ST. LOUIS • Mayor Francis Slay’s support of Missouri’s “Right to Farm” constitutional amendment, which was narrowly approved by voters on Tuesday, has drawn the ire of some animal rights activists.

Slay, who has long been a favorite of dog and cat lovers in the city, recorded a last-minute robocall that was dialed to voters in St. Louis city and county on election day. Slay said on the call that he supported the amendment to “keep food costs affordable for all Missourians.”

Statewide voters approved it by a razor-thin 2,500 votes, although 73 percent of St. Louis city voters cast their ballots against it.

The Missouri Alliance for Animal Legislation, a group that believes the amendment could relax regulations on puppy mills, criticized Slay saying: “What had to be the most disappointing development in this campaign was the last-minute efforts by Mayor Francis Slay of St. Louis to help pass this amendment.”

Until Tuesday, Slay’s support of the issue was not well known.