Baa's and Bleat's - The AASRP Podcast
Baa's and Bleat's - The AASRP Podcast
Bladder Stones With Meredyth Jones
Join us for this discussion about urinary calculi (aka bladder stones) with the one and only Dr. Meredyth Jones-Cook of Oklahoma State University. This episode covers stone types, predisposing factors, management strategies, and current knowledge gaps in the field of small ruminant urolithiasis.
The title of today's paper is Mineral Composition of Uroliths Obtained from Sheep and Goats with Obstructive Urolithiasis, published in the Journal of Veterinary Internal Medicine. Volume 31, Issue 4, Jul 2017, pages 961-1362
Access the full text here: https://onlinelibrary.wiley.com/doi/epdf/10.1111/jvim.14743
Dr. Jones also references a separate article from Vet Clinics of North America - Food Animal Practice titled Urinary Calculi of Small Ruminants. Published in July 2023, volume 39, issue 2, pages 355-370.
Access the full text here: https://pubmed.ncbi.nlm.nih.gov/37032300/
To learn more about the AASRP Research Fund visit: https://aasrp.org/Main/Main/Research/AASRP-Research-Grant.aspx?hkey=546d2e15-f2cd-4ce8-a837-a16cfd4f3790
If your company or organization would like to sponsor an episode or if you have questions about today's show, email Office@AASRP.org
Hello, and thank you for joining us. Today we are talking to Dr. Meredyth Jones from Large Animal Consulting and Education and also a faculty member at Oklahoma State. It's great to see you, Dr. Jones. Thanks you for being here with us today.
Meredyth:Thank you. Thanks, Dr. Lowry. I'm excited about visiting with you today. I've been looking forward to this.
Sarah:Let's start with a little history. Can you share a little insight into where you're from and how you got here?
Meredyth:Yes, so I uh graduated from vet school at Oklahoma State. And then after that, I went into private mixed animal practice in rural north central Kentucky. And we did everything like many of you do ducks to cows, whatever walked in the door. We worked on it. And but I always knew I wanted to specialize in food animal if the opportunity came. And so I did a residency again back here at Oklahoma State in large animal internal medicine with just a food animal emphasis. And then I was on faculty at Kansas State and Texas AM, each for six years. And that was in food animal field services. So I drove a truck at both of those places and then had the opportunity back uh back in 2018 to come back to OSU. And now I work as a hospital clinician in Food Animal at OSU.
Sarah:Awesome. This season is going to be so fun to hear where everyone has been and where they go. We all overlap so much in the veterinary world. Today we are going to be talking about urinary calculi and small ruminants. Can you start us off with some basic information about blocked animals?
Meredyth:Well, there's so much that the audience of this podcast will already know and have so much experience with them. So I think one of the biggest things that is currently a challenge to us with urolithiaasis is prevention. And that is certainly where I've tried to focus my time and spend my efforts is more on trying to figure out how to prevent this disease than necessarily in developing new ways to treat it or doing something like that. I would much rather prevent this disease. And I think any of us who have had to work on these cases would agree that with the kind of severity that we see with the disease, the expense that often accompanies trying to treat it, that we would sure like to prevent it. So, kind of the background of this paper that we're going to kind of end up talking about today. When I was in my residency here at OSU, my mentor had this idea. Well, first of all, boar goats were becoming really popular in Oklahoma during my residency. And that presented us with a lot of challenges. Many people know about what comes along with boar goats, which is worms, pregnancy, toxemia, and urolithiasis a lot of times. And of course, we see a lot of urolithiasis in the miniature breeds. We really see it in all breeds, but it seems like the boars are very common along with those miniature breeds. And so kind of he and I had this idea about using dietary cation-anion difference to prevent this. So, sort of a more complete way to look at using ammonium chloride or the other kind of what we call anionic salts to prevent this disease. And one of the things that I find, and we're getting better about it, is that for a long time we just talked about preventing stones. How are you preventing stones? Well, I'm keeping waterers clean, I'm keeping waterers warm in the winter time. Um, and what we weren't talking enough about was the stone type. Like, and it turns out that matters greatly about how we're going to prevent it. If you're preventing a phosphatic stone versus a calcium carbonate stone, that's different. And so I think we're doing a lot better job now of talking about that. And then you and I were visiting before we got started about a review paper that I finished and got published earlier this year. It's in a vet clinics in North America, Food Animal Practice. It's very much written towards practitioners where I kind of review everything that we know about urolithysis and really, you know, focus on the prevention and talk about the treatment in there also. But one of the things I focus on there is we need to know what kind of stone we're talking about. And so I started to notice in clinical cases and in some other research that I was doing, that a stone type called AMCP, which is an amorphous magnesium calcium phosphate, was popping up more, and that a lot of stones were mixed type, that they weren't pure struvite and they weren't pure calcium carbonate. And so that complicated things because if there was AMCP, which is a phosphatic and calcium-containing stone, that makes a mess out of our preventative strategies. And so, what this paper is that we're going to talk about is where I took the stones that we got from clinical cases for two years and we typed them. We found out what types of stones they were, and we looked at all as much history and information on those animals as we possibly could to try to extract some clinically useful information that could then go on and be used to help us when we are educating owners and coming up with prevention plans.
