National intervention study of mastitis control in dairy herds in England and Wales

An intervention study was carried out on 52 dairy farms in England and Wales to determine whether the implementation of a well-specified mastitis control plan in herds with an incidence of clinical mastitis of more than 35 cases per 100 cows per year would reduce the incidence of clinical mastitis, and also reduce the incidence of increases in the somatic cell counts of individual cows. A clearly defined plan for the diagnosis and control of mastitis was developed by two veterinary specialists from the research literature. The herds were randomly allocated to receive the plan either at the start of the study (intervention herds) or after one year (control herds). Data on mastitis management and the farm environment were collected during farm visits. After one year there was a significant 22 per cent reduction in the proportion of cows affected with clinical mastitis on the intervention farms compared with the control farms. There were also significant reductions of approximately 20 per cent in the incidence of clinical mastitis and in the occurrence of increases in the somatic cell counts of individual cows from below, to above 200,000 cells/ml.     

Observations on the incidence of clinical bovine mastitis in non-lactating cows in England and Wales

Epidemiological features of clinical mastitis in dry cows from a three year prospective study are described. Two hundred and seventy-three herds in England and Wales participated in the first year (1980) and 209 and 159 of them continued in the study in the subsequent two years. Clinical mastitis was recorded in 1.5 per cent of cows during the dry period in each of the three years. These cases represented between 3.6 and 4.2 per cent of samples from all clinical cases examined. The incidence of clinical mastitis in dry cows increased during the winter housing period (October to March), a peak occurring at the end of this period. A secondary peak in incidence was recorded in August. Streptococcus uberis was the predominant pathogen. Variations in the monthly incidences of cases associated with the major mastitis pathogens were observed. A greater proportion of cases which occurred during the dry period exhibited systemic signs than of cases which occurred during lactation, with the exception of cases associated with Escherichia coli. The risk of clinical mastitis was apparently higher during the last 30 days of the dry period than during the earlier stages of the dry period.     

Survey of the incidence and aetiology of mastitis on dairy farms in England and Wales

A survey of clinical and subclinical mastitis was carried out on 97 dairy farms in England and Wales, selected at random from members of a national milk recording scheme. The farmers were asked to collect aseptic milk samples from five consecutive cases of clinical mastitis and from five quarters with high somatic cell counts using a defined protocol, and they completed a questionnaire that included information on the cows sampled, the herd and the history of mastitis in the herd. The samples were collected throughout the year. The mean incidence of clinical mastitis was 47 cases per 100 cows per year (estimated from historic farm records) and 71 cases per 100 cows per year (estimated from the samples collected). Streptococcus uberis and Escherichia coli were isolated in pure culture from 23.5 per cent and 19.8 per cent, respectively, of the clinical samples; 26.5 per cent of the clinical samples produced no growth. The most common isolates from the samples with high cell counts were coagulase-negative staphylococci (15 per cent), S uberis (14 per cent) and Corynebacterium species (10 per cent). Staphylococcus aureus and coagulase-positive staphylococci together accounted for 10 per cent of the samples with high somatic cell counts; 39 per cent produced no bacterial growth.     

The virulence characteristics of strains of Escherichia coli isolated from cases of bovine mastitis in England and Wales

Of 470 Gram-negative facultative anaerobes isolated from cases of bovine mastitis in England and Wales, 422 were identified as Escherichia coli. The characteristics of 237 of these were investigated. Guinea-pig red cell haemagglutinins were possessed by 86% of strains and 12% were resistant to D-mannose. None of the strains tested invaded Vero cells. Haemolysin, Vero toxin and enterotoxin were produced by 5, 0.5 and 1% of strains, respectively. Twenty-two percent were resistant to one or more antibiotics and 4% to sodium arsenate. Transfer ability was possessed by 41% and lysogenic phage by 27% of strains; 62% possessed either one or the other and 12% possessed both. Colicin production was detected in 18% of strains; 5% produced Colicin V. Ninety-nine percent of strains were serum-resistant, while only 6% were able to grow well in bovine serum. A microscopically visible capsule was seen in 75% of strains. All strains possessed at least one of the potential virulence factors or markers studied. Several strains which possessed one characteristic only (mannose-sensitive haemagglutination or serum resistance), possessed one or more large molecular weight plasmids. None of the strains was particularly virulent for chickens following intramuscular inoculation. Of the strains which possessed one virulence characteristic, only those which were serum-resistant were re-isolated from expressed milk following intramammary inoculation of lactating cows.     

