An outbreak of avian influenza, commonly known as bird flu, has sent the price of eggs soaring and highlighted the need for precautions on farms and while working with animals.
NC State’s Dairy Research and Teaching Farms — the source of Howling Cow ice cream — and the College of Veterinary Medicine are taking several steps to prevent the spread of bird flu among their animals. The outbreak has primarily affected poultry and some cattle.
Rocio Crespo, a professor at the College of Veterinary Medicine, said bird flu poses more of a risk now than in previous outbreaks.
“I think this is because of the number of species that are affected [is] more dangerous than in the past,” Crespo said.
Crespo said transmission in birds and poultry is primarily respiratory. The disease can also spread through animal feces and the feathers of infected birds.
Crespo said birds are generally checked and tested for disease before they are sent to a slaughter plant. It’s also recommended that birds be tested when they reach three times the normal mortality rate.
“Because we are testing so constantly and it’s in the head of the poultry producers, we have been able to contain it in a flock, it does not spread to the neighbors,” Crespo said.
Crespo said when a positive test is confirmed, poultry flocks are rapidly depopulated to prevent the virus from spreading further in the population. Birds are then left in the chicken house and composted to kill the virus. Chicken houses are cleaned and disinfected after, and samples are taken to ensure that everything is negative before any repopulation can occur.
The College of Veterinary Medicine takes numerous precautions to prevent the spread of disease, Crespo said. Precautions in place include restrictions on days away from poultry and ruminants, requiring workers to change clothes, only allowing authorized individuals to interact with animals and regular testing.
Stephanie Ward, Dairy Science Extension Specialist, said NC State’s Dairy Research and Teaching Farm takes extensive precautions to prevent the spread of disease, including vaccination, utilizing milk replacer instead of raw milk to feed calves and testing milk once a month for somatic cells — a measure that could indicate infection.
“A high somatic cell count, maybe over 250,000 or 300,000, would trigger a response in most herds to pull that cow out and take a look at them,” Ward said.
Ward said cattle have also been outfitted with activity monitors, measuring rumination — part of a cow’s digestive process — and overall activity. If below normal, these measures could indicate infection.
“They’re kind of like a Fitbit for cows,” Ward said. “We can use those to monitor health.”
Carl Hollifield, director of the NC State Dairy Enterprise System, elaborated on the biosecurity measures at the Dairy Research and Teaching Farm, saying the farm subscribes to an outline of biosecurity provided by the Mid-Atlantic Secure Milk Supply plan.
“It’s varying stair-step levels,” Hollifield said. “So if you have an outbreak of something, then we would go to our secure milk supply plan and we would say, ‘Okay, these are the things that we need to start shutting down.’”
The first level of biosecurity does not involve individuals on the working side of the tour. The second level includes a tour of the working side of the farm and requires individuals to wear booties while on the farm and remove them before leaving the farm.
“Tours are never allowed to touch animals, so there’s no human interaction with animals at that level with the tours,” Hollifield said.
The third level is between farm workers and students working on the farm, which would involve washing their own boots and wearing gloved hands. Ward added that employees undergo extensive training in biosecurity and disease prevention.
Hollifield said in the event of an outbreak of a disease such as bird flu, biosecurity level four would be in place — a security level that includes measures such as washing the tires of cars, avoiding tracking manure outside of the farm and suspending public tours.
Unlike poultry, bird flu in cattle is treatable. Infected cows would be quarantined and treated by the farm’s veterinarian.
Ward said in the event of an outbreak, staff would be encouraged to use more personal protective equipment, such as goggles. Bird flu is often found more commonly in cattle workers, due to the aerosolized particles such as milk.
“It’s new to dairy, and we hope it’s the last new species that it gets to,” Ward said.
