Which of the following grains is commonly fed to horses?

Oats are commonly fed to horses due to their favorable nutritional profile and digestibility. They provide a good source of carbohydrates, which serve as vital energy for horses, particularly those in work or training. Oats have a balanced fiber content and are typically safer for equine digestion compared to other grains, which can sometimes be too rich for horses.

Additionally, oats often have a higher hull content, making them beneficial for maintaining gastrointestinal health. They also contain essential nutrients like proteins, vitamins, and minerals, contributing to a well-rounded diet for horses.

While rice, sorghum, and wheat can be used to some extent in equine diets, they are less favored than oats due to issues such as higher risk of digestive disturbances and lower overall fiber content. This makes oats the most suitable grain among the choices for feeding horses.