Our next speaker today is Dr. Neal Dyer. He's with the NDSU Veterinary Diagnostic Lab. We've asked him to speak to us about common beef diseases in North Dakota. And I suspect it's going to have to be the abridged version, or otherwise we might be here all day or maybe a whole semester. But with that, Dr. Dyer, are you available? I am. Let me see if I can do this here. There we go. Okay. Yeah, let's get started. We'll talk about some of the things actually that have been hit already. And I'll try to highlight the kinds of things that we see at the Veterinary Diagnostic Lab.  But as you say, I'm going to have to get the important stuff. I want to break this really into four categories today that I think would represent the types of things that we see respiratory disease or pneumonia, diseases that look like there's something wrong with the nervous system, diseases of the digestive system, and then a couple of things just about muscle and the skeletal system, and those kind of make up the bulk of what we see. I want to start about talking about respiratory disease and cattle, what everybody refers to as pneumonia. But now, at least in the veterinary world, more often referred to as bovine respiratory disease complex, or BRDC, and the reason that they do that is because, as Jerry already pointed out and Charlie's talked about, there are lots of things that go into making an animal develop respiratory disease, and I'm not going to talk about things that we've already talked about, but you can see that that list has already come up today. And so there's a lot of things that contribute to whether or not an animal actually develops pneumonia. And when you talk about the environment, again, things that we've mentioned related to, you know, what that animal is exposed to, how much stress is presented with, what kind of nutritional condition it's in, and that last, or the middle bullet there about ventilation and exposure to ammonia I think is worth mentioning. That's going to be dependent a little bit upon what the housing situation is for each individual animal, but ammonia will sort of destroy some of the protective qualities of the lung and the airways and when that happens, it can kind of predispose an animal to problems with pathogenic organisms. So when I think about what causes respiratory disease in cattle, really there's four viruses that probably most of you have heard of, and most of you vaccinate for, think about vaccinating for, and that's going to be BVD, BRSV, IBR, and then in the PI3 or peri influenza virus. So the reality of this is, as far as true respiratory disease, the top two are the two that we see most commonly contributing to respiratory disease in cattle that come through the diagnostic lab. IBR is primarily an abortion agent in cattle anymore. Most cattle have been exposed to IBR and they actually carry that herpes virus in their system. It would be heifers that would be more at risk for IBR, especially unvaccinated animals that would tend to have abortion problems. But it's always included in the respiratory group, so there it is. And then peri influenza is really not a significant pathogen in cattle. It can be a predisposing virus, but again, it's part of that group that shows up in most multiple vaccines. So I'm going to have just a word to say about each one of these and show you a few pictures. Traditionally, BVD, as Dr. Stuck had talked about earlier, is almost thought of as a reproductive pathogen or even a digestive pathogen. But the truth of the matter is that, I would say in the last couple of decades, it's floated to the surface as a respiratory pathogen in cattle. And any more, I would say that I find BVD positive cases more often in cases of pneumonia than I do in cases of abortion or digestive disease. So it has a real place in the respiratory group. As far as what it looks like, you know, any of these viruses can cause ocular nasal discharge. So they've got fluid running out of their nose and their eyes. They're running a fever. They're having trouble breathing. They may develop some diarrhea, just as kind of a nonspecific cause. And they may or may not get oral ulcers. I know people think about oral ulcers with BVD, but they don't always happen. If they do, it's certainly a nice clue, but that sign can't always be relied on. BRSV, I think, is probably the number one respiratory pathogen in cattle. And you can see the list of clinical signs there that go along with the BRSV infection. I think this is a really tough virus to identify. Some of you who have submitted tissue to the diagnostic lab have probably found out how it's tough to identify BRSV. It's a fragile virus, and it's not always detectable in tissue for very long. So I think there are plenty of cases that have actually had BRSV involved. But it has not been identified from a diagnostic standpoint. However, it does pop up with a fairly good frequency, and we have a couple of different tests that we use to identify BRSV in tissue. The best way to protect yourself against this, as you heard about in the previous discussion, is to vaccinate for it. Because it can be a real problem, and I'll talk a little bit more about it as a co-infection. Here's a picture of a lung that's got a BRSV problem. And really, I don't know if I can get them, if you can see the pointer on here or not. But you see all these clear spaces in between the lung lobe tissue, and that's a pretty typical finding for a viral pneumonia. You get a lot of kind of emphysema in the lung, and the virus is distributed pretty evenly through the lung, so the whole thing feels kind of firm, almost like a piece of liver would feel. And that's pretty typical for viral pneumonia, as you get this even distribution all the way throughout the lung. And so if you do happen to open up one of these animals and look, that might be kind of a general clue for you as to what you might be dealing with. As I said, IBRs are herpes virus. It does cause respiratory disease, and cattle are upper respiratory disease. It's also a reproductive problem, as I said, in cases of abortion. It can cause some neurologic disease as well. So herpes viruses across species, not just cattle, but just about anything that can have a herpes virus, tend to act like this. It's known as red nose as well, and again, this is a disease that is just smart to vaccinate for. Not so much because it would keep respiratory disease out of a group of cattle, but more because it prevents abortions. And so that just makes good sense. Tends to have higher mortality in calves. And again, this just makes sense too because animals that are infected with herpes viruses will develop immunity to them. And so calves aren't going to have as strong an immunity as an adult cow. And so if animals do get ill from this virus, it's usually going to be the younger animals. They're going to become immune to it as they get older. And they'll actually become carriers and they'll shed it into the environment. And there's not much you can do about that because it's just out there except for vaccinating. So stressed adult animals can shed this virus into the environment and be a source of the virus. If animals are vaccinated, hopefully most of them will be protected by the vaccination or just by natural exposure of the virus. You'll get some natural immunity from that and the herd as well. So here's a picture of what classic IBR looks like. And what this is is a trachea or a windpipe opened up. You can see that needle holding the voice box open and all that kind of cruddy looking lining tissue here in the trachea.  