They may be pampered and well-groomed but there is something not quite right about the cream of the international dog world - and it is all in their poo, apparently.

Nutritionists made the shocking discovery while examining the dog toilet at Crufts in Birmingham yesterday, where thousands of pets and their owners have gathered to take part in the competition which has become the pinnacle of the canine calendar.

Richard Dancy, of Oscar Pet Foods, was joined by nutritionist Dr David Frape to take a closer look at the health of some of the show dogs, which involved rather delicate probing to try and get to the bottom of the matter.

"It needs to be not like marbles and not loose. It needs to have optimum moisture and bulk," Dr Frape explained as he prodded at a tray of dog faeces.

While judges are looking at the quality of fur, brightness of eyes and a good bone structure in the hundreds of classes taking place at the show, it was the poo Dr Frape was more interested in to decide whether he was looking at a really healthy dog.

Dr Frape, who has examined the faeces of a menagerie of animals from giant pandas to camels, said the real test in a dog's health could be found at its rear end.

"The idea is to assess the faeces, or stools, of dogs as a guide to its health. Obviously you take into account a whole series of observations including the clinical history of the animal and what it has been fed.

"The other important thing here is if dogs have chronic diarrhoea, vets should be brought in because the disease is transmissible to humans and if you have got children in the family the risk of them coming infected is quite considerable, and that becomes increasingly important in the modern world where we are living in close proximity to our pets."

Mr Dancy, who had been monitoring the dedicated dog toilet all morning, said many dogs at the show had not displayed the most healthy exhibits.

"You would think here at Crufts, where you have got some of the best dogs in the world, that they would have healthy faeces but I have seen a lot that aren't and I think the diets that they are fed on are not as good as they should be."

Holding up a series of cards of various types of dog stools, he added: "We have observed the dog toilet and there are lot like exhibit 1 (diarrhoea). It may be that they are nervous because they are in a strange place but I don't think they can all be like that.

"There was one German Shepherd with diarrhoea which was quite alarming as the breed is prone to allergies such as wheat and gluten and therefore can develop an upset stomach.

"We would think that all the dogs here, because they are representing the best dogs in the world, would have a good digestion."

With a note of warning to all pet owners, he added: "If we over-fill and treat our dogs to too much rich food, especially human foods like biscuits and scraps from our plate, it can be bad for them, especially over a long period of time."

As Mr Dancy continued to demonstrate a more healthy diet for dogs, Dr Frape, considered the country's leading animal nutritionist, described his analysis of the digestive system, highlighting the rather interesting aspect of camel stools.

"Camel poo is like ping pong balls, because they live in the desert they have to retain as much moisture as possible and so their faeces tend to be dry."