This website will no longer be updated.

Thank you for all of your support! Please visit me at the new URL, - See you there!

Tuesday, December 22, 2020

Training Troubles: Aversive Methods Compromise Canine Welfare

    Anyone that has ever owned an unruly dog knows the importance of training to behavioral management. In fact, behavior concerns are one of the number one reasons that both dogs and cats are surrendered to shelters or rehomed. There are many ways to train a dog, and much as in the realms of religion, politics, and parenting, every pet owner and professional will have methods that they insist are the right way. This has more recently become a topic of contention in animal welfare circles. Positive reinforcement training (explained further below) has become increasingly popular among veterinary professionals and in zoo settings. The 'Fear Free' movement, founded in 2016 by veterinarian Dr. Marty Becker, has blossomed into a community of pet professionals dedicated to reducing fear, stress, and anxiety in all walks of companion animal interactions. Despite the popularity of 'R+' strategies in animal professional circles, trainers using aversive methods have persisted, and these methods are often hotly defended by users. Evidence-based recommendations have also been hard to come by-- a 2017 literature review found that the current available body of evidence does not strongly support that negative outcomes are associated with aversive methods. However, a new study, published December 2020 in PLOS One, provides "the first empirical study to systematically investigate the effects of different training methods on the welfare of companion dogs within and outside the training context."

Before circling back to the findings of the new study, a brief review of operant conditioning is in order. Training methods can be divided into quadrants based on what is done and why it is done. Positive and negative refer to whether a stimulus is given or taken away. Reinforcement and punishment refer to whether the intent is to increase a behavior or decrease a behavior, respectively. These combinations create the following descriptions:

Positive punishment is the addition of an aversive stimuli to reduce an unwanted behavior. For example, the unpleasant sensation of prongs against a dog's neck when pulling at the leash on a prong collar. 

Negative punishment is the removal of a desired stimuli to reduce an unwanted behavior. For example, no longer walking forward when a dog pulls. 

Positive reinforcement is the addition of a desired stimuli to increase a wanted behavior. For example, giving a dog treats when they walk with slack in the leash. 

Negative reinforcement is the removal of an aversive stimuli to increase a wanted behavior. For example, the unpleasant sensation of prong's against a dog's neck going away when they stop pulling and walk with slack in the leash. 

    The study in question sought to answer the question of whether or not aversive training methods (positive punishment and negative reinforcement) negatively impact the welfare of dogs. The answer they arrived at is yes, that these methods induce stress and impact canine mindset even outside of a training setting. This study is open access and can be read online for free. Here are the highlights:

Methods & Sample:
  • Study authors recruited 7 canine training schools
    • Schools were classified into 'aversive,' 'mixed,' or 'reward' based on the frequency with which each of the four methods discussed above were employed during six randomly selected video training sessions from each school.  
  • Head trainers at each school were asked to indicate dogs that met inclusive criteria: new to the school (less than 2 months in training) and free of underlying conditions/concerns that could increase stress (aggression, separation anxiety, etc). 
    • The final sample size consisted of 92 dogs, 28 at Aversive schools, 22 from Mixed schools, and 42 from Reward schools. Only 79 of this sample participated in the cognitive bias task. 
  • Animal welfare was evaluated both in a training setting and in a non-training setting
    • During training sessions, the first 15 minutes of the session were recorded on three different occasions for each individual dog. These recordings were evaluated for behaviors associated with stress, such as lip licking. Observers were blind to the training classification of the school when evaluating display of stress related behaviors. 
    • Saliva samples were collected from the participating dogs to measure cortisol levels, a hormone positively correlated with stress
  • To evaluate welfare outside of the training setting, dogs were made to perform a cognitive bias task.
    • This test evaluated the time taken by a dog to approach an empty food bowl in a location that had previously been associated with either an empty or a full food bowl. 
    • Dogs in a positive affective state are expected to be eager to seek out a potential reward, while dogs in a less positive affective state are expected to take longer in the same scenario to seek out the same reward
  • Behavior during training session
    • A strong association between the Aversive group and frequency of stress-related behavior displays, such as yawning and lip-licking was noted
    • Tense behavioral states were seen more frequently in the Aversive and Mixed group than Reward group
  • Cortisol levels
    • Cortisol levels were significantly higher in the Aversive group when compared to the Reward group
  • Cognitive Bias test
    • Dogs from the Aversive group were slower to seek out an anticipated reward than dogs from the Reward group. 
    • This suggests a lower affective state, associated with negative welfare

