Biosecurity Helps Keep Cattle Safe

Complete biosecurity when animals are living outside can be a challenge, particularly with the recent detection of H5N1 influenza in dairy cattle.

"When we look at dairy and beef cattle, we realize biosecurity is a little harder than it is in the hog and poultry industries," explains 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. Jardon says he thinks it likely could spread from cow to cow, but researchers are still trying to determine exactly how.

PROMISING RESEARCH

Scientists at the ISU College of Veterinary Medicine recently discovered some interesting information that may reveal evidence on how the H5N1 virus spreads.

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.

The researchers studied sialic acid levels in the mammary glands of cattle, which, prior to the flu outbreak in dairy herds, had not been considered as a good target for influenza. "In livestock, we hadn't usually looked in milk for viruses. Bacteria, sure. But, not so much viruses," explains Eric Burrough, professor of veterinary diagnostic and production animal medicine at the ISU school.

Samples from the mammary glands of two infected cows contained a rich supply of sialic acid and shed some light on how the virus attaches to hosts. In turn, this could eventually help develop measures to slow its spread. The group is trying to determine if viral transmission occurs through milking machines.

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

The ISU study was based on only a few positive samples. Researchers plan to continue examining how other cows with the H5N1 virus could be shedding. The number of cows affected as of August 1, 2024, was 175 in 13 states, a total much smaller than the over 100 million 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. Conversely, it's not fatal to cows, but they usually have a reduction in milk production, a symptom which alerts the dairy of an issue.

BIOSECURITY HELPS PREVENT SPREAD

ISU Extension beef specialist Denise Schwab says the discovery of H5N1 cases in dairy cows should be a strong reminder to 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 stresses. "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 the spread reduces the risk of diseases."

Jardon emphasizes 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.

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

Jardon says some farms have employed bird deflectors such as plastic owls or sounds to scare away birds.

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

Any animals brought from another facility or farm should be quarantined and observed for any health problems. "We do think there could be a link to cases from farms who have seen positive cases. Producers should be aware of where they are getting animals and keep new cattle quarantined for at least 30 days," Jardon recommends.

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

BIOSECURITY TIPS FOR THE CATTLE FARM

Biosecurity is key to ensuring the health of livestock on any farm. Direct animal-to-animal contact is the most significant risk for disease spread. Here are some management practices from Iowa State University Extension to help minimize the risk:

-- Use protective equipment and clothing to prevent spread from one person to a farm.

-- Isolate any incoming animals, bulls, replacement heifers, cows, calves or animals returning home from exhibitions for at least 30 days.

-- Maintain good perimeter fences to prevent neighboring cattle from entering your farm.

-- Prevent nose-to-nose contact between your cow herd and newly purchased cattle.

-- Minimize contact with wildlife when possible, and especially control rodents.

-- Obtain the health history of purchased cattle.

-- Limit who can access pens, feed storage, mixing areas, feedbunks and treatment areas.

-- Clean and disinfect all equipment before using it around healthy cattle.

-- Keep a record of all visitors to the operation.

**

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

-- Follow Jennifer on social platform X @JennCattleGal

[PF_0924]

(c) Copyright 2024 DTN, LLC. All rights reserved.