Genome-wide association study of endo-parasite phenotypes using imputed whole-genome sequence data in dairy and beef cattle.

BACKGROUND: Quantitative genetic studies suggest the existence of variation at the genome level that affects the ability of cattle to resist to parasitic diseases. The objective of the current study was to identify regions of the bovine genome that are associated with resistance to endo-parasites. METHODS: Individual cattle records were available for Fasciola hepatica-damaged liver from 18 abattoirs. Deregressed estimated breeding values (EBV) for F. hepatica-damaged liver were generated for genotyped animals with a record for F. hepatica-damaged liver and for genotyped sires with a least one progeny record for F. hepatica-damaged liver; 3702 animals were available. In addition, individual cow records for antibody response to F. hepatica on 6388 genotyped dairy cows, antibody response to Ostertagia ostertagi on 8334 genotyped dairy cows and antibody response to Neospora caninum on 4597 genotyped dairy cows were adjusted for non-genetic effects. Genotypes were imputed to whole-sequence; after edits, 14,190,141 single nucleotide polymorphisms (SNPs) and 16,603,644 SNPs were available for cattle with deregressed EBV for F. hepatica-damaged liver and cows with an antibody response to a parasitic disease, respectively. Association analyses were undertaken using linear regression on one SNP at a time, in which a genomic relationship matrix accounted for the relationships between animals. RESULTS: Genomic regions for F. hepatica-damaged liver were located on Bos taurus autosomes (BTA) 1, 8, 11, 16, 17 and 18; each region included at least one SNP with a p value lower than 10-6. Five SNPs were identified as significant (q value < 0.05) for antibody response to N. caninum and were located on BTA21 or 25. For antibody response to F. hepatica and O. ostertagi, six and nine quantitative trait loci (QTL) regions that included at least one SNP with a p value lower than 10-6 were identified, respectively. Gene set enrichment analysis revealed a significant association between functional annotations related to the olfactory system and QTL that were suggestively associated with endo-parasite phenotypes. CONCLUSIONS: A number of novel genomic regions were suggestively associated with endo-parasite phenotypes across the bovine genome and two genomic regions on BTA21 and 25 were associated with antibody response to N. caninum.

Associations between paratuberculosis ELISA results and test-day records of cows enrolled in the Irish Johne's Disease Control Program.

The effect of the Mycobacterium avium ssp. paratuberculosis (MAP) ELISA status on test-day milk performance of cows from Irish herds enrolled in the pilot national voluntary Johne's disease control program during 2013 to 2015 was estimated. A data set comprising 92,854 cows and 592,623 complete test-day records distributed across 1,700 herds was used in this study. The resulting ELISA outcome (negative, inconclusive, and positive) of each cow within each year of the program was used to allocate the cow into different scenarios representing the MAP status. At MAPscenario1, all cows testing ELISA nonnegative (i.e., inconclusive and positive) were assigned a MAP-positive status; at MAPscenario2 only cows testing ELISA-positive were assigned a MAP-positive status; at MAPscenario3 only cows testing ELISA nonnegative (inconclusive or positive) and gathered exclusively from herds where at least 2 further ELISA nonnegative (inconclusive or positive) cows were found were assigned a MAP-positive status; at MAPscenario4 only cows testing ELISA-positive that were gathered exclusively from herds where at least 2 further ELISA-positive cows were found were assigned a MAP-positive status. Milk outputs based on test-day records were standardized for fat and protein contents (SMY) and the effect of MAP ELISA status on the SMY was estimated by a linear mixed effects model structure. The SMY mean difference recorded at test day between cows with a MAP-positive status and those with a MAP-negative status within MAPscenario1 was estimated at -0.182 kg/test day; the mean difference was -0.297 kg/test day for MAPscenario2; for MAPscenario3 mean difference between MAP-positive status and MAP test-negative cows was -0.209 kg/test day, and for MAPscenario4, the difference was -0.326 kg/test day.

A survey of free-ranging deer in Ireland for serological evidence of exposure to bovine viral diarrhoea virus, bovine herpes virus-1, bluetongue virus and Schmallenberg virus.

