UK Pig Research Articles

Genetic diversity of porcine group A rotavirus strains in the UK

Rotavirus is endemic in pig farms where it causes a loss in production. This study is the first to characterise porcine rotavirus circulating in UK pigs. Samples from diarrheic pigs with rotavirus enteritis obtained between 2010 and 2012 were genotyped in order to determine the diversity of group A rotavirus (GARV) in UK pigs. A wide range of rotavirus genotypes were identified in UK pigs: six G types (VP7); G2, G3, G4, G5, G9 and G11 and six P types (VP4); P[6], P[7], P[8], P[13], P[23], and P[32]. With the exception of a single P[8] isolate, there was less than 95% nucleotide identity between sequences from this study and any available rotavirus sequences.The G9 and P[6] genotypes are capable of infecting both humans and pigs, but showed no species cross-over within the UK as they were shown to be genetically distinct, which suggested zoonotic transmission is rare within the UK. We identified the P[8] genotype in one isolate, this genotype is almost exclusively found in humans. The P[8] was linked to a human Irish rotavirus isolate in the same year. The discovery of human genotype P[8] rotavirus in a UK pig confirms this common human genotype can infect pigs and also highlights the necessity of surveillance of porcine rotavirus genotypes to safeguard human as well as porcine health.

Sequence analysis of a CTX-M-1 IncI1 plasmid found in Salmonella 4,5,12:i:-, Escherichia coli and Klebsiella pneumoniae on a UK pig farm.

In 2009, CTX-M Enterobacteriaceae and Salmonella isolates were recovered from a UK pig farm, prompting studies into the dissemination of the resistance and to establish any relationships between the isolates. PFGE was used to elucidate clonal relationships between isolates whilst plasmid profiling, restriction analysis, sequencing and PCR were used to characterize the CTX-M-harbouring plasmids. Escherichia coli, Klebsiella pneumoniae and Salmonella 4,5,12:i:- and Bovismorbificans resistant to cefotaxime (n = 65) were recovered and 63 were shown by PCR to harbour a group 1 CTX-M gene. The harbouring hosts were diverse, but the group 1 CTX-M plasmids were common. Three sequenced CTX-M plasmids from E. coli, K. pneumoniae and Salmonella enterica serotype 4,5,12:i:- were identical except for seven mutations and highly similar to IncI1 plasmid ColIb-P9. Two antimicrobial resistance regions were identified: one inserted upstream of yacABC harbouring ISCR2 transposases, sul2 and floR; and the other inserted within shfB of the pilV shufflon harbouring the ISEcp1 transposase followed by blaCTX-M-1. These data suggest that an ST108 IncI1 plasmid encoding a blaCTX-M-1 gene had disseminated across multiple genera on this farm, an example of horizontal gene transfer of the blaCTX-M-1 gene.

Opportunist dealing in the UK pig meat supply chain: Trader mentalities and alternatives

The scandal surrounding the presence of horsemeat in UK supermarket meat products has focused public attention on the problems of complex, fragmented food supply chains. Through a study of the UK's pig meat supply chain, this paper proposes a new framing of the problem in terms of opportunistic dealing adopted by the supermarkets in vertically disintegrated supply chains, where all actors attempt to pass the risks and costs onto somebody else. This outcome is the result of cultural practices and competences in buyer-led supermarket organizations where strong supermarket chains have the power to capture processor and producer margins. One consequence is that mass-market meat production and processing is close to unviable, as evidenced here by the analysis of the VION Food Group. However, there are mainstream alternatives to the retail-led dysfunctional supply chain. This paper presents an alternative integrated supply chain model using the case of Morrisons, the UK's fourth largest supermarket chain. If fragmented supply chains are not inevitable, the important issue explored in the conclusion is how the inadequacies of government policy, which understands the problem of the sector but is stuck with a competition-based mindset, obstruct the creation of a more sustainable supply chain.