Epidemiology of Toxocariasis in England and Wales

Toxocara infection occurs through ingestion of parasite eggs excreted by dogs and cats, and can cause severe morbidity. The burden of disease in England and Wales is not well described, and the impact of public health campaigns conducted in the mid‐1990s is uncertain. This paper uses data from two extensive databases to explore the trends in this disease in England and Wales from the 1970s to 2009.     

Anthrax in England and Wales 1963-1972.

The records of confirmed anthrax diagnoses held by the bacteriology department of the Central Veterinary Laboratory, Weybridge, for the years 1963 to 1972 inclusive, were analysed. During this decade, 86 per cent of the 2944 deaths recorded were in cattle and 11 per cent in pigs, correlating significantly with the cattle and pig populations in England and Wales during this period. Also, the country could be separated into high and low prevalence counties for cattle anthrax. Norfolk and Somerset had higher than usual cattle deaths per farm ratios and the reasons for this are explored.     

Pathology of naturally occurring bovine tuberculosis in England and Wales

The aim of this study was to obtain a contemporary data set of pathology in tuberculin reactor and in-contact cattle in England and Wales. Four hundred animals (200 reactors and 200 in-contacts) from 242 farms located in 14 counties in Western England and Wales were examined. The mean number of lymph nodes (LNs) with tuberculosis (TB)-like lesions per TB-confirmed animal was 1.7 in reactors and 1.5 in in-contact animals. Tuberculous lesions in both reactor and in-contact animals were most commonly observed in the LNs of the thorax, followed by the head and abdomen, particularly the mediastinal, retropharyngeal and tracheobronchial LNs. Twenty-five reactors had macroscopic lesions in the palatine tonsils. Among TB-confirmed cattle, 27% of reactors and 9% of in-contact animals had gross TB-like lesions in the lungs, particularly in the caudal lobes. Gross lesions that were not TB-confirmed were parasitic granulomas (45%), bacterial or mycotic club-forming pyogranulomas (27%) and bacterial abscesses (23%). Diagnostic sensitivity was maximised when bacteriology and histopathology were used concurrently. Stage IV granulomas, alone or in combination with other stages, constituted 63% of lesions, while 16% of lesions were stage I/II granulomas. Caseous necrosis and calcification were common features of the granulomas encountered in natural Mycobacterium bovis infections, even with pathology limited to a small number of sites. Granulomas often covered large areas of histological sections and typically contained only small numbers of acid fast bacilli.     

Clinical features of psoroptic mange in cattle in England and Wales

The clinical signs, treatments used and spread of psoroptic mange in cattle from October 2007 until March 2011 are described. The disease was first diagnosed in South West Wales, having not been reported in Great Britain since the 1980s. The likely source was identified as a farm that had imported two animals from mainland Europe in the summer of 2006. Since that time, disease has been diagnosed on a further 22 premises, the majority in South West Wales but also in South East and Mid Wales and on one farm in England. Bought in animals harbouring the Psoroptes species mite but not showing clinical signs were considered the greatest risk of introducing the infestation into a herd. This, together with the difficulties of treatment to eliminate the parasite, means that it is unlikely that this outbreak has been controlled. There is also a continuing threat of importing the disease from abroad. The disease is not notifiable in the UK.     

Blowfly strike prevalence in domestic rabbits in southwest England and Wales

The prevalence of blowfly strike in rabbits in southwest England and Wales was investigated using a retrospective postal survey of small animal and mixed veterinary practices. Questionnaires were sent to 474 practices; 219 were returned completed, giving a response rate of 46.2%. The prevalence of blowfly strike was estimated as the percentage of veterinary practices that reporting having treated at least one rabbit for strike between May and September 2005. Overall, 94.5% (+/-2.21) of practices treated at least one case of rabbit strike. Almost half, 49.3% (+/-11.3) of practices reported treating only 1-5 rabbits for blowfly strike in the study period; 32.8% (+/-4.56), 13% (+/-3.27) and 4.8% (+/-2.08) treated 6-10, 11-15 and more than 15 struck rabbits, respectively. In 46.3% (+/-4.84) of the practices most infested rabbits survived. For 40.4% (+/-4.77) of practices, about half the struck rabbits survived. However, for 13.3% (+/-3.30) of practices most struck rabbits were reported to have died. The practices reporting that most animals died were those that saw significantly fewer rabbits and fewer struck rabbits than practices where more animals survived. This suggests that training and experience in the appropriate care of infested rabbits may be critical in ensuring a favorable outcome.