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=== Introduction ===

=== Introduction ===

Most pet foods provide owners with guidance on how much, and sometimes how often they should feed their dog or cat. The amount of food a pet needs is a function of the energy content of the food and the energy requirement of the pet. Feeding guides should be used as starting point to estimate how much food to offer. Because energy requirements differ among animals, and can also vary within a cat or dog over time, the exact amount to feed must be tailored according to the needs of the individual.

Most pet foods provide owners with guidance on how much, and sometimes how often they should feed their dog or cat. The amount of food a pet needs is a function of the energy content of the food and the energy requirement of the pet. Feeding guides should be used as starting point to estimate how much food to offer. Because energy requirements differ among animals, and can also vary within a cat or dog over time, the exact amount to feed must be tailored according to the needs of the individual.

=== Feeding Guides on Pet Food ===

=== Feeding Guides on Pet Food ===

 

Most commercially manufactured pet foods provide feeding guides on the packaging. This is a mandatory requirement for those that are complete and balanced. The key principles and steps used to calculate food allowances are described in the [[Feeding Guides - Nutrition#How Feeding Guides Are Calculated|next section]]. Understanding how these principles are applied is important, as they determine how much food and energy a pet is advised to eat.

Most commercially manufactured pet foods provide feeding guides on the packaging. This is a mandatory requirement for those that are complete and balanced. The key principles and steps used to calculate food allowances are described in the next section (link?). Understanding how these principles are applied is important, as they determine how much food and energy a pet is advised to eat.

There is no international standard defining how feeding guides are calculated, and manufacturers may take different approaches, and make different assumptions on how they do this. Different products may recommend feeding different amounts of energy for the same pet, and can result in either an over or under-estimate of their ‘actual’ energy needs.

There is no international standard defining how feeding guides are calculated, and manufacturers may take different approaches, and make different assumptions on how they do this. Different products may recommend feeding different amounts of energy for the same pet, and can result in either an over or under-estimate of their ‘actual’ energy needs.

=== How Feeding Guides Are Calculated ===

=== How Feeding Guides Are Calculated ===

 

Feeding guides are calculated by dividing the pet’s daily energy requirements by the energy density of the food, following the 2 step approach outlined in figure 1 <ref name="Waltham Pocket Book">WALTHAM pocket book of healthy weight maintenance for dogs and cats. (2010) Ed. German, A. and Butterwick, R.F. Pub Beyond Designs Solutions Ltd.</ref>. (1, WALTHAM Pocket book)

Feeding guides are calculated by dividing the pet’s daily energy requirements by the energy density of the food, following the 2 step approach outlined in figure 1. (1, WALTHAM Pocket book)

Figure 1 – How feeding guides are calculated

Figure 1 – How feeding guides are calculated

*Calculate daily amount of food (g/d) = [Pet energy needs (kcal/d) x 100]/Energy density of the food (kcal/100 g)

*Calculate daily amount of food (g/d) = [Pet energy needs (kcal/d) x 100]/Energy density of the food (kcal/100 g)

=== Estimating Energy Density of the Food===

=== Estimating Energy Density of the Food===

Manufactured pet foods may provide this information on package labels, or it may be available through ‘off pack’ materials such as web sites, or on request from customer care services. In the U.S., calorie content statements are now required on all pet food labels, including those for treats and supplements. Information on the label must be provided in terms of kcal/kg and kcal per common unit (e.g., cups, cans, pieces). To use the formula above, the value in kcal/kg must be divided by 10 to provide the energy density in terms of kcal/100 g. If this information is not available it can be calculated indirectly from the amounts of macronutrients (protein, fat and carbohydrate), and fibre in the food (link to WikiVet nutrition section). The equation to calculate energy content is quiet complex and there are tools available that help avoid the need to [http://energycalculator.info/en manually calculate].

Manufactured pet foods may provide this information on package labels, or it may be available through ‘off pack’ materials such as web sites, or on request from customer care services. In the U.S., calorie content statements are now required on all pet food labels, including those for treats and supplements. Information on the label must be provided in terms of kcal/kg and kcal per common unit (e.g., cups, cans, pieces). To use the formula above, the value in kcal/kg must be divided by 10 to provide the energy density in terms of kcal/100 g. If this information is not available it can be calculated indirectly from the amounts of macronutrients (protein, fat and carbohydrate), and fibre in the food (link to WikiVet nutrition section). The equation to calculate energy content is quite complex and there are [http://energycalculator.info/en tools available] that help avoid the need to manually calculate.

