Disease

Hidden Pneumonia in Calves: Why More Dairies Use Ultrasound to Catch Respiratory Disease Early

Fri, 17 Apr 2026 20:06:16 GMT

Bovine respiratory disease (BRD) remains one of the most common and costly health challenges in preweaned dairy calves. The challenge is that many cases develop long before calves show visible symptoms.

“By the time calves show obvious clinical signs of respiratory disease, lung damage may already be present,” says Aerica Bjurstrom, regional dairy educator at the University of Wisconsin-Madison. “That’s why tools that help us detect pneumonia earlier can make a big difference in calf health and long-term performance.”

Traditional diagnosis relies on symptoms such as coughing, nasal discharge, or elevated temperature. But these signs often appear late in the disease process. In many cases, calves may look completely healthy while still carrying lung infections.

This form of illness, known as subclinical pneumonia, can reduce growth, feed efficiency and even future milk production.

“The lungs can really act as an indicator organ,” Bjurstrom explains. “Respiratory disease often reflects larger management challenges, such as poor colostrum intake, nutrition issues, or environmental stress.”

The Hidden Pneumonia Problem

Research has shown that pneumonia often develops days before visible symptoms appear.

“Ultrasound allows us to see what’s happening inside the lung tissue, even when the calf looks normal from the outside,” Bjurstrom says. “In many cases, pneumonia can be present for days before any clinical signs appear.”

Studies suggest that 50% to 80% of pneumonia cases may remain subclinical for 7 to 14 days before producers notice symptoms. That delay can allow lung damage to progress before treatment begins.

“Sometimes calves with severe pneumonia don’t show obvious symptoms,” Bjurstrom says. “But an ultrasound exam can reveal lung lesions that tell us the disease is already present.”

How Lung Ultrasound Works

Lung ultrasonography allows veterinarians to examine calf lungs in real time using portable ultrasound equipment.

A normal lung appears air-filled on the scan and produces horizontal white lines that move with each breath. These lines indicate healthy lung tissue.

Changes in the image can reveal early disease.

“Comet tails are bright vertical lines that extend down from the lung surface,” Bjurstrom says. “A few may be normal, but severe or diffuse comet tailing can suggest interstitial disease caused by fluid or inflammation within the lung.”

More advanced disease appears as lung consolidation, where portions of the lung fill with inflammatory material instead of air. On ultrasound, these areas appear as solid gray regions.

Veterinarians often use a 0 to 5 lung scoring system to evaluate severity.

“This scoring system helps identify disease before calves begin coughing or showing nasal discharge,” Bjurstrom says. “Early detection allows for earlier treatment and better outcomes.”

Dr. Ollivett demonstrates positioning for thoracic ultrasound scanning on a calf’s right lung.

(Denise Garlow, University of Wisconsin)

Why Early Detection Matters

Even when calves show no visible symptoms, lung damage can affect their long-term performance.

In one study of more than 600 Holstein heifers, calves with lung consolidation detected at weaning were less likely to become pregnant and more likely to leave the herd before first calving.

Another study found calves with significant lung lesions in the first eight weeks of life produced 1,155 pounds less milk during their first lactation.

“These findings highlight why early detection matters,” Bjurstrom says. “Subclinical disease can still influence growth, reproduction, and milk production later in life.”

Improving Treatment Outcomes

Early detection can also make treatment more effective.

“When pneumonia is caught earlier, treatment tends to work better,” Bjurstrom explains. “We’re able to intervene before the disease becomes severe and causes permanent lung damage.”

Ultrasound can also help veterinarians monitor recovery.

“That monitoring aspect is important,” she says. “It helps ensure calves are improving and reduces unnecessary retreatment.”

A Management Tool for Farms

Beyond diagnosis, lung ultrasound is increasingly used as a herd management tool.

“Ultrasound gives producers objective information about lung health,” Bjurstrom says. “That can help guide decisions about treatment, culling, or adjusting weaning timing for calves that may need more time to recover.”

Regular scanning can also reveal herd-level trends tied to management practices.

“When used consistently, ultrasound becomes a benchmarking tool,” Bjurstrom says. “It can help farms evaluate colostrum programs, ventilation, sanitation, and other factors that influence calf health.”

A Growing Tool in Calf Health Programs

Portable ultrasound units have become more accessible and easier to use, making them more common in calf health programs. With proper training, scanning a calf’s lungs typically takes less than a minute.

“The equipment requires an initial investment, but the information it provides can be incredibly valuable,” Bjurstrom says. “Earlier detection can lead to better management decisions, improved calf growth, and fewer losses.”

As dairy farms continue adopting more data-driven management practices, lung ultrasound is giving producers a new way to detect disease sooner and protect the long-term potential of their calves.

“Lung ultrasound helps us move beyond waiting for visible symptoms,” Bjurstrom says. “It allows producers and veterinarians to identify problems earlier and take action before long-term damage occurs.”

Bovine Tuberculosis Detected in Michigan Dairy

Tue, 24 Feb 2026 19:18:18 GMT

The Michigan Department of Agriculture and Rural Development (MDARD) has confirmed a case of bovine tuberculosis (TB) in a dairy herd in Charlevoix County, located west of Michigan’s Modified Accredited Zone (MAZ), where the disease is known to be present in the state’s white-tailed deer population.

(Michigan Department of Agriculture and Rural Development)

According to state officials, the detection followed identification of bovine TB in an adult cow at a USDA Food Safety Inspection Service-inspected processing plant. Through animal traceability efforts, officials traced the animal back to its herd of origin. Subsequent testing of the herd identified additional bovine TB cases.

“This latest detection of bovine TB highlights two important realities: how challenging the disease is to address; and why it is so crucial to use all of our tools for detection to swiftly identify cases and take actions to limit disease spread,” say Nora Wineland, state veterinarian for Michigan. “While finding a newly affected herd is never ideal, this case demonstrates our systems for detection and traceability are working, allowing us to quickly implement measures to protect animal health and public health in Michigan.”

MDARD reports an epidemiological investigation is already underway to determine whether additional cases may be linked to the affected herd. There are currently two TB zones within the state: a four-county area in northern lower Michigan called the Modified Accredited Zone, and the remainder of the state’s 83 counties is referred to as the Accredited Free Zone.

This is Michigan’s second confirmed bovine TB case in the past 13 months. The previous case was identified in a beef herd in Alcona County, located within the state’s Modified Accredited Zone, in January 2025. With this latest detection, a total of 84 cattle herds have been confirmed with bovine TB in Michigan since 1998.

What is Bovine Tuberculosis?

According to USDA’s Animal and Plant Health Inspection Service (APHIS), bovine tuberculosis is a chronic bacterial disease that can infect all mammals, including humans. It is caused by the bacterium Mycobacterium bovis and spreads through both direct contact between infected and uninfected animals and indirect exposure, such as contaminated feed, water or the environment.

The disease progresses slowly, often developing over several years. Infection typically begins in the lymph nodes before advancing to the lungs and chest cavity, where it can cause serious lesions.

While cattle are the primary host, the disease can also be present in white-tailed deer and elk, as well as bison, goats and certain carnivores, including coyotes.

The Symptoms

Unfortunately, infected cattle are typically asymptomatic. Detection usually occurs during live animal skin testing or, more commonly, at slaughter through our national slaughter surveillance program, according to USDA. If cattle or bison show clinical signs of tuberculosis, the disease has advanced to affect multiple organ systems, which is rare.

Can it be Prevented?

Bovine TB most often spreads through close contact, especially nose-to-nose interaction between animals, or when cattle consume feed or water that’s been contaminated. In most cases, herds become infected one of two ways: by bringing in an infected animal or through exposure to infected wildlife.

While the prevalence of tuberculosis in cattle is extremely low in the U.S., with an estimated prevalence of 7 per 1 million cattle screened, it can occur. Producers should work alongside their veterinarian to help create a biosecurity plan.

How is it Identified?

According to APHIS, the primary source of tuberculosis surveillance is carcass inspection at all federal and state inspected slaughter establishments. The other main sources of tuberculosis detection are testing animals before interstate movement and during disease investigations. Live animal testing is performed with a screening test. If positive, the regulatory veterinarian will conduct a confirmatory test.

Can it be Treated?

Unfortunately, tuberculosis in livestock is not a treatable disease. When health officials find tuberculosis in a herd, it is managed by either depopulating the herd or by testing and removing reactor animals.

Does Bird Flu Have an Effect on Cow Fertility?

Fri, 06 Feb 2026 20:52:17 GMT

When highly pathogenic avian influenza (HPAI) first hit U.S. dairies, it threw the industry into unfamiliar territory. With so many unknowns, the immediate focus was on slowing the spread and caring for the cows that were affected.

Now, with more of the puzzle pieces coming together, researchers are beginning to step back and look at the bigger picture, examining how the virus affects cows not only in the days and weeks after infection, but what it may mean for their health and performance long after.

On a recent episode of “The Dairy Podcast Show”, Jennifer Spencer and Juan Pinedo, Extension dairy specialists with Texas A&M, came together to better understand what this virus is doing to reproduction — and if infected cows will be paying the price for years.

What Does HPAI Mean for Cow Fertility?

Spencer and Pinedo are just starting to study HPAI’s long-term effects, and their work is one of the first to measure how it may impact reproduction in U.S. dairy herds. Early signs point to a real effect on reproductive performance, particularly in younger animals, though the science is still evolving.

“We really want to know if it does impact reproduction,” Spencer says. “We want to let the producers know so they can understand if they might have to cull heavier to make sure that they’re managing this and replacing the cows in a timely manner — for sustainability of the herd and also to help maintain or improve their profitability.”

Like all major health events, HPAI is predicted to have an impact on cow fertility or pregnancy loss. But for Spencer and Pinedo, they are trying to figure out to what degree.

“We know that when cows get sick, they shift their energy toward fighting an infection rather than reproducing,” Spencer explains. “If these cattle that are infected with HPAI are having reduced milk production, feed intake and rumination, then there’s a high probability it’s impacting reproductive efficiency and their performance.”

Pinedo adds this pattern isn’t unique to HPAI, but still worth studying.

