BOAS syndrome

Professor Jane Ladlow from the UK is regarded as the world’s leading expert on BOAS syndrome, which involves breathing difficulties in short-skulled breeds. She and her team have developed a testing system to determine the severity of BOAS, employing a grading scheme that we started using in Norway in 2019.

The lawyer representing the NSPA, Emanuel Feinberg, didn’t want Professor Ladlow to show all the slides and videos in her presentation, but she was still given plenty of opportunity to explain the problems. She informed the court that BOAS can manifest itself differently from breed to breed, since there are many factors affecting the syndrome. Although the factors can vary according to the different breeds, the question of how open the nostrils are seems to be important in all breeds. She naturally focused primarily on English Bulldogs, which is one of the two breeds this case is about.

Muzzle length is less of a factor

In Bulldogs it is often the entrance to the trachea (windpipe) and soft palate that creates the biggest problems. The length of the dog’s muzzle seems to matter less than what was previously assumed. Open nostrils and the width of the head and throat are more important factors.

The BOAS test is performed by subjecting dogs to moderate exercise for three minutes, monitoring their breathing before and after. This amount of exertion is chosen because experience shows that symptoms will appear after approximately two minutes in dogs that are affected, not because three minutes is considered the maximum time a dog should tolerate. They are classified as having no signs of BOAS (grade 0), or having grade 1, 2 or 3. According to Ladlow, grade 3 dogs are in a completely separate category due to their serious health issues.
She also said that English Bulldogs have shown significant progress in the UK in the last ten years, and that breeders are conscientious about having their dogs tested, both for shows and otherwise. This applies first and foremost to breeders with registered dogs that also participate in shows.

“In the past you could hear snorting in the Bulldog ring at a show. You don’t anymore,” Ladlow observed.

She denied that crossbreeding automatically produces better dogs. “We have some examples in the UK that are worse than the original,” she pointed out. She firmly believes that there is variation in the phenotype, or visible features, of the Bulldog.

Feinberg wanted to know if Professor Ladlow thought breeders were “excluding” the most severely affected dogs from testing. Ladlow replied that this could well be the case but these dogs were not used for breeding, and breeders have become extremely competent and aware of the symptoms.

Testing for heart disease in Cavalier King Charles Spaniels

Jens Häggstrøm, vet and researcher at the Swedish University of Agricultural Sciences, works with heart disease in dogs, primarily in Cavalier King Charles Spaniels. A problem affecting the valves is the most common cause of heart disease in dogs, whatever the breed. In a large number of breeds you can hear a heart murmur in dogs over ten years of age, although most of them die from other age-related causes before developing serious symptoms. What is special about Cavaliers is that they develop heart disease earlier than many other breeds, and in some cases when they are quite young. It most often manifests itself when the dogs are six or seven years old.

“Just because a dog has a heart murmur doesn’t mean it will develop signs of disease. It’s difficult to identify signs in a preclinical phase,” Häggstrøm said.

In Sweden, the Swedish Kennel Club has introduced a compulsory screening programme for heart disease, and this has now also been done in Norway. What effect do such schemes have on dog health?

“If Swedish breeders want their puppies registered with the Swedish Kennel Club, they have to follow the rules. Screening has also been done in Denmark, but more on a voluntary basis. We still haven’t assessed the results in Sweden, but the figures from Denmark show that the offspring of free-tested parents develop heart disease later in life than average. As the heritability of this disease is relatively high, the conclusion is that selective breeding helps,” Häggstrøm remarked.

He also pointed out that according to life expectancy statistics for different breeds, Cavaliers live on average one year longer than other dogs.

SM and CM in Cavaliers

Clare Rushbridge is Professor of Neurology at the University of Surrey. She has studied chiari-like malformation (CM) and syringomyelia (SM) in Cavaliers since 1995. CM is found in more or less the whole population, but only a certain percentage develop clinical symptoms (CM-P). Usual symptoms include an uncontrollable urge to scratch the back of the head, with any contact with the head causing the dog to yelp or scream in pain. A number of dogs become passive and withdrawn, which is typical of dogs in pain. The disease is diagnosed once other causes of pain have been excluded.

Dr Rushbridge also explained the condition SM. The only accurate way of diagnosing the disease is through the use of MRI scanning. This also reveals SM in dogs without clinical symptoms. Approximately 20 to 22 percent of dogs with SM develop clinical symptoms (SM-S).
When asked, Clare Rushbridge replied that she didn’t think it was possible to breed away from the problem as too much of the population already has CM, with or without clinical symptoms. If you were to try to breed away from it, all dogs would have to be screened, and they must be screened when they have turned five. If these measures were taken, selective breeding could work. But it would be a big and difficult undertaking, and Professor Rushbridge had more faith in an outcrossing project. In any case, it would need to be done in a carefully monitored and controllable way, not by random crossbreeding.