The authors conclude:
Overall, our results show that companion dogs trained with aversive-based methods experienced poorer welfare during training sessions than dogs trained with reward-based methods. Additionally, dogs trained with higher proportions of aversive-based methods experienced poorer welfare outside the training context than dogs trained with reward-based methods. Moreover, whereas different proportions of aversive-based methods did not result in differences in dog welfare outside the training context among aversive-based schools, a higher proportion of aversive-based methods resulted in poorer welfare during training. To our knowledge, this is the first comprehensive and systematic study to evaluate and report the effects of dog training methods on companion dog welfare. Critically, our study points to the fact that the welfare of companion dogs trained with aversive-based methods is at risk, especially if these are used in high proportions. 

In other words, aversive methods negatively impact the psychological state of dogs, and therefore their welfare. This further supports previous studies that have suggested as much. 

Follow me on Social Media: @AllTradesDVM

Facebook     Twitter     

Find a Fear Free Professional Near You

Monday, December 21, 2020

Another New Study Links DCM and Diet (Dec 2020)

Published in the Journal of Veterinary Internal Medicine, a retrospective analysis has again affirmed a link between certain diet types and dilated cardiomyopathy. Among the authors is Dr. Lisa Freeman, a veterinary nutritionist who has been closely working on this emerging issue since it was brought to public attention in 2018. This study was funded by Tufts' "Barkley Fund," established by the owners of a late Great Dane to further support and promote ever-improving care for dogs with heart disease. As a retrospective study, this paper has numerous limitations that the authors acknowledge. Furthermore, it does not establish a definitive causal relationship between diet and the development of DCM. Scientific establishment of such a causal relationship, if it exists, will require findings from the ongoing prospective studies that are occurring at multiple institutions. In the meantime, a correlation between diet types and DCM continues to be identified, warranting vigilance from the veterinary community, pet owners, and the pet food industry. 

The study is open access, meaning that anyone can read it online for free! You can use the hyperlink above to open it yourself. While the paper is accessible in terms of being free to read, the language of an academic paper can be intimidating for people outside of the field or profession. Here are the important highlights for pet owners and other concerned members of the public:

Methods & Sample:
  • This study collected and analyzed records from dogs seen at the Tufts veterinary hospital by the cardiology or nutrition service and newly diagnosed with DCM between 2014 and 2018. 
  • Dogs were grouped by traditional and non-traditional diet, as well as whether or not they changed diet following diagnosis
    • Traditional diets (TD) were grain-inclusive extruded (kibble) diets that did not contain peas/lentils/potatoes in the to 10 ingredients and are produced by manufacturers that meet the WSAVA recommendations for selecting a pet food
    • Non-traditional diets (NTD) were grain-free, contained peas/lentils/potatoes in the top 10 ingredients, or are not produced by manufacturers that meet the WSAVA recommendations for selecting a pet food
  • 71 dogs were included
    • 56 were eating NTD at time of diagnosis and 15 were eating TD
    • 18 breeds were represented total
  • Among dogs eating non-traditional diets, those that changed diet had a significantly longer average survival time (337 days) than those that did not (215 days).
  • Functional cardiac improvement was seen in dogs eating a NTD at time of diagnosis that switched to a TD. 
  • The number of dogs diagnosed with DCM at this specific hospital has increased over time.
The authors close the paper: "Our results are consistent with the results of 2 previous studies suggesting that in dogs with DCM eating nontraditional diets, diet change can be associated with significant improvement in some echocardiographic measurements. In addition, dogs eating nontraditional diets that had their diets changed had a significantly longer survival time compared with those that did not have their diets changed. The underlying cause and mechanisms of diet‐associated DCM are still not understood, but our findings emphasize the importance of prospective studies to better understand this issue as soon as possible."