“Just like with any other systemic disease, having a detrimental effect in repro performance is something that we will expect,” Pinedo explains.

Dig Into Herd Data

In March 2025, Spencer’s team received rapid-response funding from USDA APHIS to study how HPAI affects reproduction in dairy herds. They designed a retrospective observational study, analyzing on-farm records from January 2021 through each herd’s HPAI outbreak and beyond.

“We’re looking at data from January 2021 until they had an HPAI outbreak,” Spencer says. “How we’re determining that is based not just on what the producer says, but by also analyzing the records and looking for that drastic drop in milk production, because that’s kind of the overall sign when they had an HPAI outbreak.”

To give the team a wide view of how HPAI is affecting herds in different settings, the project spans across three dairy regions with five to 10 dairies per region. These areas include the:

South Central
Western U.S.
Pacific Northwest

“We want to get information from different environments to have a better idea of the geographical differences, and what they deal with heat-stress-wise, or the feed availability,” Spencer says. “This will give us a 30,000' view of what is happening.”

A Hit on Heifers

While the full analysis is still in progress, the team has already taken a close look at one South Central dairy, and the early patterns are raising important questions in heifers. The study found conception rates dropped during the outbreak year but appeared to rebound the following year.

“For heifers, they actually had about a 5% decrease in their conception rates during 2024 from March until December, but that appears to go back up in 2025,” Spencer reports.

Pinedo added specific figures to put the changes into perspective.

“There was a 52% conception rate, and they dropped during the outbreak to 45%. The year after, they came back to 50%,” he notes.

These numbers show that while conception rates began to recover after the outbreak, they didn’t fully return to pre-HPAI levels. Spencer notes heifers needed more services per conception, suggesting the virus may have lingering effects on reproductive efficiency.

“For heifers, we saw an increase in services per conception, but they’ve remained higher. They went from about a 1.5 up to like 2, 2.2 number of times bred for their heifers, and it’s continuing into 2025,” she adds.

Spencer admits that wasn’t what they expected.

“We didn’t think that heifers would be impacted,” she says.

Complicating things further, some of the heifers in question were born to cows infected late in gestation.

“Some of those heifers were actually from cows that were in their third trimester of their pregnancy, so that may be a contributing factor,” Spencer adds. “There’s so many moving parts in it.”

How Are Cows Being Impacted?

For cows, the pattern is more complex. Unlike heifers, which showed a relatively clear dip and rebound in conception rates, mature cows showed more varied responses to HPAI. Some herds experienced noticeable declines during the outbreak, while others were less affected.

“We did see conception rates appeared to decrease in all of the lactations,” Spencer notes. “But for the first and third and greater lactations, they seem to be going back up, whereas the second lactation seems to be kind of having a harder time rebounding.”

Those second-lactation cows are noteworthy because many were first-lactation animals during the outbreak itself.

“It seems as if perhaps a first-lactation animal, which you might think would be more resilient to recover, maybe, is having more longer-term effects on at least reproduction, as opposed to older cattle,” Pinedo adds.

These unexpected patterns have the researchers taking a closer look at the number to try and determine why younger animals are taking a bigger reproductive hit.

How Much Should We Read Into Early HPAI Data?

While the data is eye-opening, both researchers are quick to point out that the findings are still early, and there’s a lot they don’t yet know.

“This is research that is at the very early stages, and it’s a retrospective observational study,” Pinedo emphasizes. “You really want to control confounders; it’s nothing that we could jump into conclusions [about] right now.”

He lists the kinds of changes every producer lives with year to year:

“You have bull genetics that will have changed, repro program that will have changed, feed that will have changed, heat abatement technologies, so many confounders that affect repro that have to be controlled,” he says.

Spencer sees the same complexity in the field of research.

“What if they changed a breeder? Or what if they started using precision technologies on their heifers, so their heat detection rate went up? These are things we have to take into consideration,” she says.

For now, the research is still in its early stages, but the data suggest HPAI does have reproductive effects worth paying attention to, especially in younger animals. As the team continues to analyze records and track herd performance, these early insights can help producers keep a closer eye on animals who were impacted by the virus and make more informed decisions for the long-term health and fertility of their herds.

The Hardest Call in Cattle Health: When to Treat Disease

Fri, 30 Jan 2026 19:55:55 GMT

“Are we better off treating disease early or treating disease precisely?” Veterinarians of Kansas State University posed this question a recent episode of BCI Cattle Chat .

Deciding when to initiate treatment is one of the most consequential judgment calls in cattle health management. The tension between acting early and waiting for diagnostic certainty persists because there is no single correct approach. Each decision carries both biological and management consequences.

“To me, I’m looking at this and framing the question as should I be sensitive or specific in my diagnostic approach,” says Dr. Todd Gunderson, clinical assistant professor in beef production medicine at K-State.

A sensitive approach prioritizes catching disease early, accepting that some animals will receive treatment they might not truly need. A specific approach limits treatment to animals that clearly meet disease thresholds, reducing unnecessary intervention but increasing the risk of missing cases that would have benefited from earlier action. The trade-off is unavoidable.

Gunderson puts forth different clinical scenarios where either approach could be beneficial or detrimental.

“Treating scouring calves and, as a result, creating more scouring calves because I’m contaminating equipment, I’m contaminating my clothes … I’m overly aggressive at going into the calving pen,” he says.

On the other hand, waiting too long could negate any help treatment might offer.

“[If] I wait until the animal is at a pathological state where they have consolidation, they already have fibrinous pleuritis of the chest cavity or adhesion and fibrous attachments,” he says. “That animal has enough pathology that even if I kill every microbe in that animal’s system that’s causing disease, it would still not recover.”

Disease Treatment as a Dynamic Process

Rather than viewing treatment as a one-time, irreversible decision, a more effective framework treats intervention as a dynamic process. Choosing not to treat immediately does not mean choosing inaction; it means committing to close monitoring and reassessment over defined time intervals.

“I don’t get trapped into thinking that I have to make the decisions that I’m going to stick with,” says Dr. Bob Larson, professor in production medicine at K-State. “Let me make a decision today and act on it and then reassess it in 12 hours and reassess it in another 12 hours, and be flexible because I’m not good enough today to predict the next 12, 24, 72 hours and be right all the time.”

Repeated evaluations allow decisions to evolve as new information emerges, improving accuracy over time.

“Just because I acted doesn’t mean that now all my thinking is over,” Larson says. “If I act, I need to maintain vigilance, observations, reassess, be willing to change my mind.”

Make Decisions Based on the Herd

Treatment decisions should also be considered in the context of the group not in isolation. Individual animal signs can be ambiguous, but herd-level trends provide valuable context. During times of disease pressure, subtle changes might warrant treatment, while the same signs in an otherwise healthy group could justify continued observation.

“We sometimes take these decisions and try to make them in a vacuum, and you can’t do that,” says Dr. Brad White, Professor and Production Medicine Director of the Beef Cattle Institute at K-State. “Often, that individual animal is a part of a group. My expectations for that group today should impact my decision.”

This includes the recent health of the herd and the number of animals presenting as ill.

In addition, environmental and situational factors should further shape treatment thresholds. Weather conditions and recent stressors both impact disease risk and recovery potential. Incorporating these variables into treatment decisions expands diagnostic accuracy beyond the animal itself.

California Reopens Dairy Cattle Shows Following HPAI Ban

Tue, 20 Jan 2026 17:01:46 GMT

After more than a year on the sidelines, dairy cattle and poultry shows are returning to California fairgrounds. The California Department of Food and Agriculture (CDFA) has lifted its statewide ban on exhibitions, clearing the way for shows to resume.

The restriction was put in place at the beginning of 2025 as the state tracked the spread of H5N1 Highly Pathogenic Avian Influenza (HPAI). After months of surveillance and review, state officials now say conditions have improved enough to allow a cautious restart.

According to the department, the decision was based on ongoing monitoring of H5N1 activity across the state, analysis of viral trend data and consultation with state and federal epidemiologists. After a detailed review, the CDFA has determined the risk associated with poultry and dairy cattle exhibitions has declined enough to allow shows to resume, provided enhanced safeguards remain in place.

State officials pointed to stronger biosecurity awareness across the industry as a factor in the decision. Over the past year, producers and exhibitors have become more familiar with transmission risks and prevention strategies, helping reduce overall exposure concerns.

As fair season draws closer, CDFA says the move gives clearer direction to youth livestock programs, breeders and exhibitors who have spent months unsure whether animals would make it back to the show ring.

While the ban has been lifted, fairgrounds and exhibitors are being urged to stay cautious. Enhanced biosecurity measures, routine health checks and careful animal handling are still recommended, especially in high-traffic areas. State monitoring of H5N1 will continue throughout the exhibition season, with officials working alongside fair organizers and animal owners as events resume.

Inside a Simulated HPAI Outbreak in a Dairy Herd

Fri, 16 Jan 2026 19:28:32 GMT

In spring 2020, U.S. dairy producers were forced to dump millions of pounds of milk when the system around them failed. Schools closed, institutional buyers disappeared, processing plants couldn’t pivot and the disconnect between production and demand became painfully clear. That experience raised a critical question: Could similar system-wide disruptions happen again, driven not by markets but by disease?

That question helped drive a new proof-of-concept project from the Western Institute for Food Safety and Security (WIFSS) at UC Davis: a simulation model designed to examine what happens when H5N1 highly pathogenic avian influenza (HPAI) enters a dairy herd.

“This was more a proof of concept,” says David Goldenberg, food safety and security training coordinator for WIFSS at UC Davis. “Can we develop a model that would mimic a dairy farm and the resulting impacts [HPAI] would have not only on the farm but also elsewhere and down the road?”

Rather than attempting to predict the next outbreak, their goal was to understand what an outbreak would look like on a single dairy and how its impacts unfold over time.

What the Model Simulated

The team based their simulation on a small dairy herd of roughly 260 cows with the following assumptions:

No animals were purchased from outside sources; replacements were born into the herd
Labor, equipment and milking infrastructure functioned normally
Cows were assumed healthy apart from H5N1 infection
Milk from infected cows was discarded

Further, reinfections were not modeled, and the analysis focused on acute infection rather than chronic disease.

Speed of Spread Mattered More than Severity

One of the clearest lessons from the simulation was how fast H5N1 spreads through a herd might matter more than how sick individual cows appear.

The model evaluated low, medium and high infectivity scenarios. In high-infectivity cases, nearly the entire herd became sick within about 30 days. That rapid clustering overwhelmed treatment capacity, increasing the risk of dehydration, delayed care and mortality. This wasn’t because the disease was more severe but because too many animals required attention at once.

“That’s a tremendous effort to simultaneously try to treat every cow in your herd at the same exact time due to limited resources,” says Nelson Alfaro Rivas, simulation consultant with MOSIMTEC. “Unfortunately, some of the cows might succumb just because of dehydration from the disease just because you don’t have an unlimited number of veterinarians to try and hydrate the cows as they’re sick.”

In lower-infectivity scenarios, illness spread more slowly, peaking later and involving fewer animals simultaneously. The contrast underscored why early isolation, movement control and disease recognition can fundamentally change outcomes.

Milk Loss Didn’t End When Cows Recovered

Even when cows clinically recovered, milk production did not bounce back quickly.

The simulation assumed infected cows experienced either a 15% or 30% reduction in milk yield for the remainder of their lactation, figures drawn from field observations. In high-infectivity, worst-case scenarios, total milk production across the herd fell sharply within the first month.

Over time, those losses accumulated. In the most severe scenarios, the herd produced approximately 25% less milk over the modeled period compared with an uninfected baseline. Perhaps more striking, herd-level production did not return to baseline for almost a year, long after the active outbreak had resolved.

“How long does it take to recover from something like this?” Rivas asks. “All the cows were recovered by day 26, but what you don’t really see is that the herd that got infected doesn’t really recover and produce the same amount of milk as the non-infected herd until almost 300 days later.”

This gap matters not only for producers but also reframes recovery as an extended process rather than a clinical endpoint.

Recovery Didn’t Mean Economic Recovery

Because dairies run on thin margins, sustained milk loss drove decisions beyond treatment and recovery. Cows producing well below expectation after infection were more likely to be removed from the herd, even if they survived the disease itself.

“At the end of the day, farms are businesses, and you can’t keep an underproducing and therefore unprofitable cow,” Rivas says.

The model reinforced a familiar reality: Profitability, not survival alone, determines herd composition after disease events.

Where Biosecurity Fits

Biosecurity practices were not explicitly modeled as individual actions. Instead, their effects were represented indirectly through changes in infectivity. Lower infectivity scenarios approximated the benefit of practices such as isolating sick cows, cleaning equipment and controlling farm access.

Those measures come with costs — labor, time and disruption — but the simulation showed even modest reductions in spread speed dramatically altered outcomes. The model did not attempt to assign dollar values to biosecurity steps, but it made clear why reducing infectivity yields outsized returns.

Why This Matters Now

What this model ultimately provides is a clearer sense of risk timing, not new disease facts. By compressing complex outbreak dynamics into a single on-farm view, it shows how quickly routine management assumptions can be tested once disease pressure rises, particularly when multiple animals require attention at the same time. The practical consequence is that delays in recognition or response can carry operational costs that aren’t immediately visible.

The take away is not alarm but foresight. Decisions around monitoring, separation and communication that are made early shape how manageable an outbreak remains and how disruptive its aftermath becomes. By visualizing those downstream effects in advance, the model offers a way to stress-test response strategies before they’re needed, helping dairies prepare for uncertainty rather than react to it.

Why is H5N1 Showing Up in Cattle?

Thu, 18 Dec 2025 14:02:00 GMT

As H5N1 continues to be detected in U.S. dairy cattle, new research shows some modern bird flu viruses are genetically better equipped to infect bovine cells than earlier strains, helping explain why cattle are now part of the outbreak.

Highly pathogenic avian influenza (HPAI) is no longer just an avian problem. Recent detections of H5N1 in dairy cattle, including the latest confirmed case in a Wisconsin herd , have elevated concern among veterinarians, producers and animal health authorities. According to USDA, HPAI has been detected in dairy herds in at least 18 states since March 2024, with milk testing serving as a routine detection pathway.

A newly published Nature Communications study led by scientists at the MRC–University of Glasgow Center for Virus Research provides critical insight into why certain H5N1 viruses are now capable of infecting cattle and highlights that some recent H5N1 variants are better at infecting cow cells and mammary tissues than older viruses. This suggests recent spillover events are not random accidents but might reflect viral genetic traits that support infection in cattle.

“Our work shows that different bird flu viruses have very different abilities to infect cow cells and tissues,” says Professor Massimo Palmarini, from both the Erasmus Medical Center and the MRC–University of Glasgow Center for Virus Research. “While the strain currently spreading in U.S. cattle is clearly the best adapted so far, there are other bird viruses that could potentially infect cows if given the chance.”

Key Findings Veterinarians Should Know

H5N1’s ability to infect cattle varies by viral lineage and the outbreak clade stands out

Researchers evaluated a wide range of historical and contemporary H5N1 viruses in bovine cell systems. The results were clear: Replication efficiency in bovine cells differed substantially between strains. Earlier H5N1 viruses often showed limited replication, while variants of the current outbreak from clade 2.3.4.4b, including genotypes B3.13 and D1.1, performed significantly better.

Why it matters: This variability helps explain why cattle infections are being detected now, after decades of HPAI circulation in birds. This also aligns closely with what field veterinarians are seeing: dairy cows developing clinical signs, such as reduced milk production and abnormal milk, often in the absence of severe respiratory disease.

The phenotypes of the reassortant viruses described in the study using either bovine or human cells and restriction factors as indicated.

(Nature Communications (2025). DOI: 10.1038/s41467-025-67234-1)

Internal genes, not just surface proteins, drive adaptation

The study highlights that synergistic interactions among internal gene segments, including viral polymerase complex and non-structural genes, play a critical role in determining how well H5N1 replicated in bovine cells. This shifts the focus away from viral surface protein hemagglutinin alone.

Why it matters: Viral evolution that improves replication in cattle could occur without obvious changes to classical avian influenza red flags, complicating surveillance and risk assessment.

Adaptation does not mean inevitability, but it raises the stakes

The authors stop short of suggesting H5N1 is becoming a cattle-adapted virus. However, they do demonstrate a biological pathway for improved compatibility with bovine hosts.

Why it matters: If H5N1 continues circulating in cattle, even transiently, it carries opportunities for viral maintenance, farm-level spread, and additional spillover events.

Connecting Lab Findings to Field Observations

These results provide a critical biological framework for the unusual epidemiology seen in recent cattle detections. The finding that modern H5N1 variants replicate efficiently in bovine mammary cells explains why dairy herds, and not beef, have been the focus of this outbreak and why milk has emerged as a vital surveillance sample.

This shift in viral tropism is directly reflected in the field: Infections are typically identified not by respiratory distress but by sudden drops in milk yield and abnormal milk consistency. While commercial pasteurization ensures the general milk supply remains safe, the high viral loads in raw milk highlight a pressing need for enhanced biosecurity within the milking environment. Ultimately, when production anomalies coincide with local avian influenza activity, H5N1 testing should be considered an essential component of the diagnostic workup.

First Case of Avian Flu Detected in Wisconsin Dairy Herd

Sun, 14 Dec 2025 19:40:26 GMT

A case of highly pathogenic avian influenza (HPAI) has been detected in a dairy herd in Dodge County, Wisconsin, the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) announced Sunday. This marks the first confirmed detection of the virus in dairy cattle in the state.

Dodge County, Wisconsin

(USDA)

The herd was identified through routine National Milk Testing Strategy screening, not the surveillance required for moving cattle across state lines. The affected farm has been quarantined, and any cattle showing signs of illness are being separated for treatment.

Bird flu has already been detected in poultry flocks in Wisconsin. On Dec. 9, state officials reported HPAI in a flock in Marquette County, which is just one county away from the affected dairy herd.

HPAI in dairy cattle has been documented in the U.S. before, with the first detections reported in March 2024 in dairy herds in Texas and Kansas. Since then, there have been more than 1,000 confirmed cases across 18 states, primarily through targeted testing and monitoring programs. While the pace of new detections has slowed in recent months, one additional confirmed case has been reported in California within the past 30 days, indicating the virus is still a threat.

HPAI Confirmed Cases in the Last 30 Days

(USDA)

Total HPAI Confirmed Cases

(USDA)

A Wake-Up Call for Dairy Biosecurity

The Wisconsin case comes as new research from Farm Journal highlights ongoing gaps in dairy biosecurity practices nationwide. A survey of more than 300 dairy producers, presented at the MILK Business Conference, found that while many operations report having biosecurity plans in place, consistent implementation and regular review remain a challenge.

According to the survey, 68% of farms with at least 250 cows say they have a biosecurity plan, yet 34% of those producers acknowledge they do not routinely review or update it. The findings point to vulnerabilities at a time when disease threats such as HPAI, New World screwworm and bovine spongiform encephalopathy continue to raise concern across the livestock sector.

(Farm Journal)

“We need biosecurity efforts to be more impactful at the ground level,” said Kirk Ramsey, professional services veterinarian with Neogen, who reviewed the survey results. “Not only to prevent major outbreaks, but also to protect employees and families from what could be carried home every day.”

As emerging diseases continue to challenge dairy operations, the research reinforces the importance of consistent, practical biosecurity measures to reduce risk and protect herd health.

What are the Symptoms of HPAI in Dairy Cattle?

As monitoring continues, officials are urging producers to stay alert for early signs of illness within their herds, as prompt detection and response remain key to limiting further spread. Signs of HPAI include:

Drop in milk production
Loss of appetite
Changes in manure consistency
Thickened or colostrum-like milk
Low-grade fever

State officials are monitoring the situation and working closely with the farm to contain the virus and prevent further spread. DATCP emphasized there is no concern for the safety of the commercial milk supply, as pasteurization eliminates the virus. The CDC considers the human health risk low.

Read more on HPAI in dairy:

Salmonella Dublin Remains a Stubborn Dairy Health Challenge

Mon, 27 Oct 2025 13:28:30 GMT

No one wants their calves to be infected with Salmonella, but the serotype Dublin is an especially ominous threat, and it’s not going away.

According to Angel Abuela, veterinarian and instructor of Large Animal Clinical Sciences at Michigan State University’s College of Veterinary Medicine, Salmonella Dublin has become substantially more prevalent in dairy and calf-rearing facilities in the U.S. and Canada since 2012.

At the 2025 Recent Graduate Conference of the American Association of Bovine Practitioners, Abuela briefed young veterinarians on the characteristics and challenges presented by S. Dublin.

While Salmonella is most often associated with scours in calves, he notes S. Dublin usually causes pneumonia, respiratory distress and fevers instead. Calves appear listless, anorexic, dehydrated and can also suffer from septicemia and arthritis. Bloody scours are possible but not very common.

Acute infections of S. Dublin typically strike calves at 2 to 12 weeks of age, and sudden death within one to two days after onset of illness can occur due to endotoxic shock. Data from S. Dublin outbreaks shows up to about one-third of infected calves became clinically sick, and about a quarter of calves with confirmed S. Dublin diagnosis died.

For those that survive, lingering effects can include poor growth rate, ill thrift, lameness due to arthritis, and loose stools. It is less common in adult animals, but when infected, those older cattle can experience a sudden drop in milk production, slight fever, mild diarrhea and abortion. Persistent infection with intermittent fecal shedding during times of stress is also possible in adult cows.

In addition to its critical impacts on cattle health, two distinct characteristics of S. Dublin make it a high-level concern: its multi-drug resistance properties and its potential effects on human health.

“In the U.S., S. Dublin has become one of cattle’s most important multi-drug-resistant (MDR) bacteria,” Abuela notes. “The MDR has complicated the treatment of clinically sick animals and has become a threat to human medicine.”

S. Dublin is resistant to many common antibiotics used to treat bacterial infections in animals and humans. Currently, there are no approved antibiotics for veterinary use to treat S. Dublin. Abuela notes the only therapeutic tools are supportive care, including fluid therapy to correct dehydration and electrolyte imbalances, along with anti-inflammatory therapy.

As a zoonotic disease, it is possible for S. Dublin infections to spread from ill animals to humans, causing severe digestive illness and bacterial infections of the bloodstream. While uncommon, S. Dublin infections in humans are most likely to occur in the individuals caring for sick animals, including farm personnel and veterinarians who might accidentally ingest infected animal feces or fluids.

Abuela recommends the following on-farm offense strategies to help minimize the transmission of S. Dublin infections in cattle:

Providing clean, dry calving pens and avoiding large group-calving areas.
Removing calves from contact with their dams’ feces as soon as possible after birth.
Placing calves in a clean environment, where they have no contact with other calves or adult cattle.
Maintaining strict control of colostrum management.
Feeding pasteurized, rather than raw, milk to calves.
Identifying and isolating newly sick cattle immediately and ensuring that farm personnel handle sick cattle separately.
Sanitizing and disinfecting all equipment used between animals.
Ensuring personnel wash hands, boots and any common equipment used between groups of animals.

A herd veterinarian should investigate suspected cases of S. Dublin for a full diagnostic work-up, treatment and prevention plan.

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Europe's Outbreaks Raise Alarms: Is Lumpy Skin Disease Headed Here?

Tue, 21 Oct 2025 13:43:17 GMT

Lumpy skin disease (LSD) is making its way through Western Europe. There is a current outbreak in France with recent cases being reported along the Spanish border. First seen in Zambia in 1929, the disease has since spread north through Africa with outbreaks in Israel in 1989, the Middle East in the 2000s, and in 2013 it was detected in Turkey and the Balkans. Since then, LSD has been reported in Georgia, Russia, Bangladesh and China. LSD has never been detected in the Western hemisphere or Australia.

LSD is an infectious disease of cattle and water buffalo. It is characterized by firm, round nodules on the skin, mucous membranes and internal organs that can ulcerate, fever, emaciation, enlarged lymph nodes, skin edema, decreased fertility and can result in death. Cattle affected by LSD have exhibited physical weakness, reduced milk production, poor growth, infertility and increased abortion rates.

LSD is transmitted primarily through blood-feeding insect bites (flies, mosquitoes, ticks), but it can also be spread by direct contact between animals. Control relies on prompt detection, control of animal movement and vaccination.

While this virus is not a threat to humans, its production impacts on cattle can be severe. LSD morbidity can vary widely between herds depending on vaccination status. Mortality is usually low, but production losses result in an economic hit for producers due to decreased performance, costs of care and the potential for trade bans. In addition, secondary bacterial infections of the skin lesions can increase morbidity and extend recovery times. Because biting insects are the main transmission route, LSD risk is seasonal, increasing during warm, wet periods.

The Current LSD Situation

In 2025, several western and southern European countries that had been free of LSD reported their first confirmed outbreaks. Italy and France recorded initial cases in June, while Spain reported its first case this month. Last week, France banned cattle exports and bullfighting, while Spain announced a cull of affected animals and export limitations as LSD continues to spread.

La dermatosis nodular llega a España y frena el millonario negocio de vacuno con Marruecoshttps://t.co/WetPY0WLTI
— Efeagro (@Efeagro) October 15, 2025

Authorities in affected countries have implemented vaccination campaigns, movement controls and heightened surveillance. Regional and international bodies, including the Food and Agriculture Organization (FAO) and the World Organization for Animal Health, have convened experts to coordinate a response and have put together information sheets to aid in the development of LSD Contigency Plans and to answer any LSD vaccination questions .

What the U.S. Needs to Know

To date, the U.S. has not reported endemic LSD in domestic cattle, but USDA’s Animal and Plant Health Inspection Service has developed standard operating procedures for the disease. This document is meant to bolster the preparedness of the U.S. for LSD occurrence and outlines the ecology of LSD, as well as information on vaccination and disease control. The FAO has also created an accredited veterinary LSD preparedness course .

The sudden appearance of characteristic skin nodules, concurrent fever or unexplained drops in milk yield should be treated as suspicious and warrant immediate reporting to state animal health officials.

The following are some practical points for producers and vets surrounding LSD:

Know the signs: Multiple round, firm skin nodules (sometimes with ulceration), fever, swollen lymph nodes and sharp milk production drops.
Report quickly: Early notification to a veterinarian and a state health official triggers tracing, testing and control measures that limit spread.
Vector reduction: Reduce insect breeding sites, use physical barriers (screens and fans), and consider using insecticides to lower transmission.
Movement control and biosecurity: Quarantine suspect animals, disinfect equipment and limit personnel traffic to reduce mechanical spread.
Vaccination planning: Where outbreaks have occurred, mass vaccination has been a key tool to control spread. No specific LSD vaccine is currently approved for use in the U.S. as it has not been prevalent here.

LSD is primarily an animal health and economic threat rather than a public health threat, but its expanding geographic reach over the past decade should put previously unaffected regions on alert.

Southern Rust Set To Take Big Bite Out Of Midwest Corn Crop?

Thu, 28 Aug 2025 14:17:28 GMT

If one picture is worth a thousand words, then the video Iowa farmer Dan Striegel shot last week must be worth thousands more. In the video, Striegel is shown harvesting a field of emerald-green corn enveloped in a cloud of orangish-red southern rust.

“We were just getting that field opened up, and I looked over and saw that dust boiling up out of the chopper, so I shot the video,” Striegel says.

Southern Rust? Never heard of her.
What Cheer, Iowa. USA. #pftour25 #harvest25 pic.twitter.com/tiIsUc2CHl
— Dan Striegel (@djsinseia) August 21, 2025

To date, Striegel’s video has garnered more than 48,000 views on X, formerly Twitter.

“We’re in southeast Iowa, Keokuk County, and I think the southern rust is as bad here as it is anywhere,” Striegel adds. “Every field you walk in, if you’re wearing a white T-shirt, you’ll come out of there red.”

A Red Path Of Disease Mars The Midwest

Expect to see more red T-shirt-clad farmers walking out of cornfields across the upper Midwest, based on what the Crop Protection Network (CPN) southern rust map is showing.

The CPN continually updates its online, interactive map showing the counties by state where southern rust infections are confirmed. Now, in late August, the counties look like red steppingstones. They form a checkered path from southwest Michigan through northern Illinois and Indiana, into southern Wisconsin, across all of Iowa and nearly two-thirds of the way across Nebraska. Eastern South Dakota is also lit up with a string of red counties, as are parts of southern to central Minnesota.

The amount of southern rust present in the upper Midwest is worrisome to Ken Ferrie, Farm Journal Field Agronomist. In severe cases, the disease can wipe out 45% of the yield potential in a field, according to the CPN.

“At most, one in 10 growers in northern Iowa and Minnesota have seen the kind of southern rust some of them are seeing this year,” says Ferrie, who was working last week with corn growers in both states.

“It was a problem in probably eight out of every 10 fields I was in, and they’d all been sprayed at least once,” he says. “Minnesota has a corn crop that’ll knock your socks off – yield potential of 250, 270. I encouraged every grower to spray their field a second time except for two fields. One had been knocked down by hail, and the other had a hybrid that was clean.”

I spoke with a good friend of mine from Iowa yesterday that is an agronomist and farmer. He said the southern rust in corn across Iowa and much of the Midwest will take 9 to 12 bushel/acre off corn yields on average from what his team and himself are seeing. pic.twitter.com/Ad1VJ9oQBg
— Captain Cornelius1 (@ISU145) August 26, 2025

Hybrids Have Little To No Resistance To Southern Rust

A combination of early-season moisture, heat and wind formed the perfect storm for southern rust this season, allowing the disease-causing fungal spores (Puccinia polysora) to move from southern climes up to the Midwest, according to Kurt Maertens, BASF technical service representative for eastern Iowa and western Illinois.

“We’ve seen it all – southern rust, tar spot, northern corn leaf blight, gray leaf spot. Our corn has been inundated with all these fungal diseases, and we started seeing them early,” says Maertens.

If there’s a silver lining to southern rust, it’s that it does not overwinter in corn residue like tar spot does. But like tar spot, southern rust takes advantage of hybrids that have no built-in resistance. For many growers, that was an Achilles heel this season.

