Let's Take A Look At Some Dog Food Labels

 I get asked quite often what I feed my dogs. I am quite willing to share that information. Purina, Hills, and Royal Canin are all good choices. I feed Archie a regular Purina diet, the cat gets a Hills prescription diet to prevent urinary blockages, and Azza thrives on Royal Canin's Ultamino hydrolyzed protein diet. The prescription diets made by these three companies are incredibly useful for a wide array of diseases. Nothing magic here, we know that diet can reduce and delay clinical signs of many types of disease for both people and animals. A managed diet can improve performance. It can help a beef cow put on more weight faster, and can help a "no antibiotics ever" broiler chicken have a healthier gut to reduce bacterial infections. 

But the important point is that all three of these companies conduct feeding trials using real dogs to determine the nutritional profiles of their foods. Other companies analyze samples of their food in a lab only, for example burning it in a crucible to determine protein content. These kinds of assays are certainly useful, but they provide no information on bioavailability of important nutrients. Only feeding a living animal the actual food can tell you if that protein can be digested and used by the animal. If a dog food label says "food is formulated to meet the nutritional levels established by AAFCO," that food has only ever seen the inside of beakers and test tubes, not the inside of a dog. Grain-free? "Human-grade" ingredients? "Natural"? All marketing. All bullshit. All to make you, the human with the credit card, feel good. 

So this windy opening sets the stage for Archie's current situation. He got a stick jammed in the roof of his mouth a month ago or so, and some pieces of it broke off and were left behind in the tissues around his left upper molars. His bad breath prompted me to take a look in there...where I found this nasty hole in the roof of his mouth surrounded by friable, brown (necrotic) tissue. It bled when I touched it. I managed to get a large piece of stick out of the hole but even after starting some antibiotics, things weren't improving as much as I would have liked.

Of course, my imagination immediately went to the worst case scenario--abscess, lysis of the bony palate, formation of a fistula (an inappropriate hole between two spaces), damage to the roots of those huge molars. All Very Bad Things. I had to get a referral to another vet to get some dental radiographs made since my vet doesn't have dental rad equipment (it's specialized). That vet flushed a couple more small pieces of stick out, and helped calm my worst fears. She added a second antibiotic to go after the anaerobic bacteria, and recommended that I feed Archie a canned diet for two weeks to give the roof of his mouth a rest. 

Archie had not shown any evidence of pain or reluctance to eat or play, but he's a pretty stoic dog in general. Two weeks of canned food seemed reasonable. Except that I haven't calibrated any canned diets. I have no idea how much canned food to feed him. 

See, I feed Archie a calculated number of calories per day, including treats. He currently eats 1 cup of Purina Pro Plan Performance 30/20 Chicken and Rice kibble per day, divided into two meals, plus two tablespoons of plain yogurt, between 20 and 40 g of frozen green beans, and 10-20 kcals of treats. I adjust this basic plan for training and trialing days when he gets lots more treats. The kibble has 484 kcal/cup, so on most days Archie consumes around 510 kcal.

Let's examine three canned food options. Rachel Ray's Nutrish dog food comes in small plastic tubs. It looks and smells like human stew. The lamb and rice stew label says to feed an adult dog 1.5 tubs per 10 pounds per day. Archie weighs about 24 pounds so according to the label, I would need to feed him THREE tubs per day. Each tub is calculated to contain 244 kcal. Let's do the math, shall we? If I gave Archie THREE tubs of this stuff a day (not sure I could get this volume of food into him, but he certainly would give it a go), he would consume 732 kcal each day. If I give him the chicken and rice stew at the recommended volume, at 290 kcal/tub, he'd be getting 870 kcal per day. That is astonishing!

I also bought some Canidae Small Breed canned food. The chicken, salmon, and pumpkin recipe, which looks and smells as gross as that sounds, contains 123 kcal/can. The label recommends 2 cans per 6 lb of weight, so if I follow those recommendations, Archie is supposed to eat EIGHT cans of this per day. EIGHT! That's 984 kcal per day. OMG, that's even worse than the Nutrish stew. That's almost TWICE the numbers of calories that Archie needs each day.

ProPlan Focus canned food is my third example. If fed as recommended, Archie would need to eat 1.5 13-ounce cans per day of the (large breed) chicken and rice formula (their "small breed" options are grain-free and I don't feed grain-free). That comes out to about 475 kcal per day, which is in line with what he actually needs. So not only is the Purina food tested on real animals, the feeding guidelines are reasonable, not grossly over the top.

