The information below has been supplied by dairy marketers and other industry organizations. It has not been edited, verified or endorsed by Hoard’s Dairyman.
Highly pathogenic avian influenza (HPAI) associated with H5N1 (clade 2.3.4.4b) has caused outbreaks in poultry since 2022, but this infectious viral disease, more commonly known as H5 Influenza or bird flu, has hit dairy herds across multiple states with more than 1,000 herds affected as of June 5, 2025. While the dairy industry is charged with tracking viral mutations, measuring herd data and pulling that information together to learn more and provide valuable resources, there are things that producers can do at the farm level to help stop its spread.
“Activity monitoring, temperature tracking and rumination monitoring may provide a couple days’ lead time before a mass of clinically-ill cows appear,” says Kay Russo, DVM, MAHM, DACPV, partner at RSM Consulting and advocate for controlling the virus and its spread.
In addition to cow monitoring, the USDA announced they are implementing a National Milk Testing Strategy, which is a five-step plan to ensure the safety and security of the nation’s milk supply through systematic testing and monitoring.
Knowledge is power, says Dr. Russo. Knowing early that the bird flu may be infecting a herd can help producers:
- Provide supportive care to animals with the virus
- Help prevent the spread of the virus to other animals
- Alert farm employees to increase personal protective equipment use
- Minimize economic losses (for the farm and the industry)
24/7 Monitoring
CowManager, a herd management tool that uses ear sensors to measure ear temperature combined with behavior, monitors cows and provides early alerts related to health, fertility, transition and nutrition. Producers use the Health Module to catch sick cows days before they show clinical signs. The system monitors cows 24/7, tracks their well-being and detects health problems early, including symptoms commonly associated with the bird flu.
“A cow’s ear is full of vital information,” says Gerard Griffioen, CowManager founder. “CowManager ear sensors monitor an animal’s rumination, eating, activity or inactivity, and ear temperature. If a cow is not feeling well, the producer is alerted immediately, saving costs, antibiotics and labor, plus helping stop the spread of infection.”
Producers access the CowManager Health Module data on their laptop or smart phone, through a wireless router that receives signals from the ear sensor. Graphs show rumination, eating, resting, and behavior per cow, plus the system alerts if the cow’s temperature deviates from the rest of the group. The dashboard can display this information hourly or per day, allowing producers to deep dive into a cow’s health and compare her behavior to previous days. Color-coded alerts pop up when there’s an issue.
- Yellow “suspicious” — when there’s decreased activity, or moderately impaired eating and rumination time.
- Orange “sick” — indicates a cow is much less active, with greatly reduced eating and rumination time.
- Red “very sick” — the cow’s activity, eating and rumination time have seriously reduced.
- Black “no movement” — this could mean the sensor is no longer attached to the cow, or that the cow hasn’t been moving at all.
These alerts give producers critical information about their herd and allow them to make more informed decisions. Travis Brunner from DeJager Farms South in Chowchilla, Calif., 100% agrees.
DeJager Farms South turned to CowManager about 7 years ago to help improve overall herd health. “Having CowManager helps a lot with early detection,” says Brunner. “We’ll get an alert 1-3 days before we start seeing visual symptoms. The system tells me if a cow is sick or going to be sick and takes the guesswork out of it. It finds the sick cows and helps us be more proactive with treatment.”
Earlier this year, Brunner said CowManager alerted them to “suspicious” sick cows, which eventually tested positive for the bird flu. It allowed them to take preventative action and minimize the flu’s impact.
“CowManager definitely helped us,” says Brunner. “I give credit to CowManager and our employees for not losing one single cow after our herd was hit with bird flu.”
Only a matter of time
Mike Valadao of Valadao Dairy in Hanford, Calif., knew the bird flu was coming his way after hearing reports of neighboring dairies experiencing symptoms. He knew it was only a matter of time.
Valadao felt confident in his biosecurity measures and cow management protocols for their 2,200-cow dairy, however he also knew that stopping the spread of bird flu to his herd was going to be difficult.
Valadao turned to their CowManager monitoring system for help. “Early detection of the virus is critical to minimizing its impact,” says Valadao. “CowManager’s ear sensor measures ear temperature combined with eating, rumination and activity, providing us with early and accurate health alerts.”
That gut-wrenching moment
The team watched the CowManager “potential sick cow” list go from 30 to 60 to 120 within hours. That’s when they knew the virus had hit them.