“When you’re dealing with a 117-day hybrid like they grow in southern Illinois, Tennessee, and Kentucky, you don’t grow corn that doesn’t have good southern rust resistance, because they deal with it every year,” Ferrie notes. “When you move to Minnesota, and you’re planting 102- to 95-day corn, you’re probably not going to find hybrids with southern rust resistance.”

Striegel says that was true for his neighbor’s cornfield, which he custom chopped for silage. “That field had two hybrids in it, one was worse than the other, and the field had been sprayed with a fungicide,” he says.

He adds that he also sprayed his own cornfields with fungicide, but they are still inundated with southern rust.

“We’ve had southern rust before, and it’s not usually something we have to worry about, but this is really bad,” Striegel says. “I’m standing on my deck looking at the cornfield next to my house, and you know, all of the leaves from the ears down in that field are covered with it.”

Southern rust is real in eastern Nebraska. Fungicide 3 weeks ago, 2nd app today with some potassium acetate pic.twitter.com/WZubU6IBwz
— Trent Mastny (@TrentMastny) August 21, 2025

How Late Is A Fungicide Application Still Worthwhile?

Ferrie says the fields he scouted last week were at late R3 to early R4 and had already been sprayed with fungicide at least once, but the disease was rebuilding.

“Any field where farmers had sprayed two weeks previously, the southern rust and northern corn leaf blight, to a lesser degree, were coming back, especially the southern rust. It was resporating,” he says.

The intense disease pressure from southern rust, tar spot and others have kept fungicide use at high levels this season, despite poor commodity prices.

“Because of that [amount of disease pressure], we have seen increased demand for our fungicides this year,” says Maertens, who encouraged customers to get applications made at the beginning of tassel.

Maertens says he has fielded a lot of questions this summer from farmers, asking how late they could go with a fungicide application and still benefit.

“Our recommendation is to get in front of disease,” he says. “Generally, we stop applications before we get to dent (R5). That’s not to say a later application can’t have some benefit, but our best results have been before infection was able to take place.”

Southern rust is a yield enemy farmers routinely face in the Southeast, reports corn yield champion Randy Dowdy, Valdosta, Ga. He participated in the Pro Farmer Crop Tour last week and said on U.S. Farm Report he believes many Midwest farmers still have time to address disease.

“We need to implore the fungicides, the technologies out there and get after it and protect this crop, especially that crop that still has not reached dent,” he says.

Farm Journal Field Agronomist Missy Bauer likes to see farmers complete their fungicide applications on the front side of dough (early R4). “Once we get to early dent, I think it’s a little more challenging to get the payback consistently, though we’ve applied at early dent (R5), and seen a nice response,” says Bauer, who is based in south-central Michigan.

Under the tough disease pressure farmers are facing this year, Bauer is telling growers to scout fields and evaluate what growth stage their crop is in before they walk away or pull the fungicide trigger one last time.

She adds that farmers need to check the label to make sure the product used is able to address southern rust effectively. She describes these as “Cadillac” products containing the newest chemistry.

“When it comes to some of these diseases, especially southern rust and tar spot, I do believe a little bit of a Hail Mary pass can be effective,” she says. “Will it be as effective as an application you could have made on a more timely basis? Well, no, you could have made more money doing it timely, but you’re still protecting bushels and gaining ROI at the end.”

Ferrie adds that farmers might want to do the late-season fungicide application to keep their corn crop standing until they can put their harvest plan in place.

“Be doing the push test to check stalk quality,” he advises.

Southern Rust/Silage Alert!!

Southern Rust has been aggressively advancing in many fields, especially those without a fungicide treatment. In some situations the plants are shutting down prematurely and plant material is senescing rapidly.

While we typically want to get down… pic.twitter.com/aK3hGgZE19
— Pioneer Troy (@deutmeyer_troy) August 26, 2025

Striegel says some of the farmers around him are heading to fields to harvest their silage corn sooner than later, because of standability concerns. “Some of this corn got planted early, and we had a lot of heat. The crop matured quickly, and the diseases are kind of shutting it down. It’s just dying out, and guys are going to go get it,” he explains.

That’s the strategy Ferrie encourages farmers to use in regular production corn, too.

“Harvest the fields most at risk first. But if a field of corn goes down, go combine the fields where the corn is still standing and come back to that one later,” he recommends.

The reasoning is you don’t want to risk more corn going down while you’re harvesting the field of corn that already has.

“While I was driving through Iowa last week, I kept thinking that if I built corn reels to pick up down corn I’d bulk up my inventory, because I know where they’re going to get used,” Ferrie says, only half joking. “Yes, harvesting corn at 25% moisture is expensive, but down corn will kick your butt.”

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One Big Beautiful Bill Passes, What Does It Mean for Dairy Farmers?

Tue, 08 Jul 2025 15:00:00 GMT

After passing the “One Big Beautiful Bill act” (OBBB) last Thursday, the American dairy farmer has new legislation to hopefully help aid prices, offer tax relief and boost current insurance programs. Now that the dust has settled and the ink has dried, here is a closer look at what will affect the average dairy producer going forward.

The OBBB first and foremost extended the Dairy Margin Coverage (DMC) through 2031. This will ensure that producers have no gap in the insurance coverage that helps support income through the RMA. There are a few key changes made to make it a little more attractive to the producer such as changing the Tier 1 coverage limit from 5 million to 6 million pounds of milk per farm. As production per cow increases and farm sizes grow, this 20% increase was seen as necessary to support the farms that feed us. Another important change is farms can now use the highest production year from 2021-2023 as their baseline. There is also a 25% discount for producers to commit on multiple year enrollment on their premiums.

In an effort to ensure transparency for Class III and IV milk, both the House and Senate agreed that requiring a biennial USDA cost survey of dairy processors should be mandatory. The goal is to better align make-allowance estimates with timely real costs of producing cheese, butter and nonfat dry milk so the processor has less marketing power and help ensure the long-term pricing fairness.

As many dairy producers also have row crops, there are many benefits shared by extending the commodity and risk management programs like ARC and PLC as well. Higher payment caps (12.5%), higher ARC coverage (90%), higher reference prices and the ability to update base acres are a few of the highlights to help farmers.

There are many tax benefits on this bill as well. One key change is allowing farm implements to be deducted in full year one. Making it no longer a requirement to deduct large equipment purchases over several years. This puts the financial decisions in the farmer’s hands for how they want to expense large purchases. The bill also made the Section 199A deduction permanent to deduct up to 20% of business-related income as well as increasing the small business expense threshold.

For our future family farms, there are provisions that allow death tax exemptions which are now permanent. It increases the doubled Death Tax exemption which will aid in passing down farms and assets to the younger generation. While the new farmers are getting started, they have now increased the Beginning Farmer premium subsidy which helps cover a part of the cost of crop insurance and extended it from 5 to 10 years of aid.

On the animal health front, the bill ads verbiage that the USDA must spend $233 million per year on animal disease research and response efforts. This pumps significantly more money into the National Animal Disease Preparedness program as well as research in the vaccine production. With all eyes on screwworm lately, this is important for response time and veterinary preparedness to help diagnose faster as well as aid in the training of state responders on all diseases but highlights the importance of controlling threats such as new world screwworm.

While there are imperfections in all government programs, the aim of this bill was to help the American farmer and to support the family farm as well as the communities around them. We’ll learn more as time goes on about the good and the bad this bill brings but the intentions of the bill are clear and the benefits to the dairy farm, while subtle could be what makes the next five years a little easier on dairy farm economics.

Sarah Jungman is a commodity broker with AgMarket.Net and AgDairy, the dairy division of John Stewart & Associates Inc. (JSA). JSA is a full-service commodity brokerage firm based out of St. Joseph, MO. Sarah’s office is located in Winterset, Iowa and she may be reached at 515-272-5799 or through the website www.agmarket.net .

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New World Screwworm: The Billion Dollar Battle at the Southern Border

Fri, 20 Jun 2025 18:42:24 GMT

Nearly 60 years ago, the U.S. eradicated New World screwworm (NWS). Today, the risk of reintroduction is real. So real that Ethan Lane with the National Cattlemen’s Beef Association (NCBA) says it’s not a matter of if NWS will reach the U.S. but when.

“We need to spend $300 million now to save us $8 billion down the line in eradication costs,” says Lane, who serves as the senior vice president of government affairs. “This is a marathon, not a sprint, and it’s going to take years to re-eradicate New World Screwworm and push it back to Panama.”

As the fight to keep NWS out of the U.S. ramps up, the economic impact on ranchers and the industry is top of mind.

“Successfully eradicating New World screwworm from the U.S. in 1966 cost stakeholders’ tens of millions of dollars,” says TR Lansford III, DVM, deputy executive director and assistant state veterinarian with the Texas Animal Health Commission. “The freedom from NWS provides an estimated $1 billion in direct benefits to livestock producers and $3.7 billion in benefits to the general economy annually.”

Financial Impact of NWS On Ranchers
Regular, large-scale outbreaks of NWS started occurring in the U.S. in the 1930s. According to APHIS, producer losses have reached:

1930s and 1940s — $5 million to $10 million per year
1950s and 1960s — $60 million to $120 million per year
1970s — $132.1 million per year (While the U.S. successfully eradicated the devastating pest, there have been outbreaks, primarily in Texas, since then.)

(APHIS)

Experts agree if NWS reaches the U.S., eradication today will be far more expensive due to the size of the cattle herd, speed and distance of cattle movement in commerce, and increased wildlife interfaces.

“Historically it cost tens of millions, and now it’s estimated to cost into the billions of dollars to eradicate this pest if it gets back to the U.S,” Lansford says.

Based on historical data from an isolated outbreak in Texas in 1976, per-head impact reached $452 in today’s dollars, totaling $732 million.

“[NWS] is a highly impactful foreign animal pest because it is expensive and deadly,” Lansford says. “Back in 1935, when screwworms were endemic in Texas, the state lost about 180,000 head of cattle alone in that year.”

Lansford says the industry will see decreased livestock production and increased veterinary services, medication, insecticide, labor and vehicle costs for the inspection and treatment of NWS.