BACKGROUND: Deer are an important wildlife species in both the Republic of Ireland and Northern Ireland having colonised most regions across the island of Ireland. In comparison to cattle and sheep which represent the main farmed ruminant species on the island, there is a lack of data concerning their exposure, as measured by the presence of antibodies, to important viral pathogens of ruminants. A study was therefore undertaken to investigate the seroprevalence of wild deer to four viruses, namely bovine viral diarrhoea virus (BVDV), bovine herpesvirus-1 (BoHV-1), Schmallenberg virus (SBV) and bluetongue virus (BTV). RESULTS: Two panels of sera were assembled; Panel 1 comprised 259 samples (202 collected in the Republic of Ireland and 57 in Northern Ireland) between 2013 and 2015, while Panel 2 comprised 131 samples collected in the Republic of Ireland between 2014 and 2015. Overall sika deer (Cervus nippon) were sampled most commonly (54.8%), followed by fallow deer (Dama dama) (35.3%), with red deer (Cervus elaphus) (4.3%) and hybrid species (0.3%) sampled less frequently, with the species not being recorded for the remaining 5.3% of deer sampled. Age was not recorded for 96 of the 390 deer sampled. 196 of the remainder were adults, while 68 and 30 were yearlings and calves, respectively. Using commercially available enzyme-linked immunosorbent assays, true prevalence and 95% confidence intervals were calculated as 9.9%, (6.8-13.0% CI), SBV; 1.5% (0.1-3.0% CI), BoHV-1; 0.0%, 0-1.7% CI), BVDV; and 0.0%, (0.01-0.10% CI), BTV. CONCLUSIONS: The results indicate a very low seroprevalence for both BVDV and BoHV-1 in the wild deer tested within the study and, are consistent with a very low prevalence in Ireland. While serological cross-reaction with cervid herpesviruses cannot be excluded, the results in both cases suggest that the presence of these viruses in deer is not a significant risk to their control and eradication from the cattle population. This is important given the ongoing programme to eradicate BVDV in Ireland and deliberations on a national eradication programme for BoHV-1. The SBV results show consistency with those reported from cattle and sheep on the island of Ireland, while the BTV results are consistent with this virus remaining exotic to Ireland. The results provide a baseline against which future surveys of either wild or farmed/captive deer populations can be compared.

Genetic diversity of ruminant Pestivirus strains collected in Northern Ireland between 1999 and 2011 and the role of live ruminant imports.

BACKGROUND: The genus pestivirus within the family Flaviviridae includes bovine viral diarrhoea virus (BVDV) types 1 and 2, border disease virus (BDV) and classical swine fever virus. The two recognised genotypes of BVDV are divided into subtypes based on phylogenetic analysis, namely a-p for BVDV-1 and a-c for BVDV-2. METHODS: Three studies were conducted to investigate the phylogenetic diversity of pestiviruses present in Northern Ireland. Firstly, pestiviruses in 152 serum samples that had previously tested positive for BVDV between 1999 and 2008 were genotyped with a RT-PCR assay. Secondly, the genetic heterogeneity of pestiviruses from 91 serum samples collected between 2008 and 2011 was investigated by phylogenetic analysis of a 288 base pair portion of the 5' untranslated region (UTR). Finally, blood samples from 839 bovine and 4,437 ovine animals imported in 2010 and 2011 were tested for pestiviral RNA. Analysis of animal movement data alongside the phylogenetic analysis of the strains was carried out to identify any links between isolates and animal movement. RESULTS: No BVDV-2 strains were detected. All of the 152 samples in the first study were genotyped as BVDV-1. Phylogenetic analysis indicated that the predominant subtype circulating was BVDV-1a (86 samples out of 91). The remaining five samples clustered close to reference strains in subtype BVDV-1b. Out of the imported animals, 18 bovine samples tested positive and 8 inconclusive (Ct ≥36), while all ovine samples were negative. Eight sequences were obtained and were defined as BVDV-1b. Analysis of movement data between herds failed to find links between herds where BVDV-1b was detected. CONCLUSION: Given that only BVDV-1a was detected in samples collected between 1968 and 1999, this study suggests that at least one new subtype has been introduced to Northern Ireland between 1999 and 2011 and highlights the potential for importation of cattle to introduce new strains.

Aspects of bovine herpesvirus 1 and bovine viral diarrhoea virus herd-level seroprevalence and vaccination in dairy and beef herds in Northern Ireland.

