An announcement on Tuesday that Vancouver-based Earls restaurant chain will start getting all of its beef from a U.S. supplier provoked a fast and furious backlash.

The company said it tried to use Alberta beef, but there was not enough that is Certified Humane, a designation now required by Earls.

Certified Humane is a program operated by Virginia-based Humane Farm Animal Care. It includes inspections of farms, ranches and slaughter facilities and certifies meat and dairy products.

According to the organization, products that carry the Certified Humane label come from animals that have not received "unnecessary antibiotics," are not overcrowded in confinement systems and live on farms whose farmers "receive a fair price for their efforts."

Earls announced the change on Wednesday.

"We did intensive research and testing for over two years trying to use Certified Humane beef from Alberta, raised without antibiotics, steroids or growth hormones, of which there are some great suppliers in Canada — and we did use it in our Edmonton and Calgary locations as well as our flagship locations across Canada for well over two years," the chain said in a statement.

"However, there was (and is) simply not enough Certified Humane, antibiotic-, steroid-free beef in Alberta to meet the volume we use, and those we tried were unable to consistently meet our supply needs, not even a portion of it."

Earls will instead go with a U.S. supplier.

The restaurant's tweet announcing the change prompted dozens of replies — and most aren't favourable, with many threatening a boycott of the Canadian chain.

Disappointed to see <a href="https://twitter.com/earlsrestaurant">@earlsrestaurant</a> move away from Alberta Beef. Alberta farmers work hard to produce the best beef in the World. <a href="https://twitter.com/hashtag/ableg?src=hash">#ableg</a> —@BrianJeanWRP

Former federal Conservative cabinet minister Monte Solberg jumped in on Twitter as well.

Earls is caving to hysteria on humane treatment and hormones. I'll take my business elsewhere. <a href="https://twitter.com/hashtag/SupportAlberta?src=hash">#SupportAlberta</a> <a href="https://t.co/1S3h2OJyVK">https://t.co/1S3h2OJyVK</a> —@montesolberg

Earls says it's open to using Canadian beef if it can find a supplier that can keep up with the volume it needs.

Earls, founded in 1982, has about 7,000 employees at 65 locations in Canada and the United States.