Dr. Eric Barchas Q&A



photo: http://blogs.dogster.com/vet_blog_information_advice


Readers of this blog know that I have included links to a couple of pages from Eric Barchas, DVM regarding Macho B’s

death. I decided to contact him directly to see if he could shine some light on the entire situation, especially since he’s a veterinarian and has experience tranquilizing wild felids (which is something 99.99% of the people who are making noise in cyberspace can’t claim). As you read Eric’s responses you’ll notice that he freely admits that he’s speculating, giving an educated guess but isn’t claiming anything with certainty. Anyway, read on, I think you’ll find his answers interesting. Thanks for taking the time to answer, Eric!!

1. Please tell us a little about your background and education.

I graduated from the University of California, Davis School of Veterinary Medicine in June, 2000.  I have been a practicing companion animal veterinarian since obtaining my degree.

 2. How did you become involved in carnivores as a veterinarian?

My experiences with large cats occurred before and during my time as a veterinary student.  I volunteered at the Oakland, CA zoo for approximately one year prior to veterinary school.  During that time I worked with the African lions and Bengal tigers on display at the zoo.

My practice is currently limited to domesticated companion animals.  However, I have had a life long interest in and passion for big cats.

3. Please tell us a bit about your veterinary experiences  with lions and  mountain lions.

During veterinary school I spent three months in a lion research camp near Maun, Botswana.  Our days were spent tracking and studying several prides of wild lions.  Our group anesthetized lions on several instances to collect blood samples and place radio tracking collars on individuals.

In the course of my veterinary studies I participated in an optional class on wild animal capture and restraint.  The class lasted approximately 12 weeks, and focused on the safety and issues related to capturing, restraining, and sedating wild animals.  During the course my fellow students and I sedated and worked with several species, including a mountain lion, a bobcat, a bear, wild pigs, and several deer.

As part of the course I became certified to lead wild animal captures in the state of California.  However, I have not participated in any wild animal captures since graduating from veterinary school.

4. As a veterinarian, what can you say about the safety of  tranquilizing and collaring wild felids?

Tranquilizing and working with wild animals invariably carries risks.  The benefits of the procedure must be weighed against the risks.  In the United States, generally only trained individuals who are certified by state government authorities may supervise such operations.  Part of the certification process in California involves demonstrating an ability to weigh the risks and benefits of wild animal capture.  I assume, but do not know with certainty, that Arizona has similar standards.

Some common risk factors associated with anesthesia and handling of wild animals, including large carnivores, are listed below.

Anesthetic doses are based upon the weight of the animal.  Until the animal has been captured, the weight cannot be known with certainty and must be estimated.  This leads to the risk of undersedation or oversedation.  Likewise, each individual reacts differently and unpredictably to the sedatives used in chemical restraint.  A dose that leads to ideal sedation in one individual may cause over- or undersedation in another.

Undersedated animals may become agitated, may stagger, become disoriented and behave erratically, and in the case of animals that live in groups, may be attacked by other members of the group.  This happened to a lioness that my group attempted to sedate in Botswana.  The sedative caused agitation in the lioness, and several members of her pride attacked her.  We were forced to intervene, which was not a simple matter given the nature of the animals involved.

Oversedated animals may suffer from prolonged recovery times, hypothermia, respiratory depression, and other complications.

All animals are at risk while the anesthetic agent is taking effect and while it is wearing off.  Animals are, in essence, undersedated during these times.  They may be at risk from other predators or scavengers.  They may fall off cliffs or into bodies of water, leading to drowning.  They may injure themselves by falling or tripping due to poor balance.  Their judgement and decision making skills are impaired during these critical periods.

Administering an anesthetic agent to a wild carnivore involves shooting a dart at it.  The site of impact may become brusied, irritated, or infected.  If the dart inadvertently strikes the thorax (chest) severe trauma can occur.

Adverse reactions to anesthesia are rare but always possible.   Adverse reactions can range from minor skin rashes to matters as severe as kidney failure or respiratory or cardiopulmonary arrest.

Because of the multiple risks associated with capture and chemical restraint of wild felids, it is recommended that groups of trained individuals work as a team in the process.  For instance, one person may be responsible for calculating tranquilizer doses and monitoring the level of sedation.  Another may monitor the animal’s vital signs.  Another may place a radio collar.  Someone else may collect blood and fecal samples while a final team member monitors the area for the presence of other predators or scavengers.  The period of sedation should be as brief as possible.

If possible, animals that are unhealthy, stressed, dehydrated, elderly, or exhausted should not be anesthetized.  These individuals are at increased risk of complications from anesthesia or sedation.

 5. Given the often rugged and hot conditions in Africa, what steps did you have to take to ensure the safety of the drugged animal?

Lions were sedated by our group only if the conditions were deemed appropriate.  Animals would not be sedated if they were active, because this predisposes them to agitation as the sedative takes effect.  Animals would not be sedated if cliffs or bodies of water were in the vicinity.  Animals were never sedated during the heat of the day. Our preference was to dart lions that were sleeping in deep shade during the late afternoon.  We would consider the course of the sun during the afternoon to ensure that the animal would remain shaded during the capture and during recovery from sedation.

Because lions live in groups, it generally was not possible to isolate them from other predators (that is to say, other lions) prior to sedating them.  However, we did our best to confirm that no elephants, hyenas, or other large and potentially threatening animals were in the vicinity prior to sedation.  This was simplified by the fact that most animals (elephants are an exception) do everything in their power to avoid lions.

