How many calories does my dog need each day?

All living creatures need to eat to survive, if we don’t eat we starve. We all know that our body needs nutrients found in food to fulfil the growth, repair, reproductive, immunity and maintenance requirements of our bodies. These nutrients include essential and non-essential nutrient requirements. Essential nutrients are nutrients the body is unable to make itself and needs supplied in the food we eat. If essential nutrient requirements are not met, the body will suffer, and disease may occur. Think about scurvy which is caused by a lack of dietary vitamin C consumption. Non-essential nutrients can be synthesised by the body but are also available in food. Other than vitamins and minerals which are micronutrients, the body needs protein, fat and carbohydrates, these are the macro nutrients.

Protein, fat and carbohydrates are the nutrients that provide the body with energy. Energy is required by the body for normal growth, maintenance, thermoregulation, reproductive performance and physical work. All animals need a constant supply of dietary energy to survive. Without energy the body can’t function, which is why the food animals eat is first used to meet its energy needs. Once the energy needs are met, nutrients become available for other metabolic functions – maintenance, growth, reproduction etc.

Animals are capable of regulating the amount of food they eat to meet their daily energy requirements. Energy is expressed as the amount of kilocalories (Kcal) or kilojoules (kJ) in food. When food contains a low of amount of kilocalories, an animal needs to eat more food to fulfil its energy requirements.

When preparing a home prepared (cooked or raw) meal for your cat or dog, its important to know what their energy requirements are. Only then can you ensure that you prepare a meal that provides them with the energy their body needs for metabolic functions and to maintain an appropriate body condition score. Too many calories leads to obesity, while too little causes malnutrition and starvation.

The National Research Council (NRC) provides guidelines on how to calculate the energy (in Kcal) and nutrient requirements for cats and dogs. Calculating the amount of calories they need daily to satisfy their energy requirements is a two-step process. The first step requires you to know how much your pet weighs. Their bodyweight is then raised to a specified power as defined by the NRC, 0.75 for dogs and 0.67 for cats. The calculated value is called a pet’s metabolic body weight. Representing weight as metabolic body weight helps to account for differences in animals body surface areas across different sizes. Metabolic body weight is the number you will work with to ascertain all nutrient requirements and energy needs of your cat or dog. We work with Kilograms (Kg) when performing the calculation.

To determine the metabolic body weight lets look at two examples:

  1. A dog weights 15 Kilograms. To calculate metabolic body weight (MW), raise 15Kg to the power of 0.75. So, 15^(0.75) =7.62

  2. A dog weights 10 kilograms. To calculate metabolic body weight (MW), raise 10Kg to the power of 0.75. So, 10^(0.75) = 5.62

The second step to calculating your pets energy needs requires you to adjust their metabolic bodyweight from step 1 to account for their daily activity levels, as some dogs are more active or younger than other dogs so require more kilocalories to satisfy their daily energy requirements.

The NRC provides guidelines for the activity levels:

  • Active Pet: 130

  • Young Adult Active: 140

  • Active Pet Terriers: 180

  • Active Pet Great Danes: 200

  • Inactive Pet: 95

  • Older Active Pet: 105

To calculate the energy requirements of a 15Kg active pet dog with a metabolic bodyweight of 7.62, multiply 7.62 by 130 which equals 990.86 calories per day.

To calculate the energy requirements of a 15Kg inactive pet dog with a metabolic bodyweight of 7.62, multiply 7.62 by 95 which equals 724.09 calories per day.

If an inactive dog was fed the calorie requirements for an active dog it would result in the inactive pet dog gaining weight. This is why it is important to know what are the calorie/energy requirements for your pet. However, this is to be used as a guide only as some dogs have higher or lower energy requirements due to health issues. For example, a dog with an underactive thyroid may have a slower metabolism resulting in weight gain, even when fed the correct calories for their bodyweight and activity level. Always check with your veterinarian if you have any concerns about your pets weight or health. Also, consider the changes to your pets energy needs in winter and summer. They may need more calories in winter due to needing to stay warm or they might need more calories in summer as they are more active in the summer months.

The most important thing to take away from this blog is to feed the dog in front of you. Are they gaining or losing weight, are they more active in summer, do they leave food in their bowl, are they anxious or are they a working dog? All these factors affect the amount of calories they need to consume each day to meet their energy requirements.

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