Sarah:That was very upsetting to me to see that the stone's gonna be multiple times. Yes. Kind of a slap in the face because you try so hard with prevention and working with your clients, and then to be like it's an uphill battle for sure.
Meredyth:Yeah, this paper is not gonna necessarily have you leaving with a good feeling about um about a direction to go in. It it seems like the more you look for information, the more you're gonna find things that you maybe necessarily didn't want to know.
Sarah:Um let's just back up a little bit. This study was a retrospective review. Can you just kind of explain um how these studies work and why you know they're they're important and they're really useful information for us?
Meredyth:Yeah, so this, as you said, is a retrospective study. So it's kind of what it sounds like. We went backwards and looked at information. And so what a retrospective does, most of them will involve going back, pulling the medical records of cases, and then sort of reanalyzing those and with the data that they contain. So you can see some real strengths in that. You can really, you know, derive a lot of good information about patients and about what happened to them, and uh oftentimes these studies are used to provide prognoses and those kinds of things about disease processes. Some negative things about retrospectives are you may or may not have a lot of control about what got written down. So you go back and you want to look at this particular fact about these cases, and what if somebody didn't write it down, or what if you didn't know that about that case? And that's contrasted with a prospective study, which is where we set out with a plan in place about what we're gonna do. And of course, those then you have more reliable information of what exactly you want to know. So this was a retrospective, it was manipulated a little bit in that we had designed prior to the start of the study what we called an enhanced history form. So normally you would go through, we all have kind of our list of history questions we would normally ask a client, dietary history, and those kinds of things. Well, we went through what would be a routine history for a small ruminant, particularly a blocked small ruminant, and we really stretched everything out. Like what asked them a lot of detailed questions about everything. And so what that did was it gave us a better history and a more detailed history on those animals than what we would have gotten if we were just kind of doing a conversational history. So we had this form that was followed on every animal that was in the study, and then we used the rest of their medical records going forward.
Sarah:Yeah, I was surprised. I was like, wow, I don't ask all of these questions. So you guys were purposefully even before asking getting extra history. Because I was really impressed with how much information you did have, actually.
Meredyth:I mean, we had animals in this study drinking Dr. Pepper, crazy stuff. And it's because we really pushed, we really pushed certain um portions of it and were able to find out sometimes crazy information.
Sarah:I have had goats blocked just on animal cracker, so I'm not surprised at all.
Meredyth:Not surprised, right?
Sarah:Okay, so let's dive into this. Um, besides the devastating conclusion that that stones can be multiple types at once. Tell us what other interesting takeaway things we need to know from this paper.
