[Diarrhea and loss of production on Dutch dairy farms caused by the Schmallenberg virus]. / Diarree en productiedaling op Nederlandse melkveebedrijven door het Schmallenbergvirus.

At the end of August and the first two weeks of September 2011 dozens of veterinary practitioners reported to GD Veekijker (Animal Health Service) several dairy herds with cows with sudden decreased milk production, watery diarrhea and sometimes fever. In the beginning these reports came from the Eastern region of the Netherlands, after that also from the other three regions. The percentages of diseased herds per veterinary practice varied from a few till dozens per cent. Extensive bacteriological, virological and parasitological testing of the feces of sick cows did not reveal an infectious cause of the clinical problems. Recently, 50 stored blood samples of clinically diseased cattle were tested for the Schmallenbergvirus using a PCR, and 36% (18/50) tested positive. A large group of control cows (n=115) was also tested with the PCR and all cattle tested negative. Likely the Schmallenbergvirus was the primary cause of the clinical symptoms in the Dutch dairy herds. Further research will be done to confirm this.

Evaluation of the association between the introduction of data-driven tools to support calf rearing and reduced calf mortality in dairy herds in the Netherlands.

Between 2009 and 2017, calf mortality in the Dutch dairy sector showed a slight but steady increase. The Dutch dairy industry decided to act and supported the development of several data-driven tools that were implemented from 2018 on. The tools informed farmers about their calf mortality rates and stimulated them to improve. The Trend Analysis Surveillance Component of the Dutch cattle Health Surveillance System provided the possibility to evaluate the calf mortality in Dutch dairy herds before and after implementation of these tools. The aim of this study was to evaluate the association between calf mortality and i) all actions that were taken by the Dutch dairy industry to improve the quality of calf rearing and ii) other potential management or environmental factors associated with calf mortality in Dutch dairy herds. Census data from approximately 98 % of all Dutch dairy herds were available from July 2014 until June 2019. Four different calf mortality indicators were defined: perinatal calf mortality risk (i.e., mortality before, during, or shortly after the moment of birth up to the moment of ear-tagging), postnatal calf mortality risk (ear-tagging till 14 d), preweaned calf mortality rate (15 d-55 d) and weaned calf mortality rate (56 d-1 yr.). All data were aggregated to herd and monthly level and were analysed using Population-Averaged Generalized Estimating Equations (PA GEE models) with a Poisson distribution and log link function. When the period before implementation of the tools (2016-2017) was compared to the period thereafter (2018-2019), all four calf mortality indicators decreased. The relative decrease varied from 3 % (postnatal calves) and 10 % (perinatal calves) up to 18 % and 30 % in preweaned and weaned calves, respectively. Registrations of veterinary treatments such as antimicrobial use, vaccinations (calf or cow) and antiparasitic treatments were associated with calf mortality. Additionally, herds with a higher level of metabolic problems in transition cows had a higher calf mortality and also extreme outside temperatures were associated with higher calf mortality. Given that the different tools were implemented nation-wide and a control group was lacking, we could not prove that implementing the different tools caused the reduction in calf mortality. We do however, believe that all the actions and communication towards improvement of calf rearing in dairy herds led to an increased awareness among farmers towards the importance of calf rearing management and therefore a reduction in calf mortality on national level.

[Abortions, fertility problems and mastitis on a cattle farm and a sick farmer: a zoonosis? Infection with Staphylococcus aureus phagetype T543]. / Verwerpen, vruchtbaarheidsproblemen en mastitis op een rundveebedrijf en een zieke veehouder: een zoonose? Infectie met Staphylococcus aureus faagtype T543.

On a dairy farm the herdsman got a pustular dermatitis and in the herd in a year several abortions occurred, the somatic cell count of the bulk milk increased and the fertility results decreased. The cause appeared to be an infection in both the herdsman and the herd with Staphylococcus aureus type T543.

[Parafilariasis: a new parasitic disease of cattle in The Netherlands]. / Parafilariose, een nieuwe parasitaire ziekte bij het rund in Nederland.

