Table of Contents - Topics
Dr. Jerold Bell |
|
Bryden J Stanley, BVMS, MACVSc, MVetSc |
|
Dr. Rebecca Windsor DVM, DACVIM (neurology) |
Genetic Diversity of the Pug Dog
Lecture presented at the 2021 PDCA (Pug Dog Club of America) National Specialty by Dr. Jerold Bell
Download lecture:
Download lecture:
| genetic_overview_of_pug_dog_lecture.pdf |
BREEDING FOR HOMOZYGOSITY
Favorite question from the lecture: "Are absolute levels of breed homozygosity and differences in homozygosity between individual dogs important?" (Yes or No). "Why?" "Why is homozygosity within the breed or between individuals important?" Maintaining traits etc., yes, BUT ...
Homozygosity can come with issues - it can uncover detrimental recessives in the background as carriers can pair through homo. up with can create disease or fetal abnormalities, smaller litter sizes. Ultrasounds weren't always around .... since the use of this tool it showed much more fetal absorption compared when just using the xray at day 48.
Studies of dog breeds estimate that they lose on average 35% of their genetic diversity through breed formation (and he says it's actually much more than just a 3rd). In breed selection as you discard all the things you don't like ... there is a lot more lost than just a 3rd.
Any selection over generations will create:
But breeding purebred dogs involves selection. (see below *)
Common thinking today: "We can't lose genetic diversity ... that's the worst thing we can possibly do .. especially small population breeds are up in arms about genetic diversity and should they use systems that are involved to rescue endangered species etc. etc."
Breed defining genes would be expected to become homozygous due to selection over time. These include breed-selected traits for size, coat color and texture, behavior, skeletalmorphology, and other traits.
Even without close linebreeding, selection for positive traits will increase their homozygosity having originated from distant ancestors.
Modern Breed population Statistics:
Unfortunately, pug breed database is truncated and really only goes back to around 1970s or late 1960s.
*These are necessary and expected consequence of breed formation and evolution.
Favorite question from the lecture: "Are absolute levels of breed homozygosity and differences in homozygosity between individual dogs important?" (Yes or No). "Why?" "Why is homozygosity within the breed or between individuals important?" Maintaining traits etc., yes, BUT ...
Homozygosity can come with issues - it can uncover detrimental recessives in the background as carriers can pair through homo. up with can create disease or fetal abnormalities, smaller litter sizes. Ultrasounds weren't always around .... since the use of this tool it showed much more fetal absorption compared when just using the xray at day 48.
Studies of dog breeds estimate that they lose on average 35% of their genetic diversity through breed formation (and he says it's actually much more than just a 3rd). In breed selection as you discard all the things you don't like ... there is a lot more lost than just a 3rd.
Any selection over generations will create:
- Homozygosity - uniform purposeful selection for breeding goals
- Diminished frequencies of undesirable genes
But breeding purebred dogs involves selection. (see below *)
Common thinking today: "We can't lose genetic diversity ... that's the worst thing we can possibly do .. especially small population breeds are up in arms about genetic diversity and should they use systems that are involved to rescue endangered species etc. etc."
Breed defining genes would be expected to become homozygous due to selection over time. These include breed-selected traits for size, coat color and texture, behavior, skeletalmorphology, and other traits.
Even without close linebreeding, selection for positive traits will increase their homozygosity having originated from distant ancestors.
Modern Breed population Statistics:
- High deep pedigree average inbreeding coefficients (homozygosity)
- Low effective population size (limited number of founders)
- High average relationship coefficients to influential ancestors
- These ancestors appear in the pedigrees of every member of the breed, with genetic contributions of 15%-35%.
Unfortunately, pug breed database is truncated and really only goes back to around 1970s or late 1960s.
*These are necessary and expected consequence of breed formation and evolution.
BOAS
Brachycephalicism - Breeds such as Bulldogs (English and French), Boston Terriers, Pugs, Pekinese, Shi Tzus, Lhasa Apsos, have been selectively bred for short muzzles. This desire for a flat face and foreshortened skull has resulted in the brachycephalic breeds having a plethora of primary anatomical abnormalities that compromise their ability to breathe. Veterinarians are faced with the challenge of ameliorating the quality of living for these compromised little dogs.