More often than not, after assessment of all relevant circumstances we elected not to initiate a capture.

6. Are you aware of any studies or generally accepted figures for mortality rates for wild felids in collaring operations?

I am not.

7. It has been suggested that the northern Mexico/southern  US population of  jaguars is “more sensitive” (i.e. need to be  handled even more carefully than normal) than others of their species. Have you ever heard anything like this?

I have not heard discussion of this subject.  However, it is common sense that critically endangered species and subspecies need to be handled with extreme caution.

I assume that the Arizona Game and Fish authorities involved in Macho B’s capture were acutely aware of this fact and took it into consideration prior to sedating him.  I hope that they took active steps to avoid snaring him and that his capture truly was accidental.

8.  Something that has bothered me in the Macho B saga is  the rapid weight  loss he suffered in a short time (118 to 99 pounds in less than two weeks).  How can this be explained?

Rapid weight loss is a consistent feature of kidney failure.  Kidney failure causes appetite suppression and metabolic changes that lead to rapid deterioration of body condition.  In my opinion Macho B’s weight loss is consistent with kidney failure.

9. What effect do you think the collaring had on Macho  B’s lifespan? Did the collaring “kill him” as some have said?

Without knowing the status of Macho B’s kidneys prior to the procedure, I cannot answer this question with certainty.  However, I consider it unlikely that the collaring operation killed Macho B.

In my opinion it is most likely that Macho B had pre-existing renal insufficiency (the precursor to kidney failure).  The collaring operation may have exacerbated this problem and triggered progression to kidney failure.  In this case, if Macho B had not been collared his life expectancy may have ranged from a few weeks to several months.

It also is possible that Macho B was suffering from full-blown kidney failure prior to his collaring.  Macho B had been quite an elusive animal prior to his capture.  Weak kidneys may have made him less able to avoid the Game and Fish teams working in the area and more likely to be caught in a snare.  In other words, there is a chance that kidney failure lead to Macho B’s capture, rather than the other way around.  In this case, collaring the big cat would have made very little difference in his life expectancy.

Finally, there is a chance that Macho B’s kidneys were healthy prior to his capture and that an adverse reaction to the chemical agent used to restrain him, possibly combined with dehydration, stress and exhaustion at the time of the procedure, triggered acute kidney failure.  In this case, his capture may have shortened his life by several years.

The lack of pathological evidence of chronic renal disease, as reported on your blog, troubles me in Macho B’s case.  Chronic disease generally causes changes in the kidneys that are detectable by pathologists.  The absence of these changes increases the likelihood in my mind that Macho B’s capture may have contributed to him dying prematurely.  Nonetheless, I still think it is more likely that Macho B had pre-existing disease that was hastened but not caused by his capture.

To summarize, there is no way to know with certainty what effect Macho B’s capture had on his life span.

10. Given all the furor over Macho B’s necropsy/lab  results is there anything that struck you as significant as a veterinarian?

The blood test results I have seen are consistent with chronic (long term or pre-existing) kidney failure.  This syndrome is the most common cause of death among elderly cats.  I am most familiar with kidney disease in domesticated cats; however, it is highly probable that elderly jaguars suffer from similar pathology.

That said, the pathological findings reported on your blog state that evidence of chronic disease was not noted when Macho B’s kidneys were evaluated microscopically.  This does not conclusively rule out the possibility of pre-existing disease.  However, it does increase the likelihood that Macho B’s capture accelerated or even caused his death.

The necropsy and laboratory results that I have seen have given no indication of a specific adverse reaction to sedation such as crystalline deposits of chemicals or minerals in the kidneys.

11. As a veterinarian, how would you rate the advisability of collaring a geriatric wild felid?

In hindsight, it is easy to say that the capture of Macho B was a mistake.  When done properly, the benefits of collaring a geriatric wild cat can outweigh the risks in some circumstances.  Each case must be considered individually.

However, I am troubled by the fact that Macho B was caught in a snare prior to sedation.  I do not know how long he was snared before the Game and Fish team arrived on the scene.  Snared animals inevitably fight to free themselves.  It is certain that Macho B was stressed and exhausted by the time he was anesthetized.  It is highly likely that he was dehydrated.  As I mentioned above, stress, exhaustion, and dehydration are contraindications to anesthesia.

Of course, once Macho B was snared, it was impossible to release him without sedating him.  I hope that he truly was snared accidentally, and that efforts were made to avoid snaring him given his advanced age and status as a critically endangered species.

I have heard allegations that the snare that captured Macho B was baited with female jaguar scat.  These allegations, if true, are scandalous.

12. Anything else you’d like to add?

I wish to reiterate that I do not have enough information to offer definitive opinions on this case.  I am not qualified to opine whether Macho B’s capture was managed appropriately, or whether his euthanasia was premature.

My instinct is to give the benefit of the doubt to the people involved in Macho B’s capture and treatment.

Although I am intensely saddened by the death of this magnificent creature, I am certain that the people involved in Macho B’s capture cared about him very deeply.  Based on the information I have seen, I do not hold them responsible for his death.


2 Responses to “Dr. Eric Barchas Q&A”

  1. » New Interview on Southwest Jaguars Blog Covers Circumstances of Macho B’s Death in Greater Detail Says:

    […] You can find the interview here. […]

  2. Why Do Some Cats Hang Their Heads Over Their Water Bowls? – Cat Questions Says:

    […] condition. (Although the condition is common in all cats, and not just domesticated ones. Remember Macho B?) Many experts simply surmise that cats have been engineered by nature for their kidneys to be the […]

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