What is good animal welfare?

Frode Lingaas is Professor of Genetics at the Norwegian University of Life Sciences (NMBU) in Ås. He began his presentation by raising the concept of “good animal welfare”, stating how difficult it was to define, with different limits being set for different species. Therefore, it is often difficult to define when a dog can be described as “sick” or “healthy”. It isn’t the case that everything that can be diagnosed in a dog automatically means poor animal welfare. Norwegian dogs are generally extremely healthy. Health examinations performed on Cavaliers in Norway show that about 86 percent of dog owners say that their dog is in “very good” or “good” health. 

“It is a fact you can’t just ignore – no one knows a dog better than its owner, or has a closer relationship with it,” Lingaas claimed.

Professor Lingaas has examined the claim that there is no genetic variation in the breeds English Bulldog and Cavalier. Referring to his own and others’ research, he observed that even if the genetic variation is not very significant, it does exist, and is much more significant than in most inbred breeds we know of, such as the Norwegian Lundehund.

“If we are to achieve progress through breeding, two conditions must be present. The trait must be hereditary, and there must be variation in the genes. As far as these two breeds are concerned, we see signs of variation, the traits are hereditary, and that means progress is possible,” he affirmed.

He also brought up the major challenges on a purely administrative level that would result from a breed ban and from crossbreeding.

“What actually is a crossbred? A dog that is one percent one breed and 99 percent another? What are the requirements and documentation for this being better animal welfare? There’s a lack of definitions and percentages. What is the result of a publicly organised crossing project meant to be? Does it lead to better animal welfare? These are questions that should be addressed beforehand. Taking into consideration the health and welfare of the individual breeding animal is the preferable path to choose. In my opinion, the new proposal for breeding regulations being considered by the Norwegian Food Safety Authority offers better solutions,” remarked Lingaas. Of all the expert witness, he was asked the most questions by the court’s judges.

Breeding of production animals versus dog breeding

Odd Vangen is also a professor at NMBU, and has mostly worked with the breeding of production animals.  He explained the consequences of inbreeding: inbreeding depression, which is a general decline in fertility and health, and an accumulation of genetic defects as a result of the parents having single genes. He referred to the differences between breeding production animals and dog breeding. With the breeding of production animals, line breeding is avoided. Selection takes place through programmes where you balance the selection of desirable traits and genetic breadth. The father animal is owned by the community, and the individual farmer doesn’t personally choose which male animal is used.

When it comes to the diseases affecting Cavaliers and English Bulldogs, Vangen said that the likelihood of being able to breed away from these problems depends on how much genetic variation remains in the breed, what the choice there is, and how fast it goes. If you have many thousand animals to choose from, it isn’t hard to breed in the opposite direction of where the disease is. The chances of success also depend on the effective population, how many individuals are used for breeding, and the variation over generations. Many breeds are a result of inbreeding, and all breeds go in cycles of popularity. If they become less popular, this creates genetic bottlenecks.

“Some breeds should die out. If there is a high frequency of disease and low genetic variation, you have no choice but to add new genetic material. Dog breeding is conservative, and the breed concept is more entrenched there than in production animals,” Vangen remarked.

Anette Fjeld, the lawyer representing the NKK, asked why Vangen, who is active in the public debate about dog breeding, hadn’t published any of his own research on this. Vangen replied that he didn’t consider himself an authority on international literature on the subject, and that the NKK hadn’t shown any interest in him as a contributor to the debate. 

When asked whether the breeding of production animals was the “gold standard” that everyone else should strive for, he remarked that the breeding of production animals was not problem-free either, and that kinship and inbreeding were also common in this area. He thinks that one of the challenges of dog breeding is that many populations are small, but he said that there were tools from the breeding of production animals that could easily be transferred dog breeding if the will existed, even though hobby breeding is more complicated. There would be a fine balance between animal ownership and communal decisions. “If breeding goes in the right direction, there will be a noticeable improvement,” Vangen concluded.

Genetic variation – or not?

The final expert witness of the day was Professor Dannika Bannasch from the University of California. She went into great detail about the different research into genetic variation in the two breeds in question, and had a somewhat different view from Frode Lingaas when it comes to being able to breed away from the previously mentioned diseases. 

She was asked whether her figures were relevant for the Norwegian populations of Cavaliers and English Bulldogs. She replied that both breeds became established in the UK, their ancestors come from there, and there is no evidence of different genetic variation in the populations of different countries.

“Inbreeding isn’t something that happens to a great extent nowadays. It happened when the two breeds became established more than a hundred years ago,” Professor Bannasch remarked.

Day 4
On day four of the appeal, five more expert witnesses will give evidence, including Torunn Knævelsrud from the Norwegian Food and Safety Authority. The appellants’ lawyer will start her closing arguments towards the end of the day and continue on Friday.