And this is what classic IBR looks like. It causes this inflammation of the trachea or the windpipe. The truth though is that I hardly ever see this at the diagnostic lab. It's a pretty uncommon lesion now. And the reason is because people vaccinate for IBR and it's a pretty uncommon finding anymore. The only thing I'm going to say about PI3 is that it's really not a big deal. It's more of a predisposing infection. And so animals that have a pair of influence infection might develop a secondary bacterial problem. But if you vaccinate for this, I think you're pretty well protected and it's really not much of an issue in cattle. It's just included in a lot of those vaccines that are marketed as multiple viral vaccines. So that's the virus group. But again, BRSV and BVD would be the two big respiratory viruses in cattle. When you talk about bacteria, it's a longer list. And certainly of the ones that are listed there, manheimia would be an important bacteria. What used to be called pasturella hemolytica is not called manheimia hemolytica. The other one is his histophilus somni or what used to be called hemophilus somnis. That's capable of causing pneumonia all by itself. And then one that's kind of reared its ugly head here in the last 10 years is mycoplasma bovis. This is kind of a wild card because this organism is capable of doing a lot of things in cattle that are kind of a problem. Besides just pneumonia, I've seen it in cases of abortion. Certainly inner ear infections, arthritis cases, mastitis cases. And so we'll talk a little bit about mycoplasma bovis, but they are developing some vaccines. There are some drugs that are labeled for this pathogen, but it's kind of nasty and it's one that you have to pay attention to. The other ones there, the pasturella organisms and the actinomyces, those are sort of secondary problems. They show up after the damage has already started and they just create havoc. They just make things worse. So of the bacteria that can actually cause pneumonia all by themselves, manheimia and histophilus and mycoplasma would be the three to watch for. Manheimia causes what's typically thought of as shipping fever pneumonia. And that's able to, that can kill cows all by itself. The thing to remember is that most of these bacteria can be found on the tonsils of healthy animals. If I were to culture some tonsil tissue at a slaughterhouse, I could probably find all of these. So the take home message there is stress is what turns these bacteria loose. Or some kind of a viral infection turns these bacteria loose and lets them cause the disease that they cause. But they can be found in healthy animals and not do anything at all. So manheimia, as I said, is the agent that causes classic shipping fever pneumonia. In Cadillat develop problems with this. It can come on quickly and it can kill them quickly. They'll run fevers and they'll be in trouble before you know it. There are bacterias out there for it. And often what happens in cases of shipping fever pneumonia is that when the cow's immune system is trying to get rid of the bacteria, it actually causes more damage than the bacteria does. And so the body ends up sort of hurting itself. And part of the way to treat this problem is to actually see if you can cool off the immune system a little bit with anti-inflammatory drugs because the lung is sort of turning on itself to create a more severe pneumonia. And here's a picture of a classic shipping fever lung. This line here shows, if I can get this to work, it shows the difference between normal lung. Above the line is normal where it looks kind of pink and below the line is abnormal where it looks kind of dark brown or red. That dark brown part of the lung is just as solid as a piece of liver. You can't breathe through that at all. And that's a real common distribution for bacterial pneumonia. All of that inflammation is on the bottom side of the lung or the downside of the lung because that's where the bacteria drop and that's where the inflammation occurs. So if you open one of these up and you see a real distinct line like that, you're very likely dealing with a bacterial pneumonia, at least in part. And these are tough to turn around. You have to get them really early. You have to treat these calves when they're spiking a fever because when the lung gets this far, you're just not going to be able to do much about it. The pastorella organism, again, this is a secondary problem. It doesn't typically cause pneumonia all by itself, but it's around. It's cattle carry this organism, and so if they start to develop pneumonia, this will contribute to the problem. There's lots of pastorella bacturins out there that can be used. I don't think people routinely use them, but if they have a problem heard, then they probably would start to incorporate that into their vaccination program. Histophilus. Again, this organism can cause pneumonia all by itself. Probably the thing to recognize about histophilus is that it's capable of causing other kinds of problems besides just pneumonia. You can get nervous system disease with this. You can get abortion from it. You can get heart infections. And so it can present itself in a lot of different ways, and it usually doesn't do it altogether. In other words, you'll get one or the other, but you won't get all of them together. As a matter of fact, this winter we've seen an increase in the number of nervous system cases related to histophilus somnus. Just as an indicator of kind of a current trend that we're seeing out there right now. And it's often found in mixed infections. It will be found with other bacteria or with other viruses. And again, there's a bacturin available for histophilus as well. A couple of different products. So you can try and protect yourself against this one. As I said, mycoplasma bolvis is a problem organism in cattle. Bacteria tend to colonize the cells that line the airways. And all of these cells have little hairs on them, or cilia. And these cilia are active in removing dust and pathogens in particulate matter from the airways.  