Editor’s note: As of April 8, the Bovine Medical Association refers to HPAI infections in cattle as BIAV (Bovine Influenza A Virus).
First outbreak of highly pathogenic avian influenza (HPAI) It has also been confirmed in dairy cows.. Cows in the Texas Panhandle were the first to test positive for the virus, but since it was first discovered, more dairy cows have tested positive in other states, including Michigan and Ohio. At this time, there are no reported cases in dairy or beef cattle in Canada.
The HPAI virus is primarily lethal to chickens, turkeys, and many wild bird species that carry and spread the disease along their migratory routes.
U.S. veterinarians are learning more about how HPAI develops in dairy cows, but much is still unknown about how the virus spreads between animals.
The National Milk Producers Federation hosted a webinar to share multiple perspectives on what is known and what is not known about this disease. Brandon Treichler, DVM, previously he was part of a team presenting the latest findings on how HPAI occurs in dairy cows. He has worked directly with herds affected by this disease.
What we know based on U.S. herds is that symptoms of the disease include significantly reduced rumen activity, reduced feed intake, significantly reduced milk production, changes in milk consistency, and This includes changes in the texture of the fertilizer.
Treichler says decreased rumen activity is visible and visible very quickly with tracking collars. The fertilizer dries out, probably due to reduced water intake. Supportive care, including hydration, has proven to be most effective, he says. Antibiotics are not needed unless a secondary infection occurs.
Not all infected cows develop a fever. Older cows in mid-lactation appear to be more affected in terms of severity, but younger cows are also testing positive. The consistency of the milk may change in one, some, or all quarters of the breast, making it thicker and yellow, like colostrum. At this time, several cows have withered during the 10-14 day illness and some have not returned to lactation. Initially, this led to mass culling before producers and veterinarians knew HPAI was the cause.
A positive reaction was obtained from the milk sample. As a precaution, calves (or humans) should not consume unpasteurized milk and colostrum. Pasteurization kills any pathogens present. Although it is very unlikely that meat or milk from a sick animal entered the food chain, the risk to human health from exposure is very low. To date, he has not had a positive HPAI test from meat.
Producers are encouraged to enhance biosecurity protocols to limit exposure of animals to birds and bird droppings, as well as to limit exposure to cattle on other farms. Restricting the movement of people and adhering to hygiene protocols for shared facilities, i.e. trailers, are also recommended, but at this time it is not fully understood how HPAI spreads between animals.
No cattle in Canada have tested positive yet, but migratory birds that can transmit HPAI are already living overhead. Producers are being alerted to the symptoms to look out for and are encouraged to contact their veterinarian if HPAI is suspected. All producers are encouraged to review and implement biosecurity measures.
