Milk Production Affected, But Impact Limited
In Spring 2024, veterinarians investigated a strange pattern of extreme milk loss with symptoms of sickness in multiple dairy herds in Texas. Ultimately, the infectious agent involved was identified as Highly Pathogenic Avian Influenza (HPAI) virus, commonly known as bird flu. Since then, cases have been detected in 208 farms in 14 states. There have been no cases identified in Virginia. Additionally, no cases have been identified in beef cattle.
The primary symptom of disease in dairy cattle is an extreme drop in milk production, but lethargy, loss of appetite and other mild symptoms of sickness can also occur. It is uncommon for HPAI to cause death in cattle. The pattern of spread appears to be bovine to bovine transmission, and most cases have been traced to the transport of cattle. A small number of cases, less than approximately 20, have been identified in cats, alpacas and humans. In all of these cases, disease has been mild and occurred in association with impacted dairy farms.
Fortunately, the impact on trade, milk price and beef prices has been minimal. Since April, HPAI testing requirements are in place for the interstate movement of lactating dairy cattle not destined for immediate slaughter. The USDA is offering indemnification for costs associated with this testing. Funding has also been allocated to vaccine development.
It is important to keep in mind that one of the dangers of influenza viruses is rapid mutation. Fortunately, this strain does not carry with it the high mortality in cattle that is seen in birds, nor does it seem inclined to cross species barriers. However, it is critical that cattle producers remain vigilant for possible change in patterns of disease. The most important and effective prevention measure is stringent bio-security. Quarantine new arrivals and clean equipment, including trailers. This is important to keep in mind as the show season is ongoing. This outbreak so far has been milder than originally feared and will hopefully die down with continued surveillance and bio-security.
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