13.10.2020: A study presented by the Clever Dog Lab of Vetmeduni Vienna examined the extent to which a special nutritional plan has an effect on the mental aging of pet dogs. The surprising result: a diet enriched with food supplements has no positive effects, it does not lead to improvement in cognitive abilities in old dogs. In addition, even lifelong training seem not to have any effect on certain behavioural traits and cognitive abilities.

As we grow older, we experience a number of cognitive changes regarding stimulus processing, attention, memory, thinking, executive function for self-regulation and goal-oriented action control, personality, emotion and motivation. It is similar in pet dogs, where aging leads to a decline in learning, memory, attention, executive function, changes in social responsiveness and a reduced curiosity about novelty. Although there is a variety of research on the cognitive abilities of laboratory beagle dogs, very few studies have been conducted on aging in domestic dogs.

Four out of six cognitive abilities decrease with increasing age of dogs

A study on older pet dogs, presented by a research team from Vetmeduni Vienna and the University of Liverpool (Great Britain) showed that the ability to solve problems as well as sociability, boldness/courage and dependency on the owner decrease with age. To achieve their research goal, Durga Chapagain and their team enrolled 119 pet dogs of different breeds older than 6 years. Half of the dogs received a special diet (enriched with nutrients such as antioxidants, omega fatty acids, phosphatidylserine and tryptophane) while the others were given a control diet without supplements for a period of one year. The dog owners were also asked to report on previous training experiences of their dogs that they participated during their life time. After one year of dietary treatment, the researchers evaluated the dogs' behavior and cognitive measures in a newly developed test battery, the so-called Modified Vienna Canine Cognitive Battery (MVCCB).

According to Chapagain: "Our analyses show that with increasing age of the dogs, four of the six factors examined in the MVCCB decrease: Problem solving, Sociability, Boldness and Dependency. The two other factors, Trainability and Activity-independence show no change due to aging. Previous training experiences have no significant connection with any of the six factors.

Role of nutritional supplements is inconclusive for behavioural and cognitive aging

Interestingly, dogs maintained on an enriched diet for one year were no different than dogs fed with control diet when evaluated for changes in different cognitive and behavioural measures, indicating that the nutritional supplements on the enriched diet had no or least role in maintaining cognitive functions in aged pet dogs. The lead author of study, Chapagain says that as pet dogs vary so much and in different aspects, the results of this study showed that they would need a much bigger dog sample to firmly confirm whether or not enriched diet has any effect on cognition and behaviour. So, they would like to refrain from making a strong claim about the effectiveness of enriched diet here. According to the experts, before buying a certain dietary food for older dogs, dog owners should inform themselves in advance whether an appropriate food is suitable for their own animal.

Modified Vienna Canine Cognitive Battery (MVCCB): A useful tool to study age-related changes in dogs

According to the researchers, the results underscore the importance of using objective tests to detect changes in aging dogs. They emphasize that in the research settings, MVCCB is a useful tool to better identify age-related changes in pet dogs and that the creation of MVCCB is a first step in developing objective tests to identify dogs suffering from Canine Cognitive Dysfunction in the veterinary clinics. e. However, additional research with larger sample of pet dogs is needed to determine if and how training and enriched diet can affect aging in dogs.

The article "Behavioural and cognitive changes in aged pet dogs: No effects of an enriched diet and lifelong training" by Durga Chapagain, Lisa J. Wallis, Friederike Range, Nadja Affenzeller, Jessica Serra and Zsofia Viranyi was published in PLOS ONE.