Macho B may not have had chronic kidney failure after all.

Tissue samples from the last known wild jaguar in the United States showed no sign of kidney disease, the diagnosis Phoenix Zoo veterinarians made in deciding to euthanize him.

A pathologist at the UA's Veterinary Diagnostic Laboratory, which reviewed the tissue samples, said authorities may have moved too fast to euthanize the animal early this month. Bloodwork state Game and Fish officials said showed "off the charts" kidney failure could actually have indicated dehydration, said Sharon Dial of the veterinary lab.

The zoo should have kept the animal on intravenous fluids for 24 to 48 hours before euthanizing it, Dial said. State Game and Fish officials and U.S. Fish and Wildlife Service officials agreed to euthanize the animal about five hours after he first got fluids. Zoo officials made the recommendation based on blood test results.

Dial said it is unproven "dogma" among some medical experts that blood levels alone can be used to "make a definitive statement that this animal will not survive." The zoo didn't have enough information to determine whether the jaguar researchers named Macho B needed to be euthanized, she said.

"Nothing is absolute. There is nothing to say that he absolutely would have recovered, but I can say by looking at the kidneys that there is no structural reason why he would not have," Dial said last week. "I've looked at a lot of cat kidneys, not jaguar kidneys. For a supposed 15-year-old cat, he had damned good looking kidneys."

It's possible Macho B had short-term, acute kidney failure that didn't show up in the tissues, another lab pathologist said. But the lack of signs of chronic kidney failure in those tissues probably means the jaguar didn't have kidney failure at the time he was captured in mid-February, said pathology resident Jennifer Johnson.

"Animals with chronic renal failure usually don't have their coats in good shape," Johnson said "They start to develop muscle wasting or atrophy. They do not look healthy and hearty."

Shortly after the jaguar's death, Phoenix Zoo veterinarian Dean Rice said the animal probably had kidney failure when he was initially captured that would have killed him within two months — although the capture probably aggravated the condition.

Snared accidentally

Macho B's death came 12 days after its original capture in the oak woodlands of Southern Arizona, near the Mexican border. Officials said the jaguar was snared accidentally by a research project tracking the movements of mountain lions and bears. He was fitted with a radio collar and released. But researchers tracking its movements by satellite data noticed he had slowed down significantly, had an abnormal gait and had lost weight. They recaptured it March 2 and took it to the Phoenix Zoo, where it was euthanized later that day.

A UA lab-produced report on the jaguar's tissue samples, which the Star obtained through a public-records request, is the first of three outside reviews of the case.

A federal wildlife lab in Madison, Wis., is analyzing the tissue samples. Both labs' conclusions and the tissues will go to Linda Munson, a specialist on large cats and a professor at the University of California-Davis School of Veterinary Medicine. She has agreed to review the data at no charge to the state.

"We encourage a full review of each and every part of the data, so we can provide the most complete review of what took place," said Terry Johnson, Game and Fish's endangered-species coordinator.

Once all that is done, Game and Fish will post all the findings on its Web site, officials said.

The UA report's author, lab director Gregory Bradley, declined to discuss its contents, saying the work was done for the zoo and is considered confidential. But pathologists who examined the tissue samples did talk, prompting a statement of outrage from Game and Fish.

Until all three reports are in, it is "unproductive and potentially irresponsible" to discuss one piece of the findings individually, Game and Fish said in a statement sent to the Star..

"It is outrageous, unprofessional and speculative of individuals from the Arizona Veterinary Diagnostic Lab not leading the case to comment and offer opinions based on very incomplete information. Those individuals from the vet diagnostic lab had no involvement with the evaluation and treatment of Macho B when he was alive, and so their comments are not valid or appropriate," the Game and Fish statement said.

Phoenix Zoo officials referred questions about Macho B's death to Arizona Game and Fish, which defended the zoo veterinarians' recommendation to euthanize the cat.

"We recognize that in veterinary medicine, there are almost as many opinions as there are doctors and attorneys," Terry Johnson said. "In this case, you've got the guys in the room up to their elbows in data on this animal. We asked them to give their best professional opinion."

Truth versus opinion

Sorting truth from opinion will be difficult because officials chose to perform a "cosmetic" necropsy rather than a full one, outside experts said. The zoo conducted the less invasive procedure at the request of the wildlife service and the Game and Fish Department to leave the skin intact for an as-yet-undecided future use, Terry Johnson said. In a cosmetic necropsy, authorities make careful incisions so the skin can be salvaged, he said.

Arizona Game and Fish is considering using the hide to create a "live mount" of Macho B to be exhibited for educational purposes, according to an e-mail from U.S. Fish and Wildlife Service supervisor Steve Spangle, obtained through a public records request.

