companion animal nutrition

What Should We Feed Companion Animals?

• Animal’s natural dietary habits and natural form of the food consumed by the animal

• Morphology and physiology of the animal and look for resemblance to domestic species

• Availability of published studies to determine requirements

• Variety is the most important criterion (to prevent deficiencies)

• Commercial pet foods eliminate any guessing

Types of Dog and Cat Foods

• Feeding foods designed to more closely meet individual physiological needs for the age of the animal, hence the name “life-stage”

• This concept differs markedly from feeding a single product for “all life stages” (all-purpose foods)

  • Ideally, nutrients added at levels to meet the highest potential need (usually growth and reproduction)

  • But this is not a requirement

Dogs and Cats are Fed Based on Life Stage

• Life stage nutrition is the practice of feeding animals foods designed to meet their optimal nutritional needs at a specific age or physiologic state

  • Growth

  • Maintenance

  • Reproduction/lactation

  • Senior

When Formulating Diets, Always Start With Energy

• Energy is the primary regulator for food consumption

• Animals should be fed enough food to meet their energy requirements

• The non-energy nutrients in the food should be balanced relative to energy density to ensure adequate nutrient intake

• Animals eating an energy-dense food consume less of the food to meet energy needs

Energy Requirements of Dogs and Cats

• Basal metabolic rate (BMR):

  • The energy required to maintain homeostasis in an animal in a post-absorptive state (ideally after an overnight fast) that is lying down but awake in a thermoneutral environment to which it has been acclimatized

    • BMR = 70 kcal/kg BW^0.75

• The maintenance energy requirement (MER):

  • The energy required to support energy equilibrium, (where ME intake equals heat production), over a long period of time

• The daily energy requirement (DER):

  • The energy required to support energy equilibrium taking into account other factors like activity and environment

• DER of dogs and cats is often given as a range, a multiplier x BMR

  • Adult dogs: 1.2 to 1.4 x BMR

  • Adult cats: 1.1 to 1.4 x BMR

• This requirement often confuses owners and may be missed

Assessment of Activity Level of Dogs

• In sedentary dogs, estimations for DER include enough energy to support spontaneous activity, such as eating, sleeping, going outside, and up to three hours of play and exercise per day

• However, most pet dogs are minimally active (NRC, 2006)

  • ~19% of owners never play with their dogs

  • ~22% take their dogs out for exercise fewer than 3 h/week

• Solitary dogs are less active than dogs housed as a group (dogs in kennels, for example)

Assessment of Activity Level of Cats

• In sedentary cats, estimations for DER include enough energy to support spontaneous activity, such as eating, sleeping, going outside, and up to three hours of play and exercise per day

• These requirements are adjusted based on activity level and environment

• Most cats live inside with minimal outdoors access

Agencies with Oversight on the Pet Food Industry

• Association of American Feed Control Officials (AAFCO)

  • Sets nutrient standards for substantiation of claims

  • Provides model regulations for the states

  • Provides ingredient definitions

• US Food and Drug Administration (FDA)

  • Specifies some label requirements

  • Regulates health claims

  • Ensures food safety

  • Approves food additives

• U.S. Department of Agriculture (USDA)

  • Regulates some pet food ingredients

  • Inspects animal research facilities

• State Department of Agriculture (or similar agency)

  • Adopts and enforces animal food regulations

• National Research Council (NRC)

  • Evaluates and compiles nutrition research

  • Makes nutrient recommendations

Formulation, Analysis, and Labeling: Types of Pet Foods

• Generic foods: lack of a brand name, cheap

• Private label: store brands

• Popular brands: trademarked names

• Premium brands: sold in pet stores or some veterinary clinics (specialized for some metabolic conditions or allergies)

• Veterinary/therapeutic brands: “use under the direction of a veterinarian”

• Dry (12% moisture):

  • Vast majority of dog and cat foods

  • Lower cost, ease of storage, reduces tartar

• Soft-moist or semi-dry (30-50% moisture):

  • Chewier

  • Sold in bags, do not require refrigeration

• Canned (wet or moist <78% – with gravy <82% moisture)

  • Increased palatability, ease of digestion

• Refrigerated (<78% moisture)

  • Natural form, but risk of spoilage and contamination

Pet Food Labels Vary Depending on Markets

• The label is a legal document

• The pet food label is also an attractive package cover designed to sell the product

• Pet foods are regulated at their point of sale

  • The same product will have different labels depending on the intended market

Label Design

Key Elements Found on Pet Food Labels in the United States and Canada: Principal Display Panel

• Product identity

  • Manufacturer’s name

  • Brand name

  • Product name*

• Designator (intended species)*

• Net weight*

• Product vignette

• Nutrition claim

• Bursts and flags

Product Name

• Unqualified use of a term (beef, tuna,...) in a product name requires that the ingredient be at least 95% or more of the total weight of all ingredients exclusive of water used in processing, but no less than 70% of the total product