Meredyth:Okay, so uh a few things that just to kind of review it a little bit, there were 49 animals included in the study. And those 49 animals, over the two-year period that I looked at that I looked at these, had 55 episodes of urolithiasis, obstructive urolithiasis, which means six animals were repeaters. And we can talk, uh, maybe if there's time at the end, we can talk about some ideas about animals who repeat and some genetic susceptibility things that I think may be playing a role in that. But we did have six animals, even in a small study of 49 animals, six of those re-obstructed at some it within that kind of two-year period, and some of them were very short. Um, we did uh harvest 36 stones out of those 55 block situations, and the number one stone was an AMCP struvite combination. So this kind of calcium-containing phosphatic stone along with struvite mixed together. Uh, the number two stone type probably won't surprise anybody, was calcium carbonate. And then the third one was a pure AMCP, and that was quite a bit below. The top two pretty well matched was AMCP struvite combo and then a calcium carbonate behind that. We did find that intact males were more likely to get a struvite AMCP stone, whereas the castrates were more likely to get a calcium carbonate stone. I believe that was not a non-significant finally. I don't believe that that was a statistical significance, but it leaned that way. So we always have to be a little bit careful about how we read into things like that. We did find statistically significantly that um if you're so one of the questions we asked is what do you use this animal for? Breeding, companionship pet, it's a show animal, you know, it's an actual production animal. What is this thing's job? And if the owner called it a pet, it was at a significantly increased risk for calcium carbonate stones.
Sarah:That was horrible.
Meredyth:It shouldn't be. No, all we did was put significant numbers to it. I think we all knew that. Um and and that is particularly horrible because calcium carbonate is the hardest one to treat. And so we've got these animals that people love, and you know, such limited options about how to really get a cure on those. I think what goes along with that kind of pet situation is once you get to be over 36 months of age, over three years of age, you're gonna develop calcium carbonate more than you would a phosphatic stone. And so we looked at age layout and we stratified age, and age was associated with calcium carbonate development. Once you got to be 37 months old or older, you were pretty much exclusively going to get calcium carbonate in this study. Um, some other things, we did not find any seasonal variation, which is something that's always been talked about. Um, that winter time is when you see them block. We could not prove anything by wintertime. Maybe with bigger numbers, we might have shown seasonal variation. Couldn't prove anything by health status. So if they'd had pneumonia or they had some of them had had previous episodes of mange, you know, things like that. Couldn't associate blocking with any other story about their history. Um and really, even by diet, which that was super frustrating. We couldn't really associate it. You couldn't necessarily say, oh, he was on alfalfa, and so he got calcium carbonate, kind of what we, you know, as kind of something we've always clung to. And that's not even, you know, consistently um reliable. Uh, and so that was aggravating as well. Um one of the things that we some of the things that we looked at, we looked, we just described this. There was no statistics to run on this. We looked at gross appearance of the stones. So we uh asked the doctors on the case to describe in the record what do you think this stone looks like? Just whatever words you want to use. And consistently, uh probably not surprisingly, calcium carbonates were described as gold beads or brown beads, something like that. And consistently, the phosphatic type stones, AMCP, struvite, were described as sand, white, beige, those kind of terms were used in there. And I think when we start to talk about the clinical, you know, what can the practitioner take away from this? It is that you can make a reasonable initial educated guess about what kind of stone this is by looking at it.
Sarah:And these are stones that are removed at at surgery, right? Or the either at surgery or whatever.
Meredyth:Correct. Either at surgery or at vermiform removal, or that they urinated out and we caught them. So yes, they came out of the animal. Right. Right.
Sarah:Okay. Do you think just this is your opinion, I admit. If this study was done at, say, Cornell or Minnesota, do you think it would be drastically different with seasonal outcome? I know this is I'm asking you to guess.
Meredyth:Yeah, I think that's possible given I'm so I actually did this study. I should have clarified, I actually did this study while I was at Texas AM. Um, so certainly it was done in a much more temperate client than say New York. You know, the water doesn't get as cold in the waterers in the college station area as it would, say, where you live. And so I think that's possible that in a very cold place um that you might see a more of a seasonal change. I think that is definitely a a portion of the study that needs to be considered when you interpret those results. Absolutely.
Sarah:What was the youngest animal on your study?
Meredyth:Uh we had two animals, I believe, that were l we had three that were less than four months that we had stones on. Um I would have to go back and look and see exactly how young, but they were young, so less than four months, and um all three of those had AMCP strew bite. They were making phosphatic stones. And so they were probably starting to get a little grain, you know, and as they were starting to get them to grow as they weaned them, and so very young. And yeah, and with a urethra the diameter of a human hair, I mean, you know, if they develop a stone, there's no way an animal that small is likely to be able just to pass that out. I mean, yeah.
