A proposed Canadian law could halt the export of U.S. horses for slaughter in that country, one equine welfare advocate said.

Along with Mexico, Canada became a major destination for U.S. slaughter-bound horses after court actions shuttered remaining processing plants in Illinois and Texas in 2007. According to Canadian Food Inspection Agency records, 56 percent of the 93,812 horses processed in 2009 were U.S. exports.

A bill introduced into the Canadian House of Commons on June 16 would amend the Canadian Health of Animals Act to forbid the import and transport of horses for slaughter for human consumption in that country.

The bill, C-544, also amends the Canadian Meat Inspection Act to prohibit the import, export or transport of horsemeat products within Canada on grounds that those products are likely to contain the anti-inflammatory drugs Phenylbutazone (bute) and Banamine, and the sedative Acepromazine. All three drugs are commonly used by owners to treat their horses, but are banned substances under European Union (EU) food inspection regulations. Beginning July 31 all horses processed in Canadian plants must be proven free of the chemicals for their meat to qualify for entry into EU markets