Here's the bottom line. Read labels. Don't be fooled by marketing. Measure your pet's food and calculate kcal per serving (can, cup, etc.). Are they healthy now? Figure out how many calories they eat per day--including all treats. Kibble is always going to be more nutritionally dense than canned food, which is mostly water. The volume of canned food will always be more than the equivalent kilocalories of dry food. And consider feeding Purina, Hills, or Royal Canin.

The Messy Matrix of Post-Mortem Diagnostics

 I was texting with a vet school classmate last night, and mentioned that we take radiographs of some of our necropsy cases. You take post-mortem rads? She was clearly surprised. After thinking it over, I realized that it does sound odd to a GP vet that we would do that.

There are three types of necropsy cases for which radiographs can be quite helpful. The first type is gunshot suspects--we want to see if there are any metal fragments in the body and where they might be. The second type is abuse suspects--we want to look for, and document, any bone fractures. Animal rescue groups and municipal shelters and animal control usually submit these two kinds of cases, but I've had vets submit gunshot cases directly. In one memorable case, I discovered what looked like projectile entry wounds on a dog when I was examining it before starting the necropsy. But the submission form didn't mention a thing about gunshots! So I called the vet, and she admitted that she had not seen the animal herself. The neighbors had taken the dog to the vet, but it unfortunately died on the way, and the vet clinic passed the dog directly on to the lab without a thorough examination. Using the radiographs that I made, I was able to find a lead pellet lodged in the descending aorta that was the cause of the animal's death. The third type of case is a more generic legal case in which radiographs are another diagnostic tool. Racehorses sometimes fall into this category. They are usually insured to the gills, and we are asked by owners or the racetrack vet to perform a complete necropsy, even though, for example, the fractured cannon bone in a front leg is the obvious problem.

Our veterinary diagnostic lab does not have any radiographic equipment. So we rely on the generosity of the State Crime Lab which is literally next door to us. We all get gold stars for the inter-agency cooperation, but I try not to abuse the privilege. They are a busy lab. The State Crime Lab handles cases of humans who died under suspicious circumstances. Which means they have dead people there. Lots of dead people.

When I need rads for a necropsy case, I text one of the techs at the Crime Lab and set up an appointment. For small animals, we get rads before starting the necropsy. One of my techs and I will load our case, double bagged, into the back of a vet lab truck and drive next door. We back up to the dock of the Crime Lab and unload our case onto one of their gurneys. A human-sized gurney. We then follow the Crime Lab techs into a large, walk-through cooler where they store their cases. Dead people, each one enclosed in a body bag. It's super fucking creepy, and after the shock of my first trip through, I keep my eyes forward and try not to glance around. I've seen that cooler room stacked with literally dozens of bodies. Super. Fucking. Creepy. One of my techs refuses to even go to the Crime Lab, and I don't blame him for a second. 

We keep our cases bagged at all times out of respect for our Crime Lab colleagues. They don't want to see what is in our bags any more than we want to see what is in theirs. 

Their xray room is just beyond the cooler room. They have a very nice rig, all digital, quite similar to what I've seen in vet clinics, except that the table is human-sized. I bring a flash drive with me.

Taking clear, diagnostic radiographs of humans and animals is both a science and an art. There is a balance between resolution, energy of the beamed particles, and radiation damage to the patient and techs. But since neither lab is dealing with living patients, there is a lot less fiddling and more just blasting some xrays and taking a look at the result on the monitor. We don't use radiographs to FIX a problem, we use them to FIND a problem.

Horses represent a unique situation since the Crime Lab doesn't have a hoist, or any facility that could deal with such a large animal. We usually remove the part of the horse that we are interested in, most often the leg. But I did have a case in which the racetrack vet insisted that we do a more thorough examination of the caudal (neck) vertebrae. Without going into a lot of detail, my techs and I removed the neck, all seven caudal vertebrae plus the first two thoracic vertebrae, and bagged that up to carry to the Crime Lab. The rads revealed an old, poorly healed fracture in C7 and a new fracture in C2 that happened when the horse fell over as it was dying. It died from something called EIPH, exercise-induced pulmonary hemorrhage, a progressive, chronic disease. In this case, all of the horse's lungs filled up with blood very rapidly. That's a lot of lung, and a lot of blood. But that C2 fracture wasn't compatible with life either. Once we got back to the necropsy floor, we used the radiographs to precisely section the neck and photograph the fractures directly. Very interesting case that was greatly enhanced by post-mortem rads.

