Polled means no horns. Some cattle breeds have horns and some don’t. Polled cattle are that way due to breeders selectively breeding cattle that were naturally polled and perpetuating that through various breeds. Horns are useful for cattle on rangeland where they encounter predators. They aren’t as desirable in cattle that are worked with closely.
The breed I raised for fifteen years was naturally horned. I didn’t mind it because they were well-trained, but no horns is easier to manage. Cattle need more room at feed bunks if they have horns. A sudden head flip due to flies can cause injury to handlers when working closely with horned cattle. I never had trouble, but either all your cattle should have horns or none of them to keep things even and prevent bullying.
Some horned cattle breeds, such as Longhorn or Watusi, can be difficult to even get into a chute for regular vaccines.
