A new quarantine rule is being blamed for shuttering a horse processing plant in Quebec, Canada, but some horse advocates believe the closure might not be good news for slaughter-bound equines from the United States.

A combination of legislation and court rulings shuttered the last U.S. horse processing plants in 2007. Since then U.S. horses have been exported for processing in Canada and Mexico.

A new rule which took effect March 31 requires that all horses imported from the United States into Canada for processing be held at Canadian feed lots for a minimum of six months. The regulation is intended to address food safety concerns expressed by European Union (EU) buyers.

The Canadian Food Inspection Agency (CFIA) said, the Les Viandes de la Petite Nation (LPN) processing plant, in Quebec, announced April 12 that it would cease horse processing because the new EU rule affected profits. All other activities are still operating, a CFIA spokesperson said