Effectiveness of Simulated Interventions in Reducing the Estimated Prevalence of Salmonella in UK Pig Herds

Salmonella spp are a major foodborne zoonotic cause of human illness. Consumption of pork products is believed to be a major source of human salmonellosis and Salmonella control throughout the food-chain is recommended. A number of on-farm interventions have been proposed, and some have been implemented in order to try to achieve Salmonella control. In this study we utilize previously developed models describing Salmonella dynamics to investigate the potential effects of a range of these on-farm interventions. As the models indicated that the number of bacteria shed in the faeces of an infectious animal was a key factor, interventions applied within a high-shedding scenario were also analysed. From simulation of the model, the probability of infection after Salmonella exposure was found to be a key driver of Salmonella transmission. The model also highlighted that minimising physiological stress can have a large effect but only when shedding levels are not excessive. When shedding was high, weekly cleaning and disinfection was not effective in Salmonella control. However it is possible that cleaning may have an effect if conducted more often. Furthermore, separating infectious animals, shedding bacteria at a high rate, from the rest of the population was found to be able to minimise the spread of Salmonella.

Effects of low protein diets on lean genotype pigs – growth, feed/ N-intake and fat indicators

The EU nitrate directive and the increasing cost of protein sources are leading farmers to reduce the nitrogen content in livestock feed. UK pig production often employs high protein ration to ensure high growth rate and low fat deposition. The aim was to compare the performances of pigs of a lean genotype fed with a conventional (C) or 2 low protein (LP) diets, lysine supplemented (LP1) or not (LP2). 64 animals on each diet were reared from 40 to 115 kg and fed ad-libitum. Liveweights (LW) and feed intake (FI) were recorded and after slaughter backfat (P2 site) thickness was measured and samples of longissimus muscle were analysed for total fatty acids. Pen-based data were analysed examining diet and batch as main factors. There were no significant diet effects on FI. Pigs on LP2 had a lower average daily weight gain (ADG) and higher feed conversion ratio (FCR) than C or LP1 from 60 kg onwards. Between diet strategies there were no significant differences in backfat thickness, but body fat deposition was higher in the LP2 group, followed by the LP1, and C the lowest. Results confirm that the LP1 strategy allows growth performance similar to the C diet but with 11% higher intramuscular fat (IMF). Pigs on LP2 diet show an increased body fat and IMF, although subcutaneous fat thickness was little affected. LP1 results indicate that reduced nitrogen intake (C vs. LP1 by 11 to 15%) can be achieved without compromising the growth performance, however feed conversion is significantly poorer (−6%) compared to the C diet probably due to amino acids (AA) deficiencies.

BPEX Pig Health Scheme: a useful monitoring system for respiratory disease control in pig farms?

BackgroundRespiratory diseases account for significant economic losses to the UK pig industry. Lesions indicative of respiratory disease in pig lungs at slaughter e.g. pneumonia and pleuritis are frequently recorded to assess herd health or provide data for epidemiological studies. The BPEX Pig Health Scheme (BPHS) is a monitoring system, which informs producers of gross lesions in their pigs' carcasses at slaughter, enabling farm-level decisions to be made. The aim of the study was to assess whether information provided by the BPHS regarding respiratory lesions was associated with respiratory pathogens in the farm, farm management practices and each other.ResultsBPHS reports were obtained from a subset of 70 pig farms involved in a cross-sectional study conducted in 2008-09 investigating the epidemiology of post-weaning multi-systemic wasting syndrome. The reports were combined with data regarding the presence/absence of several pathogens in the herd and potential farm-level risk factors for respiratory disease. Principal component analysis (PCA) performed on BPHS reports generated three principal components, explaining 71% of the total variance. Enzootic pneumonia score, severe pleurisy and acute pleuropneumonia had the highest loadings for the principal component which explained the largest percentage of the total variance (35%) (BPHS component 1), it was thought that this component identifies farms with acute disease. Using the factor loadings a score for each farm for BPHS component 1 was obtained. As farms' score for BPHS component 1 increased, average carcass weight at slaughter decreased. In addition, farms positive for H1N2 and porcine reproductive and respiratory disease virus (PRRSV) were more likely to have higher levels of severe and mild pleurisy reported by the BPHS, respectively.ConclusionsThe study found statistical associations between levels of pleurisy recorded by BPHS at slaughter and the presence H1N2 and PRRSV in the herd. There is also some evidence that farms which submit pigs with these lesions may have reduced productivity. However, more research is needed to fully validate the scheme.