And so now the lung is vulnerable to dust, to bacteria, to particles. And all of these things can work at creating a worse case of respiratory disease. So mycoplasma bolvis tends to open the lung up to all kinds of problems. And formation of abscesses in the lung and lets other bacteria in. And so it really is a troublesome bacteria. And as I say, it can cause lots of other problems throughout the body. There are some drugs that are labeled. I think I've got them listed there. And yet there are some bacteria available, too. But I think this is an organism that more and more people are experiencing frustration with and having to deal with. And we certainly see it a lot more than we used to.  And this is an organism called okinomyces. Again, not a primary pathogen can't cause pneumonia all by itself, but it goes up later on and causes a lot of chronic changes, scar tissue, abscesses. And these kinds of changes in lungs you cannot reverse. They're not going to get better. So animals like this that have chronic respiratory disease, you know, you're best to cull them because you're not going to get these better. They're just too far down the road. So I think most of you have seen animals that have had these kinds of problems. You know how they act, you know what they look like. And these clinical signs are what you're going to have to pick up on to decide, you know, are you going to collect samples for diagnostic work? Are you going to institute some treatment? Are you going to make some management decisions? But depending upon what you're dealing with and what stage you're in, you'll see different variations on these kinds of clinical signs. I think you have to mention that viral infections in general, when they get into a herd, let's talk about BRSV, you'll get a high number of animals affected.  You'll just have to kind of weather the storm to get through the viral infection because you can't really treat for the virus. You can treat for the, you can do some symptomatic treatment, but you can't do anything to get rid of the virus. Other than possibly vaccinate in the middle of an outbreak. But what happens is the bacteria get involved and so secondary bacterial infections make the situation much worse and those are the animals that die. The ones that have bacterial co-infections or are infected with a primary, primary bacterial mnemonic agent that can actually, you know, kill them like manheimia. So mixed infections are far worse. I think you'd much rather have a pure viral infection to get it and just get through with it and let those animals recover and come back. But the bacterial infections are much tougher to turn around and you'll have more animals die when you're dealing with those. Okay, let's switch gears here and look at some of the diseases that affect the nervous system and there's a list there. As far as the lab goes, the top one, two, three, four, five would be the ones that we primarily deal with. The rabies, listeriosis and thrombo- or bacterial infections and the lead poisoning and then polio is actually a... Well, it's essentially a sulfur problem in cattle. The bottom three are more sporadic and not as commonly diagnosed. I have to put a slide up on rabies because if I don't, then I can't live with myself. Remember that North Dakota has plenty of rabies and skunks are the number one carrier of rabies in the upper Midwest. I've become a great respecter of this disease and everybody who is out in a setting where skunks can show up need to be aware of it. Any time you see an animal that's demonstrating signs of nervous system trouble, you have to think about rabies first and so if these animals look like they're having trouble chewing or swallowing, do not stick your hand in their mouth. This sounds obvious but I can't tell you how many cases I've had come in the diagnostic lab where people have done just that and then it turns out that it's a rabies case and they have to go get the shots for prophylaxis. So always keep this in the back of your mind. Talk to your veterinarian about what you're dealing with because more often than not the surprise cases occur where you have an animal and you think, oh, that can't be rabies and that it actually turns out to be rabies in fact. Keep it at the top of the list and don't forget that it's out there and cows that develop rabies are getting exposed to skunks. That's how they're picking it up. Of the bacterial diseases to talk about, we need to talk about listeria which is a bacterial disease that's associated with defeating a silage. It causes a neurologic disease in cattle and it affects a certain portion of their brain. You don't see a lot of listeria. It's usually a premise related problem where there may be a bad bunch of silage that's being fed and a person may lose a few animals. But we always look for it because it is common enough that it needs to be checked for. The thing you should remember about listeria is that it is a zoonotic disease, meaning that it can be transmitted from animals to people. This wouldn't be a very common occurrence, but if you had an animal, let's say, that was abording from listeria, you could possibly become exposed if you were pulling a calf on that animal or handling fetal tissues or placenta or something. This is one of those organisms that can affect both animals and people. Then this picture just shows you the portion of the brain. You see all these little red dots down here. These are areas that have been affected by the listeria bacteria. That's the region of the brain that's affected, the brain's stem or the bottom portion of the brain. The other bacterial disease, this is that organism that you've seen before, is staphylocis. This causes neurologic disease in cattle, as well, and it targets blood vessels. That's where the bacteria likes to go and causes inflammation. By the time that this is occurring in a cow's brain, you're not going to do much about it. It's very hard to treat. The bacterines, and I don't know the answer to this as I'm speaking about it, it didn't occur to me, but I don't know if these bacterines are licensed for neurologic histophilis. I think it's probably for the respiratory variety. This is the one that we're seeing a little bit more of this winter. We've had several cases of this pop-up. It tends to be a seasonal disease. I don't know why the neurologic form would be more common, but we definitely have had an uptick in the number of cases. Here's a brain from an animal that's affected. You see these big areas that look dark red to bloody.  