• Use of a term with a qualifier such as “...dinner,” “...platter,” “...entree,” “...formula,” or any similar designation requires that the ingredient be at least 25% of the total weight of all ingredients exclusive of water used in processing, but in no case less than 10% of the total product

• The term “with…” is intended to highlight minor ingredients and this example requires that ingredient be at least 3% of the total product

• The term “...flavor” does not stipulate a minimum percentage; the ingredient flavor designation usually indicates that beef is less than 3% of the total product

Label Design

Key Elements Found on Pet Food Labels in the United States and Canada: Information Panel

• Ingredient statement*

• Guaranteed analysis*

• Nutritional adequacy*

  • Nutritional purpose*

  • Product description*

• Feeding guidelines*

• Statement of calorie content

• Manufacturer or distributor*

• Universal product code

• Batch information

• Freshness date

Ingredient Statement

• Must list each ingredient of the food in the ingredient statement

• Ingredients are listed in descending order by their predominance by weight according to the product’s formula

• The Association of American Feed Control Officials (AAFCO) has established the name and definition of a wide variety of ingredients

• The ingredient names must conform to the AAFCO name (e.g., poultry by-product meal, corn gluten meal…)

• When a suitable AAFCO name does not exist, should be identified by the common or usual name (e.g., beef, lamb, chicken)

• Ingredients listed as “meat” or “meat by-product” must designate the mammal from which the ingredients are derived unless the meat or meat by-products are derived from cattle, swine, sheep, or goats

• Brand or trade names cannot be used in the ingredient statement and no reference to quality or grade of ingredients can be made

• The list of ingredients may be helpful

• A limitation is that it cannot be used to evaluate pet foods

  • The nutritive value of ingredients can be estimated but not definitively determined (no information about quality)

  • Must rely on manufacturer word or reputation

  • For example: “meat by-product”

    • Liver, kidney, and lungs have excellent nutritional value

    • Bone and connective tissue have poor nutritional value

• Consider these 2 ingredient lists representing 2 fancy cat foods, give opinion on which is better:

  • Food 1: wheat by-products, meat meal, chicken meal, animal fat, vitamins, minerals

  • Food 2: meat meal, wheat germ meal, chicken meal, wheat middlings, animal fat, wheat flour, vitamins, minerals

• Sometimes several related ingredients are listed separately

  • Wheat germ meal, wheat middlings, wheat bran, wheat flour

  • This could make wheat-based ingredients appear to be a lower portion of the food than is the fact

  • Also because such ingredients are inherently low in moisture, they may appear lower on the list compared with others with high moisture

• Consider these two ingredient lists representing two moist dog foods, give opinion on which is better:

  • Food 1: water sufficient for processing, meat by-products, beef, soy flour, cornstarch, vitamins, minerals

  • Food 2: textured vegetable protein, meat by-products, beef, cornstarch, vitamins, minerals

• Ingredients may be listed based on their dry contribution

  • Consider this moist food list: water sufficient for processing, meat by-products, beef, soy flour, cornstarch, vitamins, minerals

  • Textured vegetable protein (TVP) is made with soy flour and water

  • Based on the list, soy flour is listed 4th

  • In reality, TVP is the predominant component but was listed in the dry form (soy flour)

• Ingredients may be listed based on their wet contribution

  • Consider this lamb and rice dog food made with “real lamb”: lamb, brewers rice, ground yellow corn, corn gluten meal, oat groats, poultry by-product meal, beef tallow…

  • Lamb appears first on the ingredient list

    • Because its moisture content is higher than that of the other dry ingredients

  • In reality, rice corn and oats are the predominant components and not lamb

Zoo Animal Feeding: Three Critical Challenges – 1. Animal Classification

• This is fundamental for proper care, since different taxonomic groups have distinct nutritional needs

• Classification helps zookeepers understand evolutionary adaptations around feeding

• It determines whether an animal is carnivorous, herbivorous, omnivorous, etc.

• Variations within this taxonomic classification still exist

Zoo Animal Feeding: Three Critical Challenges – 2. Natural Diet Understanding

• Requires knowledge of what animals eat in their native habitats

• Includes understanding seasonal variations in wild diets

• Involves studying feeding behaviors and preferences

• Helps determine nutritional requirements

Zoo Animal Feeding: Three Critical Challenges – 3. Food Access and Substitution

• Ensuring regular supply of appropriate foods

• Finding nutritionally equivalent alternatives when natural foods are not available

• Considering factors like:

  • Seasonality of ingredients

  • Storage capabilities

  • Cost considerations

  • Nutritional equivalency of substitutes