This is first article of a three-part series about H5N1 influenza biosecurity for dairy producers from the University of Minnesota Extension’s The Moos Room podcast.
During the first episode, veterinarian and Extension educator Dr. Joe Armstrong spoke about about biosecurity measures dairy producers can take in an effort to prevent the H5N1 influenza from impacting lactating cows and other animals.
“There are a lot of biosecurity materials out there, but in my mind, a lot of times they are not specific enough to this situation to be overly helpful. They are a great place to start, but I’d like to share what I think about specific topics, so that you have some action items and things to do specifically related to H5N1 influenza,” he said. ‘I’m going to give you some things to think about and things that I recommend and we’re going to explain the why behind them, as well, so they’re not just recommendations that are floating out there without any backing to them.”
Armstrong said when it comes to some of the H5N1 biosecurity recommendations, they may at first seem foreign to what producers and others in agriculture are used to. However, while there are going to be a lot of changes, Armstrong said he believes that’s kind of the point.
“I think H5N1 influenza in dairy cattle is going to permanently change pieces of our industry and some of that is going to be biosecurity related,” he said.
Armstrong said his thoughts and the recommendations came from sitting down and thinking through what is truly important for protecting farms, as well as how to contain the virus once it’s on a farm.
“So if you’re impacted, if your herd is infected with H5N1, how do we keep it there as much as possible and not allow the spread of that virus to the shared ecosystem as much as we can and to our neighbors down the road, which may have dairy or poultry or another species?” he said.
Armstrong said there are a couple of big concepts that are at the forefront of a lot of the decisions he takes into account when he makes recommendations in regard to the H5N1 influenza.
One concept is the goal to limit the opportunities the virus has to change, either by mutation or by re-assortment with other virus that would allow it the opportunity to become more deadly or more infectious to different species.
“So the goal is to limit the circulation of the virus, because the more it circulates, the more opportunities it has to change ... This is what the CDC (Centers for Disease Control and Prevention), USDA (United States Department of Agriculture) and FDA (U.S. Food and Drug Administration) are talking about when they’re talking about the sequencing of the virus and looking for specific changes that would allow the virus to be more infectious to humans and/or increase the chances of there being human-to-human transmission,” he said.
Armstrong said because the focus has been a lot on the humans, the reality that changes to the virus can impact the species it is already in the more the virus is allowed to circulate. In other words, although the H5N1 influenza virus does not cause death in infected cows at this time, the virus can become fatal to cattle if it mutates or is re-assorted by other viruses.
“The more that the virus circulates, the more opportunities it has to change, the higher the probability becomes that the virus will become worse for cows,” he said.
The second big concept that needs to be talked about, Armstrong said is what happens with influenza virus in a population if it continues to see new hosts that have not seen the virus yet. That scenario can come into play if a producer continue to bring animals that are unexposed and naive to a premise that is impacted whether that is officially positive or impacted and not testing.
Armstrong said once H5N1 gets into a population, the virus will circulate in that population until the population has zero converts and enough antibodies, immunity and resistance to that virus, so the virus can no longer circulate.
“For that process to happen like it should and take the least amount of time, we cannot add new animals to that population, because now the animal has a new set of animals to infect and to circulate in,” he said. “So if you continue to add new animals before the entire population that’s there has a chance to zero-convert and create antibodies, you are creating the perfect scenario for an endemic situation where that virus will not ever leave, because it continues to find new animals to infect. If that happens long enough and those new animals continue to flow in and that virus continues to circulate in those new animals, the virus itself has more opportunities to mutate and more opportunities to re-assort.”
Armstrong said in theory, if that cycle continues long enough of continuing to bring new animals in without ever letting the population zero-convert, it can result in a situation where the virus could change enough to then go back to the original population. The reason for that is because the virus is then different enough that it can infect the cattle again.
“So when we talk about quarantines and not allowing animals to move and not allowing animals to leave a premise, it’s also just as important to not allow naive populations to come onto the farm, because now all we’ve done is potentially extend the time it’s going to take for the entire population to zero-convert and create antibodies or become resistant to that virus,” he said.
One topic that has been discussed, but for which there aren’t enough data yet is the flow within the dairy itself. As raw milk is believed to be one of the main ways the virus is spread, the parlor may play a key role, Armstrong said.
A first step is to identify whether naive animals are added to the population. Looking at the farm, it’s also important to acknowledge the setup. On the farm, Armstrong the most likely group of animals that are naive or have not yet been infected are the dry cows as they are often housed separately from the lactating cows. Although the dry cows community sometimes has separate personnel, perhaps even separate equipment, it isn’t unusual for members of the dry cow community to be moved into a continual flow pattern. Once again, Armstrong said it is important not to give the H5N1 virus an opportunity to spread in a naive cow. It’s the same with heifers, Armstrong said.
As H5N1 is found in raw milk, Armstrong said producers and other dairy workers need to be careful in how waste milk is handled and discarded. This includes not feeding it to any animals, such as cats, dogs and wildlife.
“If you’re going to dispose of waste milk, we really, really need to pasteurize it before we put it into manure storage. Manure storage, especially open pits or lagoons or whatever you’re using that is the environment and the shared ecosystem and is accessible by all wildlife,” he said.
When it comes to pasteurizing (heat treating) the waste milk, Armstrong said there is no need to be gentle with the milk in any way if it is going to be put into manure storage.
“You don’t have to worry about it coagulating or getting too hot. We just need to heat treat it, so I am confident that there are all sorts of people out there that can come up with a way to do that, knowing it’s not going to be food. It just needs to get into manure storage safely,” he said.
Armstrong encourages producers to treat the milk room as a restricted area and only allow personnel who are essential to the operations to go into the milk house. It’s also best not to wash off boots, hands or non-milk equipment in the milk room, as well.
“It might also not be a bad idea to enter the milk house and exit the milk house with a foot bath in place, just to make sure if there is raw milk on the floor, we are not tracking that to other location. Now, the foot bath may seem like a lot for the day-to-day. I still don’t think it’s a bad idea for the day-today, but it’s definitely the ideal when it comes to the day-to-day normal operations around the parlor. When it becomes a necessity is when your farm is infected,” he said.
As some dairies transfer raw milk to other areas on the farm, such as the calf barn, Armstrong encourages producers to pasteurize the milk first before giving it to the calves.
Another concept that is essential when it comes to preventing an H5N1 infection is to keep a clean driveway.
“Now this one can be a little contentious, because there are a wide variety of entrances to a dairy. I’ve seen them all. I really have from the most immaculate to the sloppiest. I’ve seen them. I’ve driven them. I know what the weather can do and how it depends on the season. I get it. But when we’re talking about what is transferring on equipment, this isn’t an aerosolization problem. This is a problem of mechanically moving infected materials from farm to farm, whether that’s manure or raw milk, whatever it is. If your driveway stays clean, your equipment stays clean,” he said.
Armstrong recommends producers to do what they can to keep driveways clean from mud and puddles. Spilled feed, manure or raw milk should also be cleaned up immediately to avoid any contamination of vehicles that are coming on and off the farm.
Armstrong said other topics he will cover related to H5N1 biosecurity includes livestock, transportation, equipment, dead livestock, farm-related deliveries, manure hauling equipment, manure hauling itself, manure handling, feed handling and professional services that come onto the farm.
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