Lead poisoning, almost always seen in the spring in calves. When the snow melts, they find a battery and they lick on it and they get lead poisoning and it doesn't take much lead to kill them. There are some other sources out there, depending upon each premise that might be affected, but typically we see it in cases with batteries. These animals will show you some blindness and staggering. This is tested in the lab by looking at either whole blood or tissue and we just test for the lead levels. This is pretty common. If we have a case where we'll have a calf that comes in that died suddenly and nobody really knows what's going on, a lot of those will turn out to be lead cases. Polyo is a complicated disease. When I was in vet school, it used to be so easy. We just thought about it as being related to thiamine deficiency. Well, somebody went and did some research on that and debunked that whole thing and now it's pretty much associated with elevated sulfur intake. People with polio problems in their herd need to look at the total sulfur intake in their animals, not just what might be in the feed, but you need to have your water looked at as well and think about what both are contributing to the sulfur levels. But what it does is it causes degeneration in the cortex or the gray matter of the brain. It does seem to respond to thiamine treatment, but I don't think they really know what the association between those two, with treatment and response to treatment is, but it certainly is a good reason to use thiamine if you have an animal that's affected. It's just that there's not a clear direct connection between those two things. So what happens is that the rumen converts the sulfur into sulfide and then that causes some energy depletion in the brain and the brain is real sensitive to energy depletion and then these animals show signs of nervous system disease. You can evaluate the amount of sulfide in the rumen by pulling some of that gas off the rumen and there's some instrumentation to do that and there are ways to do that. They aren't common commercially yet, but there are certainly research done that evaluates the rumen gas cap and how much sulfur and sulfide is in that gas. So I think they're finding out more and more about this with the research that they do. And we see cases of polio, I would say, sporadically. It's not real common, but we do see some cases and I've got a picture here of a normal brain on the, I guess it's on my right, that says control on it and then you see the one next to it. You see how much, how collapsed that brain looks and how much thinner it looks and that's just because the gray matter on that brain is degenerated and that's a pretty severe case of polio. Some of them aren't quite that bad, but to just give you an idea of how extreme it can be and what can happen in some of those animals and so you can see why they act like there's something wrong with their nervous system. I'm going to hit these last three just quickly just to mention a nervous coccytiosis usually related to animals that already have a coccytia infection and you can't really see any microscopic changes in the brain but these animals clearly have neurologic disease and they'll go down and die and it has something to do with some kind of a byproduct of the coccytia infection but the anecdotal stuff that I hear about this are cows that go down after they come out of a shoot they'll just drop but typically they already have some kind of coccytia infection in the intestine. I'm going to jump to the next big category which is gastrointestinal disease. The reason that I put this slide up here is just to give you an idea of when you could reasonably expect to occur because not all infectious agents are able to show up at the same time and so this is just sort of a chart with reasonable expectation of timing. As you can see like the bottom where their coccytiosis needs a couple of weeks to show up in calves as opposed to E. coli which can show up just in a couple of days. Just a word about E. coli there's a huge topic I can't possibly cover but obviously it's a bacterial infection in the small intestine it's going to affect the lining of the intestine it's going to cause a diarrhea where there's loss of fluid and so these animals are putting out tremendous amounts of fluid in their fecal matter and their dying of dehydration essentially more than their dying of the bacterial infection. There are lots of different kinds of E. coli and just because a calf has E. coli in its intestine doesn't mean anything it has to be a disease causing type of E. coli so that's the value of diagnosing what's going on because you need to know if the E. coli that's there means anything. So there are some products out there that can help you with this but it is important to know what kind of E. coli you're dealing with and when you have animals that are affected with this type of infection to replace fluids is as important as anything because that's why they're dying. A few kinds of viruses that are important rotavirus number one again this is a sporadic infection that we see from time to time you can vaccinate for this it's going to cause a similar kind of diarrhea as E. coli this loss of fluid it does affect the small intestine but again the biggest problem is that the animals losing fluids just like E. coli and in cases of pneumonia these agents will often occur together so you'll get an enteritis in the calf that's caused by both E. coli and rotavirus or E. coli and something else the other virus that we see sometimes is coronavirus this will do similar things as we talked about with rota except that sometimes you'll get some blood with coronavirus in the fecal matter that's because coronavirus damages the lining of the intestine a little bit more but again you can vaccinate for this and so there are some ways to protect calves from this problem especially if they're getting a good load of colostrum as we talked about earlier it'll help them a lot whether or not they break with coronavirus and these viruses are going to be put into the environment by animals that are carriers that are shedding it and so it's hard to identify those animals sometimes this is just a little schematic to just show you what a virus does to the intestine the normal lining of the intestine is on the left of the screen as I'm looking at it and so that's lined by nice chubby cells that are doing what they're supposed to do absorbing nutrients and the one on the right side is damaged and you can see how the cells aren't as healthy looking and so that's really what the virus does it damages the lining of the intestine makes it inefficient to absorb nutrients and makes it lose fluid and if you can wait for the virus to get through the animal system those cells will come back and you'll get a normal or relatively normal gut again but if the animal is losing too much fluid it's going to die of fluid loss and electrolyte imbalances before the intestine will repair itself and that's why scourage is such a terrible problem