Sarah:Yeah. Any of us who have taken the process off of one of those young animals, you know, they're still attached and they're so tiny, and you're just like, how would you ever? There are some animals that I swear they must be developing stones in utero.
Meredyth:I I would agree with that. It is a nightmare. And I've seen baby calves with stones. I mean, it's so you do wonder, you know, like we talk about, are there inherent metabolic differences to certain animals that they're just like they're just gonna make a stone? You know, if you give them the building blocks, they're gonna make a stone out of it.
Sarah:Um so what do you think veterinarians and producers can really take away from this study? Like, how can we put this? And I I mean, even though you are, you know, in the uh world of of university, it's you're still very boots on the ground. So I think you have would have no problem answering this for us.
Meredyth:Yeah, I have a blocked goat in the clinic right now. So um, so um absolutely I'm still I'm trying to get those teeny tiny penises exteriorized too. So um I, you know, I think a number of the things maybe that I mentioned, uh, I think, you know, knowing that these stones are multiple types and managing owner expectations about our ability to predict exactly what it's gonna take to prevent those. I think understanding that pets and those older animals over, and our study was over 37 months was the tipping point, that those animals are more likely to get calcium carbonate, which is comes with a poor prognosis, at least in my experience. And so we need to be watching those animals like a hawk and and have that right in the forefront of owners' minds as a significant health concern. Um, and then I also think this gross appearance thing that you know you really can, if you're gonna send that off to the lab, which I think you should, and we you can get it done uh at a reasonable cost or sometimes no cost, depending on uh what lab you're going to, that you can make an educated guess about what that stone composition is, or at least a major part of that stone composition, by saying, is it sand, therefore more likely to be phosphatic, or is it the bead, more likely to be calcium carbonate? I think most people know that already, but we confirmed that here. And then the other thing that I didn't really address before, we also had radiographs on a number of these animals. We did not manipulate that as part of the study. They either got radiographs as part of their workup or they didn't. We didn't act, you know, the study did not make that happen one way or the other. And there is a really good paper out there on radiography of urolithiasis, and but what we showed was was calcium carbonate really easy to see on radiographs. Those big old stones, they're always there, and you can see them pretty easily. The phosphatic stones, we actually took one sheep's stones and laid them on X ray film. Well, I guess this. Was more recent. This was more recent than film. This was digital, but I still call it film. So we laid it on the plate and radiograph those stones. So those were AMCP stones, AMCP strew vite. They are radio opaque. However, when you radiograph the animal, they are hardly ever visible unless you happen to get a big chunk of them where they've all come together, you know, and kind of line that ventral portion of the bladder. And so what we think is happening is by the time you turn up the mass on your machine enough to shoot through a goat's abdomen and pelvic area, you will burn out phosphatic stones. Calcium carbonates, they're going to be there probably, unless they're teeny tiny. And so to me, the take home from that is don't I'm very much for radiographing, especially if you're worried about calcium carbonate, because I think because of its poor prognosis, we need to be telling owners up front this is probably not going to go well, and maybe saving money and putting it into radiographs first to prognose the case. But don't ever say they don't have a stone if you don't see anything on the films, because we have really good evidence that the phosphatic stones may not show up at all. It um I I have had veterinarians send me referral cases with urinary tract disease that they radiographed them. They did their job. Veterinarian took the radiographs, did not see radiographs, did not see radiographs, and so they sent it to me saying it must be something else. And then it comes to us and it is blocked. And it wasn't their fault. I mean, we we're learnt, we're all learning as we go along here. And the thing to remember is when you're radiographing a dog with struvite, you think about that female dog with struvite, she's got a singular rock in her, or maybe multiple, but they make a rock. Sheep and goats make sand with struvite or the other phosphatics. And so sand is going to show up radiographically quite differently, if at all, compared to that female dog with that giant struvite rock that is her entire bladder lumen.
Sarah:What is the next thing that you're kind of thinking about as far as um blocked uh small ruminants?
