Cattle | June 2026
H5N1 infections among cattle in the Netherlands In January 2026, antibodies against influenza A subtype H5N1 were detected in five cows at a dairy farm in north-east Friesland. This was the first confirmed case of HPAI infection in cattle outside the United States, where a major outbreak has been ongoing among dairy cattle since 2024. The discovery followed a report of two cats becoming ill at the farm in December 2025. One cat tested positive for H5N1 and died shortly afterwards; the other recovered and tested negative. Following this, experts from the NVWA and GD visited the farm along with the farm vet on 15 January. Twenty cattle and a bulk milk sample were tested. During the visit, no cows at all exhibited any clinical signs consistent with an H5N1 infection. Antibodies against H5N1 were found in one cow that had previously been treated for clinical mastitis. No active virus was detected in any of the milk or
blood samples, however. Additional testing at a later date revealed that four more cows had antibodies. The farm was visited for a second time on 22 January, during which samples were taken from all the cattle. No virus was found on the second occasion either. Other animals present on the farm (such as dogs, cats and horses) showed no signs of illness. People who had been in contact with the cows also tested negative. According to the Dutch baseline monitoring programme, there are no indications yet of any further spread of H5N1 amongst cattle in the country. By the middle of April 2026, there were 1,093 confirmed cases across nineteen states in the USA. The investigation into this Dutch case is still ongoing.
Trauma caused by boluses One cow was submitted for necropsy in which extensive trauma to the neck region was observed. About ten such cases are seen annually. The clinical history of these animals varies considerably and include inter alia sudden death, chronic weight loss, respiratory clinical signs and difficulty swallowing. Physical examination frequently reveals swelling in the head or neck region, sometimes coupled with necrotising (phlegmonous) inflammation. Closer examination revealed traumatic abnormalities in several cases in the oral cavity, larynx or oesophagus, including ulcerations and perforations. In some cases, the tissue damage extends to the neck muscles, where cavities containing
feed residues and occasionally bolus remnants are found. Trauma caused by incorrect use of a bolus dispenser or pill dispenser, or injury sustained during drenching, are high on the list of differential diagnoses in these cases. Such injuries can arise when animals are not properly restrained during administration or if an incorrect pill dispenser size is used. Although there are no indications of a rise in the number of bolus-related incidents, these cases show that incorrectly administered boluses or incorrect drenching methods can have serious consequences and, in some cases, can even lead to death.
Animal health monitoring Royal GD has been responsible for animal health monitoring in the Netherlands since 2002, in close collaboration with the veterinary sectors, the business community, the Ministry of Agriculture, Fisheries, Food Security and Nature, veterinarians and farmers. The information used for the surveillance programme is gathered in various ways, whereby the initiative comes in part from vets and farmers, and partly from Royal GD. This information is fully interpreted to achieve the objectives of the surveillance programme – rapid identification of health issues on the one hand and monitoring trends and developments on the other. Together, we team up for animal health, in the interests of animals, their owners and society at large.
Larynx
Perforation
Figure 1.
Trauma caused by bolus (source: GD Pathology)
Red noses in calves In February, the Veekijker was consulted about a dairy farm where several calves developed red and sometimes swollen noses shortly after a normal birth. The animals were reluctant to drink, lacked a suckle reflex and were unable to stand. One calf had already been euthanised. The initial suspicion was that these were ‘dummy’ calves, as previously observed in cases of infections with bluetongue virus (BTV). This diagnosis was however unlikely, as the animals had been vaccinated against BTV and there were no indications of BTV circulating in the
Netherlands during the gestation period. Because a similar case had been reported previously, it was recommended that a calf should be submitted for necropsy. Examination revealed erosions and superficial necrosis of the planum nasale, as well as severe Escherichia coli infection with polyserositis. The affected areas included the meninges, joints and pericardium. This infection explained the neurological signs, the refusal to drink and the red nose. Although such infections normally cause fever, that sign
probably did not arise because of the rapid progression of the disease. Further investigations on the farm showed that the dry cows were not receiving sufficient energy and protein, and that the quality of the colostrum was inadequate. This probably made the calves particularly susceptible to neonatal E. coli infections. The recommendations focused on improving colostrum quality by optimising the diet of late-gestation cows and improving the hygiene for newborn calves.
Demodex infection in cattle The Veekijker received a report of a cow with itching and bald patches on the head and neck, combined with a sharp drop in milk production. The vet initially suspected scabies caused by Sarcoptes mites and took a skin scraping. However, tests revealed an infection with Demodex
Figure 2.
Cow with Demodex
Figure 3.
Cow with Demodex, recovered after treatment
bovis. The vet then looked for advice on treatment and possible routes of transmission.
highly host specific. Transmission via other animal species is therefore unlikely. Only animals with a weakened immune system generally develop clinical signs.
