Final answer:
Hay in a horse feeding program adds succulence to the ration and can help reduce costs. It provides fiber which aids in digestion but may need to be complemented with other feeds to meet nutritional needs.
Step-by-step explanation:
When used in a horse feeding program, hay provides several benefits. It does not increase costs; rather, depending on the context, it can help reduce costs by serving as a bulk feed that is less expensive than some concentrates. More importantly, hay adds succulence to the ration, which can be helpful for the horse's digestive system. It is a source of fiber, which aids in digestion and helps maintain the horse healthy.
While hay can provide some minerals and vitamins, its content may not be sufficient to meet all the nutritional needs of horses, and it should be complemented with a balanced diet including other feeds or supplements if necessary.