Biosecurity Can Help Keep Cattle Safe

REDFIELD, Iowa (DTN) -- Complete biosecurity on cattle farms when animals are living outside can be a challenge, particularly with the recent detection of H5N1 influenza in dairy cattle. But having a good biosecurity plan in place can help prevent diseases from entering the herd, experts say.

"When we look at dairy and beef cattle, we realize biosecurity is a little harder than it is in the hog and poultry industries," said Phillip Jardon, Iowa State University (ISU) Extension dairy veterinarian. "Pigs and chickens are in complete confinement. Workers can shower in and shower out, facilities are closed up, and restrictions are put in place to keep diseases out. It is more difficult on dairy and beef farms."

Veterinarians are still baffled by the spread of the highly pathogenic avian influenza, subtype H5N1, across the country.

RECENT RESEARCH SHOWS PROMISE

A group of researchers at the ISU College of Veterinary Medicine recently found some interesting information regarding how the H5N1 virus may spread.

Sialic acid, a sugar molecule found on the surface of some animal cells, acts as a receptor for influenza. Without sialic acid providing an entry point to attach, invade and infect, a flu virus is unlikely to find a potential host hospitable.

This group looked at sialic acid levels in the mammary glands of cattle, which hadn't been looked at prior to this flu outbreak in dairy herds. Scientists didn't know the udder would be a good target for influenza.

"In livestock, we hadn't usually looked in milk for viruses. Bacteria, sure. But not so much viruses," said Eric Burrough, professor of veterinary diagnostic and production animal medicine at the ISU school.

Samples from the mammary glands of two infected cows found a rich supply of sialic acid and shed some light on how the virus attaches to hosts, which could help develop measures to slow the spread of the virus. The ISU group is trying to determine if the transmission could be through milking machines.

Since milk that is sold commercially in stores is pasteurized, it is safe, as research consistently shows pasteurization neutralizes viruses such as influenza. But the cows on the farm still provide a suitable home for the flu virus. Burrough said this could show mammary glands as being passively infected by the virus.

The ISU study was based on just a few positive samples, and researchers plan to continue looking at how other infected cows could be shedding the virus. The total number of cows affected by this virus as of July 23, 2024, was 169 in 13 states, a much smaller number than the millions of birds that have been euthanized since the start of the H5N1 outbreak. The virus spreads much more quickly in poultry barns and is lethal to birds, but not to cows. Infected dairy cows usually have a reduction in milk production, which alerts the dairy of an issue.

BIOSECURITY HELPS PREVENT SPREAD

ISU Extension beef specialist Denise Schwab said the announcements of H5N1 cases in dairy cows should remind beef cattle producers to be aware of their herd health and examine their current biosecurity plan.

"Basic biosecurity practices are essential daily steps for the prevention of all diseases, and cattlemen should always be alert to the potential of disease spread," she said. "Diseases can be spread by aerosol, direct animal-to-animal contact, oral (through feed or water), reproduction, vector-born (biting or sucking insects), or by vehicles and fomites (shoes, clothes, contaminated feed, needles). Everything we do to prevent spread reduces the risk of diseases."

Jardon said cattle producers and dairies should have a good biosecurity plan in place. The use of protective equipment such as gloves, clothing and face shields is helpful in dairy parlors, he said.

"We use several boot washes throughout the farm to keep waste from one area out of another area," Jardon said. "The disinfectant in these is changed at least once per day. When trailers are leaving or entering the farm, the outside and tires are sprayed down with disinfectants, too."

Jardon said he knows of farms who have bird deflectors such as plastic owls or sounds to scare away the birds.

Veterinarians and other visitors should have boots designated to that farm or use disposable boots to prevent bringing in anything on their footwear.

Any animals brought from another facility or farm should be quarantined to be observed for any health problems.

"We do think there could be a link to cases from farms who have seen a positive," Jardon said. "Producers should be aware of where they are getting animals and keep new cattle quarantined for at least 30 days."

It is impossible to prevent all disease spread risks, but producers can minimize the impact by using good management practices.

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

Follow her on social platform X @JennCattleGal

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