May 18, 2015

(Dan) Hey folks Dr. Dan from Doc Talk. Thanks for joining us today. Today my guest is gonna be Dr. Dave Rethorst who is the Director of Outreach and a veterinarian from the Beef Cattle Institute here at Kansas State University. We’re gonna talk about a very common disease –
blackleg in beef cattle and other clostridial diseases. I’m glad you joined us. Stay tuned and enjoy our show.

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(Dan) Folks, welcome to Doc Talk. Dr. Dave welcome to Doc Talk again. (Dave) Glad to be here. (Dan) It’s always good to have my friend and colleague Dr. Dave Rethorst who is a veterinarian here at Kansas State University in the College of Veterinarian Medicine and is the Director of our Outreach Program at the Beef Cattle Institute. Dr. Dave we’re gonna talk about something that you’ve had a little bit of experience with. (Dave) Just a case or two. (Dan) We’re gonna talk about blackleg. And it’s one of those things that there is not a more used vaccine in the United States beef industry from… (Dave) Absolutely not. (Dan) And there’s good reason. But one, it works. But you know, we have… let’s go back, kind of the history and what black leg is and what it causes. (Dave) Well, blackleg is caused by a member of the clostridial family clostridium chauvoei, and it’s a soil born organism, so you know when you get real dry soil conditions like the drought we’ve experienced, we get more of these spores coming to the surface we see. But a veterinarian by the name of O. M. Franklin developed the first
blackleg vaccine back in the 1800’s because these calves were dying and they were finding these real dark gaseous lesions in the muscle. And he figured out that he could make a vaccine with these clostridial spores and prevent the disease. So, very common disease and a vaccine that works very effectively. (Dan) And one of the things that always amazed me in cow/calf practice and that is you can’t predict… there’s some pastures that have a lot of spores that are blackleg pastures and some pastures that don’t and within the same section of land you could have people with quarters or with 80s and here’s a blackleg hot spot and here’s not. (Dave) Right, right. There’s areas that are endemic. I’m familiar with an area in the northwest corner of the Flint Hills that there’s quite an area that is blackleg endemic. You just have to vaccinate pasture cattle and even the soil that’s in their feedlot has blackleg spores in it. (Dan) And it’s also one of those things that always seems like that when we have a calf die of blackleg it’s always the best calf, the most aggressive growing calf and that probably has something to do with it forging and… (Dave) Foraging. (Dan) …just putting itself at risk. (Dave) Right. So, when… kind of talk to me about, you’ve had some blackleg cases… dead calf in the pasture is
kind of the… (Dave) Dead calf in the pasture is usually what we find. There’s times we’ll see a calf that you know is walking real stiff, particularly in the hind legs or something, and be drought conditions. Particularly if you’ve lost a calf already you’ll start seeing these lame calves. And sometimes we can shut that off with some vaccine and some antibiotics when we see these calves alive, but usually our first hint is just finding a dead calf in the pasture. (Dan) And then from that getting a diagnosis can… requires getting samples, getting them to the D Lab. (Dave) Absolutely. Get an necropsy done, get the samples to the D Lab, make sure that’s what we’re dealing with. (Dan) Yep. And it always amazes me that when you would make an indention on there, you could hear the crackles underneath the skin and leave an indention in
the spot where… (Dave) It will crack and pop and you cut into that muscle and it’s just a real dark, dry gaseous muscle. (Dan) Cool. Let’s take a break, when we come back we’re gonna start talking vaccination protocols for black leg Stay tuned.