Saturday, December 12, 2020

I Didn't Get in to Vet School: What Next?

     Every year, there are more prospective veterinary students than seats in veterinary programs. In fact, some schools have an applicant to seat ratio of over 15! It's an unfortunate reality and the underlying reason that many bright, qualified people will receive disappointing emails, letters, or calls in the coming months. If you're among them, don't fret! The results of your application cycle are not a reflection of you, your abilities, or your worthiness. Sometimes it truly is just bad luck in a system that cannot accommodate everyone every year. Consider these next steps:

1. Allow yourself to grieve as needed, but don't be too discouraged. 

It's hard to face rejection, and it's okay to feel sad, disappointed, or discouraged. Allow yourself to experience those emotions, but don't dwell in them! Many successful veterinarians took more than one try to get accepted to their program, and a gap year can be a wonderful thing. Keep an eye out later this month for an upcoming series of interviews with current veterinary students discussing how a gap year benefited them. I personally had a gap year after not being accepted to a program, and I would not change it in hindsight, even if I somehow could. 

2. Contact the programs you applied to and ask for a packet review.

Most, if not all programs will allow you to call and have your application packet reviewed for deficiencies or weaknesses. Sometimes, strong applicants are denied for the sole reason that there just aren't enough seats. Usually, though, schools will be able to offer at least one concrete area for improvement. Take this criticism constructively, and try to identify any areas of overlap if you were rejected from multiple schools. If you're unsure who to contact, the AAVMC has a list of admissions emails for each veterinary school. 

3. Equipped with information from your packet review, create an action plan for improvement. 

  • GPA

  GPA is possibly the most difficult to address, and the best approach depends on how deficient your GPA is relative to what the school is asking for, as well as what point in your education that you're in. If a school lets you know that GPA was the weakest part of your application, but that it wasn't disqualifying, it may be worth just trying again next year. If your GPA is disqualifying (ie 2.95 and a school requires a 3.0 or higher) then you may need to consider taking additional non-degree seeking courses or enrolling in a Masters program. There are one and two year Masters programs out there, and may can be completed primarily online. Another option is seeking out schools with lower GPA criteria for admissions. These schools place more weight on other aspects of your application, and may be a better fit if you don't want to continue taking additional classes. 

  • Essays

  If the biggest complaint your prospective program has is your essays, the good news is that essays are very easy to improve! You may get generic feedback such as 'the essays in your application were not very strong.' If the school does not offer anything more specific than that, your first step should be to have your essays reviewed by people you trust-- an academic mentor, a veterinary colleague, or a family member or friend. If you don't have anyone to ask, you can always reach out on forums such as the APVMA Facebook Group or Student Doctor Network. I'm also happy to review essays (you can send to It may be helpful to write entirely new essays, rather than trying to build around your initial ones. You may also find that you've changed since your application was submitted and you have new ways to address the prompts. As we approach the opening of the next application cycle, I'll post an article on essay tips.

  • Letters of Recommendation

 An admissions committee may tell you that your eLORs weren't up to snuff-- and this is hard to hear! If you are told you need better recommendations, reach out to the people who wrote them for you. Have a conversation about what went wrong; do they need to see something more from you to write a stronger recommendation, are they new to writing recommendation letters, etc. If you aren't comfortable having this conversation, which can be tough, you may need to reconsider who you get letters from this next cycle. Regardless which program you apply to, at least one LOR should be from a veterinarian. If you only have a close relationship with one veterinarian, your options are discussing the initial letter with them or shadowing under a new veterinarian before next cycle applications are due. Other strong options for letters include: employers/managers, instructors for extracurricular activities (band, dance, etc), academic advisors, and professors. Building relationships and networking can be difficult, but it is essential for gaining strong recommendations, and it is a good skill to begin developing now, as it will continue to be essential in your career. 