Welfare science into practice: a successful case example of working with industry

AbstractClose collaboration between science and industry is essential for the formulation of evidence-based welfare policies. However, there is a need to recognise and manage potential challenges that may arise during collaborative projects. An applied animal welfare science project evaluating the inclusion of welfare outcome measures into UK pig farm assurance, with a view to industry implementation, is used as a case example to illustrate potential challenges. This project encountered difficulties associated with differences in understanding and expectations, discussion of controversial welfare issues, challenges to personal values and conflict between academic and industry outcomes. With the assistance of an independent review conducted during the project, potential solutions were developed and successfully implemented. It is proposed that similar science-industry partnerships should allow sufficient time for dialogue, distinguish between experimental and applied science, ensure sufficient involvement from interested parties and use facilitation techniques to develop consensus.

Porcine respiratory disease complex Part 5: Primary bacterial disease

In this fifth article on the PRDC, attention is turned to the role of primary bacterial infection. The two most important primary and respiratory bacteria –Actinobacillus pleuropneumoniae and Haemophilus parasuis–are described in detail both as single disease causing organisms and in their role within the complicated disease picture so common on UK pig farms in the last two decades.

Application of a bacteriophage cocktail to reduce Salmonella Typhimurium U288 contamination on pig skin

Multidrug-resistant Salmonella Typhimurium U288 is a significant pathogen of pigs, accounting for over half of all outbreaks on UK pig production premises. The potential of this serovar, and other salmonellae, to enter the food chain during the slaughtering process requires that efforts be made to reduce the prevalence of these bacteria at both the pre- and post-harvest stages of production. A bacteriophage cocktail (PC1) capable of lysing various Salmonella enterica serovars was designed using the broad host-range phage Felix 01, and three phages isolated from sewage. PC1 applied to pig skin experimentally-contaminated with U288 achieved significant reductions (P<0.05) in Salmonella counts when stored at 4 °C over 96 h. Reductions of >1 log₁₀ unit were observed when the ratio of phage applied was in excess of the bacterial concentration. The treatment was found to be effective at a multiplicity of infection (MOI) of 10 or above, with no significant reductions taking place when the MOI was less than 10. Under these conditions U288 counts of log₁₀ 4.1-4.3 CFU were reduced to undetectable levels following the application of PC1 to pig skin (>99% reduction). These data suggest phage cocktails could be employed post-slaughter as a means to reduce Salmonella contamination of pig carcasses.

A pilot investigation of Farm Assurance assessors’ attitude to farm animal welfare as a confounding factor to training in pig welfare outcome measures

AbstractThe effect of Farm Assurance (FA) assessors’ attitude to farm animal welfare on the inter-observer reliability of some welfare outcome measures achieved following training was investigated as part of a larger project examining the feasibility and benefits of the incorporation of some on-farm welfare outcome assessments into UK Pig Farm Assurance Schemes. A total of thirty-one FA assessors were trained in three training sessions to assess the following welfare outcome measures: body lesions, tail lesions, severe tail lesions, lameness and pigs requiring hospitalisation. Assessment of photographs, live observations of individual pigs and pens of pigs were used to generate inter-observer reliability data. A previously validated farm animal welfare questionnaire was used to assess the FA assessors’ attitudes to farm animal welfare. Principal Component Analysis of FA assessor scores for this questionnaire resulted in two major components, with component 1 termed ‘pigs have mental welfare’ and component 2 termed ‘people-centric, pigs as profit’. FA assessors demonstrated a range in attitudes to farm animal welfare and, when assessing the same pigs, recorded a range in prevalence of welfare outcome measures and degree of agreement with a gold standard following training. There were only seven out of a possible 98 significant correlations between the FA assessor scores for components 1 and 2 and their recorded prevalence of welfare measures and levels of agreement with a gold standard. In particular, FA assessors’ scores for component 1 were significantly positively correlated with the recorded prevalence for pigs requiring hospitalisation in two of the three training sessions although there was no effect on the agreement with a gold standard for this measure. These results indicate that training in welfare outcomes, defined by a standard protocol, is relatively unconfounded by observer attitudes to farm animal welfare. To obtain better levels of agreement between assessors, and therefore more reliable data, it is recommended that FA schemes concentrate their resources on providing good quality training in a well-defined protocol and reliability testing and that they do not need to attempt to account for the attitudes of the FA assessors to farm animal welfare.

