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Johne's disease (JD) is a chronic disease of ruminants endemic in the UK and other countries and responsible for large economic losses for the dairy sector. JD is caused by Mycobacterium avium subspecies paratuberculosis (MAP), which typically infects calves that remain latently infected during a long period, making early detection of infection challenging. Cow to calf transmission can occur in-utero, via milk/colostrum or faecal-orally. Understanding of the different transmission routes to calves is important in informing control recommendations. Our aim in this longitudinal study was to measure the association between the transmission routes via the dam and the environment on a calf subsequently testing serologically positive for MAP. The study population comprised of 439 UK dairy calves from 6 herds enrolled between 2012 and 2013. These calves were followed up from birth until 2023. At birth individual calf data was captured. During follow-up, individuals entering the milking herd were quarterly tested for the presence of MAP antibodies using milk ELISA. Cox regression models were used to measure the association between exposure from the dam (in-utero and/or colostrum) or from the environment (long time in dirty yard) and time to first detection of MAP infection. An association between calves born to positive dams and probability of having a MAP positive test result remained after excluding potential MAP transmission via colostrum (Hazard ratio: 2.24; 95% CI: 1.14 - 4.41). Calves unlikely to be infected with MAP via the in-utero or colostrum route, had 3.68 (95% CI: 3.68 1.45-9.33) higher hazard of a positive test result when they stayed longer in a dirty calving area. The effect of the dam infection status on transmission to calves precedes the dam's seroconversion and persists after excluding the potential role of transmission via colostrum. The association between time spent in a dirty calving area and probability of a MAP positive test result highlights the role of environmental contamination as a source of infection in addition to the dam., Competing Interests: Declaration of Competing Interest All authors declare that they have no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Endemic sheep and cattle diseases represent a constant strain and impact to animal health and welfare, the environment, public health, and the economy. Quantifying this impact helps to inform decisions on surveillance and control of livestock diseases. This systematic literature review had two objectives; to describe the economic impact of endemic sheep and cattle diseases in the United Kingdom using a broad conceptualisation of impact, and to investigate what variables (e.g. medication costs, loss of production) and methods are included in these calculations. The Prisma protocol for systematic literature reviews was followed. Searches were performed in Pubmed, Scopus and Web of Science using selected and trialled search terms. A total of 1129 papers were identified and screened for relevancy; 38 papers were selected for full review extracting and analysing data on disease, impact and methods. From this final selection of papers it was found that; 1) research in this area is mainly focused on the dairy sub-sector, 2) the most mentioned diseases were mastitis and lameness in dairy cattle; bovine viral diarrhoea in beef cattle; and ectoparasites in sheep with reported animal-level costs of £ 77-£ 548/cow/year, £ 26-£ 185/bovine animal/year and £ 40-£ 47/ewe/year, respectively, 3) numerous methods and variables were used to calculate or estimate the economic impact with most studies focussing on the direct producer impacts and less on the wider implications and affected stakeholders; and 4) it was common for studies to look at one disease in isolation rather than consider disease impact on the farm as a whole. It is recommended that future economic impact calculations on livestock disease include wider implications to estimate the true cost of disease. To generate the necessary data, a wider, more inclusive conceptualisation of impact will be needed to support the collection of data and facilitate communication between stakeholders. Systematic health data recording combined with assessment calculations and metrics that allow comparability within or across livestock sub-sectors will increase the informative value of these impact calculations., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

A variety of antimicrobials and antiparasitics are used to treat British cattle and sheep to ensure animal welfare, a safe food supply, and maintain farm incomes. However, with increasing global concern about antimicrobial resistance in human and animal populations, there is increased scrutiny of the use of antimicrobials in food-producing animals. This systematic review sought to identify and describe peer and non-peer reviewed sources, published over the last ten years, detailing the usage of, and resistance to, antimicrobials and antiparasitics in sheep and cattle farming systems in Britain as well as identify knowledge gaps. Applying the PRISMA review protocol and guidelines for including grey literature; Scopus, Web of Science, Medline, and government repositories were searched for relevant articles and reports. Seven hundred and seventy titles and abstracts and 126 full-text records were assessed, of which 40 scholarly articles and five government reports were included for data extraction. Antibiotic usage in sheep and cattle in Britain appear to be below the UK average for all livestock and tetracyclines and beta-lactam antibiotics were found to be the most commonly used. However, the poor level of coverage afforded to these species compared to other livestock reduced the certainty of these findings. Although resistance to some antibiotics (using Escherichia coli as a marker) appeared to have decreased in sheep and cattle in England and Wales over a five-year period (2013-2018), levels of resistance remain high to commonly used antibiotics. The small number and fragmented nature of studies identified by this review describing anthelmintic usage, and the lack of available national sales data, prevented the identification of trends in either sheep or cattle. We recommend that additional efforts are taken to collect farm or veterinary level data and argue that extraction of this data is imperative to the development of antimicrobial and antiparasitic resistance strategies in Britain, both of which are needed to reduce usage of these anti-infective agents, curb the development of resistance, and safeguard national agricultural production. Finally, metrics produced by this data should be generated in a way to allow for maximum comparability across species, sectors, and countries., (Copyright © 2020 Elsevier B.V. All rights reserved.)