Meredyth:Yeah, so like most people, um, some of my research got COVID. Um they shut many universities shut down research to any measurable amount. Um, there was a there was a set series of studies I was working on around the same time that I was doing this one, where I was putting artificial implants in goat bladders, female goat bladders, because I could retrograde them up the urethra than have to avoid surgery in them. And um I was putting them on calculogenic diets to artificially, well, it wasn't artificially, they were making stones on these little implants. And then I could harvest, and that's kind of where the AMCP thing came from, because I was getting AMCP off of those implants, and that was the first I'd heard of it. Um the idea there was that I could design studies for prevention that would use less animals. When you're working on a sporadic disease, you'd have to have a million goats on two different diets to be able to get one or two of them to block so that you could actually say, Oh, yeah, this made a difference or whatever. And so I would like to go down that road some more. Um it ended up, I was able to develop a calcium carbonate model and a phosphatic model doing that. And so those were fun projects to do because you were just kind of making it up as you go along. Like there's really wasn't a lot of precedent for that kind of project. And so that's part of research I really love is you know, you have a problem, we're gonna have to invent something to overcome the problem in research, and that happens a lot, and so that was kind of fun. So, yeah, I think I'm always gonna work on your lithiasis. It um, you know, the bug bit me during my residency, and that was a very long time ago, and it's still here. I still and you know, it's because I battle the disease every day, just like you guys do. I mean, it is just one that is just not gonna go away.
Sarah:Just for our producers that are listening, just clarify. So it's the phosphorus ones that the ammonium chloride helps, correct?
Meredyth:Correct. That's the idea, is that those are the those are the target stones. Yeah, the sandy ones.
Sarah:And so with the calcium ones.
Meredyth:Well, cross your fingers and pray. I think we do not have good preventive measures for calcium carbonate. The the the party line has always been avoid high calcium containing feeds. And then that gets everybody confused because we tell you to have a two to three to one calcium to phosphorus ratio to prevent phosphatics. But if you get much above three, you're probably gonna start getting into calcium carbonate. The other issue is there's probably decent reason to believe that using ammonium chloride to prevent phosphatic stones may very well play a role in the increase we have seen in calcium carbonate stones over the years. They have, if you talk to some universities, they will tell you they exclusively see calcium carbonate stones and that they have seen a huge increase over the years. They'll have faculty members that have been there for 30 years, and they'll say, Yeah, we see we started out our careers pure phosphatic, now it's pure calcium carbonate. And the reason for that is the acidification of the body that occurs with ammonium chloride use does cause the kidneys to excrete calcium out into the urine. And so you're preventing these little phosphate ones, but then you may be putting more calcium out there to make a calcium stone. And then it gets even muddier when you think about something like AMCP that has both calcium and phosphorus in it. Um, yeah, so it is, yeah, and so I think this is part of where we were going with this study too, is you need to, to the best of your ability and to the best of what you know to be true about this herd and this particular animal and its purpose and what it's fed, you need to decide what do I think is your most likely stone that you're gonna get. And then you need to make the best decisions you can. It's never gonna be perfect, but say maybe you've got that four-year-old pet weather, and everything I've told you today says a pet weather is probably gonna get calcium carbonate. We're probably I'm probably not gonna recommend ammonium chloride in that animal because I know that he's more calcium, more likely to make a calcium, heavy calcium stone than a phosphorus stone. And so that's where I think the the Bet Clings North America chapter comes in because I think it though kind of the way I put it together, there's a a chart. I mean, who doesn't love a chart? Um, where you go down and you assess this animal's job and you know, water intake, and you go and look at all these parameters to try to decide what is the best combination of preventive factor factors I can do for this particular animal in this particular situation.
Sarah:There's nothing worse than being the vet and your clients doing everything you've told them and their goat still blocks.
Meredyth:It just and if you read this paper, there are animals in there that have no risk factors whatsoever other than being a boy, which is the ultimate one. And so then that leads to my ultimate prevention strategy, which is if you want to have a pet goat, get a girl. You know, that's uh um avoiding males unless you just need males is probably the most reliable way to prevent urolhysis.
Sarah:Yep, for sure, for sure. Do you have something specific that you want to add?
