Biosecurity best tool to fight H5N1

PLOVER, Wis. — As confirmed cases of HPAI H5N1 climb in the western U.S., increased vigilance by dairy producers plays a vital role in preventing infection and treating affected cows in the event the virus strikes.

Dr. Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory, has been involved in the aftermath of the virus since it was first confirmed in the Southwest in March.

Poulsen spoke to attendees at the Professional Dairy Producers Herdsperson Workshop Oct. 29 in Plover.

As of Nov. 20, there have been a total of 550 dairy herds with confirmed cases of H5N1 in 15 states. Three of those states have reported cases in the past 30 days. California reported 202 for a total of 336 to date; Utah reported 13, all in the last month; and Idaho had two cases, for a total of 35.

“California is exploding right now,” Poulsen said. “Biosecurity and surveillance are the most important for dairy farmers, especially for what is happening right now with the flu.”

Poulsen said the best answers on how to stop the virus are still eluding officials, making biosecurity and surveillance on dairy farms more important than ever.

“Biosecurity is our best tool right now to decrease disease and increase productivity, and not just for this virus,” Poulsen said. “We have fewer antibiotics that work or are available. It might not seem awesome, because it’s not a solution in a syringe, but it’s very effective.”

Biosecurity has not been widely embraced in the dairy sector because the process of implementing these plans can be unwieldy.

“Anyone can go to securemilksupply.org and look at biosecurity plans,” Poulsen said. “But they are exceedingly complicated, expensive, take a ton of time, and (require) a lot of record keeping. This makes it challenging to invest time and money in biosecurity when you are just trying to get through that day. And until now, we’ve all been able to get by.”

Standardized biosecurity plans were built in response to a potential outbreak of a disease like foot-and-mouth, Poulsen said.

“We have to be able to ensure business continuity, maintain the food supply and continue animal movement,” Poulsen said. “You can’t just turn off dairies. But some of our public health officials don’t get it. You can’t just stop all commerce. You can’t stop the movement of all cattle, which is the first thing many regulatory agencies request. It’s not appropriate to stop all animal movement. How many farms don’t grow their own heifers?”

The National Milk Producers Federation has taken secure movement plans and distilled them down to several main points, helping to simplify the process of implementing layers of biosecurity on dairy farms.

“Think about your farm as a castle that has a protective moat around it,” Poulsen said. “That is the line of separation and the only way to get in and out is the drawbridge — a controlled entry. But how many Wisconsin dairy farms have only one or two entrances? That’s a challenge because we’re continually expanding, adding new buildings and barns. But, the line of separation is really important.”

Poulsen said the key point is to know who is coming onto and going off the farm, and keeping vendors and visitors in one area without crossing the line of separation.

“It’s not about protecting the environment from an infectious disease getting out,” Poulsen said. “It’s about protecting the farm from the environment.”

Poulsen said dairy farmers should carefully consider who needs to be on the inside of the line of separation. He recommends ensuring all delivery trucks can be received outside of the line of separation, as well as locating dead animals outside the line for pick up.

Depending on the layout of the farm, Poulsen recommended talking to the milk hauler to see if there is a way to keep the milk truck outside the line of separation, bringing only the hose across.

Poulsen said it is tough to establish where the hoof trimmer should be.

“They probably need to be inside,” he said. “Their trailers are pretty clean, but it can’t be 100% clean — we can’t bathe it in Purell. That really is the key point of biosecurity — all that dirt, all that organic debris can be a risk.”

As a veterinarian, Poulsen questions the need for the vet truck to come within the line of separation. He encourages determining if there are other options for transporting supplies during a vet call.

In addition to creating a line of separation, personal cleanliness is paramount, Poulsen said. He advocates for clean, disinfectable footwear, hand washing and laundered clothing.

“I always washed my boots between every farm, but only changed my coveralls if they were dirty,” Poulsen said. “Now I change my coveralls between every farm and change sleeves between every cow.”

Both the Wisconsin Cheese Makers Association and the U.S. Department of Agriculture are providing money for dairy farms to provide dedicated farm uniforms, uniform laundering and disinfectable rubber boots to employees.

Biosecurity plans recommend a vehicle wash station at the dedicated entrance. Poulsen said he acknowledges this is both impractical and expensive, but he does suggest keeping track of what trucks enter and leave the farm.

“We aren’t sure how long the virus survives in the environment,” Poulsen said. “Typically flu viruses are really weak; they should not survive UV light and hot water. We don’t know why it’s spreading in the very hot weather we see in California. We don’t see it as a respiratory transmission. There is something that is not typical, something different. We think the initial transmission from a wild bird was a unique circumstance.”

Taking proactive steps to secure their farms is crucial for dairy farmers, Poulsen said.

“We’re seeing current estimates on lactation losses between $200-$400 per cow, with no idea what will happen in the next lactation, and the average cull rate on affected farms is 50%,” Poulsen said. “We need to be testing lactating animals, surveilling for the virus. We need to recognize how bad this is.”