Mettler is an uncommon word that is used to refer to a person who is responsible for the upkeep of farm animals. Some of the synonyms that can be used for this word include herd keeper, animal husbandman, and livestock keeper. Other terms that may be used to describe a person who is responsible for the care of animals on a farm include rancher, shepherd, and stockman. Each of these words is used to describe someone who takes care of animals, but they may be used in different contexts depending on the specific type of animal or the region in which the person is working. Regardless of the term used, it is important to recognize the important role that these individuals play in keeping livestock healthy and productive.