What purpose does the interdental space (bars) serve in a horse?

The correct answer highlights that the interdental space, commonly referred to as the "bars," plays a role in the horse's ability to efficiently discharge indigestible matter. This space is located between the incisors and the molars and does not have any teeth. The bars provide a surface that aids in the elimination of materials that the horse might inadvertently ingest but cannot digest. This is particularly important in maintaining a healthy digestive system, as it allows for the expulsion of foreign particles or indigestible items that could cause discomfort or digestive issues.

In terms of the other options: cutting forage and chewing relate more to the incisors and molars during the feeding process. Grinding feed is primarily associated with the molars' action, which helps to break down the feed for better digestion. While the interdental space plays a role in the overall process of eating, its specific purpose is more aligned with the management of indigestible materials.