Definitions—In the preceding sections of this chapter the word “animal” or “animals” shall be held to include all brute creatures, and the words “owner”, “person”, and “whoever” shall be held to include corporations as well as individuals, and the knowledge and acts of agents of and persons employed by corporations in regard to animals transported, owned, or employed by, or in the custody of such corporations, shall be held to be the acts and knowledge of such corporations.