13. For the purposes of paragraph 11 above and Annex 2 to this Part of this Schedule “herd” means the bovine animals kept on a holding which–
(a)in the case of female animals, are in milk or in calf; and
(b)in the case of male animals, have been used for breeding purposes,
and are managed as a separate production unit at the time notice of the decision of the Scottish Ministers to slaughter the animal is given to the keeper or other person in charge of the animal.