Mark Plunkett, a taxidermist in the Verde Valley, skinned Macho B's carcass and sent the hide to a tanner to insure its preservation for storage and for any future use, Johnson said. Once the analysis of Macho B's death is complete, the department will work with the Fish and Wildlife Service to decide how to permanently archive the skin and other remains, he said.

Preserving the jaguar's body for use had trade-offs. A complete organ-system by organ-system necropsy would likely have provided better evidence about what led to its death, said David Jessup, a senior wildlife veterinarian for California Fish and Game. Tissue samples of the brain and spinal cord were not taken, for example, and they might have explained the jaguar's unusual movements in the days before he was recaptured March 2.

Oldest known wild jaguar

Macho B was the only one of four jaguars that have been photographed in Southern Arizona and southwest New Mexico since 1996 that was known to be still living in the wild. He was also the oldest known wild jaguar anywhere. At the time of its capture, state officials pegged its age at 15 to 16. The vet lab said the cat was 16 to 18.

The UA report offered these conclusions about the jaguar's tissues:

• The tissues examined didn't indicate significant kidney disease.

• A small area in one section of kidney tissue showed papillary necrosis — a kidney disorder in which all or part of collecting ducts entering the kidney die. That, along with the presence of mineral and salt deposits in the kidney's inner section, suggest "there was a degree of dehydration."

• The papillary necrosis and the mineral buildup suggest the animal had pre-renal azotemia, a condition in which blood doesn't flow through the kidneys and nitrogen-based wastes build up inside them.

• Sections of the kidneys known as tubules, an area where waste materials are concentrated into urine, showed mild to moderate dilation — a sign that cells there were farther apart than normal. But the dilation was probably brought about by intravenous fluids the cat had been receiving for five hours before its death, and wasn't significant.

Dial acknowledged that she didn't know how feasible it would be to keep a wild animal such as a jaguar on IV fluids for an extended period because it would not stay quiet and would become agitated under those circumstances.

"If he'd been a domestic cat, I don't think he would have been euthanized," she said.

As evidence that cats can survive acute renal failure, she pointed to a study published last year in the Journal of American Veterinary Medicine. It found that more than half of 32 domestic cats treated for acute renal failure at a New York City veterinary hospital over seven years survived. These cats' initial bloodwork showed average values slightly lower on key indicators than what Macho B had, but some of the cats had sharply higher values than the jaguar did.

The cats' survival rate depended to a large extent on their urine concentrations — the higher, the better their chances of survival, the study showed. Macho B's urine concentration was low, according to a urinalysis conducted shortly after his death. But many veterinarians say urinalyses conducted on cats with large amounts of IV fluid in them are not accurate because the fluids dilute urine concentrations.

Some vets less critical

Some veterinarians who examined the lab report and necropsy at the Star's request didn't disagree with Dial and Johnson, but were less critical of the agencies' decision to euthanize the jaguar.

"It might have been nice if we could have kept it alive a little longer so that fluids could have worked. But the fact that the cat hadn't moved for awhile makes me think that something was going on and we don't know what that was — it could be a central nervous system problem or problems in other locations," said Lawrence McGill, a veterinary pathologist in Salt Lake City who is a spokesman for the American College of Veterinary Pathologists.

Ladan Mohammad-Zadeh, a Tucson veterinarian specializing in intensive care, said after reading the reports that she didn't consider Macho B's condition irreversible but she didn't want to second-guess the decision to euthanize. She said she believed the cat had acute kidney failure because the bloodwork showed extremely high levels on a number of crucial indicators, including phosphorous and potassium.

It can take a few days from the time of injury to the kidneys before the problems show up in tissues, said Mohammad-Zadeh, of Southern Arizona Veterinary Specialty and Emergency Center. The only way authorities could have known if the cat's problems were treatable would be to keep it on fluids for several days, she said.

Veterinarian Jessup, of the California Department of Fish and Game, said he doubted the zoo's euthanasia recommendation was based solely on the bloodwork because vets seldom make recommendations only on those numbers.

"If this were the only problem, more aggressive fluid therapy, anti-inflammatory drugs and other medications might have helped. … I strongly suspect the animal was non-responsive or poorly responsive," he said, and that there is more information in other medical records at the zoo that contained a full rationale for euthanasia.

But in any case, said Dial, of the UA veterinary diagnostic lab, a full necropsy would have been best for a full understanding.

"The lack of total transparency in the handling of the case will not allow full understanding of what could have been done better" she said. "It is important to learn from every experience, to come together and improve the understanding of everyone involved so that there is no repeating of past mistakes."

"We recognize that in veterinary medicine, there are almost as many opinions as there are doctors and attorneys. In this case, you've got the guys in the room up to their elbows in data on this animal. We asked them to give their best professional opinion."

Terry Johnson, Game and Fish's endangered-species coordinator

Contact reporter Tony Davis at 806-7746 or