Click below for a summary of the lecture regarding the new insights into the Brachycephalic predicament as explained by Bryden J Stanley, BVMS, MACVSc, MVetSc, Diplomate ACVS Michigan State University, at the 2018 PDCA National Specialty Health Seminar (attended by Amy McLelland of Pickwick Pugs)
Click below for a summary of the lecture regarding the new insights into the Brachycephalic predicament as explained by Bryden J Stanley, BVMS, MACVSc, MVetSc, Diplomate ACVS Michigan State University, at the 2018 PDCA National Specialty Health Seminar (attended by Amy McLelland of Pickwick Pugs)
| brachycephalic_stanley.pdf_summary_of_lecture.pdf |
or click below to download the complete lecture (allow time for the download as it is a large file).
| brachycephalic_pug_club_2018_pdf.pdf |
video of power point graphics:
Doctors Frank and Cujdik presented a seminar at the 2023 PDCA National Specialty on BOAS as well as conducted health screening for 2 solid days.
Pickwick's Mr. High Falutin' (Mr. Drysdale) completed the BOAS health screening which consisted of a thorough examination, listening with a digital stethoscope, before and after a brisk walk (the length of the huge hotel) and received the best score possible of a "zero", meaning he showed no signs of any BOAS issues. Since he is just shy of a year of age, he did not qualify for an OFA certificate but we will be repeating the screening throughout his life if he participates in our breeding program.
It was interesting to note from the lecture that it is not possible to hear the respiratory problems without a stethoscope for grades of 1 and 2. By the time you can hear the breathing noises (without a stethoscope) the dog is in more significant distress and would receive a grade of 3. So, just because you can't necessarily hear problems with the naked ear and without assistance of a stethoscope, does not mean the pug is not dealing with issues such as elongated soft palate. Panting is ok ... it's natural and normal for any dog. What you don't want to hear is a "wet" noise in the panting along with other sounds for different conditions. Notes from the 2023 lecture posted here soon.
Here are video examples which were shared during the lecture of the different grades.
Here are video examples which were shared during the lecture of the different grades.
BOAS Functional Grading System Grade 0
BOAS Functional Grading System Grade 1
BOAS Functional Grading System Grade 2
BOAS Functional Grading System Grade 3
BOAS Pharyngeal Noise
PDE
"Finding a Cure for Pug Dog Encephalitis", 2022 National Health Seminar at the PDCA (Pug Dog Club of America) National Specialty, presented by Dr. Rebecca Windsor DVM, DACVIM (Neurology). She also presented a lecture at the 2023 PDCA Nationals in Virginia Beach and 3 Pickwick pugs participated in the research testing.
Eliza, Emma, and Mr. Drysdale participated in the PDE study. They showed no signs of PDE in the examination but they will be a part of the study in helping with statistics in comparison with other pugs who suffer from this horrible disease. The trial is paid for by a wonderful nonprofit, Ethos Discovery, and led by Dr. Rebecca Windsor. With every exam they complete, they are able to learn more about the rate of occurrence of this devastating disease. Additionally, the opportunity to test for the early form of PDE, with the screening exam we participated in, allows them to identify and treat dogs with this early form of the disease in hopes of preventing them from developing the severe and fatal symptoms of PDE. To learn more about this trial, you can visit their website. Ethos PDE trial. To learn more about Ethos Discovery, a 501(c)3 nonprofit incubator of scientific innovation (who covers ALL costs associated with this clinical trial ... which involves stem cell therapy and $25,000 + per pugs with PDE being treated), and their mission to "improve health outcomes for humans and animals with complex medical problems", you can visit ethosdiscovery.org.
Here is Dr. Windsor's presentation at the 2022 PDCA National Specialty:
Eliza, Emma, and Mr. Drysdale participated in the PDE study. They showed no signs of PDE in the examination but they will be a part of the study in helping with statistics in comparison with other pugs who suffer from this horrible disease. The trial is paid for by a wonderful nonprofit, Ethos Discovery, and led by Dr. Rebecca Windsor. With every exam they complete, they are able to learn more about the rate of occurrence of this devastating disease. Additionally, the opportunity to test for the early form of PDE, with the screening exam we participated in, allows them to identify and treat dogs with this early form of the disease in hopes of preventing them from developing the severe and fatal symptoms of PDE. To learn more about this trial, you can visit their website. Ethos PDE trial. To learn more about Ethos Discovery, a 501(c)3 nonprofit incubator of scientific innovation (who covers ALL costs associated with this clinical trial ... which involves stem cell therapy and $25,000 + per pugs with PDE being treated), and their mission to "improve health outcomes for humans and animals with complex medical problems", you can visit ethosdiscovery.org.
Here is Dr. Windsor's presentation at the 2022 PDCA National Specialty:
