H5N1 in dairy cattle: producer perception may be as important as biosecurity guidance

A Michigan study suggests that the effectiveness of H5N1 biosecurity on dairy farms depends not only on the measures available, but on whether farmers believe those measures can actually work. Producers who considered biosecurity effective were far more likely to change their practices, while many continued to focus on wildlife and airborne transmission rather than more manageable pathways such as cattle movements, personnel and shared equipment.

The study surveyed commercial dairy producers in Michigan after the emergence of highly pathogenic avian influenza H5N1 in US dairy cattle. The questionnaire was sent to virtually all licensed dairy facilities in the state, with 120 complete responses from 766 deliverable surveys, a response rate of 15.6%. Eighteen respondents reported confirmed or suspected HPAI on their farms.

Veterinarians are the main trusted source

Producers were generally well informed. Around 76% described themselves as moderately to very familiar with HPAI, while 83% considered that they had received sufficient guidance.

The most commonly cited source of information was the veterinary profession, selected by 72% of respondents, ahead of government agencies such as USDA, MDARD and CDC at 52%, industry organisations at 48%, and agricultural extension at 43%. Academic publications were used by 24%, while news media and social media were cited by only 8% and 5%, respectively.

This gives veterinarians a particularly important role not only in disease detection but also in translating rapidly changing scientific evidence into decisions that farmers can implement.

Wildlife dominates producers’ perception of risk

The survey reveals an important gap between perceived and potentially controllable transmission routes. Wildlife was identified by 74% of producers as a likely route of H5N1 introduction, followed by airborne transmission at 34%. Only 23% selected cattle movements, while 12% identified workers shared between farms. Other possibilities, including feed, were reported less frequently.

The authors argue that producers may therefore be overemphasising routes that appear difficult to control, such as wild birds and airborne spread, while under-recognising management-related pathways that may be more amenable to biosecurity intervention...

Current experimental and field evidence increasingly points to the importance of mammary infection, milk-associated exposure and cattle-to-cattle transmission! Viral shedding can also continue beyond the visibly clinical phase, strengthening the case for controls on animal movement, personnel and shared equipment.

Only 37% changed biosecurity practices

Despite relatively high awareness, only 37% of respondents reported changing their farm biosecurity in response to H5N1 concerns.

Measures included restricting access to the farm, introducing sanitation stations and improving signage. The remaining 63% reported no additional changes.

Farm structure appeared to matter. Among farms without reported HPAI, operations with 15 or more employees were 2.26 times more likely to implement changes than farms with fewer than five employees. Farms using robotic milking systems were 2.07 times more likely to report changes than those using parlour or rotary systems. Herd size, production system and somatic-cell count showed no clear association with implementation.

Believing biosecurity works changes behaviour

The strongest finding concerns perception of effectiveness. Among producers who believed that strengthening biosecurity could delay or prevent H5N1, the estimated probability of implementing changes was 45.7%, compared with 21.4% among producers who did not consider biosecurity effective.

That represents a 24.3 percentage-point difference. Producers who believed in biosecurity effectiveness also had more than three times the odds of implementing changes.

The mediation analysis suggests that concern about H5N1 explained part of this relationship. Around 39% of the total association between perceived effectiveness and behavioural change was mediated through concern about the disease, whereas farmers’ perception of their own relative farm risk played a much smaller role.

The message is therefore not simply that farmers need to be told H5N1 is dangerous. Communication appears more likely to change behaviour when producers are simultaneously convinced that specific actions are practical and capable of reducing risk.

H5N1 affects production long after clinical recovery

The study also provides useful field information from the 18 farms reporting confirmed or suspected infection. The median clinical phase lasted 21 days, but reduced productivity persisted for a median of 40 days, suggesting that the economic consequences continue after visibly sick animals recover.

Producer-estimated HPAI-related mortality averaged only 0.34% of lactating cows, but the median estimated economic loss reached $152 per lactating cow, with reported losses ranging from $34 to $526.

The economic estimate is close to an earlier research estimate of $158 per cow, lending some support to the producer-reported figures.

The paper notes previous evidence of substantial damage to mammary secretory tissue during H5N1 infection, including replacement by fibrotic tissue that can persist after the virus is no longer detectable.

Many farmers still consider their own farms relatively safe

Among farms without reported infection, 53% of producers considered their farm at lower H5N1 risk than other farms, while 43% considered their risk similar and just 4% considered it higher. Those perceiving lower risk commonly cited closed herds, restricted human movement and smaller farm size as protective factors. This illustrates a classic risk-perception problem: producers may recognise H5N1 as a serious industry-wide threat while still considering their own operation comparatively protected.

The lesson is about communication as much as biosecurity

The study does not demonstrate which biosecurity intervention is most effective, nor can its cross-sectional design establish cause and effect. The sample was also limited to Michigan and the number of affected farms was small. The respondents may have been more engaged with HPAI and biosecurity than non-respondents. But the findings identify an important weakness in disease preparedness.

Farmers may be less likely to invest time and money in measures aimed at cattle movements, employees or equipment if they believe the virus primarily arrives through uncontrollable wildlife or airborne exposure.

Communication should present H5N1 as a relevant but manageable farm-level threat, clearly identify evidence-supported transmission pathways and emphasise practical interventions that producers can actually implement.