George Caldow

Parachlamydia involvement in bovine abortions in a beef herd in Scotland

WE report the preliminary findings of an investigation into Parachlamydia involvement in bovine abortions in a spring-calving beef herd in Scotland. To our knowledge, this organism has not yet been recognised in bovine abortions from British herds.nnThe herd has experienced an annual abortion rate

Molecular detection of Chlamydia-like organisms in cattle drinking water.

A substantial proportion of the causes of infectious bovine abortion remain largely undiagnosed, potentially due to the presence of previously unrecognised infectious agents. Recently, several reports have demonstrated the presence of Parachlamydia sp. in placental and foetal tissues derived from bovine abortions of unknown aetiology but the route of transmission remains undefined. The drinking water from one such recent case study was analysed for the presence of Parachlamydia sp. as a potential source of infection. Chlamydiales sp. 16S rRNA genes were PCR-amplified from the drinking water and a 16S rRNA gene clone library constructed. DNA sequencing of thirty-one clones indicated the presence of organisms belonging to the Parachlamydiaceae, specifically the genera Parachlamydia and Neochlamydia. Seven 16S rRNA gene sequences were identical to a Parachlamydia sp. sequence obtained from placental tissue from an abortion case originating from the same farm. These results raise the possibility that the drinking water is a source of Parachlamydia, which may play a role in infectious bovine abortion.

SBV in a dairy herd in Scotland

WE would like to report serological evidence of Schmallenberg virus (SBV) infection in a dairy herd in south-west Scotland in 2012.nnThe herd is managed as two separate groups: group P, consisting of 190 cows that had access to pasture grazing between May and September 2012; and group R, consisting of 60 cows that were housed throughout 2012 and were never at pasture. Both groups shared the same building from the end of September 2012, but were managed and milked separately.nnAs part of routine herd health surveillance, we tested bulk milk for antibodies against SBV on the two separate groups in December 2012. The sample from group P …

Clostridium perfringens type-D enterotoxaemia in cattle: the diagnostic significance of intestinal epsilon toxin.

The aims of this study were to describe 42 cases of Clostridium perfringens type-D enterotoxaemia in cattle seen between 2003 and 2014 and to determine the diagnostic value of detecting epsilon toxin in bovine intestinal content. All cases in the series had histological brain changes considered pathognomonic for C. perfringens type-D enterotoxaemia in sheep and goats and the epsilon toxin of C. perfringens was concurrently detected in the intestinal contents of 15 (36 per cent) cases. The data from the case series indicate that intestinal epsilon toxin has a sensitivity of 56 per cent compared with histology of the brain for diagnosis of bovine C. perfringens type-D enterotoxaemia. The diagnostic specificity of detecting epsilon toxin in bovine intestinal content was investigated by screening intestinal contents of 60 bovine carcases submitted for postmortem examination. Epsilon toxin was detected in 11 (18 per cent) carcases but no pathognomonic histological brain change was found in any. The specificity of intestinal epsilon toxin was estimated to be 80.4 per cent. These studies demonstrate that for a definitive diagnosis of C. perfringens type-D enterotoxaemia in cattle histological examination of the brain is essential as the presence of epsilon toxin in the intestinal contents alone is neither sensitive nor specific enough.

Psoroptic mange in a Scottish beef herd

PSOROPTIC mange can have a profound effect on infested cattle, resulting in intense pruritis and a chronic hypersensitive reaction (Ginn and others 2007). The species of mite that causes psoroptic mange in cattle is morphologically indistinguishable from the Psoroptes ovis responsible for sheep scab and is currently referred to as the cattle adapted strain of Psoroptes species (Mitchell and others 2012). Occasional cases have been reported from Ireland (DAFM 2009, 2010) and Great Britain (Millar and others 2011), but until recently there had been no diagnosis made in cattle in Scotland since the early 1980s (Linklater and Gillespie 1984).nnWe would like to provide details of a case of psoroptic mange in a cow and calf imported to south-east Scotland from Ireland. The diagnosis was made in a two-month-old British Blue calf. Three weeks after arrival on the holding, the calf was presented to the private veterinary surgeon showing pruritis and patches of partial alopecia over the left thorax and left thigh. There was some exudation from the skin and areas of crusting particularly over the thoracic region. Two days later, the dam of the calf became pruritic and …

Role of Schmallenberg virus infection in congenital malformations in ruminants in Scotland in spring 2017

Scotland’s Rural College (SRUC), together with the Moredun Research Institute, carries out surveillance for Schmallenberg virus (SBV) infection in cattle and sheep. This article reports findings relating to diagnoses of fetopathy associated with SBV infection and other congenital malformations in these species made between January 1 and May 5, 2017.

