The Department of Agriculture has said there has been a high compliance rate with new animal welfare regulations at the annual Ballinasloe Horse Fair.
Transfer of Ownership legislation has been combined with an animal passport regime to cover sales.
Billed as Europe's longest-running horse sale, the 2014 staging of the Ballinasloe Horse Fair is the first to take place with new rules governing the trade of horses.
Since July, every transaction has to be declared and registered with the equine Passport Issuing Organisation.
Department officials have been conducting spot checks on approach roads to Ballinasloe and at the town's Fair Green.
The acceptance of the new rules is seen as part of a growing awareness of animal welfare and benefits this brings to the industry.
Organisers of the horse fair said crowds compare well to previous years.