  • Experience

 A gap year is the perfect opportunity to build on this aspect of your application. During my gap year, I took a job working ass a technician at an emergency veterinary clinic. You can look for a job, seek out shadowing opportunities (just ask!), pursue research (talk to the faculty at your undergraduate institution, if you can), or otherwise buff up your resume. You can also revisit what you included in your experiences. Did you include everything? I am a strong proponent of including anything that shaped you as a person, built your character, or otherwise contributed to your identity and life perspectives. Marching band. Dance. ROTC. High school debate club. Working as a server. Working in retail. Working as a babysitter. These things teach leadership, teamwork, responsibility, they demonstrate reliability, dedication, and work ethic. Every person applying will have some level of animal hours, veterinary hours, and sometimes research hours. Extracurricular hours are what will set you apart as a unique and diverse individual that brings a mix of experiences to the table that no one else has. Show off who you are through the experiences section of your application. Truly, do not leave anything off that you spent a substantial portion of your life ( >100-200 hours) doing. 

4. Consider applying to some different schools.  

There are a number of factors to consider when you're applying to veterinary program. If you find that there is something difficult to address barring you from a specific school (such as GPA), consider scrapping that school from your list next year. It's a good idea to re-apply to your top preference programs, because a repeat application alone can work in your favor. However, if a school reports that your GPA would need to be substantially higher for consideration, or you would need more additional hours than you can gain in one cycle, put the time, effort, and money of applying into a different program. 

5. Make the most of your year off!

Veterinary school is going to be an intense, very devoted period of your life. Use your unintended gap year as an opportunity to travel, to work, or to generally pursue personal wellness. Of course you'll need to work on aspects of your application packet, but that doesn't need to exclude chasing happiness, too. Ultimately, one year or two years is a drop in the bucket of your professional journey. It'll be okay that you start later than you anticipated. 


Current veterinarians and veterinary students: What other advice would you offer to those who received rejections this year?

Thanks for reading! 

 Follow me on Social Media: @AllTradesDVM

Facebook     Twitter     


Saturday, December 5, 2020

Shady Science? DCM Research and Expression of Concern

    This piece should be prefaced by saying that PLOS One's commitment to transparency and diligence in maintaining scientific integrity is commendable. Their timeline in following-up on this particular issue, however, is disappointing and has left many pet owners confused. In May 2020, new research was published evaluating correlation between diet types and heart size parameters in Golden Retriever. This research had an 'Expression of Concern' added to it four months later, in September: 

"The article is being reassessed in light of issues raised post-publication, and the journal is investigating the validity of the concerns raised as well as their implications for the reliability of the article’s conclusions. Meanwhile, the PLOS ONE Editors issue this Expression of Concern."

    Now three months later, no additional updates have been issued. While the PLOS ONE editors explicitly stated that the very validity of the raised concerns was under investigation, this addition has not stopped various parties from using this Expression to delegitimize the research and dismiss the concerns surrounding grain-free and boutique diets. In the interest in providing a balanced narrative, each concern should be individually examined. It is imperative that the conversation not be dominated by misplaced dissent. The current study provides one more piece to the puzzle, and will hopefully not find itself unduly compromised by an unreasonable expectation of perfection.

    The possible origin of the alleged concerns is worthy of note. They closely mirror those presented in a Pet Food Industry article authored by Dr. Ryan Yamka, PhD, owner of a pet food consulting group and co-founder of Guardian Pet Foods.  At the end of his article, Dr. Yamka indicates he had written to PLOS, and he includes a reference number for his case: 06641324. He welcomes readers to cite it if they decide to follow suit and write a letter themselves. The concerns published by PLOS One are as follows.

"Questions were raised around the criteria used to categorize diets, including about the rationale of including global company sales details in these criteria given the objectives of the study."