BACKGROUND: Infections with bovine herpesvirus 1 (BoHV-1) and bovine viral diarrhoea (BVD) virus cause diseases of cattle with a worldwide distribution. The primary objective of the present study was to describe aspects of herd-level BoHV-1 and BVDV seroprevalence (based on testing of pooled sera) and control on farms in Northern Ireland, including vaccine usage. An indirect antibody ELISA test (SVANOVA, Biotech AB, Uppsala, Sweden) was applied to serum pools which were constructed from serum samples taken for a cross-sectional study of a convenience sample of 500 Northern Irish dairy and beef cow herds in 2010, for which vaccination status was determined by telephone survey. The herd-level seroprevalence of BoHV-1 and BVDV in Northern Ireland was estimated in non-vaccinating herds and associations between possible risk factors (herd type and herd size (quartiles)) and herd-level prevalence were determined using chi-squared analysis. RESULTS: The herd-level seroprevalence (of BoHV-1 and BVDV) in non-vaccinating herds was 77.3% (95% CI: 73.6-80.9%) and 98.4% (95% CI: 97.3-99.5%) respectively in the cross-sectional study. A significant difference existed in BoHV-1 herd-level seroprevalence between dairy and beef herds (74.7% vs 86.5% respectively; p < 0.02) though not for BVDV seroprevalence (98.5% vs 98.3% respectively; p > 0.91). A significant association was found between herd size (quartiles) and herd-level classification for BoHV-1 herd-level seroprevalence based on cut-off percentage positivity (COPP) (p < 0.01) while no such association was found for BVDV (p = 0.22). 15.5% and 23.8% of farmers used BoHV-1 and BVDV vaccines, respectively. BoHV-1 vaccine was used in 30% of dairy herds and in 11% of beef herds, while BVDV vaccine was used in 46% and 16% of dairy and beef herds, respectively. CONCLUSIONS: The results from this study indicate that the true herd-level seroprevalences to bovine herpesvirus 1 and bovine virus diarrhoea virus in non-vaccinating herds in Northern Northern Ireland are 77.3% (95% CI: 73.6-80.9%) and 98.4% (95% CI: 97.3-99.5%), respectively. The present study will assist in guiding regional policy development and establish a baseline against which the progress of current and future control and eradication programmes can be measured.

A multi-methods, multi-actor exploration of the benefits and barriers to milk recording on Irish farms using the COM-B model.

Milk recording is a critical tool in dairy farming, providing individual cow information. When used effectively, this data contributes to on-farm productivity, herd health management decisions and supports prudent veterinary prescribing of antimicrobials. Although an industry and government priority, uptake has been relatively slow in Ireland. This multi-methods, three-part study aimed to gain a comprehensive understanding of the benefits to farm performance, and factors driving uptake of milk recording on Irish dairy farms. It involved an economic analysis of N=516 farms from 2008-2019, a workshop with N=26 stakeholders and an online survey of N=197 non-milk-recording farmers. Quantitative and qualitative data were analysed using econometric models and thematic analysis respectively. Results were synthesised using the COM-B model to gain a deeper understanding of what drives the target behaviour. The study revealed that agricultural education, farm location, farm specialisation in dairy and membership of a farmer discussion group were the main factors influencing uptake of milk recording. Milk recording was associated with a €39.04/cow increase in gross margin, a 177.58 litres/cow increase in milk yield and a reduction of 13,450 cells/ml in bulk milk tank somatic cell count readings. Infrastructural constraints, cost, lack of benefits and workload were the most reported perceived barriers to milk recording by farmers. The Behaviour Change Wheel illustrates how to utilise findings and systematically develop future interventions to increase milk recording uptake. This study highlights the importance of a multi-methods approach to agricultural technology adoption and the need for evidence-based methodology when developing behaviour change interventions.

Bovine herpes virus-1 (BoHV-1) in cattle-a review with emphasis on reproductive impacts and the emergence of infection in Ireland and the United Kingdom.

Bovine reproductive disease attributable to bovine herpes virus-1 (BoHV-1) was first described in Germany in the 19th century, being recognised primarily as the cause of infectious vulvovaginitis and balanoposthitis until the mid-1950s when a more virulent strain of the virus (BoHV-1.1) associated with respiratory disease (infectious bovine rhinotracheitis; IBR) emerged in the western United States. Subsequently, IBR emerged as a clinical condition in Europe, from the 1970s onward. While the ability of BoHV-1 to produce respiratory disease is now well recognised, the potential negative outcomes of infection on fertility and reproduction are less frequently considered. This review was conducted against the background of the prioritization of disease caused by BoHV-1 as one of several diseases to be addressed by Animal Health Ireland, with the twin goals of summarizing the published literature on the potential outcomes of infection at different stages of breeding and pregnancy, and of describing the emergence of BoHV-1 as a significant pathogen in Ireland and the UK.

