The surveys provided for in Article 1 shall be conducted in such a way as to provide a breakdown of the pig population into at least the following categories: ...
D. breeding pigs with a live weight of 50 kg and higher;
(a) boars;
(b) covered sows, of which:
(b1) sows covered for the first time;
(c) other sows, of which:
(c1) gilts not yet covered.