    The rationale for the criteria used was explained extensively by the authors in the ‘Materials and Methods,’ section as well as the ‘Discussion.’ Guided by clinical experience as well as the previous findings from the FDA’s preliminary report , the authors defined the categories on the basis of pulse legume content (represented in 93% of cases reported to the FDA), absence of grains (represented in 91% of cases reported to the FDA), and manufacturer size (inversely correlated with prevalence of case reports). The decision to use global company sales as a criteria, which was of particular interest in the expressed concern, has a precedent in earlier commercial pet food research, namely a 2014 study in JAVMA that assessed thiamine concentrations in canned cat foods. That study utilized the same criteria and did find a significant difference in thiamine concentration in foods produced by smaller companies.
    To further characterize the rationale for including sales as a criteria, it is helpful to closely assess the data reported from the FDA in the context of the annual revenue of those companies. As the authors of the current study noted, there appears to be an inverse relationship between the number of cases reported to the FDA and market share held by the manufacturing companies. In the June 2019 update, the FDA’s update included a graph representing brands with ten or more reports associated, totaling 431 reports. Of those 16 brands, 8 brands associated with 236 reports are produced by companies with less than $1 billion annual revenue, 4 brands associated with 145 reports are produced by companies with between $1 and $2 billion, and the remaining 4 brands associated with 50 reports are produced by companies with greater than $2 billion. Further evaluation of those 4 brands from the largest companies also supports the trend. While Nutro and California Natural are owned by Mars Pet Care, their individual sales are each less than $1 billion of the company’s $18 billion revenue. Given the study’s objectives, which included evaluation of differences in taurine and echocardiographic parameters in association with diet in light of the FDA’s investigation, these criteria are entirely justified.

"Concerns were raised about potential confounds in the study, for example due to the inclusion of adult, puppy, and prescription-only foods, and due to inclusion of raw and kibble diets in the non-traditional group whereas the traditional group only included kibble"

    While an argument could be made that exclusion of raw diets would have been more appropriate, it is expected that if they were included, they would not be included with traditional diets, because they are not traditional. Commercially available raw diets are a relatively modern development. Raw diets have been reported to the FDA in associated with development of DCM.  That said, many dogs are fed combination diets, and it’s likely that many of the dogs consuming raw foods were also consuming kibble diets in conjunction. While this presents a limitation to the study (and indeed, was discussed as a limitation by the authors), it does not invalidate the findings nor render them less useful. Further studies could better elucidate the differences between non-traditional kibble alone, raw alone, and combination diets of both.
    The inclusion of puppy food only pertained to two diets included in the sample, and one of those was labeled for all life stages. The prescription diets also meet the criteria for ‘traditional diets’ and are labeled as complete and balanced adult maintenance diets per AAFCO feeding trials. As the diets in question still met the criteria outlined for the purposes of the study, it isn’t problematic that they were included. Furthermore, their exclusion likely would not change the results and conclusions, as they represent such a small portion of the sample size. This study was concerned with overarching data trends, not individual points of data. The sample groups represent real dogs presented to the clinic for wellness checks. While these criticisms would be warranted for a randomized double-blind laboratory controlled study, applying them toward a study of this nature, a case-controlled study on publicly owned animals, is misplaced.

"Soybeans are in the legume family, but soybeans and soy products were not considered as legumes for the purpose of categorizing diets in this study. The authors have requested a correction to clarify that this was an intentional exclusion, and they have noted that this aspect of the study design aligned with how soy products are being handled in a related FDA investigation."

    The authors adequately addressed this concern. 

"Questions were raised about the statistical analyses reported in the article."

    The current study utilized typical, widely employed statistical analyses. This included not only the data means, standard deviations, and p-testing (null hypothesis significance testing) but also appropriate, more specific analyses: Fisher’s exact test and Spearman’s Rank-order correlation evaluation. Fisher’s exact test, which is intended to examine significant association between two different categories of data, was used appropriately to assess statistical associations with clinical findings between the diet groups. Spearman’s Rank-order correlation evaluation, which assesses two ranked variables for the strength and direction of an association between them, was used appropriately for evaluating correlation between diet groups and taurine levels.
    One of the publicly offered criticisms of the current study was the failure to employ ‘proximate component analysis.' The exact meaning of this statement is difficult to parse out. ‘Proximate component analysis’ typically refers to the percent make-up of various nutrients in a given formulation. If this was the intended meaning, this type of analysis would have been inappropriate for the current study, though it could prove useful for future investigations. Alternatively, the author of the criticism may have meant ‘principal component analysis,’ or even ‘factor analysis,’ which is commonly confused with the former. Both of those methods seek to reduce the number of variables in a given data set, albeit through differing means. In any case, while the goal of the present study was to determine if there are differences in the assessed clinical parameters (taurine and echocardiographic findings) between two broad categories of food, a future study seeking to further hone in on specific aspects associated with the differences within one of the broad diet groups could benefit from additional statistical analyses.