The Irish cattle population structured by enterprise type: overview, trade & trends.

BACKGROUND: The cattle sector is the most important economic production unit of the Irish farming and agri-food sector. Despite its relevance, there has been limited quantitative information about the structure of differing cattle production types and of the connections between them. This paper addresses this gap by providing, for the first time, an overview of the Irish cattle population structured by enterprise type. METHODS & RESULTS: We collected data from the cattle register for the period 2015 to 2019 and assigned registered herds to one of 18 different herd types using a recently published herd type classification approach. This allows, for the first time, to exploring changes in enterprise types and subtypes over time, and describing the movements between these subtypes and from these subtypes to slaughter. CONCLUSIONS: The overview and associated classification presented in this study will form the basis for a number of future comparative studies, including cross-sectoral assessments of profitability, estimation of the extent of animal health losses on Irish cattle farms or structural analysis of Greenhouse Gas (GHG) emissions across production systems.

Risk factors for detection of bovine viral diarrhoea virus in low-risk herds during the latter stages of Ireland's eradication programme.

BACKGROUND: A national programme to eradicate bovine viral diarrhoea (BVD) has been in place in Ireland since 2013. To inform decision making in the end stages of eradication, and support the development of post-eradication surveillance strategies, an understanding of risks of infection in a low prevalence system is required. METHODS: A case-control study design was implemented. The study population comprised bovine herds that had calves born and tested negative for BVD virus (BVDV) every year from 2013 to 2019 (n = 46,219 herds). We defined cases as herds which had one or more test positive calves for the first time in 2019 (n = 204). Controls (n = 816) were randomly sampled from the herds which remained test negative in 2019. The effects of herd size, management system, inward movements, including those of potential trojan dams (pregnant animals brought into the herd that could potentially be carrying infected calves in utero), and proximity to herds testing positive in the preceding year, were investigated. Network analysis approaches were used to generate variables measuring connections with test positive herds through inward cattle movements. A generalised linear mixed model, including a county-level random effect, was used to explore these risk factors. RESULTS: Our final model retained ln (herd size) (Odds Ratio (95% CI): 1.72 (1.40, 2.12)), distance from test positive herds (0.54 (0.44, 0.66) for each extra land-parcel boundary crossed to reach the closest herd which tested positive the preceding year), and ln (potential trojan dams + 1) (1.29 (1.05, 1.60)). The same variables were retained in the model where herds with confirmed transient infections only (n = 25) were excluded. CONCLUSIONS: Our findings suggest that care with biosecurity at farm boundaries and visitors and equipment entering the farm, and avoidance or careful risk assessment of purchasing potentially pregnant animals, may help prevent introduction of BVDV to low-risk herds. At policy level, consideration of herd size, proximity to test positive herds and purchasing patterns of potentially pregnant cattle may help target surveillance measures towards the end of the eradication programme.

Combining expert knowledge and machine-learning to classify herd types in livestock systems.

A detailed understanding of herd types is needed for animal disease control and surveillance activities, to inform epidemiological study design and interpretation, and to guide effective policy decision-making. In this paper, we present a new approach to classify herd types in livestock systems by combining expert knowledge and a machine-learning algorithm called self-organising-maps (SOMs). This approach is applied to the cattle sector in Ireland, where a detailed understanding of herd types can assist with on-going discussions on control and surveillance for endemic cattle diseases. To our knowledge, this is the first time that the SOM algorithm has been used to differentiate livestock systems. In compliance with European Union (EU) requirements, relevant data in the Irish livestock register includes the birth, movements and disposal of each individual bovine, and also the sex and breed of each bovine and its dam. In total, 17 herd types were identified in Ireland using 9 variables. We provide a data-driven classification tree using decisions derived from the Irish livestock registration data. Because of the visual capabilities of the SOM algorithm, the interpretation of results is relatively straightforward and we believe our approach, with adaptation, can be used to classify herd type in any other livestock system.

A Herd Investigation Tool in Support of the Irish Bovine Viral Diarrhoea Eradication Programme.