to kill them before their gut can repair itself the only real parasite that I'll talk about in a minute but cryptosporidium is a parasite in calves that it's sort of a question mark in my mind it's not an invasive organism it just sits on the lining of the intestine and causes problems with absorption but it usually occurs with something else you don't see cryptosporidium it's a problem all by itself but it's a problem when it's there with E. coli or with rotavirus it's one of those secondary problems that comes in it's difficult to treat there's no vaccine for it and so you wouldn't know you had this unless you set a sample to the diagnostic lab and they identified it and then you could get together with your veterinarian and decide what you needed to do Salmonella is a serious bacteria Salmonella can cause disease so calves aren't unique people can get Salmonella infections which is a good reason why you need to have good hygiene when you're handling animals that have scours because you can get some of this yourself and you don't want it so you want to wear gloves or wash your hands but Salmonella bacteria is invasive it can cause tissue damage and so these animals will have blood in their diarrhea and they will be sick and often the cows can get sick so maybe you're dealing with this bacteria because this one's able to do some damage beyond just normal fluid diarrhea this can actually get in and cause some systemic disease and do some bad things so there are bacteria out there for Salmonella I don't think that people are crazy about them as far as how efficacious they are but in some cases there's a problem they may be appropriate here's a picture of an intestine that's affected by Salmonella and the thing to look at is this intestine is cut open and laid flat and you see that tube that tubular structure running down the middle of the intestine all that is is dead intestinal cells and inflammatory material and it just forms a big tube and so you can see that Salmonella completely strips the intestine of anything useful potentially passed in the fecal matter and in fact you might see those those kind of those casts those inflammatory casts coming out of animals they'll actually defecate those right out of their intestine because they're just loose in there if you see that that's a bad sign that means you're probably going to lose that animal because they're not going to repair that stretch of intestine it's just too much damage so if you do see blood in the feces Clostridium and Salmonella Coxidia BVD and coronavirus would be the ones that I would be thinking about some pathogens don't cause bleeding in the bowel and so if you do see blood it helps you at least make a short list of things that might be there and of course you need to try and narrow that down by some diagnostic work I'm just going to show you a few pictures here of an intestine here's a nice green intestine this is pretty normal for anything that's starting to decompose or rot so as you look at this it doesn't really tell me much of anything anytime you opened up a calf that died of something you can see gut that looked like this but if you see something that looks like this where you have a real regional area of reddening like this where I'm drawing the arrow along here this tells you that you're probably dealing with something real this is probably a bacterial infection because only a certain part of the bowel is infected rather than the whole thing looking red and kind of green colored if you open that up you can see there's normal intestine on the top there it looks kind of tan colored but you can obviously see there's a problem at the bottom too with all that blood so this would be something like clostridium or salmonella could do this too here's a section of bowel you're focusing on the intestine but your clue here is in the middle instead this big white round structure you see here is a lymph node and when you get big lymph nodes and pieces of intestine that tells you that there's some inflammation there and that's just because the lymph node is responsible for the immune response in the gut and if it's responding to something it gets big and so this is a case of anoritis in the calf too that was a bacteria a couple more cases of salmonella type diseases when you open this intestine up look at it it looks real rough and this is just more inflammation in dead cells that line the intestine disease that cause oral ulcers there's a short list the ones with the stars by them are foreign animal diseases and we do not want those in North Dakota but you always have to come in the back of your mind think about that when you have oral ulcers obviously much more likely we would have BVD or rough feed stuff that would be causing it but part of our job as a lab is to think about those other diseases as well picture here some oral ulcers you can see how that's the gums on this calf are worn down to the red tissue and then here the tongue on this one pulled out you can see actually the only normal part of the tongue here is down at the white tip now all of this is stripped off you can see why and actually I think this is foot and mouth disease that was taken at Plum Island lab in New York but you can see why that's so painful who would want to eat with a tongue like that it would be really hurt this is a piece of small intestine from an animal affected by BVD and the thing to look at is this dark area down here on the bottom I can find it right down here where that arrow is showing up on the bottom that's kind of red and if you cut that intestine open and look at it this is what you would see you got that little spot that little yellow spot it looks like mucus on the surface there that's a little spot of dead tissue that the BVD virus targets and that's you know sort of characteristic for BVD infections those kinds of ulcerations okay I'm going to finish up quickly here with just a couple comments about diseases in muscle because it's just a couple I think that occur enough that I should just mention them to you one of them is what you would know as white muscle disease or vitamin E selenium deficiency we see this sporadically depending upon some kind of nutritional problem in the animal and vitamin E and selenium have antioxidant properties and if they're not present then you get some damage in the muscle the other way that we can get degenerative disease in muscle is some kind of a toxic agent and plants occasionally cause it but more often it's some kind of a feed mixing problem or you might get too much of a in this case menensin and feed and that can cause especially in horses not so much in cattle but you can get some pretty dramatic changes in muscle so here's some heart tissue from an animal it's affected with I think this was a menensin case but you see