Knackers collected sick, dying or worn-out livestock for slaughter and rendering, and in the absence of any veterinary alternative effectively decided which animals were beyond saving. As animal-welfare and veterinary-licensing law tightened through the 19th and 20th centuries, that diagnostic judgment was reserved to licensed veterinarians, leaving the knacker's trade as regulated carcass disposal alone.
The knacker's medical judgment no longer exists as a living trade. Here is what erased it, and which profession took on the work.
c. 500–1761
The farrier's thousand years
For over a millennium, the farrier was both blacksmith and doctor to the horse, treating lameness, colic and wounds through an apprenticeship system rather than formal study, alongside itinerant 'cow-leeches' who dosed cattle and sheep with folk remedies. No scientific institution existed to test whether any of it worked, and treatment quality depended entirely on an individual craftsman's word-of-mouth skill.
What else was happening then
1761
Bourgelat opens the world's first veterinary school
Claude Bourgelat founds the Royal Veterinary School at Lyon under order of Louis XV, driven by the need to fight rinderpest scientifically rather than treat livestock disease as farriers' folk knowledge.
1791
London opens a veterinary college
The Veterinary College, London — later the Royal Veterinary College — opens, becoming the largest and longest-established veterinary school in the English-speaking world.
1865
Rinderpest creates Britain's state veterinary service
After veterinarian J. B. Simonds diagnoses rinderpest in London cattle, Parliament passes the Cattle Diseases Prevention Act and creates a State Veterinary Department, an early template for government animal-health agencies.
1884
The USDA creates the Bureau of Animal Industry
Daniel Elmer Salmon, the first American to hold a veterinary degree, becomes founding chief of the US Bureau of Animal Industry, the country's first federal veterinary agency.
Where that work lives now
Treats patients from goldfish to horses that cannot describe a symptom, and carries the legal power to end their suffering by euthanasia.
🐾 Veterinarian →