(Dan) Hey folks, welcome back to Doc Talk. Dr. Dan Thomson and Dr. Dave Rethorst. And we’re from the Beef Cattle Institute at Kansas State University where Dr. Rethorst is a veterinarian and serves as the director of outreach for us and spends a lot of time… he’s got a lot of experience in the field as 35 years of veterinary practice, 40 years of veterinary practice and still continues to see cases and function in the field with people here in our industry. But let’s get to some of the strategies of preventing blackleg. And I think the biggest strategy that we want to talk about first, is let’s start out with the baby calves and work through branding. We’ll just kind of go from birth to slaughter and we’ll cover this. But when are… if we have blackleg and we know blackleg is in the pasture, how early can we vaccinate these calves? (Dave) We can vaccinate these calves at birth if we need to. One of the members of the clostridial family is clostridium perfringens and that plays into our overeating, causes our overeating and some of the things that we see in baby calves. So we’ve got a lot of producers using blackleg vaccine at birth just on preventing the overeating form of the disease, but they also get some true blackleg protection there. So, if we’re in one of these real endemic areas, we can do it at birth. Typically what we do is at spring branding time, we’ll come in and give those calves a seven way blackleg, and then we’ve got good protection until fall and usually we’ll give those calves another blackleg as we’re getting ready to wean them. (Dan) OK. So, if we’re in an endemic area and we’re gonna give these calves… we can do it right off the bat when we’re tagging ’em. (Dave) Right. (Dan) And that’s a good chance to grab ’em and give ’em a blackleg and that’s where I hear most people if they’re gonna give one earlier than branding, which folks at branding we’re talking three months of age, three to four months of age and so, another opportunity is at branding cause then those calves are starting to forage a little more. (Dave) Right. (Dan) Not just relying on Mother’s milk, they’re starting to nibble and graze and get closer to those spores. So we’re definitely… and we’re coming into that drier time of the year usually. (Dave) Absolutely. Right. (Dan) So, you said a seven way product. (Dave) Right. (Dan) And so, go ahead. (Dave) OK, so the seven way product is seven strains of clostridium. We’ve got our chauvoei, which causes the blackleg. And then there’s septicum and novyi and two strains of septicum and a couple others in there that… (Dan) Right. That are more… not necessarily causing issues, but when we develop these vaccines they were easy to grab ahold of. (Dave) Right. (Dan) And we have those antigens in there. And there are also products that leave those antigens out. (Dave) Right. (Dan) You can get a two-way or four-way, or seven-way to cover for those different products, but the big thing is work with your local veterinarian. (Dave) Right. Work with your veterinarian. You know, there’s some places that they’ll routinely vaccinate cows for black leg every year, just because of the true blackleg disease. In these drought areas they’re vaccinating mature cows every year. (Dan) Yep. Folks, we’re gonna take a break. When we come back, more about blackleg with Dr. Dave Rethorst and we’re gonna move into the stocker and feedlot phases. You’re watching Doc Talk. We’re sure glad you joined us.

(Dan) Hey folks, welcome back to Doc Talk. Dr. Dan Thomson. Dr. Dave Rethorst. We’re with the Beef Cattle Institute where Dr. Rethorst is a veterinarian and also director of our outreach. And we’re talking about blackleg. And one of the things as we left the last segment talking about ranch strategies and things like that, really work with your local practitioner. They understand the geology. They understand the geography. They understand the endemic disease, especially if you’re new to an area. Make sure you get a practitioner that you can visit with and really understand where you’re living, the environment that your cows are in. There are a lot of regional vaccination programs that the veterinarians can provide a lot of insight towards. (Dave) Absolutely. (Dan) So, when these calves go to the feedlot, you said we’re gonna give ’em a blackleg when we wean ’em. So, if they’ve… talk to me a little bit because there’s a lot of debate out there as far as blackleg on arrival to the feedyard or to the backgrounder operation. (Dave) Right. And it’s… we can as a general rule assume that nearly all calves have a blackleg early in life. (Dan) Right. (Dave) But, the difference starts coming as we prepare for weaning. Crusty, old curmudgeons like me still like to give a blackleg when we’re getting those calves ready to wean, just give another booster into ’em when we know we’re in good shape. There’s places that don’t and you know, these calves going into the feedyard, we can see blackleg cases in the feedyard. These calves go in there and if they’ve had to put new dirt in the pens and like I said, really dry, these calves start licking the soil for some reason and we can start seeing blackleg outbreaks in the feedyard, if we haven’t kept the vaccinations up. (Dan) And I’ve seen it too where we built new pens, so we expand the feedyard into a new area, and we’ve just roughed up the soil in that area and place naive calves on that. I’ve also seen where we’ve gone in and scraped pens in unprotected or non-vaccinated calves and had some pen to pen blackleg outbreak. (Dave) Right. (Dan) And so I guess, my recommendation is if I don’t know the history of those calves or I know that they haven’t received blackleg… (Dave) Get another dose in ’em. (Dan) Definitely. Definitely gonna use one with the lack of expense to this product. You know the other thing is, is and you can comment to this, but as we’ve gone through the last 34 years we’ve changed the blackleg vaccines. They’re not the 5cc intramuscular products, now they’re 2cc’s and Sub-Q. (Dave) Right. And really tissue friendly products. And our cost is still minimal on the thing. So, they’re really safe to use. A study we did years ago when I was in Nebraska was looking at weaning weights comparing 5cc seven way to 2cc seven way and just that difference, just there was seven pounds of weaning weight, just by what blackleg vaccine we chose. (Dan) Going to that smaller dose. (Dave) Going to the smaller dose. (Dan) So, we’ll wrap up here folks. But one other thing, is that re-vaccination however, in the feedlot, is not only not necessary, but can decrease intakes and knock cattle off feed. (Dave) Right. (Dan) So, if you’re going to use a blackleg, work with your local veterinarian. Use one on arrival at the feedlot if you don’t know the history or if you know the animals haven’t had one. More on blackleg and on clostridial vaccines with Dr. Dave right after this message.

