Identification passports were also issued for all racehorses, including pedigrees, vaccination, laboratory test results, and other required information.
It was demonstrated in hypothyroid animals and people that replacement of thyroxine alone corrected the measurable manifestations (laboratory test results) of hypothyroidism.
Reasons for euthanasia include incurable (and especially painful) conditions or diseases, lack of resources to continue supporting the animal, or laboratory test procedures.