It shall be the duty of every owner, keeper or custodian of a dog,
cat, or ferret four months old or older to have such dog, cat, or
ferret inoculated with the anti-rabies vaccine approved by the Secretary
of the Department of Health and Mental Hygiene. The inoculation shall
be repeated as often as the Secretary of the Department of Health
and Mental Hygiene may, from time to time, specify.