these big pale areas in the heart and that's pretty typical heart should be kind of a red brown color and if you're seeing some big pale areas in it that's not a good thing and that's a sign that you have tissue damage over here on these cross sections of heart you see all these pale areas here that's the same the same phenomenon that muscle is just not working well anymore so then I'm going to just wrap it up with one inflammatory disease in muscle that everybody's familiar with and that's black leg and the reason I mention it is because while it is sporadic it does show up in a while it's caused by a clostridium bacteria that's found in the soil and the theory is that cattle ingest this bacteria when they're feeding and the bacteria stays in the body and then some sort of a traumatic event or some kind of an event in the body causes those bacteria to multiply and release a toxin that damages muscle tissue and so you get this dark red black muscle that gives the disease its name black leg the thing about black leg is there's a great vaccine available and it's not expensive and people should use it because it's always the best animals that get black leg and die from it and it gets to be expensive when it happens so I think vaccinating for black leg is really a good idea here's a picture of the disease here and you can see where it gets its name it looks black and that's just because all that muscle tissue is dead and fallen apart and then I think I got one picture of a heart that's affected by black leg just to tell you that there is a variation on the theme of this disease where the heart is affected and so you may not actually see it in the muscle in these kinds of cases because it's in fact the heart that's showing the problem and I think whoops I got one more this is an injection site just to warn you that when you do put a needle in a muscle there's a reaction and you can see all that pale area is dead and then the dark red to black on the outside of it there that's around it is just blood and muscle tissue that's degenerating so you got to be careful about vaccinating in large muscle groups like that and I think that's it yeah that's it ok so thank you I'll try to answer any questions that was kind of fast but I think I hit the big stuff Thank you Dr. Dyer are there any questions out there I'll wait for a second Yeah we have one here at LeMore this Biomoss question was is that control E. Coli I guess some of the salesmen are saying that it does anybody know the answer to that? Biomoss Mono-Aligosaccharides oh ok well I may have to have Jerry help me with this I'm not as clinical as I used to be I'm guessing what they're trying to do is protect the lining of the intestine from the E. Coli attaching to it that's going to depend upon the type of E. Coli involved again because there's several different types of the ways that they attach to the intestine vary so Jerry have you got any information on that? You know I tried to track some of this stuff down one time Carl it wasn't really successful there's almost no scientific literature that demonstrates efficacy of this stuff it's observational anecdotal and I don't mean to discount that sort of thing but I guess you'd like to see a little bit more than just observational anecdotal data as to whether it works or not because that's really the question if I use this can it help and I can't answer that question yeah Carl if you're talking you must be on mute No I'm on mute again Jerry I was going to say from a nutritional standpoint I think you're right there's a lot of antecedal evidences out there that shows that it does work in certain instances but there's not a lot of depth of data to really show that I'm sure all tech would probably dispute some of that comment but they are a supplier of what called biomass in certain situations it does seem to show up and it's become more prevalent now and people have used it testimony that there is some effect especially in baby calf scours and Carl I don't mean to leave the wrong impression if there's data out there I'd be more than willing to change my mind if I saw something and I haven't seen it either but that was a question we had right that I had from down in McIntosh County that was what feed additives can you put into control calf scours coxidiosis and I think the question revolves around biomass and anaphors but is it in the cow herd or the calf or both what's your viewpoints well I think anaphors work I don't know again a biomass I'm not that familiar with but if you're looking for a coxidius stat I would think you'd be feeding it to the calves because they're the ones who are going to be susceptible to the problem and they're the ones who are going to break with disease I mean I almost never seen I don't see many adult cows with coxidia you know a lot of younger animals I think the question relates around trying to reduce the incidence by feeding monensin to the cow herd prior to calving or during calving what do you think I'll take a stab at and let Carl and Neil jump in here too but I think there's only one anaphore that's labeled to be used in adult beef cows monensin now will or monensin reduce perhaps the level of shedding of coxidia in the environment could be and that's the idea of course because there's no way to get it into the calves unless you want to formulate some type of method where they're going to get it into their system I don't know what that is so that's the only logic behind feeding cows or monensin is to cut down shedding and then some people have thought it made a difference that's my best answer


Good morning all, today I will be dealing about research designs or epidemiological methods. So research is known as epidemiology when it occurs among a group of people. So epidemiology we can split the word epidemiology as epi, demos and ology. So epi means distribution, demo means people, we know demography and ology is study. So the study of distribution of something in a group of people is epidemiology. The research is we are searching something again and again. So commonly there are few methods to conduct a proper epidemiological study. So when we come across a problem which occurs among a large group of people we need to do a epidemiological study. So there is fundamental difference between an epidemiologist and a clinician. Clinician is people go to a clinician for getting a checkup or getting a treatment for a particular disease that is an individual, an individual going to a doctor for get a treatment. So what happens when many people are affected with the same disease just like we are seeing the corona or COVID-19 disease. So doctors cannot actually solve the problem. So what happens is epidemiologists go to the public and treat the disease. So what they do is they conduct a study and they find out how