[Mycoplasma mastitis in dairy cattle]. / Mycoplasma mastitis bij het rund.

The most important characteristics of Mycoplasma mastitis on dairy farms are described, based on two case studies. Clinical symptoms, diagnostics, epidemiology, and a plan of action are presented. In the herds investigated, Mycoplasma mastitis was characterized by multiple affected quarters unresponsive to treatment with antibiotic and/or anti-inflammatory agents. Most striking were a sandy sediment, brown colouring, and rice-like structure of the milk of affected animals. Clinical symptoms differed in the two affected herds. Diagnosis was based on bacteriological investigation of samples of milk and synovial fluid taken from infected cows. Affected animals were culled immediately, and the herds were monitored by repeated testing of bulk milk samples. It was concluded that a consequence of the increasing size of cattle herds in the Netherlands is that subclinical/clinical Mycoplasma mastitis may be diagnosed more frequently than in the past. In the case of Mycoplasma mastitis, farmers and veterinary practitioners are advised to draw up a plan of action together, incorporating aspects such as diagnostics at cow level, direct culling of affected animals, hygiene during milking, including post-milking teat disinfection, and routine monitoring of bulk milk. Unpasteurized milk should not be given to calves.

[High mortality in a herd with signs of jejunal hemorrhage syndrome]. / Hoge mortaliteit in melkveekoppel met beelden van jejunal hemorrhage syndrome.

Eleven cows from a herd of 80 dairy cows (14%) died over a 7-month period. Death occurred within 12-24 hours of the onset of the first clinical signs, namely, dullness and a decrease (mean 25%) in milk production. Within 12 hours the cows were unable to rise, felt cold, and were restless. Examined mucous membranes were pale. Two of three cows examined at necropsy had blood in the jejunum and high counts of Clostridium perfringens. Jejunal hemorrhage syndrome was diagnosed in these two cows on the basis of the clinical signs and postmortem findings.

Eosinophilic myositis due to Sarcocystis hominis in a beef cow.

A case of eosinophilic myositis (EM) in an 8-year-old beef cow was investigated. The animal originated from a herd in which a high incidence of the disease had been observed in slaughtered adult females over a period of 2 years. Histologically, the lesions in the muscles were characterized as granulomas with a central core of degenerate eosinophils and remnants of necrotic muscle fibres, surrounded by a rim of epithelioid cells and fibrous tissue with an infiltrate consisting predominantly of eosinophils radiating outwards. Degenerate sarcocysts with a thick (7-9 microm) wall were present in the suppurative centre of most lesions. Intact sarcocysts with similar morphology were present in adjacent muscle fibres but without an associated inflammatory reaction. By transmission electron microscopy the sarcocysts were identified as Sarcocystis hominis, based on the morphology of villar protrusions of the sarcocyst wall, which were broad-based and cylindrical, with a blunt distal end, and contained numerous long microfilaments. Circumstantial evidence indicated a human source of infection, human faecal material having been spread on the pasture grazed by the cattle. The findings supported a causal relationship between S. hominis infection and EM in cattle.

[Coccidiosis causes diarrhea in calves in the pasture. Pasture coccidiosis caused by Eimeria alabamensis]. / Coccidiose als oorzaak van diarree bij pinken in de weide. Weidecoccidiose veroorzaakt door Eimeria alabamensis.

A severe outbreak of diarrhoea in young (age 18-20 month) cattle 14 days after their first turnout is described. In the manure large numbers Eimeria alabamensis oocysts were found. This infection is considered as a case of coccidial diarrhoea in (older) calves at pasture.

Myiasis in sheep in The Netherlands.

In 1999, among 164 randomly selected Dutch sheep farmers, a questionnaire was carried out to estimate the prevalence of myiasis in sheep and to investigate factors associated with the occurrence of myiasis. The total number of sheep and/or lambs on the reference date 1 August 1999 was 12,200: 5243 ewes, 225 rams, 3393 ewe- and 3339 ram lambs. On 86 (52.4%) of the farms 349 (2.9%) of all sheep and/or lambs contracted myiasis, of which two died. Myiasis was seen significantly more frequently on farms with over 25 ewes compared to smaller farms. Cases of myiasis were detected from April to September, with a peak (47.1%) in August. Occurrence of myiasis was most frequently associated with hot and humid weather and was mainly observed (69.1%) in the area around the tail.Ewes and ewe lambs had significantly more myiasis when compared with rams and ram lambs. There was no relationship with tail docking, with breed, with the time of shearing, with the kind of soil (clay, sand, etc.), with the environment (bush, trees, water, etc.), with the type of treatment (pour on, dipping, spraying), the used insecticides (synthetic pyrethroïds, diazinon, cyromazin, etc.), the number of preventive treatments, the time of treatment or the number of observations on the herd (once a day, once a week, etc.).

Factors associated with bacteriological cure during lactation after therapy for subclinical mastitis caused by Staphylococcus aureus.

The objective of this study was to determine the factors that were associated with the cure of subclinical mastitis caused by Staphylococcus aureus treated during lactation. One hundred forty-three quarters that were infected with S. aureus were available from a number of treatment trials. Analysis of these data showed that the most important factors associated with cure were age of the cow, somatic cell count at the time of treatment, presence of the infection in the front quarters, and stage of lactation. Other factors, such as number of infected quarters per cow and sensitivity or resistance of the strain to penicillin, were not significant. Because of the relatively low probability of cure, it is important to know risk factors for cure and, hence, to choose cows for treatment with great care. Using these data, a prediction equation was developed to determine the cure rate of subclinical mastitis caused by S. aureus when treated during lactation.

[Factors affecting the cure rate of Staphylococcus aureus in the drying out of cows using antibiotics: a literature review]. / Factoren, die van belang zijn voor de genezing van Staphylococcus aureus bij het droogzetten van koeien met antibiotica: een literatuuroverzicht.

The choice of dry cow antibiotics should be based on clinical efficacy studies. The choice also depends on the sensitivity pattern of S. aureus, and the expected length of the dry period. There are many quarter, cow and herd factors that influence efficacy of dry cow therapy. These factors include somatic cell count, front-versus-hind quarter, age, and the number of infected quarters in a cow. Nutrition of cows at the end of the lactation and hygienic conditions on the farm and off are also important. The effect of extra treatments at dry off are questionable.

Factors associated with bacteriological cure after dry cow treatment of subclinical staphylococcal mastitis with antibiotics.

Data from five dry cow antibiotic therapy trials were analyzed. Records were only included for cows with > or = 1 culture-positive quarters that were subclinically infected with Staphylococcus aureus. Data for 406 quarters affected with S. aureus from 283 cows on 73 farms were analyzed for quarters, cows, and herds. The probability of cure of an infected quarter decreased when SCC increased, when another quarter was infected in the same cow, when the infection was in a hind quarter, and when the percentage of samples that were positive for S. aureus was higher before drying off. Variables predicting complete bacteriological cure of a cow were log SCC, age of the cow, and the number of infected quarters. The probability of a cure decreased as SCC increased. The probability of cure decreased as age increased, and cows with more than one quarter infected were .57 times less likely to be cured than cows with 1 infected quarter.

[Cesarean section in cattle: always act sensibly]. / Keizersnede bij het rund: denkt al doende.

The autopsies of 11 cows, that died after a caesarean section, are described. In a number of cases the operation had performed without the requisite professional skill and care. The opinions of 54 practising veterinarians who responded to an anonymous questionnaire about the operations are described.