The Moos Room™

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Joe Armstrong: Welcome to The Moos Room, everybody. This is your host, Dr. Joe Armstrong, and last week I promised you it would not be just me and I straight up lied to you. This week was a mess, absolute mess. Brad was in Wisconsin for the World Dairy Expo. Emily was at all extension conference and I was deathly ill with whatever new bug my toddler brought home from daycare. It was a bad one. The worst one he's brought home yet. You again, are stuck with me three weeks in a row, this has never happened before.
I apologize that you're stuck with just me on this episode. We're going to take the time this week to update the case study we've been talking about in relation to BVD. If you haven't listened to our previous episodes on this topic, I really encourage you to do so. Go back and listen to Episode 102 and 128 and then everything in this episode will make sense. All right. Where we left things last time was our producer had decided to test for BVD because we had so many things going wrong, despite them doing everything right.
We went over the strategy for how to test and how to do that in a cost-effective way by pooling samples, testing the calves, and using those results to infer our results for the dam of those calves as well. The whole goal of all of this testing is to find PIs, if there are any in this group, and make sure that we get rid of them so they stop creating more of themselves. Again, like I said already, please go back and listen to Episode 102 and 128 to get the background on this. With that, let's jump into the results. When all our sampling was said and done, we had three pools of about 50 animals with ear notches for testing.
We're going to pool those results to keep the cost down. If we get a negative pool, then all those animals are negative. If we get a positive pool, we have to go back and test that pool animal by animal to figure out which animal caused the whole pool to be positive. Of those three pools, we had two pools that were positive and one pool that was negative. Negative pool, we discount those animals. They are truly negative, can't have a PI in those 50 animals. The other two pools, we had to go back and test animal by animal, calf by calf to see which ones were causing that whole pool to be positive.
We did that. We got the pools tested, animal by animal, by calf by calf, and we ended up with six PIs total, or six positive BVD animals in the 150 or so calves that were tested. You hear me correct myself there because we don't technically truly know that they're PIs at this point. They tested positive for BVD. They could be transiently infected with BVD. Is that very likely? No, but it's possible. In the ideal world, we would take those six animals and test them again two to three weeks later. If they're still positive, we know they're a PI and not just transiently infected with BVD.
Now, in the real world, how often are we going to do this? In this case, with only six positive out of 150, my take on it is, if there's logistics involved and this producer has a day job and all these other things going on and the calves aren't super accessible, then we just say, okay, we're fine with culling those six PIs, and figuring out what to do with the next steps based on the fact that we're culling those six PIs. Now, the reasons to retest would be if you have super valuable animals or animals that have a sentimental meaning to you.
If you want to absolutely make sure that they're a PI animal, then you do need to go back and re-sample them and retest two to three weeks after the initial sampling and see if they're positive again. That will confirm they're absolutely a PI and it couldn't be transient BVD flowing through. We've got six positives in this group of this herd, and we're going to cull those six PIs. That's where we're starting from. What do we do next? Well, like I talked about previously, the next thing to do is to take those positives and identify their dams. We need to go back and test their dams for BVD. If there's a PI cow or a PI heifer in your herd, it's going to produce a P1 calf.
If the calf is negative, we know the dam is not a PI, so we don't have to go back and test those. With a positive result, we need to double-check that that dam is not also a PI. We're going to go back and find the dams of those six calves and those are going to get tested. That's number one on our list. Now what we talked about last time we were on this case is it's really important to cover all our bases. If we miss testing an animal and that animal ends up being a PI, we've made zero ground because that PI animal will then be around while there's pregnant animals around and we create more PIs and we're right back where we started.
Now's the time to make a list. In addition to the dams of those six positives that we already know about, we got to make a list of all the cattle that have not been tested yet because we have to have a test on everyone. That includes the fall herd for this producer, all their natural service bulls, and their replacement heifers because we don't have any tests on those animals yet. We have to cover them because if there's a PI hiding in those animals, we could be right back where we started real quick if we don't find it. Now, testing for these additional animals, it's all the same.
There's a couple of different strategies I'd like to walk through and really it depends on how many animals are there. We were trying to save money by testing the majority of the animals and just doing the calves and then using that test and that result to say, "Okay, if it's negative, then I know the dam's negative. If it's positive, then I know I got to go check the dam." What it really comes down to is how many animals are there. In a fall herd, sometimes there's less animals, and in this case, there's only between 15 and 20 pairs. Does it make sense to just test the calves at this point and then have to come back and test the dams later?
I don't think so. We got to think about logistics and time and time being the most valuable resources for farmers and producers and veterinarians, everybody. Time is the most valuable resource. With that small number, I say let's just get an ear notch on everybody. We'll take the fall herd, the cows, the fall herd, the calves, the replacement heifers, and the bulls, and we'll put those all together. We'll pool them in groups and then do the same thing that we already did. If we get a positive pool, we'll go back and test individual animals in that pool. At the end of this, we'll have everyone that is currently on the ground on this farm tested for BVD.
