Antique Calf (Anti suckling) collar. Went over a calf's muzzle. If it tried to suckle it's mother the splayed spikes dug into her udder making her kick the calf away. These were used on smaller farms where the calf was kept with the mother for longer but the farmer wanted the calf to be weaned.
Condition good, stitching intact with all six original spikes in place.