Demodicosis is caused by Demodex mites. This mite lives in the sebaceous glands of almost all mammal species and is
Number of IBR infections remains high Only a single cow in this dairy herd was affected. On the advice of the Veekijker, the animal was treated and kept separate from the rest of the herd temporarily. In the end, the cow recovered completely. The number of samples submitted for
confirmation of suspected IBR cases in the first quarter of this year was higher than during the same period last year and is also higher than in the autumn of 2025. We are also seeing an increase in the proportion of farms where the IBR virus
has been detected. One striking point is that about half of these farms had the status ‘IBR-free’. This confirms that IBR is still circulating actively in the Netherlands and that vigilance and diagnosis in good time remain important.
Data analysis explained Impact of BTV 3 on the fertility of dairy cows in 2024 and the effect of vaccination
and the effect of vaccination has been investigated. Animal health monitoring scheme data was used for this, supplemented by the results of tank milk antibody testing for BTV 3 in the spring of 2024.
The outbreak of bluetongue virus (BTV 3) in 2023 and 2024 resulted in a large number of animals getting sick, as well as causing significant fertility problems in dairy cows. In the current, more detailed study, this impact has been quantified,
The results showed that the BTV 3 epidemic of 2024 had negatively affected the fertility of dairy cows. This was
manifest in the higher age at first calving (AFC) among heifers, longer calving intervals, more inseminations, a lower non-return rate within 56 days (NR56) and an increase in abortions, premature calvings and non-eartagged calf mortality. It was observed for example that the percentage of premature calvings almost tripled during the period when BTV 3 was spreading (Figure 4).
Percentage of premature calvings
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Figure 4. Average premature birth percentage on dairy farms between January 2022 and December 2025, broken down by BTV 3 tank milk antibody levels in the spring of 2024 and BTV 3 vaccination status in 2024.
Vaccination of the whole dairy herd in 2024 helped to mitigate some of these negative effects and was associated with a reduced impact on the rates of abortions, premature calvings and mortality among non-eartagged calves. A high prevalence of BTV 3 naturally acquired antibodies was also found to have a protective effect on these indicators; the combination of natural immunity and full vaccination offered the most protection.
The impact of BTV 3 on other fertility indicators remained limited. The number of inseminations per inseminated cow increased only slightly, for instance. On dairy farms where the BTV 3 infection remained limited in 2023, a slightly higher age at first calving (by up to a maximum of 7 days) and a longer calving interval (by up to a maximum of 8 days) were observed in 2025. The effect of vaccination on these key indicators was therefore also limited. However, in the
spring of 2024, farms with a high prevalence of BTV 3 naturally acquired antibodies clearly experienced fewer adverse effects of BTV 3 infections on these key indicators. It can be concluded that the BTV 3 epidemic of 2024 was associated with a temporary reduction in fertility. Both natural immunity and vaccination limited the impact of BTV 3 infections on fertility.
Health of cattle in the Netherlands, first quarter of 2026 VETERINARY DISEASES
SITUATION IN THE NETHERLANDS
Category Monitoring results, (AHR) first quarter of 2026 Implementing Regulation (EU) 2018/1882 of Animal Health Regulation (AHR) 2016/429 (category A disease) Lumpy Skin Disease (LSD) Viral infection. A, D, E Infections never detected in the The Netherlands is officially disease-free. Netherlands. Outbreaks in France and Spain.. Foot and Mouth Disease (FMD) Viral infection. A, D, E No infections detected in the Netherlands. The Netherlands has been officially diseaseOutbreak in Turkey has spread to Cyprus and free since 2001. Greece. Implementing Regulation (EU) 2018/1882 of Animal Health Regulation (AHR) 2016/429 (categories B to E) Bluetongue (BT) Viral infection. D, E No new infections detected in the Bluetongue virus serotype 3 outbreak in the Netherlands. Netherlands since September 2023. Also a few cases of BTV-12. Bovine genital Bacterium. D, E Campylobacter fetus spp. veneralis not campylobacteriosis The Netherlands has been disease-free since detected. 2009. Monitoring of AI and embryo stations and of animals for export. Bovine Viral Diarrhoea (BVD) Viral infection. C, D, E The status* of 91.8 per cent of dairy farms Control measures required by the dairy is ‘BVD-free’ or ‘BVD not suspected’. industry are compulsory for dairy farms but The status of 24.5 per cent of all non-dairy voluntary on beef cattle farms. farms is favourable (BVD-free or BVD not suspected). Brucellosis
Bacterium. Zoonosis. The Netherlands has been officially diseasefree since 1999. Monitoring via antibody testing of blood samples from aborting cows. Viral infection. The Netherlands has been officially diseasefree since 1999. Monitoring via antibody testing of blood samples from slaughtered cattle and bulk milk. Viral infection. Detected since 2022 in cattle in Europe (Spain, Italy, Portugal and France). Viral infection. Control measures required by the dairy industry are compulsory for dairy farms but voluntary on beef cattle farms.