In March 2007, cutaneous nodules were observed on the neck, shoulder and back of a breeding bull imported from France in November 2006. The nodules opened spontaneously and produced a haemorrhagic exudate. The cause was Parafilaria bovicola, a filariid nematode not endemic to The Netherlands. The worm can cause substantial economic loss because of the need to trim carcasses and because of the diminished value of hides. The infection is spread by the fly Musca autumnalis, which is common in The Netherlands. Because treatment does not stop the infection from spreading, the bull was culled to prevent the risk of infection of the national herd. To our knowledge, this is the first case of Parafilaria bovicola in The Netherlands.

[Bluetongue in The Netherlands; description of the first clinical cases and differential diagnosis. Common symptoms just a little different and in too many herds]. / Bluetongue voor het eerst in Nederland: beschrijving van de klinische verschijnselen en differentiaaldiagnose.

For the first time Bluetongue (BT) has been diagnosed in the Netherlands. The clinical symptoms of BT on five farms during the first outbreak ever in the Netherlands are described. Fever and swollen sensitive coronets leading to reluctance to stand and walk were sometimes the first symptoms. Later lesions in the mouth occurred with foamy salivation and respiratory problems. In other cases a swollen head with swollen lips and foamy salivation were the first clinical signs. Also sudden death occurred. In the first sixteen confirmed cases morbidity and mortality were lower than described in outbreaks in other countries. Good collaboration between practitioners, specialists of the Animal Health Service (GD-Deventer), and specialists of the Food and Consumer Product Safety Authority (VWA) and CIDC-Lelystad (Wageningen UR) led to a rapid notification and ultimately confirmation of the suspected diagnosis BT.

[First case of pithomycotoxicosis (facial eczema) in the Netherlands]. / Pithomycotoxicosis of facial eczema bij het rund voor de eerste maal aangetoond in Nederland. Zonnebrand als koppelprobleem op rundveebedryjven.

Between mid September and the beginning of November 2005, the Animal Health Service (AHS) received thirteen reports offarms on which several animals showed severe symptoms of solar eczema. Blood chemistry showed very high levels of GOT/AST and GGT indicative of severe liver damage. Farm visits to eight farms showed that the animals--previous to the start of the symptoms--had been grazing 24 hours/day and received no additional feed. Ingestion of poisonous plants or medications was considered unlikely to have caused the liver damage, and liver fluke infections were present on only two farms. Microscopic examination of specimens of grass revealed the presence of spores of Pithomyces chartarum in samples taken from six of nine farms. This fungus produces the mycotoxin sporidesmin, which causes severe liver damage and pithomycotoxicosis (facial eczema). This article is the first to describe Pithomyces chartarum in cattle in mainland Europe. Further research on the distribution and re-occurrence of Pithomyces chartarum infection and sporidesmin survival in grass silage is recommended.

Surveillance of cattle health in the Netherlands: Monitoring trends and developments using routinely collected cattle census data.

Since 2002, a national cattle health surveillance system (CHSS) is in place that consists of several surveillance components. The CHSS combines enhanced passive reporting, diagnostic and post-mortem examinations, random surveys for prevalence estimation of endemic diseases and quarterly data analysis. The aim of the data-analysis component, which is called the Trend Analysis Surveillance Component (TASC), is to monitor trends and developments in cattle health using routine census data. The challenges that were faced during the development of TASC and the merits of this surveillance component are discussed, which might be of help to those who want to develop a monitoring and surveillance system that includes data analysis. When TASC was developed, there were process-oriented challenges and analytical related issues that had to be solved. Process-oriented challenges involved data availability, confidentiality, quality, uniformity and economic value of the data. Analytical issues involved data validation, aggregation and modeling. Eventually, the results had to provide information on cattle health that was intuitive to the stakeholders and that could support decision making. Within TASC, both quarterly analysis on census data and, on demand, additional in-depth analysis are performed. The key monitoring indicators that are analyzed as part of TASC all relate to cattle health and involve parameters such as mortality, fertility, udder health and antimicrobial usage. Population-Averaged Generalized Estimating Equations, with the appropriate distribution (i.e. Gaussian, Poisson, Negative Binomial or Binomial) and link function (independent, log or logit), are used for analysis. Both trends in time and associations between cattle health indicators and potential confounders are monitored, discussed and reported to the stakeholders on a quarterly level. The flexibility of the in-depth analyses provides the possibility to conduct additional analyses when anomalies in trends of cattle health occur or when developments in the cattle industry need further investigation. In addition, part of the budget for the in-depth analysis can also be used to improve the models or add new data sources. The TASC provides insight in cattle health parameters, it visualizes trends in time, can be used to support or nuance signals that are detected in one of the other surveillance components and can provide warnings or initiate changes in policy when unfavorable trends occur.

Use of composite milk samples for diagnosis of Staphylococcus aureus mastitis in dairy cattle.

OBJECTIVE: To measure relative sensitivity and relative specificity for use of composite milk samples, compared with that of individual gland milk samples, for diagnosis of Staphylococcus aureus mastitis. ANIMALS: 505 cows suspected of having subclinical mastitis. Of these cows, 172 were considered infected with Sta aureus, based on the results from individual gland samples. PROCEDURE: Composite and individual gland milk samples were collected from cows suspected of having subclinical mastitis, and results of bacteriologic culturing of samples from the same cow were compared. Results were interpreted at the cow level. Relative sensitivity and relative specificity for composite samples were computed from 2 x 2 tables, using results from individual gland samples as references. RESULTS: Relative sensitivity for use of composite milk samples in diagnosing Sta aureus mastitis was 0.63. The relative specificity was 0.98. Factors influencing the relative sensitivity for composite samples were the number of infected glands per cow, the amount of Sta aureus shedding from infected glands, and the proportion of the composite milk obtained from each gland. CLINICAL IMPLICATIONS: Collecting composite instead of individual gland milk samples increases the number of false-negative results in diagnosing Sta aureus mastitis. By collecting consecutive samples from the same cow or by increasing the inoculum volume at culturing, this problem can be diminished.

Epidemiological characteristics of bovine herpesvirus 1 infections determined by bulk milk testing of all Dutch dairy herds.

Samples of bulk milk were taken from all 33,636 Dutch dairy herds in November 1994 and tested for the presence of bovine herpesvirus 1 (BHV-1) antibodies with a gB-blocking ELISA. Sixteen per cent of the herds had a negative BHV-1 status in the bulk milk. Farms with only dairy cows were 1.9 times more likely to have a negative or weakly positive BHV-1 status than herds which also had beef/veal animals. Farms in areas containing less than one herd/km2 were 1.5 times more likely to have a negative or weakly positive BHV-1 status than herds in areas with more than three herds/km2. Differences in numbers of animals per unit area were not significantly associated with BHV-1 status. The probability of herds having a negative or weakly positive BHV-1 status decreased linearly with herd size by a factor of 1.2 per 10 animals. The purchase of stock was significantly associated with a negative or weakly positive BHV-1 status, but there was an interaction between farm type and purchase of stock. For farms with both dairy and beef/veal animals there was a weak association between the purchase of stock and BHV-1 status. For pure dairy herds the probability of having a negative or weakly positive BHV-1 status decreased linearly with the numbers of purchased stock by a factor of 1.3 per 10 animals purchased.

[Alcohol poisoning in dogs]. / Alcoholvergiftiging bij de hond.

The clinical symptoms of ethanol intoxication in a Jack Russell terrier dog of 5 kg, that consumed 50 ml of whisky (40%) within 15 minutes on an empty stomach are described. The clinical case is completed with literature information on clinic, pathogeneses and therapy.

[BSE: clinical diagnosis and field experience]. / BSE: klinische diagnostiek en veldervaringen.

The clinical diagnosis 'suspected of having BSE' is difficult. Cows older than 2.5 years, presented to the private veterinary practitioner with disturbed locomotion present for more than 14 days and with no detectable cause, should be investigated with suspicion. Questions on changes in behaviour of the animal and during the examination attention on exaggerated responses to handling and sound can give additional information. Notification of suspected cases and gained field experiences are discussed.

[Analysis of symptoms associated with bovine herpesvirus 1 vaccination]. / Analyse van gezondheidsklachten na BHV1 vaccinatie.

Between 1 May 1998 and 22 February 1999, it was compulsory for Dutch cattle farmers to take measures against bovine herpesvirus 1 (BHV1). Cattle on farms that were not certified as infectious bovine rhinotracheitis (IBR)-free had to be vaccinated twice a year. During the vaccination programme, both farmers and veterinarians reported side-effects of the vaccine. These reports were collected by the Stichting IBR/BVD Schade (SIS; Foundation for IBR/BVD Damage) in order to draw up a damage report. In 1999 in total 6977 cattle farmers lodged complaints which they considered to be related to the vaccination against BHV1. On these farms, 15,150 herd vaccinations had been performed, 10,269 of which were associated with one or more symptoms. During the compulsory vaccination period, 13% of the herd vaccinations led to symptoms and complaints. In March 1999, a number of vaccine batches were found to be contaminated with bovine virus diarrhoea (BVD) virus. For the purposes of this analysis, a 'known contaminated' herd vaccination was defined as one in which at least one 'known contaminated' batch or lot of vaccine was used. In total, 987 of 1007 herds vaccinated with 'known contaminated' vaccines developed one or more symptoms compatible with acute BVD. There were no commonly seen combinations of symptoms. For this reason, and because the start and end dates were not reported for 55% of the symptoms, it was not possible to detect a symptom pattern. Therefore there were no 'suspect' batches of vaccine which, although not contaminated with BVD virus, gave rise to symptoms. The number of BVD symptoms was determined for those herds with vaccination-related symptoms. There was no difference in the distribution frequency between batch numbers or between 'known contaminated' batches and 'non-suspect' batches. The farmers' definition of chronic wasting was used in this investigation, with the inevitable large differences in definition. The symptom chronic 'wasting' was reported for 3209 of the 10,269 herds with vaccination-related symptoms. On 161 farms (164 herd vaccinations) 'chronic wasting' accounted for more than 20% of the symptoms. As expected, other symptoms were reported in addition to wasting. The symptom 'chronic wasting' was reported more often on forms where a 'known contaminated' vaccine was used. Inactivated vaccine was used for 154 herd vaccinations. In 34 cases, one or more symptoms of acute BVD were reported. The frequency was the same as that for live vaccines. The frequency of reported symptoms tended to be lower with the inactivated vaccine. On the basis of the SIS data, no relationship was found between vaccine batch and reported symptoms. This may be because (i) the classification of a vaccine as 'known contaminated', 'non-suspect', and 'not known' may not have been in keeping with the real status of the vaccine, (ii) farmers may have reported symptoms selectively, and (iii) there is no relationship with vaccination against BHV1.

[Suffocating, slow calves with a thick neck. Iodine deficiency in cattle]. / Benauwde, slome kalveren met een dikke hals. Jodiumdeficiëntie bij rundvee.

On a dairy farm situated 200 km from the sea on sandy soil an increasing problem arose during 3 years with new-born calves showing a thickness over the larynx. The calves and close-in heifers proved to be severely deficient in trace elements. The new born calves had goitre. The clinical picture, diagnosis and therapy/prevention are discussed.

[Botulism poisoning in cattle, a case report, diagnosis and prevention]. / Botulismevergiftiging bij runderen, een case, diagnostiek en preventie.

On a dairy farm 22 animals die in 14 days. After 10 days the clinical diagnosis is confirmed: clostridium botulinum type D intoxication. The clinical, diagnosis, therapy and prevention are discussed.

[I&R (identification and registration) system cattle: an analysis of its use during a foot-and-mouth-disease outbreak in The Netherlands]. / I&R-systeem rund: een analyse ten behoeve van het gebruik tijdens een mond- en klauwzeer-uitbraak in Nederland.

The performance of the Dutch cattle I&R system was analysed, with emphasis on the potential use of the system for the control of an outbreak of foot and mouth disease (FMD). The analysis showed that not all mutations were centrally registered within the three working days that are allowed to pass between the actual change and the obligatory report. In particular, young calves and cattle heading for slaughter were reported too late. During an outbreak of FMD, the best strategy to trace animals off a farm seems to be first to identify all animals on the farm, using a preprocessed list of the animals that should be present on the farm according to the I&R system. Then all the animals that have left the farm during the last month can be traced in the central I&R computer or by asking the person to whom the farmer sold the cattle (the next owner). In the present study, 54% of the animals were localized within one day, and 94% within one week. Finally, some suggestions for improvement for the system are given.

[Detection of hyperketonemia with the aid of monitoring milk production and two milk tests]. / Detectie van hyperketonemie met behulp van beoordeling van de melkproductie en twee melktesten.