Working up a necropsy case requires an array of qualitative and quantitative diagnostic tools--gross examination (sight, touch, smell), bacterial culture, PCR tests, radiographs, even blood tests. The art comes in navigating the messy matrix of making a good differential list, obtaining the right samples, and selecting the right diagnostics for each case. Sure, anybody can run all the tests on every case, but what's the purpose of that? It is far more challenging, and satisfying, to find the most elegant path through the matrix.

"Well, Didja Skin'Em?"

 Some of the lab's clients are rather ... colorful. My favorites are the guys that run small beef cow/calf operations. I learned years ago how to schmooze with just about anybody, and some of these crusty old guys can get downright chatty with the right schmoozing. I never fail to learn something new and useful. Maybe I learn a new word, or get more detail about a management procedure. It's always a lot of fun. In fact, I see the time I spend talking to them on the phone or in person as part of my job, not an interruption.

There are two important reasons for this. Firstly, I can always get a more detailed history from them directly than they will ever write down on the submission form. I get them to tell me all kinds fascinating details about how they are managing, or in some cases, mismanaging their herd. And secondly, I'm building their trust in the lab. Building their trust in me and my team's ability to help them solve their problem. 

We recently had a guy bring in a couple of young pigs, about 5 or 6 months old. Yeah, I know, pigs aren't beef calves. But this guy was cut from the same cloth. It wasn't my day in necropsy but I always get called when producers show up because everyone in the lab knows that I like to chat with them. I was standing on the dock, looking down into the bed of his truck at two dead pigs. Body condition looked good. They were clean, well kept. But certainly dead. And he was telling me and my colleague that the entire pen of nine pigs was sick. I let him talk on until he mentioned staggering. Ah ha! I asked him, were any of them dog sitting (that means sitting back on their haunches like a dog) or head pressing (that means pressing their head into a corner)? Yes, he said, all of them. Head tremors or seizures? I asked. Yes, that too. Turns out he had some nice videos of these exact behaviors, which he showed me on his phone. How about the water supply? Hoses and spigots still working? Tanks full? Oh, well, yeah, it seems that he did have a bit of trouble with the water supply in that pen when we had a freezing spell a few days earlier. Only that pen affected? Yes, only that one. 

They literally teach you about this in vet school: water deprivation leading to sodium toxicity and death in pigs. The videos were magnificent--I had him send them to my work cell right away. The water deprivation leads to an electrolyte imbalance that affects the brain. The neurological signs I asked him about are considered textbook signs of the sodium toxicity.

I was so excited to get this case for us to work up that I never let him feel bad about killing his pigs. I gave him some advice about how to save the remaining pigs, and thanked him for bringing the case. He called me two days later and reported that he had followed my advice and saved the remaining pigs in the pen. With some ingenious sample collection, my colleague and I were able to make a convincing argument that it was indeed sodium toxicity that was the problem. We considered other differentials such as pseudorabies (also called Aujesky's disease) and rabies that could cause the same neurological signs, but we tested for and eliminated the first and rejected the second as reasonable (unlikely to affect an entire pen at the same time). In the end, it was a solved case and a happy client!

At the other end of the spectrum is the old guy that called up a few weeks ago wanting to bring in a calf that had died overnight. He had lost five or six calves in a 24-hour period. My brain was spinning out a list of possible differentials when he said, I think they were shot. Oh, okay, I said, we can take a look and see if that is the case. Odd differential, as I was thinking about things like lightening strike or infectious agents that can kill several animals at the same time. But sure, getting shot is possible too. 

So I did the necropsy on this calf and didn't really find much of anything except that it had a lot of intestinal worms. Those absolutely can kill a calf if the parasite burden is high enough, but the calf was in good flesh and it wasn't a definitive finding. I found nothing else that was particularly helpful or diagnostic as to the cause of death. And as is my usual procedure, I called the producer to let him know this. He started yelling at me, saying, I brought that calf in so you could prove it was shot! I told him that there was no evidence that it had been shot. He replied, well, didja skin'em? I paused, trying not to laugh, and said, sir, I did a complete, thorough necropsy and there was no evidence of any projectile trauma in this calf (no, we don't skin animals for most necropsies). 

By this point, I have unfortunately seen quite a few animals with gunshot wounds and I am confident in my ability to identify that. Definitely no gunshot in this case. But this old crank managed to get the county sheriff's office involved and they contacted the lab director for more information last week. We sent them the final report and I thought that was the end of it. 

But no, no, my year will not end so quietly. This cranky old guy is bringing us another calf today. One of seven more that died last night. He still thinks they are being shot! I'll try again to find a cause of death. I hope this calf tells us a better story, although I suspect that he won't be satisfied with anything less than being presented with the bullet that killed the calf.