(Dan) As we came back from break. Dr. Dave, you know one of the things you were involved with recently was a case of blackleg outbreak in a feedyard. (Dave) Yes, in feeder cattle. These were six weight feeder cattle that the guy bought in December in a feedlot in the northwest corner of the Flint Hills here. And within the last month he had calves started dying and I got involved with the local practitioner. And it turned out that it was blackleg in the feedyard. They hadn’t cleaned pens or anything, but the cattle, they didn’t have a vaccination history on them when they bought them and they did not vaccinate the cattle on arrival. And with the dry conditions we’re seeing, we saw blackleg. Very expensive lesson. I think they lost eight or nine head at $1,500 dollars a head. (Dan) Yep. Can make the vaccine look pretty cheap. (Dave) Yep. Fifty cents a head, would of shut it off. (Dan) Alright. Well, one other clostridial bacterin that we typically, that we get vaccinated for all the time is tetanus. (Dave) Right. (Dan) And people don’t know that tetanus, a lot of people don’t know that tetanus is a clostridial species or that. But when are we gonna use the tetanus vaccine? (Dave) There’s, again, endemic areas, there’s ranches I worked with in Nebraska, we use tetanus vaccine routinely even when we were castrating calves or a lot of time just routinely because we could see tetanus from an umbilical infection. More commonly with the advent of the banding that we’re doing on bigger cattle… (Dan) For castration? (Dave) For castration we need to be giving a tetanus vaccine when we band those cattle. (Dan) Right and a tetanus toxoid is the preferred method because it takes the animal seven to ten days to build an immune response to the tetanus toxoid. (Dave) Right. (Dan) So, the eight way clostridial, or the eight way blackleg with tetanus, by the time that we would have this problem which is two, three, four weeks out, post banding that animal will have a chance to build immunity. (Dave) Absolutely. (Dan) OK, and I think that’s one of the things you hear people say anti-toxin or toxoid, really the toxoid is appropriate. (Dave) Yea. (Dan) The anti-toxin is extremely expensive and… (Dave) And in short supply a lot of times. And the toxoid works well. And basically we can get that clostridial tetani, it’s in addition to our normal seven way vaccine, becomes an eight way. And it’s readily available. (Dan) Sounds like a winner. Any closing comments on clostridials? (Dave) Just that… talk to your local veterinarian. Make sure you’re using an appropriate vaccination program. It’s a cheap disease, the vaccine… or it’s a cheap vaccine, excuse me. The vaccine works well and it’s very cost effective. (Dan) Cool. Well, thanks for being here. (Dave) You bet. My pleasure. (Dan) Folks, thanks for watching Doc Talk. Remember if you want to know more about what Dr. Dave and I do here at vet school, you can find us on the web at Remember to always work with your local practitioner. Thanks for watching Doc Talk today. I’m Dr. Dan Thomson and I’ll see you down the road.

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