THERE is life in the old dog yet – or there should be if it receives the vital combination of high-quality food, careful management and prompt veterinary attention, a major US study has shown.
The results of a 10-year experiment at pet food manufacturer Eukanuba’s Cincinnati research kennels were described at a round-table discussion in London on 25th September.
A total of 39 adult Labrador retrievers, 27 bitches and 12 dogs were enrolled in the study which began in July 2004. The animals were healthy with a mean age of 6.7 years and were all former breeding stock obtained from approved kennels.
Among this group, 90% reached the typical life-expectancy for the breed of 12 years, with 66% living to an advanced age of between 13 years one month and 15 years five months, while 28% achieved an “exceptional lifespan” above that range. Indeed, the oldest dog standing, a golden Labrador named Bunny, has just reached the 17 years and two months milestone, said David Morgan, the company’s scientific communications manager.
Acclimatisation
Before entering the study, all the dogs went through an acclimatisation period during which they were neutered and their food intake was adjusted to achieve the required body condition score of between 2 and 4 on a standard five-point scale.
The diet was based on the company’s standard commercial product for mature dogs and they were given plenty of exercise, with opportunities to interact with both their care-givers and each other, and regular veterinary examinations, he said.
Professor Stuart Carmichael of the Surrey veterinary school and former Kennel Club chairman Professor Steve Dean were invited to inspect the dogs at the research centre when all the survivors were between 15 and 17 years old. Both veterinary surgeons maintained that they had been initially sceptical about the claims relating to the group’s remarkable good health and advanced longevity.
Said Prof. Carmichael: “I have a picture in my mind of what a 17-yearold Labrador would look like – and it certainly wasn’t how these dogs were that I saw running about. Yes, some of them did have minor problems but they looked happy and healthy and they were able to exercise.”
Prof. Dean was equally impressed that the food manufacturer did not suggest that its products were the sole reason for the dogs’ healthy state. “They emphasised that diet was just one thing within the owner’s control that would influence longevity – good husbandry and prompt veterinary attention were just as important.” Prof. Carmichael noted that the veterinary care offered was good but not exceptional.
Most dogs that exited the trial did so due to cancer: they were given palliative treatment until the regular quality of life assessments indicated that the animal should be euthanased. But they did not receive surgery, chemo- or radiotherapy for the condition.
The important factor for these animals was that any treatment was given promptly, whereas many clients would delay taking their dogs to their veterinary practice. The extended period of good health experienced by the dogs highlights the misconception among many owners that ill health is an inevitable consequence of age.
“These animals were not only living longer, they were living better,” Prof. Dean said. “What owners really want is a dog that can live to 16 years and stay healthy. They don’t want one that reaches 12 and becomes gradually more decrepit until the decision is made for euthanasia. They want the dog to have a high plateau of goodquality life right until it drops off the edge in the last few months.”
To achieve the same results, many veterinarians will have to reconsider their approach to dealing with a geriatric dog, suggested Dr Penny Watson of the Cambridge veterinary school and another member of the expert panel reviewing the company’s findings.
Need to stick with high quality
Many practitioners are still recommending low protein diets for older animals in the belief that this reduces the load on the dog’s kidneys. Instead, the study provides further evidence of the need to continue providing highquality protein to maintain the dog’s lean body mass.
Previous studies have demonstrated that about 30% of the factors determining longevity in a dog will be genetic, but vets can offer advice on modifying the factors accounting for the remaining 70%, like exercise, diet and general husbandry.
Dr Watson hoped that the study could be the first of several longterm studies that would tease out how these various factors interact and allow vets to offer advice more specifically tailored to the breed and individual dog.
“We need studies that produce reliable evidence: we have relied too long on popular anecdote,” she said, adding that this individualised advice would have to take into account the life-stage of the dog.
“While it is accepted that obesity is a risk factor for many diseases, there is a paradox that body condition is protective against a number of conditions in older dogs. It is the younger dogs that must not be overweight.”
One issue that will need to be reassessed is age at neutering, the panel agreed. This group of long-lived dogs were spayed or castrated late in life and there is increasing evidence that a fully functional reproductive system is highly advantageous in extending the dog’s life-span.
So it may be prudent to assess the dog’s breed, home environment and expected lifestyle before resorting to surgery. There is likely to be an increasing range of products that prevent the dog reproducing while allowing it to remain entire, Dr Vicki Adams, a veterinary epidemiologist, suggested.
Obesity is a major factor contributing to a lower than expected lifespan for many companion animals. Prof. Dean noted that dry dog food has been a blessing for dog owners in many respects but causes problems because owners cannot believe that the small amount of kibble on the bottom of their dog’s bowl will satisfy its hunger. He recommends that the owners should see for themselves by soaking the food in water and allowing it to expand.
Former practitioner and cat owner Debra Bourne felt that vets should persuade pet owners that they can show love for the animal by increasing its enjoyment of its food but reducing the amount offered. Both cats and dogs will obtain satisfaction from playing with toys that will dispense small amounts of food at a time.
As those small quantities of food swell in the stomach, they will set off its innate satiety response and there is less likelihood that the pet will wolf down the food only to vomit it back up, she said.
David Morgan said that a paper describing the main findings of the study was nearing completion and would be submitted for publication soon. He hoped this would be the first of many such papers as there are large quantities of data still to be analysed, notably from the annual DEXA (dualenergy x-ray absorptiometry) scans carried out under general anaesthetic which analysed the dogs’ body composition.
He was optimistic that these findings would contribute significant information which will change the recommendations that veterinarians give to their clients and result in the pets living longer and healthier lives.