'Tis the Season...For Bovine Abortions

 Winter is the season for bovine abortions. Two-thirds of bovine abortion cases are closed with no cause determined. That's an average that holds true in veterinary diagnostic labs across the country. As a side note, miscarriage is not used in vet medicine. Vets use the word abortion to cover the loss of a fetus in animals.

Despite the statistics, I recently had a bovine abortion case for which I was able to get a diagnosis. The fetus looked like all aborted bovine fetuses, that is, not very diagnostic. But this time the vet sent us some placenta, a very rare sample indeed. Bovine placentas are membranes studded with these raised, thick, slightly cup-shaped structures. There are two parts to these structures, a dam side and a fetal side. They supply nutrients and blood and waste removal for the placenta.

At first glance, this sample was fairly typical for placentas (even unicorns have "typical"). It had been picked up off the ground so it had bits of leaves and grass and dirt stuck to it. It was torn so had probably been partially eaten by the dam, foxes, or the farm dogs. But some of those cup-shaped structures looked off to me. Wrong color, wrong texture. I made sure we trimmed those in for histopathology. Turns out they had fungus growing deep inside of them! There was a strong immune response to the fungus, causing disruption of placental function, early fetal death, and the subsequent abortion.

They teach us about all the causes of abortion in vet school. Even so, my histopathologist said it was the first case of fungal placentitis that he'd ever seen in his decades-long career. It will probably be the only one I ever see too. So for once I had a rare successful bovine abortion case. 

On the other end of the scale is a bovine fetus I unwrapped a couple of weeks ago. I always do a physical examination of animal remains before starting a necropsy. As I was looking this one over, I noticed that it was missing both ears, the right eye (crows, most likely), the last couple of centimeters of its lower jaw, and then...whoops! I turned it over and found that it was missing all of its abdominal organs. All of them, including the skin of the abdomen and the umbilicus. Neatly removed along with all of the ligaments that hold them in there. The abdominal cavity of that fetus was smooth and clean as a whistle. Farm dogs are efficient. Amazingly, the diaphragm was intact so I sampled what I could--lungs, heart, thymus. Not much hope of getting a diagnosis from this one. I called the vet and asked her why she sent me the case. Turns out she had received a call from the producer about the abortion, and she told him to box the fetus up and get it to the lab. She didn't know it was in such bad shape. I gave her a pass as this does happen now and then. 

Production animal necropsies come with unique challenges. In order to get diagnoses for the cause of death, we have to be flexible and creative with the samples that we get. 

Except for maggots. I don't do maggots.

Bird-Shaped Bags of Maggots

 We get a lot of backyard chickens submitted to the lab for necropsy. The State Vet has a grant that pays for the necropsies and surveillance testing of these birds, so there is no cost to the owners. It's a good way to encourage people to submit birds. And it allows the lab to keep at least a partial eye on reportable diseases in the backyard bird population that represent threats to the commercial poultry industry in the state. 

Unlike commercial poultry, which are usually submitted live, with as many as 10 to 20 birds per case, backyard birds are usually already dead when the owners bring them to the lab, and there is usually just one bird per case. 

I've seen enough backyard birds wrapped up in Walmart plastic bags or scented trash bags that just the sight (or smell) of either is enough for me to know it's a backyard bird necropsy. For the record, scented trash bags, and scented dog poop bags, make me gag. The smell of dog shit layered with "baby fresh" scent is just nasty. It still smells like shit, but now with extra steps. A dead bird wrapped in a scented trash bag is still just as dead.

Many backyard bird owners don't know much about livestock husbandry. Their intentions may be good but execution is often weak. We see chickens stuffed with intestinal worms, literally so many worms that the chicken starved to death because no food could pass the ball of worms in its gut. We see birds filled with tumors caused by the Marek's disease herpesvirus. That disease is reliably preventable with a vaccine administered by a hatchery at the day of hatch. We hear tales of woe in which the owner got some birds from a neighbor, from the nice lady at the flea market, from this guy over in Conway, and they put the new (surprise! diseased!) birds in their flock with no quarantine period, and ended up with a visit from a livestock inspector come to depopulate their entire flock because they now all have a very transmissible, reportable disease. I ask owners about their biosecurity measures, and get a puzzled head tilt from most of them. But all of that is ultimately a matter of education. 

One small problem with some backyard bird owners is that they wait too long to bring us a dead bird. Autolysis, the changes that happen to tissues after death, is rapid in birds. I don't expect most people to know about autolysis, but I do expect them to have at least a basic idea about the other thing that happens to dead animals that are outside for more than a few hours. And that thing is maggots.