This retrospective case-control study investigates the relationship between seroconversion to Mycobacterium avium subspecies paratuberculosis (MAP) and raised somatic cell count (SCC). The study consists of 112 case cows from three dairy farms in the UK; for each case cow with a positive antibody titre, there was a seronegative control cow for comparison. Seroconversion was monitored using milk ELISA antibody titres for MAP taken at quarterly intervals. SCCs were recorded at the time a positive antibody titre was first recorded as well as at the previous and subsequent milk recording in order to explore a temporal relationship between the two events. The previous and subsequent milk recordings were a month before and after seroconversion was identified. The results showed that cows that were infected with MAP had an increased SCC around the time that they first became seropositive, providing evidence for a temporal relationship between the two events; high SCCs were particularly prevalent before and at the time of first detecting seroconversion. The explanation is being discussed that potentially an underlying, currently not studied, factor may be predisposing both events, the progression of paratuberculosis is predisposing the host to mastitis, or indeed intramammary infections help initiate paratuberculosis progression., Competing Interests: Competing interests: None declared., (© British Veterinary Association 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Omphalitis contributes significantly to morbidity and mortality in neonatal calves. Diagnosis of omphalitis is based on the local signs of inflammation-pain, swelling, local heat and purulent discharge. An abattoir trial identified an optimal, sign-based, scoring system for diagnosis of omphalitis. A sample of 187 calves aged between 7 and 15 days old were clinically examined for signs of umbilical inflammation and compared with postmortem examination of navels. On postmortem findings, 64 calves (34.2 per cent) had omphalitis. In the examined omphalitis cases, the most commonly affected umbilical structure was the urachus (78.1 per cent). Multivariable logistic regression revealed that thickening of the umbilical stump over 1.3 cm (P<0.001), discharge (P<0.001), raised local temperature (P=0.003) and the presence of umbilical hernia (P=0.024) were correlated and positive predictors of omphalitis. Discharge from the umbilical stump was associated with intra-abdominal inflammation (P=0.004). Assigning weights based on the multivariable logistic regression coefficients, a clinical scoring algorithm was developed. The cumulative score ranged from 0 to 9. Using this scoring system, calves were categorised as positive if their total score was ≥2. This scoring method had a sensitivity of 85.9 per cent, specificity of 74.8 per cent and correctly classified 78.6 per cent of all calves., Competing Interests: Competing interests: None declared., (© British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

To implement appropriate and effective disease control programs at the national level, up-to-date and unbiased information on disease frequency is needed. The aim of this study was to estimate the prevalence of selected endemic infectious diseases in the population of dairy herds in Great Britain. Bulk milk tank (BMT) samples from 225 randomly selected dairy farms, stratified by region and herd size, were tested for antibodies against bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1, Mycobacterium avium ssp. paratuberculosis, Leptospira Hardjo, Salmonella spp., Coxiella burnetii, Fasciola hepatica, Neospora caninum, and Ostertagia ostertagi. Furthermore, the presence of BVDV, C. burnetii, and Chlamydia-like organisms was determined by PCR. The apparent herd prevalence was estimated as a weighted proportion of positive herds. The true prevalence was calculated when a test was used with known test characteristics for the cut-off value used. Among unvaccinated herds, the true prevalence of BMT antibodies against BVDV was estimated at 66% [95% confidence interval (CI): 56-77%], M. avium ssp. paratuberculosis 68% (95% CI: 59-77%), bovine herpesvirus type 1 62% (95% CI: 52-73%), Leptospira Hardjo 47% (95% CI: 34-60%), and Salmonella spp. 48% (95% CI: 39-56%). The apparent prevalence of BMT antibodies against C. burnetii was 80% (95% CI: 75-85%), F. hepatica 55% (95% CI: 48-62%), N. caninum 46% (95% CI: 38-54%), and O. ostertagi 95% (95% CI: 91-98%). The BVDV, C. burnetii, and Chlamydia-like antigens were detected in 5 (95% CI: 2-9%), 29 (95% CI: 21-36%), and 31% (95% CI: 24-38%) of herds, respectively. Our results show that dairy cows across GB are frequently exposed to the studied pathogens, which are endemic at high levels with some geographical variations. These prevalence estimates provide a much-needed basis to assess whether nationwide control programs for the studied pathogens are justified by their potential economic, environmental, and public health implications. Should surveillance and control programs be initiated, the estimates presented here are a baseline against which progress can be assessed., (The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).)

