For us humans, it's a wonderful feeling to walk around in the summer wearing short sleeves and flip-flops. Aside from the fact that it's simply great to feel the sun on our skin, our bodies also get rid of excess heat in this way. Sweat glands are distributed all over the human body. When we are at risk of overheating, these glands produce sweat. The evaporation of sweat then provides cooling.
Cats and dogs also have sweat glands on their skin, but they don't use them to cool their bodies (except for the sweat glands on their paw pads). Dogs lose most of their body heat through panting. Therefore, they do not benefit from bare skin in terms of regulating their body temperature.
Some people want to do something good for their dogs and have them shaved for the summer, thinking it will keep them cool. They do not realize that this procedure actually has the opposite effect! A dog's fur acts as an insulating layer. There is an air layer between the individual hairs that keeps the dog cool in the summer and warm in the winter. When this insulating layer is removed, for example, by shaving, not only do the hairs go away, but the cooling effect in the summer is also lost. As a result, the dog has difficulty maintaining its body temperature.
Another disadvantage of shaving is that the skin is now more exposed to the sun, which can lead to sunburn. It also happens that a dog's fur simply doesn't grow back after being shaved. This phenomenon is called post-clipping alopecia, also known as hair loss after shaving, and it occasionally occurs in dogs. In this condition, the fur grows back extremely slowly after being shaved or partially shaved (for example, during surgery). Normally, the fur fully regrows within three to four months. However, with post-clipping alopecia, it takes much longer. Fortunately, in this type of alopecia, hair growth usually resumes spontaneously after a period of about six to twelve months. But it can take between 18 and 24 months for the fur to fully regrow. As a result, several months after shaving, the dog still looks freshly shaved." (Source: medpets.at)
In other words, in winter the dog will feel cold, and in summer there is a risk of sunburn. The fur grows normally in all areas that were not shaved or trimmed.
It can also happen that after a shave, the fur grows back even denser, creating a vicious cycle and turning your pet into an uncontrollable ball of fur. Shaving the outer coat changes the structure because the protective hair regresses, and the undercoat increases. More undercoat leads to inadequate air circulation in the fur. The sun rays no longer bounce off the protective outer coat, and the undercoat absorbs the sun rays. This traps heat even more effectively and can lead to overheating or hotspots. The lack of air circulation also promotes the development of eczema, matting, and dull fur.
Giving your pet a shave is therefore not recommended (with few exceptions: dog breeds with single-layered hair WITHOUT undercoat, such as Poodles, Maltese, Yorkshire Terriers, Havaneses – but the shave should not be too short‼️). For dogs WITH undercoat, this procedure does more harm than good. It's best to discuss with a professional dog or cat groomer what the appropriate coat care for your pet looks like and how to properly remove the undercoat. They will know exactly what the optimal solution is for your pet's breed and will not simply recommend a shave, which may be quick and easy but cannot be considered needs-oriented‼️"