The tag on every animal feed product is labeled with information required by the FDA, with ingredients listed in descending order of predominance–from most to least inclusion.

"However, this is not always enforced and there is no guarantee that listing of ingredients reflects the inclusion rate of the finished product," said Randel Raub, PhD, director of Equine Business Development and Technical Services for Purina Mills, during his Purina Equine Veterinary Conference presentation on "Beyond the Feed Tag: Horse Feed Ingredients, Quality and Safety Issues."

Raub emphasized that the higher the level of a horse’s expected performance, the less tolerance a horse has to nutritional variations.

Raub said he believes that owner selection of feed relies on trust in the manufacturer for consistent quality. Responsible feed manufacturers evaluate their products in multiple ways: serial laboratory analyses to ensure quality and physical specifications of ingredients, and visual inspections. As an example, choke is minimized by pelletizing feed to a specific size and an easily chewed consistency, so this is confirmed via inspection. Assays scan for the presence of mycotoxins and aflatoxins, fungal substances that are harmful to horses.

"The cost of testing for quality control is more economical than the consequences that may result from not testing," Raub noted.

He also stressed that mills producing equine feed should be free of ionophores (rumensin), antimicrobial compounds that are toxic to horses but used in cattle feed.

Only ingredients approved by FDA and American Association of Feed Cont