I rather like this time of year because there are proportionally fewer sick dogs being brought in to see me and more healthy dogs, and there tends to be more time for chatting with clients and playing with their animals. It's a nice respite from being so serious all the time.

I have noticed that during cold weather more and more owners are dressing up their beloved dogs, and sometimes their cats, in clothes. There is a booming market in dog garments despite the economic downturn, as more and more people are looking to brighten up their lives with a splash of colour on their pets.

Straight off the bat, I think the idea of putting clothes on cats is absolutely stupid, with the exception, perhaps, of the totally hairless Chinese crested variety. All cats have a bountiful coat that will keep it warm even in the snow, so a little Hong Kong cold weather is not going to perturb cats at all.

Many cat owners point out that their animal appears to be cold because it likes sleeping next to the heater, on top of a warm video player or, in the case of my cats in the clinic, behind the computer monitor where it is nice and warm. With this flimsy piece of logic these owners justify their notion that their cats need clothes.

Well, the good news is that cats aren't stupid. In chilly weather they have a natural instinct to look for shelter from the cold and that is what your cat is doing. By finding that naturally warm area of your house it is essentially conserving its energy, and it is this efficient use of energy that increases an animal's survival chances in the wild. It doesn't mean that your cat needs clothes.

Cats also have other natural instincts that are just as important, such as grooming. Your cat licks its fur constantly to keep itself clean and prevent its fur from getting matted. It is important that your cat can do this - and I would say it is cruel to prevent such natural behaviour by clothing it.

The fur on cats and dogs is very sophisticated, given millions of years of evolution without clothes, especially when compared to that crappy layer of fabric some owners put on them. Each hair follicle has an individual muscle fibre that can change the angle of each hair to regulate warmth.

It's actually quite amazing when you think about it. There are millions of hair follicles on a typical dog or cat and each one has its own erectile mechanism, the purpose of which is to fluff up the fur to trap more air as insulation when necessary. When you put clothes on your dog or cat, you stifle this intricate mechanism and your animal loses its ability to regulate its body temperature.

As you can imagine, this could have fatal consequences, especially in warmer weather. I would say that putting clothes on a dog during the warmer seasons can be considered a form of cruelty and should definitely be avoided.

Are there exceptions to this? I think there are. Animals with a smaller body mass have more trouble maintaining body heat than large animals. To balance this out, smaller animals tend to have faster metabolisms and generate more body heat, with the added cost of having to eat more often.

So chihuahuas and other breeds that are small and have little fur may benefit from having an extra garment during the coldest parts of the year, when the temperature drops below 7 degrees Celsius. I have to admit that my Afghan hound wears a rain jacket when it's raining in the summer, or else its fur becomes unmanageable.

Just remember that if you do put clothes on your dog, make sure it's only for a short, supervised period of the day. Don't leave the jacket on continuously. And be sure to brush your dog to get rid of the matted patches of fur that will occur after wearing such clothes.

Don't be deluded into thinking you are putting clothes on your dog because it is cold; you are doing it because you think it's cute. Your dog doesn't care about how it looks, but it can feel very uncomfortable when it overheats.