Inter-observer reliability testing of pig welfare outcome measures proposed for inclusion within farm assurance schemes

Consistency of assessment is essential to the farm assurance process. This study evaluated the inter-observer reliability of 31 farm assurance assessors, six veterinarians and four researchers for five pig welfare outcome measures proposed for inclusion into the UK pig farm assurance schemes. These were (1) tail lesions, (2) body lesions, (3) lameness, (4) pigs requiring hospitalisation and (5) oral behaviour. The following inter-observer reliability testing methods against a gold standard Trainer were used: a comparison of farm prevalence and the numbers of affected pigs in each pen identified by observers, Cohen's kappa (κ), Kendall's W, proportional agreement, sensitivity, and specificity. All measures achieved potentially high levels of inter-observer reliability and it was concluded that none should be excluded from farm assurance at this stage. However, across all the measures, 45% of observers did not record an overall farm prevalence 'close' to that of the gold standard Trainer. With the level of training and testing that took place in this study there would be a danger of significant bias occurring in a national assessment scheme. The data collected enabled some comparison of the methods used to assess inter-observer reliability. It is suggested that when the aim is to achieve agreement between observers on the overall farm prevalence the inter-observer reliability testing should focus on the closeness of the overall farm prevalence recorded by observers, but that other types of analysis may be helpful during training.

Influenza2010: Zoonotic Influenza and Human Health: Part-B

The epidemiology of influenza virus in pig populations is unique, with different lineages of viruses identified based on spatio-temporal characteristics. Co-circulation of viruses leads to the generation of new strains through genetic reassortment and the consequences of independent evolution of influenza viruses in pigs gives rise to considerable genetic diversity at continental level. Whilst the pig has been postulated as a mixing vessel for the generation of new influenza viruses, more recent work would indicate that this is a complex dynamic. However, the emergence of pandemic (H1N1) 2009 virus (pH1N1) in humans is postulated to have derived from pigs. Limited surveillance studies in pigs have revealed changes in virus diversity through the occurrence of novel reassortant viruses containing genes from both avian, human and swine sources. The correlates for successful cross-species transmission are multi-factoral and include host, virus and the impact of prior immunity to endemic swine influenza viruses. The pH1N1 virus has spread from humans to pigs in numerous countries. The future dynamics of infection with this virus in pig populations will be complex and impacted by the immune status and characteristics of viruses circulating in pig populations in different regions. Detailed studies of the transmission, infection dynamics and immunopathology of pH1N1 virus in pigs and it’s comparability to human infection will be reported. These studies have also been extended to understanding the epidemiological and evolutionary characteristics of pH1N1 virus in pigs and the associated occupational risks. Preliminary data indicates that the virus has a high capability to transmit within and between pigs and has become established in UK pig populations. The impact of prior immunity to endemic swine strains will, we predict, impact the future epidemiology of influenza virus in pig populations around the globe. Furthermore, clusters of infection within farm networks have been detected through detailed epidemiological investigations, which have also revealed potentially higher seroprevalence to pandemic virus amongst pig veterinarians compared to cohorts of ‘non-exposed’ humans. The implications of these results will be discussed. Events subsequent to the emergence of the pandemic virus have provided further focus and interest in pigs relating to the evolution and ecology of influenza viruses relevant to veterinary public health.

The UK pig cycle: a spectral analysis

PurposeThe purpose of this paper is to identify cyclical patterns in the prices and production of UK pigmeat, 1989‐2008.Design/methodology/approachThe approach takes the form of spectral analysis.FindingsResults show evidence of both annual and seasonal cycles, but there is little evidence of a three‐to‐four‐year cycle. The likely cause of the latter's absence is increasing imports and a changing market structure.Practical implicationsConventional wisdom is that the traditional pig cycle is of three‐to‐four years' duration and the UK's pig policy is based partly on its existence and that the design and implementation of UK pig policy are predicated on the basis of a traditional cycle is misplaced.Originality/valueNo previous or recent empirical investigation of the UK pig cycle exists, perhaps because its existence is considered to be axiomatic.