A randomised controlled trial was used to investigate the effect of three complex management intervention packages to reduce the burden of E. coli O157 in groups of young-stock on cattle farms in England and Wales. All intervention farms were assigned measures to avoid buying in new animals and having direct contact or sharing water sources with other cattle. Furthermore, package A (7 farms) aimed to keep a clean environment and closed groups of young-stock; package B (14 farms) aimed for improved water and feed hygiene, whilst package C was assigned both A and B. The control farms (26 farms) were asked not to alter their practices. Farms, which were assigned intervention package A, exhibited a 48% reduction in E. coli O157 burden over the 4.5 months (average) of observation, compared to 18% on the control farms. The effect of package A compared to the control farms in a crude intention-to-treat model was RR = 0.26 (p=0.122). When the risk ratio was adjusted for actual application of the different measures, the effect of intervention package A became stronger and statistically significant (RR = 0.14 p=0.032). Statistical evidence (p< 0.05) showed that dry bedding and maintaining animals in the same groups were the most important measures within the package and weak evidence (p< 0.1) showed that a closed herd policy and no contact with other cattle may also be of importance. Compliance with the other measures in package A had no influence on the effect of the package. No evidence of effect of the other two intervention packages was found.

The research with respect to displacement of the abomasum (DA) in dairy cattle is reviewed. Evaluated articles describe epidemiological and experimental studies. The occurrence is elevated with regard to breed, gender, age, concurrent diseases, environmental aspects and production levels as contributing factors and emphasis is placed on the effects of nutrition and metabolism. Reviewing the experimental work, distinction is made between the research into gas production in the abomasum and hypomotility of the abomasum, since both represent presumed pathways in the development of DA. Although the different fields of research have positive contributions to the understanding of the pathogenesis of DA, contradictions in the different studies are present. This is partly due to extrapolation of results from sheep to cows, or because of a low number of cows in the experiments. Finally, general suggestions are made for further research in the field of the pathogenesis of DA.

Concern over the spread of infectious animal diseases has led to attempts to improve the biosecurity behaviour of farmers. Implicit within these behavioural change strategies are different geographies of knowledge that enact different versions of disease. Some versions are fixed whilst others attempt to live with disease by accommodating difference. This paper explores how these different strategies fare in attempts to promote biosecurity to farmers. The paper compares farmers' responses to 'high-risk' and 'population' strategies of biosecurity behaviour change in relation to bovine tuberculosis in cattle. Drawing on quantitative assessments of biosecurity and farmer interviews, the paper suggests that biosecurity behaviour change initiatives that draw on locally situated practices and knowledges of disease are more likely to have an impact on biosecurity behaviour than those which attempt to standardise biosecurity and disease. Through a process of constant tinkering and rewiring biosecurity to fit local social and ecological conditions, approaches like the high-risk strategy represent one way of living with the uncertainties of disease. It is argued that thinking more broadly about the nature of disease should lead policymakers to re-evaluate the purpose of disease control and their approaches to it. [ABSTRACT FROM AUTHOR]

Simple Summary: Bovine leukemia virus (BLV) caused a severe cattle neoplastic disease called enzootic bovine leukosis (EBL). EBL causes significant economic losses in farming by reducing milk production, reproductive performance, and fertility, and through cattle culling or death. The BLV proviral load (PVL) represents the quantity of BLV genome that has integrated into the host's genome in BLV-infected cells. It has been reported that PVLs differ according to the genetic background of the host, and some studies of BLV-associated host factors have reported on polymorphisms within the bovine major histocompatibility complex (MHC), namely bovine MHC is bovine leukocyte antigen (BoLA-DRB3). However, there is a great diversity in the PVLs associated with carrying various combinations of these alleles, especially for heterozygous alleles. Therefore, this research investigated whether heterogeneity in BoLA-DRB3 allele combinations would affect PVLs during BLV infections in different ages and breeds of cattle in Japan. This is the first report where the association between heterozygous allelic combinations and BLV PVLs phenotypes (HPLs, LPLs) was analyzed. Our findings augment current understanding about the immunological role played by BoLA heterozygosity in BLV-associated PVLs and biocontrol in BLV infections. Enzootic bovine leukosis is a lethal neoplastic disease caused by bovine leukemia virus (BLV), belongs to family Retroviridae. The BLV proviral load (PVL) represents the quantity of BLV genome that has integrated into the host's genome in BLV-infected cells. Bovine leukocyte antigen (BoLA) class II allelic polymorphisms are associated with PVLs in BLV-infected cattle. We sought to identify relationships between BoLA-DRB3 allelic heterozygosity and BLV PVLs among different cattle breeds. Blood samples from 598 BLV-infected cattle were quantified to determine their PVLs by real-time polymerase chain reaction. The results were confirmed by a BLV-enzyme-linked immunosorbent assay. Restriction fragment length polymorphism-polymerase chain reaction identified 22 BoLA-DRB3 alleles. Multivariate negative binomial regression modeling was used to test for associations between BLV PVLs and BoLA-DRB3 alleles. BoLA-DRB3.2*3, *7, *8, *11, *22, *24, and *28 alleles were significantly associated with low PVLs. BoLA-DRB3.2*10 was significantly associated with high PVLs. Some heterozygous allele combinations were associated with low PVLs (*3/*28, *7/*8, *8/*11, *10/*11, and *11/*16); others were associated with high PVLs (*1/*41, *10/*16, *10/*41, *16/*27, and *22/*27). Interestingly, the BoLA-DRB3.2*11 heterozygous allele was always strongly and independently associated with low PVLs. This is the first reported evidence of an association between heterozygous allelic combinations and BLV PVLs. [ABSTRACT FROM AUTHOR]