I don't do maggots. 

Thankfully, the surveillance tests we conduct can be performed with a tracheal swab so I don't need to dive in and collect rotten tissues. I've had enough bird-shaped bags of maggots submitted for necropsy that my techs know that I won't even unwrap those birds all the way. Once I see maggots spilling out of the Walmart bag shrouds, I cut a hole in the bags for the head, flick maggots out of the bird's mouth to swab the trachea then tell my techs, I don't want to see any more of this. And away it goes to the incinerator, maggots and all. 

Changes, and A Tale of Cow Conjunctivitis and Pneumonia

Things have been grim this year. Pandemic. No toilet paper in the stores. Being afraid to even go in said stores. Losing my little old Mimi. 

I've decided to take the blog in a new direction. A bit of an experiment, just to see how it works. This is nothing new--CircusK9 has evolved more than once since I started it lo these dozen years ago. 

I want to talk more about my job. I love my job. Despite the inherent ick factor that some people might have about the subject, my job provides me with an endless stream of absurd and interesting tales.

Like this one. I have developed a good working relationship with a clinic in SW Arkansas. This three-vet practice sees all species, and they send most of their necropsy cases to the lab. Because of the distance from their clinic to Little Rock, and because they are not on the route of one of our regular couriers, the vets often conduct field necropsies of production animals and send us a "box of parts" instead of the entire cow. Cheaper and faster.

One of the vets has been working with a beef cow-calf operation for some weeks that is having a big problem with conjunctivitis in the herd. The usual bacteria responsible for this is Moraxella bovis. That's the one you learn about in vet school. But that's not what they got back from swab samples. They got a species of Mycoplasma. They started to treat the conjunctivitis but some of the cows began dying from respiratory disease.

Cows are prey animals and have an amazing capacity for hiding respiratory disease until things become pretty disastrous in there. I've opened up cows to find 80% or more of their lungs full of pus and bacteria, and heart and lungs stuck to each other and the body wall with expansive fibrin adhesions. This is not good. Most vets who work with these animals, including me, suspect that cows harbor subclinical bacterial pneumonias pretty much all the time, and are just waiting for some stressor--transportation, parturition, change in weather, change in feed--to cross that line into severe respiratory disease.

So my friend sent me two boxes of parts from two cows from the conjunctivitis herd. He also sent some horrifying pictures of the conjunctivitis--I will spare you. I never really got anything definitive from the parts other than confirming that it was a bacterial pneumonia. He kept calling me to talk about this Mycoplasma they had isolated from the eyes, not Moraxella. It was a species I had not heard of, and I initially thought I just wasn't understanding him clearly. He often calls me when he's in a windy field standing over a dead cow so there is lots of background noise. 

See, Mycoplasma bovis is a common culprit in bovine respiratory disease. Mycoplasmas are special bacteria--they don't have cell walls. They like to form microabscesses which are very difficult to treat. In fact, cows with Mycoplasma pneumonia are often not treated (they are culled). The lungs my vet friend sent to me did not look like Mycoplasma lungs. They looked like Mannheimia or Pasteurella lungs. But we failed to culture those bacteria. And you can't really culture Mycoplasma. We rely on PCR tests to identify that one. But I didn't initially request a Mycoplasma PCR because, well, the lungs didn't look like Mycoplasma lungs.

It's weird how distinctive these different bacterial infections can be. And after you see dozens of gnarly cow lungs, you get a feel for how the different bacterial pneumonias present grossly. My pathologist agreed--the tissue damage we saw on the microscope slides of the lungs was most consistent with Mannhemia. How come we didn't culture it? Sometimes that happens. Failure to culture doesn't mean it wasn't there.

But my vet friend kept going on about this "bovoculi"--and I finally put it together. 

Mycoplasma bovoculi--get it? bov = cow, oculi = eye--is a Mycoplasma implicated (link will open a PDF) in the past few years in a particularly nasty cow conjunctivitis. I found out that it likes to hang out with its friend Mycoplasma bovis. Which we found in the lungs of these cows when I had the PCR test run.

Some vet school adages really prove to be true, over and over. Common diseases commonly present uncommonly. I missed the Mycoplasma connection in this case, but I guarantee it won't happen again.

Sweet Mimi

Yesterday, Mimi's burdens became too heavy, and I had to pick them up and help her take the last steps of her journey. 

Little old girl, you can now run fast, run far, and take long naps in the sun.

You were with me for 15 years--it will never be long enough. 

Quicksilver Let's Play House 9/5/2005-11/11/2020