Interdependence of welfare outcome measures and potential confounding factors on finishing pig farms

The factors influencing the observed prevalence of some welfare outcome measures were investigated as part of a larger project examining the feasibility and benefits of incorporating on-farm welfare outcome assessments into UK Pig Farm Assurance Schemes. All finishing pigs (>40 kg) on six farms that had pens containing 25 pigs or less were assessed for dirtiness, body lesions, tail lesions, bursitis, lameness, oral behaviour and pigs requiring hospitalisation. The overall small number of significant correlations between the measures across all farms (29 out of a possible 120) and the lack of a significant correlation between any pair of measures on all six or even five farms suggests that no measure can be reliably replaced by another. On the three farms with the highest farm prevalence of dirtiness there were significant negative correlations between pen prevalences of dirtiness and recorded tail and/or body lesions ( p < 0.02). The prevalence of pigs requiring hospitalisation was positively correlated with lameness on four farms ( p < 0.001) and tail lesions on three farms ( p < 0.005). Using a univariate general linear model the time of observation was only found to correlate with one measure, the dirtiness of the pigs ( p = 0.004), with the prevalence of dirtiness in pens on the three ‘dirtiest’ farms increasing as the day progressed. There was no effect of the stocking density, group size, time since feeding and time since straw provision on the prevalence of any of the outcome measures. It is recommended that to prevent bias in the recording of tail and body lesions farm assurance assessments are conducted on pigs with a prevalence for dirtiness of less than 17%. Lower prevalences of dirtiness are more likely to occur on some farms first thing in the morning.

The effect of sampling strategy on the estimated prevalence of welfare outcome measures on finishing pig farms

The effect of sampling strategy on the estimates of prevalence of some welfare outcome measures was investigated as part of a larger project examining the feasibility and benefits of incorporating some on-farm welfare outcome assessments into UK Pig Farm Assurance Schemes. All finishing pigs (>40 kg) on 6 farms that had pens of 25 pigs or less were assessed for dirtiness, body lesions, tail lesions, bursae, lameness, oral behaviour and pigs requiring hospitalisation. A statistical sampling methodology was applied to the data to generate 10,000 random samples for each measure, on each farm and for every possible number of sampled pens on that farm. The 95% confidence interval range, the proportion of samples outside a ‘tolerance’ range and the proportion of samples that would wrongly classify the farm with respect to a ‘threshold’ were calculated for each measure on each farm for every possible sample size. It was found that even large sample sizes were unable to accurately reflect the whole farm for measures with very low prevalences (lameness and pigs requiring hospitalisation). For the other measures, as the number of pens sampled increased, the confidence interval range and the proportion of samples outside the ‘tolerance’ range reduced. The differing inter-pen variation in prevalence on a farm gave rise to differences in accuracy of prevalence estimates between the farms. Those farms with a true farm prevalence close to the threshold required more pens to be sampled to achieve the same level of accuracy of classification as other farms with similar confidence intervals but a more extreme prevalence. The effect of sampling on the estimate of prevalence should be considered when an accurate prevalence of the whole population is required.

A survey of fluoroquinolone resistance inEscherichia coliand thermophilicCampylobacterspp. on poultry and pig farms in Great Britain

To estimate the proportions of farms on which broilers, turkeys and pigs were shedding fluoroquinolone (FQ)-resistant Escherichia coli or Campylobacter spp. near to slaughter. Freshly voided faeces were collected on 89 poultry and 108 pig farms and cultured with media containing 1.0 mg l(-1) ciprofloxacin. Studies demonstrated the specificity of this sensitive method, and both poultry and pig sampling yielded FQ-resistant E. coli on 60% of farms. FQ-resistant Campylobacter spp. were found on around 22% of poultry and 75% of pig farms. The majority of resistant isolates of Campylobacter (89%) and E. coli (96%) tested had minimum inhibitory concentrations for ciprofloxacin of > or =8 mg l(-1). The proportion of resistant E. coli and Campylobacter organisms within samples varied widely. FQ resistance is commonly present among two enteric bacterial genera prevalent on pig and poultry farms, although the low proportion of resistant organisms in many cases requires a sensitive detection technique. FQ-resistant bacteria with zoonotic potential appear to be present on a high proportion of UK pig and poultry farms. The risk this poses to consumers relative to other causes of FQ-resistant human infections remains to be clarified.