Counterintuitive increase in observed Mycobacterium avium subspecies paratuberculosis prevalence in sympatric rabbits following the introduction of paratuberculosis control measures in cattle

Paratuberculosis (Johne’s disease) is caused by the bacterium Mycobacterium avium subspecies paratuberculosis (Map). Achieving herd-level control of mycobacterial infection is notoriously difficult, despite widespread adoption of test-and-cull-based control strategies. The presence of infection in wildlife populations could be contributing to this difficulty. Rabbits are naturally infected with the same Map strain as cattle, and can excrete high levels in their faeces. The aim of this study is to determine if implementation of paratuberculosis control in cattle leads to a decline in Map infection levels in rabbits. An island-wide, test-and-cull-based paratuberculosis control programme was initiated on a Scottish island in 2008. In this study annual tests were obtained from 15 cattle farms, from 2008 to 2011, totalling 2609 tests. Rabbits (1564) were sampled from the 15 participating farms, from 2008 to 2011, and Map was detected by faecal culture. Map seroprevalence in cattle decreased from 16 to 7.2 per cent, while Map prevalence in rabbits increased from 10.3 to 20.3 per cent. Results indicate that efforts to control paratuberculosis in cattle do not reduce Map levels in sympatric rabbits. This adds to mounting evidence that if Map becomes established in wild rabbit populations, rabbits represent a persistent and widespread source of infection, potentially impeding livestock control strategies.

Hepatic lipodystrophy of Galloway calves

HEPATIC lipodystrophy of Galloway calves is a rarely reported disease in the UK (Duff and others 1997, Macleod and Allison 1999), having first been diagnosed in 1965 in south-west Scotland (Stewart and others 1982). The condition has also been reported in North America since 2000 (Hazlett and Rumney 2000, Wyoming State Veterinary Laboratory 2007). The aetiology and pathogenesis of the disease has not been established; it is thought to have a genetic origin, although this has not been proven.nnOver the past 12 months, as part of an EBLEX-sponsored postmortem examination project at a fallen stock collection centre in County Durham, we have identified three calves fitting the case description for this condition. In summer 2014, we identified two, two-month-old male blue-grey calves from farm A, which had a 50-cow Galloway herd. The sire of both calves was an 11-year-old unregistered whitebred shorthorn bull, which had sired 200 calves in its lifetime. The first calf was recumbent with tenesmus, halitosis …

Gamma interferon responses to proteome-determined specific recombinant proteins in cattle experimentally- and naturally-infected with paratuberculosis

Johnes disease (JD), is a fatal enteritis of animals caused by infection with Mycobacterium avium subspecies paratuberculosis (Map). Diagnosis of subclinical JD is problematic as test sensitivity is limited. Th1 responses to Map are activated early, thus detection of a cell-mediated response, indicated by measuring interferon gamma (IFN-γ) stimulated by mycobacterial antigens, may give the first indication of sub-clinical infection. Crude extracts of Map (PPDJ) have been used to detect the cell-mediated response in infected cattle. More specific, quantifiable antigens may improve test specificity and reproducibility. Map-specific proteins, MAP_3651c and MAP_0268c, raised a cell-mediated immune response in sub-clinically infected sheep. Results presented in this manuscript demonstrate these proteins elicit a cell-mediated response in experimental and natural infections of cattle. Individual ranked IFN-γ responses of experimentally infected calves to PPDJ showed a high, statistically significant association with ranked responses of recombinant Map antigens. Responses of infected animals were higher than the control group. Threshold values determined using data from an experimental infection were applied to naturally infected animals. Some animals exhibited responses above these threshold values. Responses to MAP_3651c on a farm categorised as high-risk for JD showed strong evidence (P<0.001) that responses were significantly different to lower-risk farms. The IGRA test may prove to be an additional tool for the diagnosis of JD, and inclusion of specific antigens a refinement however, understanding and interpretation of IGRA results remain challenging and further investigation will be required to determine whether the IGRA test can detect exposure and hence predict clinical JD.

Case-control study on bleeding calf syndrome

WE write to request the continued support of cattle practitioners in our effort to identify the causes of the emerging condition of bleeding calf syndrome, now renamed bovine neonatal pancytopenia.nnCases of an unexplained haemorrhagic diathesis in young calves have been reported from several