In addition, it is relevant to know to what extent milk production data can provide information about hyperketonaemia. In 12 selected herds, milk samples were collected from 114 cows that had been lactating for maximally 70 days. During regular milk testing, two additional milk samples were taken to assess the 'Nitroprusside test' and the 'Ketolac BHB' test. After collection of milk samples, blood samples were taken to measure serum beta-hydroxybutyric acid. The prevalence of hyperketonaemia appeared to vary between herds from 1 to 9 per 10 lactating cows. The sensitivity of the Nitroprusside test was higher than the sensitivity of the Ketolac BHB test at threshold values of beta-HBA > 1.5 mmol/l. The Ketolac BHB test in comparison to the Nitroprusside test appeared to provide a smaller chance of false-positive test results at a given level of sensitivity. The serum beta-hydroxybutyric acid concentration was correlated with milk yield/day and the milk fat concentration of an individual cow.

[Vitamin B12 supplementation and milk production on farms with 'chronic wasting' cattle]. / Vitamine B12-suppletie en melkproductie op bedrijven met 'slijtende' runderen.

From early 1999 onwards, cattle health problems accompanied by chronic wasting of unknown aetiology were reported on a number of dairy farms. An association between these health problems and the compulsory use of gE-negative marker vaccines against bovine herpesvirus 1 was presumed by farmers. On one dairy farm an increased milk production of 50% was reported within a few days after parenteral vitamin B12 treatment. Therefore, the current study was designed to determine the effect of parenteral vitamin B12 treatment on the milk production of dairy herds with wasting cattle. A randomized blind trial was performed in five problem herds and two control herds. On each farm five lactating cows were injected intramuscularly with 20 mg vitamin B12 and paired with five untreated lactating cows. The milk production of treated and untreated animals was measured for 19 days following treatment and compared to pre-treatment production. No effect of vitamin B12 treatment on milk production was established on either problem farms or control farms. Neither was a difference detected in the response to vitamin B12 treatment between problem herds and control herds. In a second experiment, parenteral vitamin B12 treatment was applied in three problem herds by local veterinary practitioners. The results of this experiment were in line with the results of the first experiment.

[She does behave funny, but she is no 'crazy cow' (BSE)]. / Ze doet wel raar, maar is geen 'gekke koe' (BSE).

Since 1999 18 cows with 'crampiness' were presented for clinical inspection. Most animals were called upon because of clinically 'suspected BSE' by the local veterinary practitioner. The clinical picture of the disease and the differences with BSE are discussed.

[Reliability of bacteriological studies of composite samples in the diagnosis of subclinical udder infections in cattle]. / De betrouwbaarheid van het bacteriologisch onderzoek van mengmonsters voor de diagnose van subklinische uierinfecties bij rundvee.

This study evaluated the reliability of making bacteriological cultures of composite milk samples for the diagnosis of subclinical udder infections in dairy herds. Quarter samples as well as composite samples were collected from 482 cows with suspected subclinical mastitis from 69 Dutch dairy farms. The samples were used to measured somatic cell counts and to prepare bacteriological cultures. The sensitivity and specificity of the bacteriological cultures of the composite samples were compared with those of the quarter samples. The sensitivity of Staphylococcus aureus, Streptococcus uberis, Streptococcus agalactiae and Streptococcus dysgalactiae was 57.9%, 65.2%, 86.6%, and 60.3%, respectively. The specificity was higher than 98% for all four bacteria. Although information is lost when composite samples are used, composite samples are useful, especially for large dairy herds. The advantage and disadvantages of the use of composite samples are discussed.

[Testing area Wehl: study of risks of contacts in behalf of foot-and-mouth disease]. / Proefgebied Wehl: onderzoek naar risico's van contacten ten behoeve van mond- en klauw-zeerbestrijding.

A study on contacts between livestock holdings was conducted in a geographically defined area of 4 by 6 km in the Netherlands. The farmers were asked to record all contact on and off farm during a period of 2 weeks. The number of contacts in the 2 week period was high, on average 91.8 contacts per farm. The risk of spreading foot-and-mouth disease on or off the farm was greater for cattle farms than for swine farms. Relatively more people had contact with the animals while visiting cattle farms, thereby causing the higher risk. Most contacts occurred over short distances. Almost 50% of the contacts were within the research area. This finding confirms the importance of restricted areas around farms with foot-and-mouth disease infections.