it distributes and where it is getting distributed and what is the time, place and person distribution and they solve the problem. That is all about epidemiological method. So when to conduct epidemiology and how to conduct epidemiology? So it depends on the disease. So basically we know prevalence of anemia. We have seen leptosporosis, we have seen low birth weight, there is factors and a conventional suture or stapler which is used for suturing the wounds. So all these are different problems and all these four are to be dealt with different epidemiological studies or epidemiological study designs. So basically a research design or epidemiological study, research and epidemiology is almost the same. The research is we are trying to find out a new solution or a solution for a problem. Epidemiology is the problem occurs among the people. So basically the designs are divided into two, the observational and experimental. It is very clear that one is just an observation and one is an experiment. So when a clinician is treating a particular patient and epidemiologist treating a group of people or a mass of people, clinician treats the patient within the clinic or within the hospital whereas epidemiologists go to the public and treat the disease. You cannot treat a single patient, you have to find out how the disease spreads, where it is getting started. So all this you have to find out and treat the disease and only the disease will be cured from a mass of people. So observational is an epidemiologist just observing the situation and finding out a solution. It is just like our coronavirus. COVID-19 disease, we are not treating the disease by applying any medicine or a vaccination. We are observing where it is getting spread and how fast it is getting spread. So we are asking people to go for a lockdown. So there are lot of things involved in observation study but the epidemiologists will not do any purposeful intervention from his side. So we will be just an observer. But whereas in experimental, the clinician or researcher or epidemiologist will do an intervention from his part to find out the cause of a disease or find out the effect of a particular drug. So clinician or researcher or epidemiologist will have a significant role in experimental study whereas in observation study he just act as an observer but still find out the solution of the problem. So under observation studies we have the major divisions, one is descriptive study and one is analytical study. So in observation study before that we need to find out a problem. Suppose you imagine a cholera outbreak in your city. So cholera outbreak must have started from a sewage containing water supply and lot of people are getting affected. So you are appointed as an epidemiologist and you are going to the location and you are finding out the disease, you are finding out the people, their symptoms and you are trying to find out where it is started and how it is getting distributed which all groups of people is getting affected.  Hypothesis means an assumption, your doubt without any evidence, without any proper evidence. The data which you collected by asking questions, how, when, where, you ask many questions related to the cholera, what are the symptoms, where it started, how it started, who all are affected. All you ask and make a hypothesis, make an assumption and you could say that a particular restaurant or particular pump or particular common tap is the, is, you cannot say is, it could be, it should be an assumption, could be the source of infection and these many people are affected. So drinking water from this pipe or drinking water from that particular hotel could be the cause of cholera. So you are making a hypothesis. That is a descriptive study, basic, it's a basic thing. The first study should be descriptive study in any epidemiological design. So you have a data that is, the cholera is caused due to drinking water from that particular pipe, a common pipe. But you cannot say that the cholera is due to that disease. To say that you need to test the hypothesis which was made in descriptive study. So testing hypothesis you have to do analytical study. So from the data you need to compare the data. So when you do analysis on the data with a comparison group that is known as analytical study. So only after analytical study you can say that this could be the reason for that particular disease. So these are the basic observations that in both case the ophthalmologist is observing it, he is not putting any extra intervention from his spot. He is just observing. One is making a hypothesis. So we will be seeing some of the descriptive study design. So you can see an article, a study of acute vision loss and postpartum period. And HIV associated meningitis people. So it is something like description of a certain condition. So it is known as a case report which is just a descriptive study design, one of the descriptive study design. The next one is pneumositis, carinine pneumonia and necrosis of candidiasis in homosexual men. So it has become case series.  These all are descriptive patterns of a study. They are just describing a certain condition in a few people or a group of people. The next one is the prevalence and determinants of hypertension in a group of people. This has become cross-sectional study because the people will be asked questions only at one point of time. There will not be any follow up still. They are asking only questions, only the reports will be checked and data will be collected. So these are and one more thing which I left out is longitudinal study. So the same cross-sectional study is being repeated or if there is a follow up the same group of people is asked questions after a period of time that will become longitudinal study or follow up study. So in all these studies that is case report, case series, cross-sectional study, longitudinal study. We are just describing a condition of people and we are trying to create a hypothesis. We are not trying to analyze anything out of the data but we are just seeing the data and we are creating a hypothesis. But whereas in analytical study which is also part of observation study we can see that there is one study design which is known as case control study. We will be dealing in detail about all these study designs, case control and cohort study. But as of now case control study is nothing but analytical study. So in all analytical study that is in case control and cohort we are trying to test the hypothesis. So there will be always a comparison group. The only testing of hypothesis is possible. So in this case that is control group will be there. So this is the comparison group. So risk factors of development of color or carcinoma. So these are the patients and we will be taking one group of people without the