GENEVA (AP) — Swiss voters are casting ballots in a referendum on a cattle farmer's proposal to have the government subsidize herders of goats and cows if they let their animals keep their horns.

Voters decide on three issues Sunday as part of Switzerland's form of direct democracy. Referendums follow petition drives mustering at least 100,000 signatures to bring issues up for a vote and ultimately change the constitution.

Polls suggest a tight race on the proposal to subsidize farmers who don't de-horn their animals, seen as more humane by proponents. The federal government opposes it, citing costs.

The other referendum issues involve ensuring Switzerland's constitution precedence over international treaties, and whether to allow insurance providers to secretly monitor people suspected of insurance fraud.