“Infested wounds and/or mucous membranes and lesions created by this pest cause significant distress and damage to an animal, which can lead to chronic conditions making the animal less marketable and less productive in its lifespan,” he adds.

USDA Investment to Fight NWS
The reopening of Moore Air Base in Texas as a sterile fly distribution facility has an estimated price tag of $8.5 million. A brand new production facility, which would take two to three years to build would cost $300 to $600 million, depending on location and resources.

“That doesn’t include what it would cost to continue to operate one of those facilities,” Lansford says. “Certainly, research dollars also need to be spent to develop more effective treatments and other methods and modalities that we can use to help offset not only the infestations, but help prevent those infestations.”

USDA is also investing $21 million in the renovation of an existing fruit fly production facility in Metapa, Mexico, to further the long-term goal of eradicating NWS.

Border Closing Impacts U.S. Cattle Industry
Since May, Agriculture Secretary Brooke Rollins has suspended imports of live cattle, horses and bison from Mexico to keep NWS out of the U.S. Many U.S. cattle feeders depend on Mexican cattle to fill feedlots, especially now when the U.S. cattle inventory is at a 74-year low.

“Mexico exports, on average, 1.2 million head of cattle to the U.S. each year,” says Kathy Simmons, chief veterinarian for NCBA.

Obviously, that number will take a hit with the border closed, but Simmons says even prior to the May 11 suspension, mitigation protocols for NWS, including wound inspections, for cattle from Mexico allowed less than 25% of the usual numbers to cross the southern border each month.

As the U.S. fights to limit the impact of NWS, it’s a long-term battle, reminds Lane with NCBA.

“They’re getting those flies on that leading edge of the incursion. As I understand it, that is slowing the advance in a way that is very good to see,” he says. “The fact is, there are just so many different vectors. There are so many different ways this thing can move north, and we’re going into the hot season where flies thrive. So it’s really about slowing it, about preparing and about making sure we have the resources to meet it and push it back down as quickly as possible. But certainly everyone’s trying to focus right now on trying to hold the line as much as humanly possible.”

As Lansford has come to realize: “This pest will be one that leaves quite a mark on our economy.”

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Rollins Rolls Out 5-Point Plan to Contain New World Screwworm

Wed, 18 Jun 2025 19:01:29 GMT

Today Secretary of Agriculture Brooke Rollins announced a five-pronged plan to combat New World screwworm (NWS) – a pest that would devastate ranchers if it made its way across the border.

Rollins made her announcement at the Moore Air Base facility near Edinburg, Texas. Moore was instrumental as a sterile fly production lab to rid the U.S. of NWS in the 1960s and 1970s. Hundreds of millions of flies were reared, sterilized with radiation and dropped from aircraft to eliminate the parasitic pest that preyed upon wildlife and livestock. According to a USDA spokesperson it will cost an estimated $8.5 million to get the base up and running as a distribution facility.

U.S. Secretary of Agriculture Brooke Rollins this morning launched an $8.5 million sterile New World screwworm (NWS) fly dispersal facility in South Texas and announced a plan to enhance USDA’s already robust ability to detect, control, and eliminate this pest.

(U.S. Department of Agriculture)

According to the Texas Wildlife Association , there are currently more than 1,800 cases of livestock infestation in southern Mexico. The flies are moving north and are currently 600 miles from the south Texas border.

“We have defeated the screwworm before, and we will do it again,” Rollins says.

Here in McAllen, TX to announce a BOLD 5-pronged plan to combat the deadly parasite called New World Screwworm – which would devastate ranchers if it made its way across the border.

We are protecting producers, strengthening biosecurity, and ALWAYS standing up for American… pic.twitter.com/VHOlqZyZ9a
— Secretary Brooke Rollins (@SecRollins) June 18, 2025

Her five-pronged plan to combat NWS includes:

Stop the pest from spreading in Mexico.
Rollins plans to continue partnering with her Mexican counterparts and using sterile insect technology to stop the spread. This includes investing $21 million to produce up to 100 million additional sterile flies weekly.

“We are first enhancing the international sterile fly production and investing $21 million in renovation of an existing fly facility in southern Mexico, which will provide up to 100 million additional sterile flies every week to stop the spread,” Rollins says.

Currently, the only sterile fly facility is located in Panama. It’s jointly run by the Panamanian government and the U.S. government. USDA had previously announced its plan to invest in the retrofiting of a fruit fly facility in Chiapas, Mexico, to produce additional sterile flies.

According to the National Cattlemen’s Beef Association , “The Chiapas facility produces about 117 million flies per week, but to form an effective barrier along the U.S. southern border, we need upward of 300 million sterile flies per week.”
Protect the U.S. at all costs.
Rollins temporarily closed the southern border to live animal imports and intercepting illegally introduced livestock. USDA is working closely with Mexico to improve surveillance.

“I do believe we have met and moved into a new era of productive partnership —perhaps better than ever before — with our Mexican counterparts,” Rollins says.
Maximize our readiness.
This will be achieved by partnering with state animal health officials to update emergency management plans and stockpile therapeutics for ranchers.
Take the fight to the screwworm.
The domestic fight includes establishing a sterile fly dispersal facility at Moore Air Base. Rollins says they are exploring options for building a domestic production facility at Moore that could produce up to 300 million sterile flies per week.

“We can’t get a brand new facility up and running probably before two or three years. So, that’s why we’ve got to really focus on the today,” Rollins explains.

She also announced USDA will be hosting listening sessions in affected areas starting next week.
Innovate Our Way to Eradication.
Leverage the sound science including USDA’s Agriculture Research Service (ARS) to continue to quickly develop novel treatments, preventatives and response strategies. Rollins says this includes working with land grant universities in Texas, Arizona and New Mexico. She listed these key strategies during the press conference:
- Develop better fly traps and lures
- Provide local training
- Improve surveillance methods
- Create new response strategies

Nearly 80 lawmakers led by House Ag Committee Chair Glenn “GT” Thompson (R-Pa.) sent a bipartisan letter on Tuesday to Rollins urging immediate action and promising congressional support for the significant funding required.

The letter included this message, “When looking solely at the historical impact of NWS in Texas, USDA’s Animal and Plant Health Inspection Service (APHIS) estimates a contemporary outbreak would cost producers $732 million per year and the Texas economy a loss of $1.8 billion. Extrapolating those results to the states within the historic range of NWS pre-eradication, a contemporary outbreak of NWS could cost producers $4.3 billion per year and cause a total economic loss of more than $10.6 billion. This does not account for the possible expansion of NWS beyond the historic range.”

U.S. Congresswoman Monica De La Cruz (R-Texas) was at the announcement and recently shared in a letter to Rollins these key advantages of the Moore Air Base location:

Border proximity: The proximity to the border with Mexico is crucial for effective monitoring and control of potential incursions of invasive fly species. A facility in this region would allow for rapid response and containment, minimizing the spread of infestations into the U.S.
Existing agricultural infrastructure: The region boasts a robust agricultural sector with established infrastructure and expertise in livestock management. This existing framework would facilitate efficient integration of the sterile fly facility and streamline its operations. Additionally, Moore Air Base has operations runways equipped to distribute sterile flies.
Strategic location: Moore Air Base offers a central location for distribution of sterile flies to other areas in the southern U.S., if such a need arises. Additionally, this base was the site of a facility used in the 1960s to successfully combat NWS.
Economic impact: The establishment of such a facility would provide valuable economic opportunities for the region by generating jobs and stimulating local economies.

U.S. Congressman Ronny Jackson (R-Texas) summarized at the announcement, “This is important to the whole country. We are going to be aggressive about this, and we are going to make sure that we don’t get screwed by the screwworm.”

Your Next Read: Urgency in Action: We Must Eradicate New World Screwworm

U.S. Cattle Industry Urges Mexico's Border to Remain Closed Over Spread of New World Screwworm

Tue, 13 May 2025 20:26:20 GMT

New World screwworm (NWS) has been detected in Mexico only 700 miles from the U.S. border. With the impending threat, National Cattlemen’s Beef Association (NCBA) says it’s not a matter of if the U.S. gets the deadly pest — but when.

Mexican officials said Tuesday they won’t close the southern border to cattle from Central America, but the U.S. cattle industry strong supports USDA’s decision over the weekend to suspend cattle, horse and bison imports from Mexico , saying the 15-day suspension will likely be extended due to Mexico’s lack of action so far.

NWS Detected 700 Miles From the U.S.
It’s an issue that started in November. The detection of NWS in Chiapas, which is near the Guatemala border, caused USDA to close the border to cattle imports. While shipments resumed in February, USDA says Mexico isn’t doing enough to eradicate the invasive pest, causing an even greater threat to the U.S. cattle industry. And now NCBA wants the U.S. to ramp up efforts as well.

“When we discovered New World screwworm flies in the southern border of Mexico right before Thanksgiving back in November, at that point in time, USDA provided counsel, they provided some money to help the Mexican government try to stop the incursion of the fly,” Colin Woodall, CEO of NCBA, told AgriTalk’s Chip Flory.

“But unfortunately, because of the ineptitude of the Mexican government, quite frankly, the corruption of the Mexican government, the inability to actually allow the planes that are carrying the sterile males to land and to be able to do their job, they have now come further north,” Woodall says. “And right now we know that New World screwworm flies have been detected just 700 miles south of the U.S. Border.”

Woodall told AgriTalk’s Flory that the pest is now way too close for comfort.

Mexico Won’t Close Mexico/Central America Border
According to Reuters, Mexico’s agriculture minister said on Tuesday it will take a long time to eradicate the pest. While the officials said they won’t close Mexico’s southern border to cattle from Central America, Mexico will tighten the flow of cattle from the south of the country to limit the potential spread of the screwworm.

“We are going to be restricting cattle movement from the south of the country much more tightly,” Mexican Agriculture Minister Julio Berdegue said on Tuesday, adding that “closing the border is a complex issue that needs to be carefully analyzed, because it also impacts the national meat supply.”

