An animal’s needs aren’t fulfilled by dragging a carriage with a bit in its mouth.

We live in a time when virtually all uses of animals — from the chickens in battery cages to orcas in marine parks — are contestable because all such uses can be occasions for abuse and exploitation. Also, it is now well established that animal abuse, even in the case of children who witness it, operates as a model for violence to humans.

Fortunately, we also live in a time when concerns about animals and human-animal relationships have spawned robust fields of academic inquiry (respectively, cognitive ethology and human-animal studies).

http://www.nytimes.com/roomfordebate/2014/01/17/horse-carriages-are-not-just-a-ride-in-the-park/consider-both-sides-of-human-animal-relationships