B, D, E
No infections detected.
C, D, E
No infections detected.
D, E
No infections detected.
C, D, E
The status of 84.7 per cent of dairy farms is ‘IBR-free’ or ‘IBR not suspected’. The status of 22.3 per cent of all non-dairy farms was favourable (IBR-free or IBR not suspected).
Bacterium. Zoonosis. Not detected in the Netherlands since 1994. Monitoring through blood smears from cattle that died suddenly. Bacterium. Control measures required by the dairy industry are compulsory in the Netherlands for dairy farms but voluntary on beef cattle farms.
D, E
No infections detected.
E
84.2 per cent of dairy farms have a favourable PPN/IPP status (nationwide programmes) (A/6 or better).* 14.0 per cent of all non-dairy farms have a favourable PPN/IPP status (A/6 or better).
* The BVD status as determined using the GD programme.
Enzootic bovine leukosis
Epizootic Haemorrhagic Disease (EHD) Infectious Bovine Rhinotracheitis (IBR)
* IBR status as determined using the GD programme
Anthrax
Paratuberculosis
* Paratuberculosis status as determined using the GD programme
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Continued table
VETERINARY DISEASES
SITUATION IN THE NETHERLANDS
Category Monitoring results, (AHR) first quarter of 2026 Implementing Regulation (EU) 2018/1882 of Animal Health Regulation (AHR) 2016/429 (category A disease) Rabies Viral infection. Zoonosis. B, D, E No infections detected. The Netherlands has been officially diseasefree since 2012. Bovine tuberculosis (TB) Bacterium. Zoonosis. B, D, E No infections detected. The Netherlands has been officially diseasefree since 1999. Monitoring of slaughtered cattle. Trichomonas Protozoan. C, D, E Tritrichomonas foetus not detected. The Netherlands has been disease-free since 2009. Monitoring of AI and embryo stations and of animals for export. Q fever Bacterium. Zoonosis. E No infections detected in aborted foetuses In the Netherlands, this is a different strain to submitted for necropsy. the one found on goat farms with no established relationship to human illness. From the first quarter of 2023 onwards, this is once again part of the standard aborter pathology protocol. Article 3a.1 Notification of zoonoses and disease symptoms, ‘Rules for Animal Husbandry’ from the Dutch Animals Act Leptospirosis Bacterium. Zoonosis. The status of 98.3 per cent of dairy farms is Control measures required by the dairy ‘leptospirosis-free’.* industry are compulsory for dairy farms but The status of 29.7 per cent of all non-dairy voluntary on beef cattle farms. farms is ‘leptospirosis-free’. Two new infections at dairy farms. * Leptospirosis status as determined using the GD programme
Listeriosis
Salmonellosis
Yersiniosis Regulation (EC) no. 999/2001 Bovine Spongiform Encephalopathy (BSE)
Bacterium. Zoonosis. Infections have occasionally been detected in cattle. Bacterium. Zoonosis. Control measures required by the dairy industry are compulsory for dairy farms but voluntary on beef cattle farms. Bacterium. Zoonosis. Infections detected occasionally in cattle.
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Two infections detected in cows presented for necropsy.
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The bulk milk results of 97.8 per cent of dairy farms are favourable (the national Qlip programme).
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Six cases of Yersinia spp. infections have been detected.
Prion infection. The QAOH status for the Netherlands is ‘negligible risk’. Monitoring has not revealed any further cases of classical BSE since 2010 (88 cases overall from 1997 to 2009).
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No infections detected.
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Royal GD P.O. Box 9, 7400 AA Deventer The Netherlands
T. +31 (0)88 20 25 575 info@gdanimalhealth.com www.gdanimalhealth.com
VETERINARY DISEASES
SITUATION IN THE NETHERLANDS
Continued table
Category (AHR)
Monitoring results, first quarter of 2026
Other infectious diseases in cattle Malignant Catarrhal Fever Viral infection. (MCF) There are occasional cases in the Netherlands.
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One infection confirmed upon necropsy.
Liver fluke
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Infections were detected at 34 farms and in four animals presented for necropsy.
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Not shown to be present in aborted foetuses presented for necropsy.
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No samples submitted for examination. No infections detected.
Neosporosis
Tick-borne diseases: Anaplasma phagocytophilum
Parasite. Liver flukes are endemic in the Netherlands, particularly in wetland areas. Parasite. In the Netherlands, this is an important infectious cause of abortion in cows. Ticks infected with Babesia divergens, Anaplasma phagocytophilum and Mycoplasma wenyonii can be found in the Netherlands. A PCR test is only available for Anaplasma phagocytophilum.
GD3611/08-26