MEXICO AGRICULTURE MINISTER:

WILL TAKE A LONG TIME TO ERADICATE SCREWWORM FROM MEXICO AND CENTRAL AMERICA
— PiQ (@PiQSuite) May 13, 2025

Derrell Peel, Oklahoma State University Extension Livestock Marketing Specialist, spoke with Drovers about the geography of southern Mexico and how the NWS has been able to move further north.

“Mexico has that narrow point down there at the bottom, the Isthmus of Tehuantepec, then to the east of it is the Yucatan Peninsula. To the west is the rest of Mexico, and that narrow gap is, historically, where we established the boundary way back when,” Peel explains. “When we initially controlled screw worm in the U.S., we pushed it down through Mexico and got it past below that isthmus, and that was the boundary for years. Then we eventually got it down to Panama, but it got away from them. In Panama, it came back up through Central America, and now that’s the reason we closed the border. It’s actually jumped past that isthmus and is into a part of Mexico now where it’s going to be increasingly difficult to contain it, just physically. That’s the concern and the reason for this latest action.”

NCBA Blames Corruption in Mexico’s Government
Woodall told AgriTalk the country has poorly managed the situation so far and was pointed with his words, saying it’s because of the Mexican government’s failures that Rollins stepped up and closed the border on Sunday to “send a very clear signal that they have failed, and they’ve got to step up their approach.”

“We do know that the first meeting to review the ban is in about 15 days, and then it’ll be reviewed on a month-by-month basis,” Woodall said on AgriTalk. “That’s what the secretary has said. But unless they do something miraculous as far as changing the approach that they are taking in trying to address this in Mexico, I doubt that it’ll be lifted in 15 days just because of what we’ve already seen. They’ve had six months to step up here and try to address it, and they’ve fumbled the ball.”

“They’ve had six months to step up here and try to address it, and they’ve fumbled the ball.”

Colin Woodall, Chief Executive Officer, NCBA

The corruption claims are rooted in what the U.S. has experienced over the past several months. As the U.S. has tried to ramp up efforts to help stop the spread, Woodall told Flory that there have been instances where the government wouldn’t allow U.S. planes to fly over impacted areas, or not allow those planes to land.

“Will they allow that without additional hurdles or trying to extort money from these planes?” Woodall says. “Will they be true cooperators in helping us get those sterile flies delivered into the country? And can we show that there is a check in their northern approach? If we can look at some things like that, then we’ll be willing to go back to the table, because as I said, we know that this is an economic impact on us, but it’s also a pest that we do not want here domestically.”

The Risks of NWS If It Enters the U.S.
The risks are high. Not only is the U.S. beef cattle herd the smallest in more than 60 years, NWS can be lethal to other species.

“We have to be prepared, and that’s why I talked about it. We need to make sure producers understand what to look for because if you don’t catch it fast, you’re going to lose that animal,” Woodall says. “Also this is not just a cattle issue; we’re talking all warm-blooded animals. This can be on birds. This can be on hogs. It can be in pets like dogs. And it can be in people. So, this is going to be a significant issue that we have to deal with not just as a cattle industry, but us in agriculture because I think it also could look really bad from an optics standpoint if somebody’s dog gets screwworms and they want to blame us as agriculture for being responsible for it.”

“This is not just a cattle issue; we’re talking all warm-blooded animals. This can be on birds. This can be on hogs. It can be in pets like dogs. And it can be in people.”

Colin Woodall, CEO of NCBA

Woodall says NWS is a nasty parasite. It hasn’t been in the U.S. since the 1960s, but the reason it’s so difficult to manage is it lays larva, and the larva dig into the flesh of the animal, basically eating the flesh.

“That’s how it develops,” Woodall says. “And so, if it’s not treated, within four to seven days, you can lose an animal. This is a significant animal health issue.”

Currently, there’s a sterile fly production facility in Panama. Jointly funded by the U.S. government, the facility produces a little more than 100 million sterile flies a week, according to Woodall.

“Now, when we were dealing with this down in southern Mexico, 100 million were enough to be able to stop it,” he says. “But now that they have gone through that phytosanitary border and are coming north, that’s no longer going to be enough. We do not have enough sterile flies.”

NCBA Is Working with Congress and USDA to Ramp Up Sterile Fly Production Domestically
NCBA is talking to both USDA and Congress about building a sterile fly production facility in the U.S. When NWS was a problem in the U.S. more than 60 years ago, there was a production facility based in Texas.

There is legislation to do just that. The STOP Screwworms Act was introduced by Rep. Tony Gonzales (R-TX) and Sen. John Cornyn (R-TX). It would fund the opening of a new sterile fly facility in the United States, with the legislators saying the bill would help protect both livestock and human health from the New World screwworm.

“One of the things that we’re also talking to the secretary about and also with Congress is how do we have the funding to build a sterile fly production facility here in the United States because that is the only way we’re going to stop these flies, get them out of the United States, out of Mexico, and ultimately push back into South America,” he says.

“One of the things that we’re also talking to the secretary about and also with Congress is do we have the funding to build a sterile fly production facility here in the United States?”

Colin Woodall, CEO, NCBA

He says in the ‘60s, it took more than 400 million sterile flies a week to eradicate the issue.

“We are focused on getting the domestic production up and running as quickly as possible, so is Secretary Rollins,” Woodall says. “She’s doing a tremendous job in leading this effort. This is something that she has taken on personally. And so I have a lot of faith in her and her willingness to help us as an industry push back this pest, eradicate it as quickly as possible and try to get back to normal training.”

Groups like the Texas & Southwestern Cattle Raisers Association (TSCRA) also support a bill to protect the U.S. from NWS.

“The STOP Screwworms Act is a vital step in protecting the U.S. cattle herd from the growing threat of the New World screwworm. This legislation provides USDA the support needed to construct or retrofit domestic sterile fly production infrastructure which Texas Southwestern Cattle Raisers Association believes is essential in preventing a widespread outbreak,” President Carl Ray Polk Jr. said in a statement. “We are grateful to both Sen. Cornyn and Rep. Gonzales who understand the importance of acting quickly to support cattle raisers and ensuring the threat of the New World screwworm is taken seriously at the highest levels in Washington.”

Read More: U.S. Suspends Mexican Cattle, Horse and Bison Imports Over Screwworm Pest

Second Bird Flu Strain Found in U.S. Dairy Cattle, USDA says

Thu, 06 Feb 2025 14:36:48 GMT

U.S. dairy cattle tested positive for a strain of bird flu that previously had not been seen in cows, the U.S. Department of Agriculture said on Wednesday, ramping up concerns about the persistent spread of the virus.

The H5N1 virus has reduced milk output in cattle, pushed up egg prices by wiping out millions of hens, and infected nearly 70 people since April as it has spread across the country.

Genome sequencing of milk from Nevada identified the different strain, known as the D1.1 genotype, in dairy cows for the first time, the USDA said. Previously, all 957 bird flu infections among dairy herds reported since last March had been caused by another strain, the B3.13 genotype, according to the agency.

Reuters reported news of the detection of the second strain on Wednesday ahead of USDA’s announcement.

The second strain was the predominant genotype among wild birds this past fall and winter and has also been found in poultry, the USDA said. It was identified in dairy cattle through an agency program that began testing milk for bird flu in December.

“We’re seeing the H5N1 virus itself be smarter than all of us,” said Beth Thompson, South Dakota’s state veterinarian.

“It’s modifying itself so it’s not just staying in the poultry and the wild waterfowl. It’s picking up a home in the mammals.”

Wild birds likely transmitted the second strain to cattle in Nevada, said J.J. Goicoechea, Nevada’s agriculture director. Farmers need to ramp up safety and security measures to protect their animals, he said.

“We obviously aren’t doing everything we can and everything we should or the virus wouldn’t be getting in,” he said.

“We didn’t get a hold on it before,” Hansen said. “We want to avoid that same scenario from happening in Nevada.”

Dairy herds that were formerly infected may be at risk again from the second strain, experts said.

“Now it looks like we have new strains of virus that may escape some of the immunity associated with the other strains of viruses that could exacerbate the epidemics among animals and wildlife,” said Gregory Gray, a University of Texas Medical Branch professor studying cattle diseases. “It’s alarming.”

Your Next Read: Beef-on-Dairy: A Critical Solution to the Shrinking U.S. Cattle Herd

Dairy Report: Margin Pressure Continues to Mount for Dairy Producers

Wed, 15 Jan 2025 15:52:29 GMT

Dairy producers are starting the year off with margin pressure following the latest round of USDA reports. A rally in grain prices following a cut to corn yields helped push feed costs higher.

Milk prices were also under pressure. Class III February price futures fell to near $20.27 per cwt., down 65 cents, but did gain back some of those losses later in the week. Block cheese started last week at a two-month high at $1.94 but closed lower as some support melted in the wake of the WASDE report.

USDA is forecasting lower production in 2025 due to slower growth in output per cow.

Foot-and-Mouth Disease Found in Germany

First time in nearly 40 years Germany is dealing with an outbreak of foot-and-mouth disease. It was confirmed in a herd of water buffalo on the outskirts of Berlin. The disease causes fever along with mouth blisters in animals including cattle, swine, sheep and goats. German officials say they are taking steps to contain the disease.

The illness doesn’t pose a danger to humans, but they can transmit it. Officials say affected animals have already been euthanized and the country has already set up an exclusion and monitoring zone. The last case of foot-and-mouth disease occurred back in Germany in 1988.

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Play Offense on Clostridia in Calves

Fri, 08 Nov 2024 15:00:00 GMT

Clostridia are as common as dirt on farms. In fact, they’re found in the dirt

These Gram-positive, anaerobic, spore-forming bacteria are often found in soil and manure, or in feedstuffs that have been contaminated, according to Dr. Luke Miller , veterinary elite dairy advisor at Alltech.

“Because they’re spore-formers, soil contamination caused by clostridia can last through the winter,” Miller noted. “They can last in the desert, during heat stress, cold stress – all that stuff has very little effect on clostridia.”

One good thing about clostridia is that the bacteria are not transmitted from animal to animal. But because they are ubiquitous to the environment, they often colonize in the digestive tract of cattle, potentially very early in life. Clostridium perfringens is a strain of particular concern in preweaned calves.

