What are by-products?
“By-products” are often criticized in popular media, leading to erroneous assumptions about the quality of diets containing these ingredients. Based on their media portrayal, you may question what by-products are in the first place, and what role they play in your pet’s diet.
By-products are “secondary products produced in addition to the principal product,” as defined by the Association of American Feed Control Officials (AAFCO), an organization that publishes pet food labelling and laboratory standards.
By-products are common in most people’s homes — whey protein is a by-product of cheese production, while cornmeal and beet pulp are plant-based by-products. In commercial pet foods, by-products are typically animal ingredients such as liver, spleen, and kidneys (organ meats). According to the official AAFCO definition, by-products “do not include hair, horns, teeth and hooves.”
By-products found in pet foods are items not commonly eaten by humans in North America, but they are considered highly desirable in other cultures. Offal, black pudding, and haggis are dishes regularly consumed by humans around the world and they fit into the category of animal by-products.
What nutritional benefits do by-products provide?
By-products are a rich source of essential nutrients like protein, fat, vitamins, and minerals. These nutrients play critical roles in the body, supplying the body with energy (calories), providing essential amino acids for development and maintenance of lean body tissue, and supporting the immune system. In fact, by-products like liver are more nutrient-dense than skeletal meats (e.g., chicken breast or steak).
An essential nutrient is one that cannot be created by the animal and so must be provided in the diet. Animals (including humans) have requirements for nutrients, not ingredients. For that reason, it is more important to consider the nutrients that by-products provide, rather than focus solely on an ingredient list. Most importantly, the overall quality of ingredients can vary, so the nutritional value of a pet food cannot be measured by the ingredient list on the label.
What are the environmental implications of using by-products in pet feed?
Using only skeletal meats for human and animal consumption creates tremendous waste and results in increased demands on livestock populations. Using by-products in pet food helps reduce waste and improve environmental sustainability by using a greater proportion of harvested livestock (pork, poultry, or cattle) for improved nutritional value. By-products provide an important and concentrated source of essential nutrients to meet pets’ metabolic needs.
Should I feed my pet a diet that contains by-products?
A diet recommendation for any pet should be based on a nutritional assessment that includes a medical history, dietary history, and physical examination performed by your veterinary care team. Ultimately, the goal is to feed your pet a complete and balanced source of nutrition that is species-specific and life-stage appropriate. This goal can be met with or without by-products, provided that essential nutrients are present in the required amounts and proportions.
By-products can provide an accessible source of essential nutrients, so there are no health advantages gained by avoiding them. Talk to your veterinary care team to collaborate on a nutritional plan for your individual pet.
