 monthly courses. All it says is to give a rabbit the 28 days course once and then again before meeting or breeding with other rabbits.
I believe it really is only a one off treatment unless they mix with other rabbits at which point all buns in question should complete the 28 day course.
I think I will be writing to the manufacture though just to be sure
The Panacur leaflet says they recommend 2-4 9 day courses a year. I'm unsure how Lapizole only needs one 28 day course and Panacur needs to be repeated if the active ingredient in both is the same