Their presence in the gut flora does not necessarily cause problems, unless something changes that triggers a growth spurt. Miller said this could be a dietary change like a calf overeating starch; an external wound; or an internal tissue injury like a liver abscess. In any of these cases, a decrease in or lack of oxygen can quickly create the anaerobic environment that triggers clostridial growth and can cause the bacteria to flourish.

When this happens, the bacteria release damaging toxins that can cause calves to experience inflammation, shock, cardiac arrest, and even death. Miller described the symptoms of clostridia overgrowth as ranging from “ADR – ain’t doin’ right” with general malaise and poor growth; to severe diarrhea and abdominal pain; to rapid-onset bloat and sudden death. Nearly every calf raiser has experienced the frustrating scenario of “fine at one feeding, dead the next,” caused by clostridia.

But there are measures that can help you stay ahead of clostridia in calves, including:

1. Consistent management routines – Feeding calves at the same time, every day, can help prevent clostridia flare-ups. Vigilant cleaning of maternity pens and calf housing environments also can help. And, if possible, avoid calves going off feed, as “slug feeding” can trigger clostridia proliferation.

2. Vaccination – Vaccinating dams and performing excellent colostrum delivery is the most effective way to confer clostridium immunity in young calves. Miller said the selected strains for vaccination may vary according to regional pathogenic loads, but might include enterotoxemia, blackleg, redwater, and tetanus. Older heifers – particularly those on pasture – may require direct vaccination against clostridia organisms.

3. Feeding functional organisms – Enhancing the gut microbiome with direct-fed microbials has been shown to tame clostridia in both research and practice. Prebiotics, probiotics, and/or postbiotics may help create a favorable gut environment that supports beneficial bacteria that compete with clostridia, regulate pH, and/or promote healthy digestion.

To the third point, a study published in the journal Antibiotics compared the responses of calves fed two separate probiotic products compared to non-treated controls when challenged directly with an oral dose of Clostridium perfringens. Both products significantly reduced the incidence and severity of diarrhea while improving general impression and appearance scores of calves. Additionally, 60% (6/10) of the non-treated controls died, while only 2/10 died in one of the treatment groups, and 0/10 died in the other.

A Chinese study in which the probiotic Bacillus subtilis natto was added directly into the milk ration of preweaned Holstein calves showed the supplemented calves had improved average daily gain and feed efficiency compared to control calves. And a Japanese study showed that supplementing the milk replacer ration of newborn calves with Bacillus subtilis C-3102 promoted the growth of beneficial bacteria in the rumen microbiota, which could contribute to the improvement of feed efficiency after weaning.

Consult your veterinarian and nutritionist to devise a plan to best control clostridia in your calves.

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Evaluating the Economics of Adding Management Practices or Products to the Farm

Mon, 23 Sep 2024 20:11:19 GMT

Most of the management practices implemented on the farm are either to manage disease or increase milk production. The market is flooded with products that can help with both goals. Understanding the economics of management practice adoption can make it easier to make adoption decisions.

Determining Disease Costs

Disease costs can be calculated using the simple equation: C = L + E or Costs = Losses + Expenses. Expenses are more straightforward to configure because they include the costs we typically associate with treating the disease, like drugs or added labor. However, preventative expenses are often overlooked. For example, using a pre or post-dip should be considered when evaluating mastitis expenses. Losses can be more challenging to estimate because the costs are not direct. Losses may come in the form of lost milk yield, decreased fertility, or lost milk premiums.

If nothing is done to manage or prevent a disease, the total cost of the disease comes from losses alone. Once a management practice is added, the losses will decrease to a certain point, and expenses will increase. A technical optimum is reached when disease incidence drops to a point where the incidence rate can go no lower regardless of what management practice is added. In that case, expenses are the highest portion of the total disease cost. Often, the economic optimum, the point where we see no financial returns to lowering a disease incidence rate, comes well before the technical optimum.

Marginal Level Milk

The adoption of products or changing management practices to increase milk yield should be evaluated using marginal economics. This means the cost and benefit of increasing milk per pound. Like disease management, a point will come in which the benefit of increased milk yield will not cover the costs. All costs should be considered to make the marginal level milk yield as accurate as possible. For example, feed costs typically increase as milk yield increases, so when determining the potential benefit of adding a product to the farm, feed costs and the costs of the product need to be considered.

Before adopting a product or changing a management practice, try to consider the whole picture. Determine which direct and indirect benefits or drawbacks might occur from management adoption. Overestimating costs of management practices can help ensure that hidden costs may be accounted for.

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Control Flies, Prevent Disease

Fri, 20 Nov 2020 05:10:51 GMT

The following commentary does not necessarily reflect the views of AgWeb or Farm Journal. The opinions expressed below are the author’s own.

If fly season has not yet begun in your part of the country, it soon will. While we’ll probably never “win” the war on flies, early action and a season-long control strategy can prevent stress, lost performance and disease associated with flies and other external parasites of cattle.

The issue made headlines this week, when an unusually large hatch of black flies, in this case southern buffalo gnats, apparently caused the deaths of a bull and a cow on an Arkansas farm.

In addition to animal-welfare and performance impacts, flies, ticks and other external parasites transmit disease such as pinkeye and anaplasmosis. Prior to last year’s changes to the veterinary feed directive (VFD) rules, producers sometimes used medicated minerals or other free-choice feeds containing chlortetracycline (CTC) for prevention of pinkeye, an extra-label application. By law, medicated feeds can only be used in accordance with the label, and with the VFD rules in place, veterinarians must confirm the intended use complies with product labels before writing a VFD order.

Given those restrictions, and with antibiotic use falling under increasing consumer scrutiny and regulatory action, producers can benefit by working with their veterinarians to focus more on parasite control and less on medicated feeds for preventing those diseases.

Oklahoma State University Livestock Entomologist Justin Talley, PhD, says external parasites cause enormous economic losses to the cattle industry in the United States. Horn flies lead the way, causing an estimated $1.36 billion in annual losses in U.S. livestock herds. Stable flies cause an additional $672 million in losses, followed by horse flies at $296 Million, face flies at $191 million and ticks at $162 million.

Talley says when horn flies are present, control efforts can bring an average of 1.5 pounds of extra gain per week. Generally, 200 to 300 flies per animal constitutes an economic threshold, where treatment will pay.

Stable flies tend to accumulate on the lower part and legs of the animal, with five to 10 flies per leg a typical economic threshold. Populations typically peak in the spring and again in the fall.

Face flies are not a biting fly, but cause stress and play a role in transmission of Moraxella bovis, the pathogen that causes pinkeye in cattle.

Horse flies and deer flies can serve as mechanical vectors for Anaplasma marginale, the bacteria causing anaplasmosis in cattle. Veterinarian Gregg Hanzlicek, at the Kansas State Veterinary Diagnostic Laboratory, says flies carry, but don’t amplify the anaplasmosis pathogen, meaning the bacteria flies pick up when feeding is the maximum they will be able to pass on to the next animal when they take their blood meal. Control is important though, as flies can travel significant distances and introduce anaplasmosis into beef herds.

Several species of ticks, particularly the dog tick, serve as biological vectors for the anaplasmosis pathogen. When ticks feed on a positive animal, the bacteria establish inside the tick and reproduce, and the concentration can reach very high levels. When the tick feeds on an animal it will pass those bacteria through the saliva.

Fly control efforts should begin early in the season, before populations explode. Talley says to avoid encouraging pesticide resistance, don’t use pyrethroid tags more often than one year in three, and do not use organophosphate tags more than two years in a row.

Insect growth regulators (IGRs) and feed-through larvicides offer additional options. These generally are formulated with mineral blocks or mixes. They pass through the animal and kill or inhibit fly larvae in the manure. In the southern United States, use these products in the early spring, with timing moving later further north, to match the time flies begin laying eggs prior to the seasonal spike in population growth.

The cost of insecticide ear tags averages around $3.20 to $4.45 per cow per season. Pour-on products range from $2.50 to $9.50, depending on the number of treatments needed. Generally, Talley says, ear tags combined with an IGR provide cost-effective control.

Effective fly control requires planning and flexibility to account for seasonal and regional variation. Your veterinarian can help identify strategies for protecting animal health, welfare and performance while preventing pesticide resistance in flies and antibiotic resistance in pathogens.

Better Understanding the Mystery of Metritis

Fri, 20 Nov 2020 02:04:26 GMT

Affecting even the healthiest cow on the farm, metritis, a metabolic and infectious disease experienced in transition animals, is a common illness that can have negative impacts on milk production and future pregnancy rates.

According to a University of Kentucky extension article, approximately 12% of freshening animals experience some degree of metritis after calving, with the incidence rate being greater in those that experience a difficult birth, have twins or have a retained placenta. In a DAIReXNET webinar, Dr. Stephen LeBlanc, DVM, from the University of Guelph discussed the factors that contribute to the occurrence of metritis along with the impact of the disease.

Defined as a foul smelling, reddish brown discharge from the vulva, LeBlanc explained that all cows experience some form of bacterial contamination within the uterus after calving. E. coli is commonly the initial bacterial contaminant associated with metritis.

Once infected, cows with severe metritis had lower pregnancy rates at first service and by 120 days in milk. Additionally, in both mild and severe forms of metritis, cows experienced lower milk production. This especially held true in more mature animals, as they produced an average of 600 lbs. less milk compared to a healthy cow.

LeBlanc noted that only 10% to 45% of cows who are diagnosed with metritis have a fever. Before treating the uterine disease, LeBlanc suggests consulting with your veterinarian to develop a treatment protocol. Antibiotics can be used to help shorten the length of the infection, however, most animals who were treated were cured 7 to 12 days after treatment.

Although metritis is a common metabolic disease, LeBlanc reported that there are steps one can take to help offset its occurrence.

Research suggests animals who spend less time at the feedbunk and that had lower dry matter intakes prior to calving had an increased risk to developing the infection. Additionally, cows who experienced subclinical hypocalcemia also had a greater chance of metritis. Calcium is important for uterine muscle contractions and for the best immune response to fight off bacterial challenges, according to LeBlanc.

Watching for cows who show these symptoms could reduce the prevalence of metritis on your operation.

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