Meredyth:There were other stone types in here. There were silicates in there and there were oxalates in there. And you talked about different areas of the country. I think the stone makeup does change a little bit by where you are in the country. So if you're out in the west with silicate type soils, you may see that. And then a lot of this is null and void when it comes to silicate. Um, this animal I have in the hospital right now appears to be a pure calcium oxalate. And I have never seen an oxalate stone, an animal obstructed by oxalates before. Um, and so that threw me a new loop that I, you know, I've been at this 20 some years, and and uh I think I've got an oxalate case right now. And so silicates and oxalates are probably not dependent on pH at all. They're probably purely plant related. Um, and so those, if you're in an area where you've got a lot of oxalate plants or a lot of silicate plants, you know, a lot of this discussion about pH uh isn't really going to apply in those situations. So I would just throw that out just for a little bit more geographic inclusivity. Um that there may be listeners that are in areas where the stone makeup is different because of the plants they have.
Sarah:Great. One more factor. Great. They're on all the things.
Meredyth:Right.
Sarah:Anything else?
Meredyth:The phase of the moon. We did not look at that. I guess I could go back and do that, but I'll I'll let you rest. I feel like I've abused you enough today.
Sarah:Okay. I'll give you a breach. Yeah, yeah. I know you are big on social media. This is your opportunity to give a shout out for anybody if you'd like to point them in that direction. I mean, you're giving to us, so let us give back. Yeah.
Meredyth:So um uh my company, Large Animal Consulting and Education, is at large animal CE. Uh, is the my social media handle on um Facebook and Instagram. I'm not cool enough to have any of the other ones. I can I can barely manage the two that I have. Um and uh feel free to reach out to me there with questions. I know that probably I have maybe now created more questions than answers for many of you, and that's really why I'm on those is to help, not to uh, you know, that's what I'm there for is to answer questions and to give people the information that they need based on what I've had the opportunity to learn. Um and so you can find me there. Uh, you can find me at largeanimalce.com. There is a contact form. That's probably just the easiest way, just to go to the site and do a contact form. And that way you don't have to remember an email address, and that's largeanimalce.com.
Sarah:Awesome. Okay, so I've decided this season we're gonna end every um podcast with this question. Um, what do you see as the next problem that researches need to think about and address in small ruminant medicine? So it can be in your field, you can shoot for the moon, something totally new. What it what are your thoughts?
Meredyth:Well, my first knee-jerk response is funding, funding for research. That's the next thing we need to conquer, um, which I realize is not at all what you're looking for. Um, but I do want to give a shout out to AASRP, uh, not only for sponsoring this podcast and developing this podcast, which I think many people have found incredibly helpful, but they have also started a research fund. And that helps people like me. And there are even private practitioners who have been awarded research grants when they're in a unique situation where they can generate. If you want more data generated on diseases that are of interest to you, um, consider donating even five or ten bucks because it just goes in the pot with everything else, you know. And um, because ASRP did look forward and say there is not great funding out there for sheep and goat research. And um, so that is a just a little uh side thing about um something really terrific that AASRP has done is establish that fund. As far as, you know, I think parasites are always going to be there. I think anybody who doesn't say parasites is part of that question, um, but some things where I see holes, um, I think respiratory disease, we do not know enough about sheep and goat pneumonia. Uh I suspect on the pneumonia side of things, the dairy, I I'm pretty meat goat-oriented. I suspect dairy goat folks would bring up OPP as part of CAE and OPP as part of that respiratory thing. And then I think drug use, withdrawal times, um, those kinds of things are a place where for we're getting better all the time because those are pretty straightforward projects to run. But again, people need funding to run them. And so I think the more that we can know about how the drugs we've historically used in cattle work in sheep and goats, um, that will be tremendously helpful. So there's like four answers for your one nice question.
Sarah:So lots to work on.
Meredyth:Lots of work to do. Yeah.
Sarah:So much. Yes, we are excited, ASRP, that we have. I think twice now we've awarded a research grant. And um currently, I think we're doing it every other year. Uh, we're still figuring it out and figuring our budget out. But yeah, it is super exciting. Um all right. Well, thank you again, Dr. Jones, for joining us today in Boz and Bleats. And we'll see you next time.
