Changes

==Roles in the Body==

==Roles in the Body==

'''Energy expenditure and requirement for intake is dependent on the '''Basal Metabolic Rate''' ('''BMR''', the energy required for normal physiologic functions in a fasted, thermoneutral environment); activity level (normal physical activity and exercise); dietary thermogenesis (energy used during digestion and assimilation of food); and adaptive thermogenesis (energy needed to maintain body temperature in cold environments)'''. In a thermoneutral environment BMR accounts for approximately 60% of the animal’s total daily energy expenditure, while normal activity is 30%, and dietary thermogenesis accounts for 10% energy utilization.1 Energy expenditure for adaptive thermogenesis varies with temperature, humidity and coat thickness.2

'''Energy expenditure and requirement for intake is dependent on the '''Basal Metabolic Rate''' ('''BMR''', the energy required for normal physiologic functions in a fasted, thermoneutral environment); activity level (normal physical activity and exercise); dietary thermogenesis (energy used during digestion and assimilation of food); and adaptive thermogenesis (energy needed to maintain body temperature in cold environments)'''. In a thermoneutral environment BMR accounts for approximately 60% of the animal’s total daily energy expenditure, while normal activity is 30%, and dietary thermogenesis accounts for 10% energy utilization<ref>Case LP, et al. In Canine and Feline Nutrition: A resource for Companion Animal Professionals. 2011 Third Ed. St. Louis: Mosby p.59-61.</ref>. Energy expenditure for adaptive thermogenesis varies with temperature, humidity and coat thickness<ref>National Research Council (NRC). Physical Activity and Environment. In Nutrient Requirements for Dogs and Cats. 2006 Washington, DC: National Academies Press p.267-273.</ref>.

'''Resting energy requirement (RER)''' accounts for both BMR and dietary thermogenegisis. RER is determined by lean body mass, but may vary with age, breed, gender, neuter status, and the presence of disease. For both dogs and cats, RER can be calculated using exponential equations based on body weight using ('''70*BWkg0.75''').3 '''A number of factors can influence daily energy requirements, such as breed, reproductive or neuter status, activity level (e.g., sedentary vs. working dog), and environment (e.g., indoor vs. outdoor, kennel/cattery vs. a home)''' and relying on published maintenance energy requirement (MER) equations can be problematic if these variants are not account for.  

'''Resting energy requirement (RER)''' accounts for both BMR and dietary thermogenegisis. RER is determined by lean body mass, but may vary with age, breed, gender, neuter status, and the presence of disease. For both dogs and cats, RER can be calculated using exponential equations based on body weight using ('''70*BWkg0.75''')<ref>Klieber M. The fire of life. 1961 New York: John Wiley & sons.</ref>. '''A number of factors can influence daily energy requirements, such as breed, reproductive or neuter status, activity level (e.g., sedentary vs. working dog), and environment (e.g., indoor vs. outdoor, kennel/cattery vs. a home)''' and relying on published maintenance energy requirement (MER) equations can be problematic if these variants are not account for.  

'''Normal MER variation in cats4 can range from 29-85.5 kcal/BWkg0.75''' and in '''dogs5 can range from 54.5-441.1 kcal/BWkg0.75'''. It is important to note that in both dogs and cats daily MER values can actually fall below calculated RER based solely on body weight. Adipose tissue is less metabolically active than muscle and obese dogs and cats will have lower than expected RER based on body weight measurements alone. Larger cats (>5.5 kg) have lower metabolic energy requirements on a per kg basis than lean or “normal” weight cats.4 In a meta-analysis study on energy requirements of adult cats, the MER was best represented by the equation 77.7 * BWkg 0.711.  

'''Normal MER variation in cats<ref name ="Berm">Bermingham EN, et al. Energy Requirement of adult cats. Br J Nutr 2010;103:1083-1093.</ref> can range from 29-85.5 kcal/BWkg0.75''' and in '''dogs<ref>Bermingham EN, et al. Energy Requirement of adult dogs: A meta-analysis. PLOSone 2014;9:e109681.</ref> can range from 54.5-441.1 kcal/BWkg0.75'''. It is important to note that in both dogs and cats daily MER values can actually fall below calculated RER based solely on body weight. Adipose tissue is less metabolically active than muscle and obese dogs and cats will have lower than expected RER based on body weight measurements alone. Larger cats (>5.5 kg) have lower metabolic energy requirements on a per kg basis than lean or “normal” weight cats<ref name="Berm"/>. In a meta-analysis study on energy requirements of adult cats, the MER was best represented by the equation 77.7 * BWkg 0.711.  

Activity level has the most significant impact on canine energy requirements with inactive dogs having lower metabolic energy requirements on a per kg basis than sporting or working dogs.5 In one cross-sectional survey of pet owners in Australia and the US, only 60% of dog owners reported walking their dogs on a regular basis, with 40% receiving no walks at all.6 The average activity level for those receiving regular walks was four 40 minute walks per week. In a recent meta-analysis5 study pet dogs with the lowest activity (resting) level had an energy requirement of 95*BWkg0.75.  

Activity level has the most significant impact on canine energy requirements with inactive dogs having lower metabolic energy requirements on a per kg basis than sporting or working dogs.5 In one cross-sectional survey of pet owners in Australia and the US, only 60% of dog owners reported walking their dogs on a regular basis, with 40% receiving no walks at all.6 The average activity level for those receiving regular walks was four 40 minute walks per week. In a recent meta-analysis5 study pet dogs with the lowest activity (resting) level had an energy requirement of 95*BWkg0.75.  

==References==

==References==

1. Case LP, et al. In Canine and Feline Nutrition: A resource for Companion Animal Professionals. 2011 Third Ed. St. Louis: Mosby p.59-61.

1. Case LP, et al. In Canine and Feline Nutrition: A resource for Companion Animal Professionals. 2011 Third Ed. St. Louis: Mosby p.59-61.

2. National Research Council (NRC). Physical Activity and Environment. In Nutrient Requirements for Dogs and Cats. 2006 Washington, DC: National Academies Press p.267-273.

2. National Research Council (NRC). Physical Activity and Environment. In Nutrient Requirements for Dogs and Cats. 2006 Washington, DC: National Academies Press p.267-273.