 

Estimating the energy content of home-made foods can be a challenge. It requires access to reliable published information on the nutritional content of food ingredients commonly used in pet foods <ref name="NRC">National Research Council (NRC). (2006) '''In Nutrient Requirements for Dogs and Cats and CTS.''' 2006 ''Washington, DC: National Academies Press '' p.28-48</ref>, or human foods <ref name="Food Standard 2004">Food Standards Agency (2002). '''McCance and Widdowson’s The Composition of Foods.''' Sixth Summary Edition. Cambridge: Royal Society of Chemistry [https://www.gov.uk/government/publications/composition-of-foods-integrated-dataset-cofid Online Resource]''</ref> and the ability to quantify the relative contribution of each ingredient to total daily intake of each nutrient. This may require access to complex databases and software, or seek advice from an independent expert that can assess the nutritional value of home-made diets link <ref name="WSAVA">WSAVA Global Nutrition Guidelines. '''[http://www.wsava.org/sites/default/files/JSAP%20WSAVA%20Global%20Nutritional%20Assessment%20Guidelines%202011_0.pdf Online Resource'''.</ref>. This is a significant disadvantage in feeding foods prepared at home (link to section on home prepared foods)

=== Estimating Energy Needs ===

=== Estimating Energy Needs ===

In addition to bodyweight, there are a number of other factors that influence the energy requirement of the pet. These include activity, life-stage, reproductive status, and environmental conditions. Activity level can contribute to more than 30% of the daily energy requirement in highly active working dogs, such as Border Collies <ref name="NRC" />. However, recent studies have shown that adult pet dogs are relatively ‘inactive’ receiving on average only 4 walks of 40 minutes duration per week <ref name=''Christian''>Christian, NE, et al. '''Dog ownership and physical activity: A review of the evidence.''' J. Phys Act Health 2013; 10:750-759</ref>. The energy requirement of inactive dogs is lower than their active counterparts <ref name=Bermingham>Bermingham EN et al. '''Energy requirement of adult dogs.''' [http://www.ncbi.nlm.nih.gov/pubmed/27417154 PLOSone 2014; 9:e109681.] </ref> <ref name=Thes>Thes, M, et al. '''Metabolizable energy intake of client-owned adult dogs.''' [http://www.ncbi.nlm.nih.gov/pubmed/274171548 J. Anim. Phys. Anim. Nutr.] </ref> and this represents a more realistic starting point for most adult pet dogs and cats.

 

In addition to bodyweight, there are a number of other factors that influence the energy requirement of the pet. These include activity, life-stage, reproductive status, and environmental conditions. Activity level can contribute to more than 30% of the daily energy requirement in highly active working dogs, such as Border Collies (2; NRC, 2006). However, recent studies have shown that adult pet dogs are relatively ‘inactive’ receiving on average only 4 walks of 40 minutes duration per week (6; Christian et al 2013). The energy requirement of inactive dogs is lower than their active counterparts (7; Bermingham, 2014, 8. Thes et al, 2016) and this represents a more realistic starting point for most adult pet dogs and cats.

Equations to calculate energy requirements can be complex and cumbersome to use (table 2). Using these equations, energy requirements have been calculated for adult dogs, adult cats, puppies and kittens (link to excel file)

Equations to calculate energy requirements can be complex and cumbersome to use (table 2). Using these equations, energy requirements have been calculated for adult dogs, adult cats, puppies and kittens (link to excel file)

Portion control is a cornerstone of responsible feeding, and feeding guides help owners ensure that they are feeding the correct amount of food to their pet. The feeding guide should be used as the foundation for estimating how much food to offer, but the exact amount should be tailored to meet the individual needs of the pet. To maintain a ‘healthy’ bodyweight, pets should be fed according to their ‘ideal’ body weight, which may not be their ‘current’ bodyweight. In addition regular monitoring of bodyweight, along with additional nutritional assessments such as body condition scoring (PFMA Size-o-meter http://www.pfma.org.uk/pet-size-o-meter; 9; WSAVA Nutrition Toolkit, http://www.wsava.org/nutrition-toolkit, 10. FEDIAF Nutritional Guidelines ) will help detect early changes, and inform adjustments in the food allowance, to ensure the pet stays at their ‘ideal’ bodyweight.

Portion control is a cornerstone of responsible feeding, and feeding guides help owners ensure that they are feeding the correct amount of food to their pet. The feeding guide should be used as the foundation for estimating how much food to offer, but the exact amount should be tailored to meet the individual needs of the pet. To maintain a ‘healthy’ bodyweight, pets should be fed according to their ‘ideal’ body weight, which may not be their ‘current’ bodyweight. In addition regular monitoring of bodyweight, along with additional nutritional assessments such as body condition scoring ([http://www.pfma.org.uk/pet-size-o-meter PFMA Size-o-meter]; <ref name=WSAVA Nutrition Toolkit>[http://www.wsava.org/nutrition-toolkit) WSAVA Nutrition Toolkit], <ref name=FEDIAF>FEDIAF Nutritional Guidelines</ref>) will help detect early changes, and inform adjustments in the food allowance, to ensure the pet stays at their ‘ideal’ bodyweight.