Do domestic livestock (Horses) have to be specified on your firearms certificate before you can humanely dispatch them, I'm sure the answer is probably yes, but hey?
All I seem to be able to find was this...........
Firearms Act 1968 CHAPTER 27
10 Slaughter of animals.E+W+S(1)A person licensed under [F35the Welfare of Animals (Slaughter or Killing) Regulations 1995 to slaughter horses, cattle, sheep, swine or goats] may, without holding a certificate, have in his possession a slaughtering instrument and ammunition therefor in any slaughterhouse or knacker’s yard in which he is employed.
(2)The proprietor of a slaughterhouse or knacker’s yard or a person appointed by him to take charge of slaughtering instruments and ammunition therefor for the purpose of storing them in safe custody at that slaughterhouse or knacker’s yard may, without holding a certificate, have in his possession a slaughtering instrument or ammunition therefor for that purpose.