disease that is without the color or carcinoma and we will be comparing the risk factors and we will try to find out or we try to test the hypothesis and reach into a conclusion. So this is case control study. This is always a retrospective study. We are going back. We will be asking questions or we will be taking data from the previous records. But this is one of the famous study the Framingham Hart study. This is a cohort study. This is a forward looking study. This is the study goes to the future. Okay. This study started dated back to 1948 and the study is still going on. So this is known as cohort study. Cohort means a group of people who shares common characteristics. So people with cardiovascular disease there risk factors will be assessed in the future or their risk factors will be assessed at frequent interval of time. We will not be asking questions and we will be taking data from their previous history. Instead we will be checking data, we will be collecting data from the follow-ups. Once the study started we will keep follow-up at regular interval and we will be collecting data. So such study is known as cohort study and in cohort study also there will be a comparison group. People who is not developing this cardiovascular disease. At the beginning of the study cohort study there will not be any disease in the cohort group. Over the period of time few will develop the disease and the other will remain as a comparison group. It is little complicated. We will deal this later but right now we will just check the concept cohort means a group and at the beginning of the study there will not be any disease in the group and over the period of time the cohort will be divided into two that is disease and non-disease and we have a comparison group that is non-disease and we will be comparing this and we will be comparing the risk factors. Whereas in case control study the study is started with case. Already cases are there we just need to find out some controls age and gender match controls and we will be comparing and we will be checking the risk and we will be testing the hypothesis. So the analytical study has basically two parts that is two components one is case control study and cohort study. Case control study means we will be doing on the cases and we will be taking controls.  So cohort study is always very time consuming, very expensive, very administratively complicated whereas case control study is very simple we can conduct it very easily because case is already there we just need to find out the control and conduct study whereas in cohort study sometimes the cohort will not turn into two groups over a particular period of time so it might take us to complete a cohort study. But always cohort study is better than case control study. So our study designs has become like this observational and experimental and descriptive study and analytical study. Descriptive has four parts our four designs case report series of case report that is case series cross sectional study population will be taken only at one point of time longitudinal study the same group of people will be followed up to regular intervals over a future period. In analytical study where the hypothesis will be testing there are two components case control and cohort study case control is retrospective cohort is prospective study in case control cases are already there we need to find out the controls age and gender matched controls in cohort study the cohort group will not be having any disease at the beginning of the study over a period of time it might develop into a disease or non-disease in both the study designs we need to have a comparison group in case control study the control group is our comparison and cohort study there will be a non-diseased group for comparison so finally we'll be testing the hypothesis and we'll be doing a risk estimation so all this risk estimation will be dealing in future classes so the experimental study design the in the beginning I have told you the basic two designs are observational and experimental so far we have completed observation study and observational study descriptive and analytical where the researcher or epidemiologist is just observing the condition or the decision whereas an experimental study design the clinician or researcher has a significant role or a intervention purposefully on the people or the study subjects so you can see that a study a comparison between test fluorine and proper fold in improving the laparoscopic sleeve gastrotomy in this two group of people are getting two different drugs case all these drug trials will be experimental study because two group of people the researcher are giving two different group of medicine to different group and finding out their outcome and comparing this and trying to find out which drug is better in observation study there will not be any such thing any intervention any manipulation from the part of research or an experimental study there will be manipulation or intervention from the part of research that is two different drug will be given to different groups and will be checking the outcome of the disease outcome of the medicine on the disease so this is known as randomized control trial the important part is trial trial means the investigator has a significant role so control means there will be always a controlled group in this study randomized means the groups will be randomly selected the participants will not be knowing which group they are going to participate there will be randomly selected or allocated to the groups so that is about randomized control trial so in experimental study we have two designs randomized control trial and non-pantomized trials in non non-randomized only the differences the participants are not allocated randomly they'll be knowing which group they are being being by which group they are getting allocated to or getting participated so always the randomized trial has a better advantage than the non-randomized okay so all these study designs will be dealing in detail in later classes so this is all about the promo gico study design this is a very broad classification the first division is observational and experimental and observational where the clinician has just an observer descriptive and analytical this is testing hypothesis sorry this is creating hypothesis in descriptive and analytical this is testing hypothesis in descriptive we have case report case series constitutional longitudinal study designs in analytical we have case control and cohort studies whereas in experimental study we have randomized trial and non-randomized trial this is a very broad classification but this is apt for to understand the basics of a pachromological studies so will be dealing in detail about the study within in future classes thank you