“With CowManager, we were able to catch infected cows two to three days before they showed clinical signs, allowing our team to intervene and begin treatment immediately,” says Valadao. “We watched the list on an hourly basis and knew which cows were off. The app showed signs that a cow may not be feeling well. We knew something was up.”
Ear temperature as a key parameter
“CowManager’s ear sensors measure the temperature of a cow’s ear, which is a unique, valuable indicator of managing herd health,” says Valadao’s breeder and herd consultant, Mike Parreria. “The change in ear temperature along with changes in behavior mean a cow, in no uncertain terms, is getting sick.”
Parreria works with other herds in California. He says herds using CowManager have bounced back from bird flu much quicker than herds without the cow monitoring system.
“On dairies without CowManager, I’m seeing an average turnaround time of 60 days to rebound from bird flu,” says Parreria. “At Valadao, they saw a 45-day recovery period. Milk production, which had dropped by 20 pounds per cow per day on average, returned to normal and there were fewer complications from other health challenges that many neighboring producers have seen amplified by bird flu. Having CowManager has also benefited the Valadao repro program post-infection, as Mike’s cows have had less reproductive challenges compared to other herds I’m breeding.”
“CowManager definitely helped reduce losses associated with the bird flu,” reports Valadao. “It started on day 1 because the team had an accurate list of cows that needed attention. I was actually able to see those cows get better via the CowManager app; I watched their data improve shortly after we treated them. Early detection was a key component to our cows bouncing back.”
Stop the Spread
Along with monitoring cows, detecting disease early and following state and federal guidelines, Dr. Russo shares the following additional tips on how to help stop the spread of the flu.
- Keep it out (biosecurity) — Keep unnecessary people off your farm and don’t bring in animals with an unknown infection status. Request a RT-PCR test for any animal you’re buying, including youngstock.
- Keep it in (quarantine) — If you’re infected, don’t allow unnecessary people on your farm; try not to spread it to your neighbors or other operations. Also, dispose of waste milk by pasteurizing it prior to disposal, to avoid wildlife exposure and the perpetuation of the virus cycle.
- Manage the susceptible population — H5N1, the HPAI virus type found in dairy cows, doesn’t just disappear from a farm. On average, producers replace 30% of their herds each year with replacement heifers. If, for example, only 10-15% of the youngstock have been infected and mount immunity, that leaves 85-90% of them naïve, providing a constant naïve host for the virus to jump into. This means the virus can hang out on a dairy indefinitely, constantly mutating, constantly providing a risk to employees who handle these animals. A vaccine for susceptible cattle populations may be helpful.
Another potential option is truly closing a herd to allow all susceptible animals to develop protection against H5N1 before bringing in more naïve animals. Naïve animals add fuel to the fire.
According to the American Veterinary Medical Association, the USDA has approved two field safety trials for vaccine candidates designed to protect dairy cows from the virus. As producers wait for those vaccines to be tested and approved, taking advantage of innovative technology that gives them accurate and real-time information is important to maintaining herd health and reducing economic losses.
“CowManager is an extra set of eyes on your herd, 24 hours a day, updating on possible issues and cutting down on unnecessary cow touches,” Griffioen says. “It provides valuable insights that empower producers to use real-time data anytime, anywhere to make more informed decisions regarding herd health and performance.”
Outbreaks of bird flu continue to rise in poultry and dairy cows, as well as in other animals. Dr. Russo believes the virus will be here for the long haul, but that we can all do better to rein it in.
“It’s been difficult to track virulence to date, and the long-term implications on cow health and future lactations aren’t clear,” she adds. “It’s not dairy producers’ fault that the virus got into dairy cows, but it is now their responsibility to help stop it and ensure the sustainability of the dairy industry.”
For the most current bird flu information related to dairy cattle, producers can visit this USDA APHIS site:
https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock
In addition, producers should work with their veterinarian to stay informed about bird flu developments and to implement effective biosecurity practices to protect their herd.
About CowManager
At CowManager, we believe a successful dairy producer is a prepared dairy producer. With our revolutionary cow monitoring ear sensors, we ensure they’re always ahead, prepared for what’s coming, with actionable insights. We believe in working together to help producers reach their goals, whatever their ambitions are. Whether they have 20 or 20,000 cows, with CowManager they’ll have eyes on all of them. In the United States, CowManager is distributed and supported by Select Sires Inc.