You'll notice I said currently on the ground and that's because we know we had PI animals around pregnant cows during that critical period of gestation where that calf is taking inventory on itself. Most likely, we have probably created more PIs. We just can't test them yet because they're still in the cows and won't hit the ground until next calving season. There's our real next steps is test everybody that doesn't have a test currently, find any more PIs that might be hiding in the group. Then we need to plan on testing every calf that hits the ground next calving season in the spring, and potentially also the fall herd to see what PIs we created by having the PIs around our pregnant animals this year.
We identified this problem in 2022, found that we have BVD-PIs in our group. We're hoping to be able to say with this producer and after we get done with testing and everything, to confirm that we're potentially PI free in 2023 by testing all of our calves that hit the ground and then probably continue testing as well in 2024 just to be absolutely sure that we are PI free. The whole thing's a mess. This is why BVD keeps me up at night. That's why I worry about it so much. It becomes so difficult and frustrating to deal with because it feels like the disease is somehow playing a three-card Monte game with you and hiding itself, and it is.
When we think of it from a disease standpoint, it's absolutely fascinating that this disease has evolved to be this way. Now that it doesn't make it any less frustrating to deal with, but it should make you feel like it's just fine to ask for help when you're dealing with something like this. It's so complex. It takes a team to figure it out. It takes a lot of talking about the logistics of how things are going to work to get things straight. You got to get your team assembled to deal with something like this. If you're worried about it, you got to get your veterinarian, your nutritionist, herd managers, everybody who's involved on the farm together to talk about it because it is so complex, everyone's got to be on the same page.
Now up until this point, I've been avoiding a topic a little bit, but it's important that we talk about it. What do we do with these PI animals? What do we do with these animals that are causing all these problems that are producing this virus constantly and harming everyone around them? The very, very first answer is you cannot pass this problem off to someone else. You've seen through the series how complex this whole issue is to try to get your head around, and it likely was caused by just one PI initially making this whole situation get started. You can't pass that on to somebody else's. These PI-positive calves, they have to leave your herd. They cannot go to the sale barn, absolutely not. That would just wreck someone else's day, wreck someone else's years. It could potentially ruin their cattle operation.
These calves that are PIs, these animals that are PIs because there could be cows and Heifers in this herd as well that are PIs, they have to leave the herd but they can't be someone else's problem. The very first thing you can do if you're interested in what to do with these PI animals is they have to live somewhere and be finished out where they're around zero other cattle. They cannot have any contact with any other cattle. I would prefer that they're on a site that doesn't even have cattle anywhere near it and you can finish them that way.
I know, I've had people finish animals that way whether they're completely isolated. They're at mom and dad's place that hasn't had cattle for 40 years and they stay in that lot and they never leave that place, they never go anywhere, they never have any contact. They're not even within half a mile of other cattle and that's fine. You can do that and then they have to go from there straight to slaughter. That works just fine. Now, the other option is, if you have cows or bulls that are positive, they can go direct to slaughter. They cannot go to the sale barn. They cannot go anywhere else. They have to go directly to slaughter. You cannot risk that animal getting back into the general population.
Then sometimes there isn't an opportunity to raise them somewhere else away from everything. At that point, the best thing to do is euthanize those animals. They are a danger to everyone else around them, and that might seem harsh but it is the absolute best solution if they cannot be raised isolated from other cattle. Sometimes that's the answer and it's just a fact. We cannot be spreading this problem to other people and jeopardizing their way of living because we feel bad about having to do something that's necessary.
All right, I think I've given you plenty to think about. We're going to keep this episode short. As you can probably tell my voice is not going to hold up much longer. We'll probably give an update on this herd once we get everything wrapped up and feel like we've got everything in a nice little package. I really, really, really want to be able to come back to you guys and say, "I got this figured out. This herd is great. They're doing wonderful," because these people deserve it, they do everything right, so many things right and things just aren't working out for them and having something to put our finger on and say, "Hey, this is it. This is what's causing these issues." If we can fix that and I can get these guys rolling, I'm super excited to come back to you and say, "Hey, everything is beautiful. They're in love with their cow herd again just like they used to be." That is the ultimate goal through all of this is to get them back to loving having their calves.
As you know, if you have comments, questions, scathing rebuttals, you can send those to themoosroom@umn.edu. That's T-H-E M-O-O-S R-O-O-M@umn.edu. Please follow us on Twitter @UMNmoosroom and @UMNFarmSafety. Catch Bradley on Instagram @umnwcrocdairy. Check out our website extension.umn.edu. Thank you for listening, everybody. I will try my hardest to make it so it's not just me next week. I really, really, really don't want you to have to listen to me four weeks in a row. Thank you for listening though. Have a great week.
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