The food giant Mars is under fire from animal welfare campaigners after it emerged that one of its subsidiaries has been sponsoring bear-baiting competitions. Pet food manufacturer Royal Canin said it was "horrified" to learn that it had sponsored a contest near Vinnytsia in Ukraine earlier this year.

Footage taken by Four Paws, an international animal welfare organisation, shows dogs being set on a chained brown bear over a two-hour period. As a small audience looks on, the dogs attack and bite the bear – which is unable to defend itself because its claws have been removed and it is chained to a tree.

Several men control the bear's movements using a chain, dragging it around a fight area demarcated with Royal Canin-branded plastic tape. An official awards points to the individual dogs and trophies carrying the Royal Canin logo are awarded to the owners.

Royal Canin, a French company bought by Mars a decade ago, makes food for cats and dogs. It promotes itself with the slogan "respecting the animal nature of dogs and cats". But Dr Amir Khalil, a vet and project leader at Four Paws – which has a memorandum of understanding with Ukraine's department of ecology to eradicate bear-baiting – questioned the company's animal welfare commitments.

"Royal Canin says it places animals' wellbeing at the centre of its philosophy," Khalil said. "By sponsoring appalling bear-baiting, Royal Canin is reducing wild animals like the brown bear to the rank of second-class animals."

The brown bear is protected by law in Ukraine, but the country has long faced accusations of cruelty towards bears, which are made to perform in the country's zoos and circuses. Khalil said a popular act involved getting bears drunk on beer.

Bear-baiting contests take place between four and six times a year, according to Four Paws, which says it has evidence Royal Canin sponsored more than one event. The charity estimates that there are between 15 and 20 baiting bears in Ukraine. It said the animals live in tiny cages and are released only for training or competitions. The bears are taken from their mothers a few months after they are born. They are often deprived of food and water to make them weaker opponents for the dogs. "It is not enough for Royal Canin to distance itself verbally from such activities," Khalil said. "The company must take responsibility and support the government in securing a species-appropriate life for the bears concerned."

In a statement to the Observer, Royal Canin said: "As a company with knowledge and respect for animals at our heart, we condemn any activities that harm or endanger animals. Royal Canin has been absolutely horrified to see these images linked with our brand.

"The sponsorship of this event is not consistent with Royal Canin's animal welfare policy, our philosophy of pet-first or our vision." It said that when Four Paws International raised the incident in May, it was investigated and the company undertook immediate action to cease sponsoring this event. It had reminded sales and marketing staff of its policy on animal welfare and sponsorship due diligence. It said: "Having not seen the video at this stage, we did not understand the true nature of the event that took place. This has been a humbling experience for Royal Canin.

"We again thank Four Paws International for bringing this practice to our attention, and in doing so reminding us that diligence in ensuring our policy is followed is paramount." The company said it had pledged to work to improve the welfare of Ukrainian bears and dogs involved in bear-baiting.