The Arizona Game and Fish Department has published a web page offering more details about the final day of Macho B’s life. Macho B was the USA’s only known wild jaguar. A tracking collar was placed on him after he was captured by Arizona Game and Fish officials in February. The big cat quickly fell ill. He was re-captured and euthanized approximately two weeks later.

A few days ago I posted about the incident, and speculated that Macho B’s initial capture may have hastened his death, but was not likely to have been the cause of it.

Here are some quotes from the Arizona Game and Fish website, along with my comments. As with my last post, a moderate amount of speculation is included in my comments.

During the necropsy [animal autopsy], we didnt find anything out of the ordinary for a cat of Macho Bs advanced age, said Dr. Rice, a veterinarian and executive vice president at the Phoenix Zoo. But, given the extremely small size of his bladder despite aggressive intravenous fluid therapy, it was apparent that his kidneys were shutting down. I expect the histopathology reports to show that this animal had been experiencing kidney failure for awhile. Kidney failure is more a matter of weeks or months, not days.

Intravenous fluids treat kidney failure by helping the kidneys to flush toxins out of the bloodstream and into the urine. If Macho B’s bladder failed to fill, this implies that the condition of his kidneys was grave. In my experience, few cats survive if they fail to produce urine despite aggressive intravenous fluid therapy.

This implies that euthanasia may have been the kindest choice for Macho B in the situation (although I would not want to be responsible for making such a decision in the case of a national treasure such as Macho B).

There are few therapies for cases of kidney failure that do not respond to intravenous fluids. One option, dialysis, is not feasible in a wild animal. Another option, combining fluids with medications (furosemide and dopamine) that increase urine output and theoretically increase kidney blood flow, is commonly used in humans and dogs. However, this combination therapy has not been proven effective in any species, let alone jaguars. Dialysis and combination therapy are merely symptomatic treatments. They do little to treat the underlying kidney disease; that would require a kidney transplant, which is not possible at this time in jaguars.

I agree with Dr. Rice that Macho B’s kidney disease was most likely pre-existing. However, any attempt to guess how long Macho B would have lived had he not been captured would require an extreme amount of speculation.

Veterinarians indicated that Macho B showed no physical signs of illness that could have been detected by the biologists that originally collared him after he was unintentionally captured during a mountain lion and bear study. Diagnosis of kidney failure depends on running blood tests to analyze the blood urea nitrogen (BUN) and creatinine levels, which are the two most important indicators of kidney function.

Blood tests run Monday upon arrival at the zoo showed Macho Bs BUN was greater than 180, but an exact level could not be determined because the maximum reading on the diagnostic equipment was 180. The upper limit of a normal BUN level is 30. The cats creatinine level was 15.2 with the normal range being .3 to 2.1.

It is true that cats with mild or moderate kidney disease can appear completely normal upon physical examination. The cat could have appeared completely normal when he was first captured, even if he was suffering from kidney disease.

I am a bit disappointed that the exact level of Macho B’s BUN was not reported. Although the machine used could not read values greater than 180, samples can be diluted to obtain exact values. If the technicians running the tests were not comfortable performing this procedure, the samples could have been sent to a reference laboratory for more precise results.

That said, any BUN greater than 180 is extreme. Likewise, a creatinine of 15.2 often indicates a hopeless situation.

Arizona Game and Fish Department biologists had hoped to learn more from blood samples taken at the original capture, but the samples were deemed to be inadequate for testing. The blood samples were collected for use in DNA analysis in accordance with the capture protocol developed by leading jaguar experts. They were not intended to determine the health or condition of the animal at the time of the collaring, which would have required a different blood handling process.

After this incident, I’m confident that leading jaguar experts will change the protocol. DNA analysis requires a few drops of blood. Samples for blood chemistry analyses (which test, among many things, kidney function) require approximately three cubic centimeters–a very small amount of blood from such a large cat. Both samples are straightforward to obtain. As long as a jaguar is anesthetized, there is no reason not to obtain a slightly larger sample of blood. I’ll bet the Arizona Game and Fish officials are regretting their decision not to collect a comprehensive blood sample from Macho B at his initial capture. If nothing else the sample could have proved that his kidneys were already compromised, saving the officials from some of the painful scrutiny they are dealing with now.

The jaguars initial capture was guided by protocols developed in case a jaguar was inadvertently captured in the course of other wildlife management activities. The plan, which was created in consultation with leading jaguar experts, includes a protocol for capture, sedation and handling.

This quote makes an important point. I have been involved in wild cat captures. Such procedures are complex, harrowing, and prone to complications. They are not to be undertaken lightly.

No self respecting biologist would capture a jaguar without doing his homework. All of the information I have seen indicates that the people who captured Macho B performed their due diligence. They planned carefully. Their protocols were well thought out. Things went badly. That isn’t necessarily their fault. I am not convinced that anything was done wrong.

The loss of Macho B is heartbreaking. But I personally don’t feel that finger pointing is appropriate.

Photo: Macho B in happier days. Courtesy of Arizona Department of Game and Fish