BMI in dogs – is it informative?

According to a study from the USA, around one third of our four-legged friends are carrying a little too much weight. Obesity can have serious health consequences, and not only for humans: bone and joint problems, diabetes, shortness of breath and increased susceptibility to cardiovascular disease. This not only affects the dogs’ quality of life enormously, but also has a negative impact on their life expectancy. In addition, being overweight often leads to a reduction in activity, which in turn causes the weight to increase even more.

To be able to control the dog’s weight, the owner is often referred to the BMI. This is already widely used in relation to the ideal weight of humans, but can also be used in a modified form as a guide for the dog.

The BMI of the dog is also called WTH, which means ‘Weight to Height ratio’. First of all, it is necessary to weigh and measure your own dog in order to subsequently compare the determined value with the ideal value of the breed. The size of the dog is determined in a standing position, from the ground to the highest point between the shoulder blades.

However, it should be noted that the ideal values of weight and size are only indicative and the actual values may vary greatly depending on the breed. The sex of the dog should also be taken into account, as females are usually lighter and smaller than males.

The BMI can be calculated as follows:

(kg / 0,45) / (cm / 2,54) = BMI

If the result of the calculation is above 3, the dog may already be suffering from obesity. In this case, training and diet should be adapted accordingly. However, in some dog breeds, a value above 3 is completely normal and does not necessarily mean that the dog is overweight.

From a value of 2.5, it is nevertheless advisable to move the training to softer surfaces in order to minimise the risk of injury.

We have calculated the BMI value of ten different breeds based on ideal weight and size:

Determining the BMI to monitor the dog’s weight must be viewed critically and should only be regarded as a rough guide value. This does not look at whether a dog is actually obese or just muscular. However, it does show how much effort a dog has to put in to get the body moving. The higher the value, the more strenuous for the dog.
Other methods should be used to assess the dog’s weight and to detect any possible obesity. For example, the Body Condition Score (BCS), which tests the dog for visible and noticeable signs of obesity, is suitable for this purpose. Since the dog’s weight increase is usually evident in the rib cage, lumbar spine and abdomen, the ribs can be palpated to check. If these can be felt slightly (and not pronounced) at the sides, the dog is within the range of the ideal weight. Also, the waist should be clearly visible from above and a tucked-in belly line should be visible from the side.