Federal law would indicate that livestock feed and pet food labels conform to regulations in 21 CFR 501. You should also follow the guidelines for the species/animal class as indicated in the Association of American Feed Control Officials (AAFCO) Official Publication (OP).
Livestock labeling is addressed in AAFCO OP Chapter 4, Model Regulations under the Model Bill.
Pet food labeling is addressed in AAFCO OP Chapter 4, Model Regulations for Pet Food and Specialty Pet Food Under the Model Bill. You will have to Purchase access to the AAFCO OP.
Mock Label