RETHINKING POLICY OPTIONS FOR INDUSTRY: APPROPRIATENESS IN POLICIES FOR INDUSTRY AND UK FARMING AND FOOD

This article assesses the appropriateness of lean supply and partnership relationship management policies as a means of invigorating industry, using the example of the UK pig and beef industry. The analysis assesses the extent to which it is operationally feasible, and with what commercial consequences, in UK pig and beef supply chains and markets. The analysis demonstrates that the lean and partnering approach is not always operationally feasible. Furthermore, when it is operationally feasible dominant players only – such as multiple retailers – appear to benefit commercially from its adoption. Given this, alternative policy options may be required in the future for such reinvigoration of industry. A framework to guide policy selection is provided.

Pig in the middle: farmers and the delivery of farm animal welfare standards

Purpose – The purpose of this paper is to examine the attitude of UK pig farmers to the delivery of improved farm animal welfare standards and to investigate how they contribute to this objective through their membership of a range of different farm assurance schemes.Design/methodology/approach – The analysis focuses on three main groups of pig farmers: farmers engaged in conventional farm assurance schemes; farmers participating in specific animal welfare schemes; and certified organic farmers. In total 54 farmers were interviewed about their participation in farm assurance schemes and their attitudes to animal welfare and towards the retailers and consumers they supply. Each answer was analysed individually and a list of themes identified for each type of scheme. These were compared and synthesised in an overall analysis.Findings – The analysis identified how differently or similarly the different groups of farmers viewed the issues related to animal welfare. The findings revealed that, while farmers sh...

Stairways to heaven or treadmills to oblivion?

PurposeThis paper aims to assess the findings of a research project that investigates the scope for lean strategies to be adopted in beef, lamb and pig supply chains.Design/methodology/approachThe paper reports on action research carried out in three red meat supply chains. The methodology is inductive and qualitative, using a multi‐case, multi‐site approach. Each of the supply chains was analysed from farm gate to consumer, interviewing multiple participants at each stage of the supply chain.FindingsThe analysis demonstrates that, although a lean approach has been introduced in the pig supply chain, it is much more problematic in beef and lamb supply chains. Furthermore, the majority of participants in the UK pig supply chain – the first to adopt lean strategies – have not received the commercial improvement (the “stairway to heaven” of higher returns) that was anticipated. On the contrary, the majority of participants in this supply chain are experiencing a strategic “treadmill to oblivion” of continuous lean operational efficiency, but with low commercial returns.Research limitations/implicationsThe research is based upon three red meat supply chains – beef, lamb and pig. It would be beneficial if further in‐depth studies could be undertaken in other agri‐food supply chains to further validate the findings.Practical implicationsIf government agencies and/or multiple retailers develop lean strategies in UK beef and lamb supply chains, it is not at all clear that this will benefit all parties in these chains. This raises important questions about the efficacy and appropriateness of lean strategies in supply chains that do not have the same demand, supply and power and leverage characteristics as those in which lean principles were first developed.Originality/valueThis paper should be of value to researchers in this area and to managers responsible for strategy formation in UK agri‐food supply chains.

Cutting across nature? The history of artificial insemination in pigs in the United Kingdom

Artificial insemination (AI) has a considerable cultural significance in addition to its economic and technical impact. This study is the first to examine the history of its application to pigs, and uses evidence provided directly by both the scientists involved in its development, and some of the farmers who were among the first to use it, in addition to archival and published sources, to show how the scientific studies of the 1950s evolved into a widely available commercial product by the 1980s. It describes the initial scientific work and quantifies the extent to which the technique was used at various points in time, showing that by 1990 nearly one half of UK pig herds were using AI for more than 25% of all services. It traces changes in the techniques employed and argues that these were the result of a multi-dimensional process of contemporaneous change. The various dimensions are identified firstly as authorities, meaning the people and organisations controlling the perception, administration, control, and so on, of the technique; secondly the discourses employed by the authorities; and thirdly the media by which the discourses were disseminated. Finally, it is suggested that this approach might be used more widely to examine the construction of other technologies.