"Reporting errors were noted, including errors in Tables 1 and 2, for which the authors requested a correction, and other issues raised to the journal that may impact categorization of some included foods as traditional versus non-traditional."

    It may be fair to remove some included foods and request that the authors issue a correction to their data. Based on the public issue of these concerns, not all of the issues raised are as significant as others. For example, while a diet with traits that fit both the TD and NTD groups may be fair to omit, such an omission would be unlikely to influence the overall data trend, since the dog eating the diet in question did not have abnormal parameters. In fact, it’s possible that exclusion of this diet would strengthen the significance of the author’s findings, since it was included in the NTD group. However, concerns raised about a mistake in naming a diet (listed as a partially pork formulation, when that company does not produce a pork diet) are almost certainly secondary to a mistake in the owner's reporting of diet history, and while such inconsistencies should be investigated and clarified, it is very unlikely such an error would compromise the study, the data, or the conclusions. The protein source was not evaluated as part of this study.
    Concerns about the classification of Merrick based on their acquisition by Nestle Purina are also misplaced. While Merrick is owned by Nestle Purina PetCare, a public statement has been issued that they continue to operate independently, with no changes at the hands of Purina secondary to the transaction.

"Questions were raised as to whether three months on a given diet is a sufficient duration to impact cardiac/DCM outcomes, and whether diet history prior to a subject’s current diet may impact the study outcomes. Concerns were also raised about differences between groups in the average time on the current diet."

    This was discussed extensively as a limitation by the study authors. Namely, while it represents a limitation for the evaluation of the echocardiographic parameters and should be considered for future studies, it is not expected to impact the taurine analysis, based on prior knowledge that changes in taurine can occur in a matter of weeks, which is well within the three month (12 week) minimum period. The length of time on a certain diet, and the impact of prior diet history on findings, is a limitation not just to this current study, but to analysis of publicly owned animals as a whole. While it is significant that the average length of time on a given diet was nearly twice that for dogs in the NTD group when compared to the TD group, this may simply reflect consumer behavior differences between the owners that are most likely to feed each. Assessment in this area would best be explored in a randomized clinical trial with a population of laboratory animals. Given the investments necessary to conduct a study of that nature, in terms of both time and finances, it would be unreasonable to discount more feasible research on the basis of that limitation alone. These differences are something to consider when evaluating the data, but not something which invalidates the data or subsequent findings. 

"Questions were raised about the validity of the conclusion statement, “Grain free diets, produced by small companies, including legumes within the top 5 ingredients represent a risk for the development of taurine deficiency and echocardiographic abnormalities consistent with DCM in the golden retriever.”"

    Given that the questions surrounding the validity of the conclusions likely arise from the concerns stated above, it is fair to say that the conclusions remain valid in light of the concerns being misplaced. In medicine, a risk factor is something associated with an increased chance of developing a disease. The findings of the present study are consistent with a correlation between the consumption of NTD (grain-free, small company, containing legumes in the top 5 ingredients) and clinical traits associated with disease. That correlation represents a risk factor. 


While PLOS One is doing the responsible thing in transparently responding to received concerns, investigating the validity of said concerns, and reassessing the paper in light of them, that these illegitimate concerns were received at all illustrates one more example of what has become a concerning trend of industry pushback to researching this topic. There should be no question that the industry has been negatively impacted by this investigation, with market trends showing that consumers are drifting away from grain-free varieties of food. What has become problematic is that rather than proactively seeking to identify the underlying cause and change formulas appropriately, the response from the industry has largely been to downplay and minimize the importance, or even existence, of this issue. Read more here.  

Most of the content in this article was originally included in a letter to the editors of PLOS One.

Follow me on Social Media: @AllTradesDVM

Facebook     Twitter