Bovine viral diarrhoea (BVD) is an important endemic disease of cattle. In Ireland, an industry-led compulsory eradication programme began in January 2013. The main elements of this programme are the identification and elimination of persistently infected (PI) calves by testing all new-borns, the implementation of biosecurity to prevent re-introduction of disease and continuous surveillance. In 2016, a standardised framework was developed to investigate herds with positive results. This is delivered by trained private veterinary practitioners (PVP). The investigation's aims are 3-fold: firstly, to identify plausible sources of infection; secondly, to ensure that no virus-positive animals remain on farm by resolving the BVD status of all animals in the herd; and thirdly, agreeing up to three biosecurity measures with the herd owner to prevent the re-introduction of the virus. Each investigation follows a common approach comprising four steps based on information from the programme database and collected on-farm: firstly, identifying the time period when each virus-positive calf was exposed in utero (window of susceptibility, taken as 30-120 days of gestation); secondly, determining the location of the dam of each positive calf during this period; thirdly, to investigate potential sources of exposure, either within the herd or external to it; and finally, based on the findings, the PVP and herdowner agree to implement up to three biosecurity measures to minimise the risk of reintroduction. Between 2016 and 2020, 4,105 investigations were completed. The biosecurity recommendations issued more frequently related to the risks of introduction of virus associated with contact with neighbouring cattle at pasture, personnel (including the farmer), the purchase of cattle and vaccination. Although each investigation generates farm-specific outcomes and advice, the aggregated results also provide an insight into the most commonly identified transmission pathways for these herds which inform overall programme communications on biosecurity. The most widely identified plausible sources of infection over these years included retained BVD-positive animals, Trojan births, contact at boundaries and indirect contact through herd owner and other personnel in the absence of appropriate hygiene measures. While generated in the context of BVD herd investigations, the findings also provide an insight into biosecurity practises more generally on Irish farms.

A large-scale epidemiological model of BoHV-1 spread in the Irish cattle population to support decision-making in conformity with the European Animal Health Law.

We present a new modelling framework to address the evaluation of national control/surveillance programs planned in line with the European Animal Health Law (AHL) for livestock diseases. Our modelling framework is applied to the cattle sector in Ireland where there is need for policy support to design an optimal programme to achieve bovine herpesvirus type 1 (BoHV-1) free status under the AHL. In this contribution, we show how our framework establishes a regional model that is able to mechanistically reproduce the demography, management practices and transport patterns of an entire cattle population without being dependent on continuous livestock registry data. An innovative feature of our model is the inclusion of herd typing, thereby extending these beyond the categories of dairy, beef and mixed herds that are frequently considered in other regional modelling studies. This detailed representation of herd type-specific management facilitates comparative assessment of BoHV-1 eradication strategies targeting different production types with individual strategy protocols. Finally, we apply our model to support current discussions regarding the structure and implementation of a potential national BoHV-1 eradication programme in Ireland.

Stakeholder perceptions of non-regulatory bovine health issues in Ireland: past and future perspectives.

BACKGROUND: In recent years, there have been multiple (political, environmental, cultural) drivers of change in Irish agriculture, including the establishment of Animal Health Ireland (AHI) in 2009, to provide leadership of non-regulatory livestock health issues (diseases and conditions of livestock that are endemic in Ireland but which are not currently subject to international legislation). In this study, we describe the opinion of stakeholders (farmers, veterinary practitioners and agricultural industry professional service providers), elicited by means of a survey, on their perceptions of changes in selected non-regulatory bovine health issues over the last 10 years and priority issues relevant to non-regulatory bovine health to be tackled over the next 10 years. RESULTS: A total of 673 individuals participated in the online questionnaire. For the majority of the non-regulatory bovine health issues, most participants felt there had been improvements over the last 10 years. However, professional service providers were generally more conservative in their response to improvements on-farm compared to farmers. Several issues, particularly BVD and udder health/milk quality, were viewed more positively by all relevant respondents. There was reasonable agreement between responses from different respondent types and sectors regarding the top three priorities relevant to non-regulatory bovine animal health for the next 10 years in Ireland, which included antimicrobial resistance (highlighting measures to reduce both on-farm usage and resistance), anthelmintic resistance, greenhouse emissions and calf welfare. CONCLUSIONS: The results are encouraging, demonstrating a perception of improvement in a number of non-regulatory bovine health issues in Ireland over the last ten years. With respect to the next 10 years, stakeholders prioritised antimicrobial and anthelmintic resistance, greenhouse gas emissions and calf welfare, which aligns closely with broader societal concerns. This information is useful to AHI, particularly with respect to future priorities. However, these concerns are broad in scope and will require further considerations, including collaborations, between AHI and partnering organisations. Given that there were differences between farmers and professional service providers in responses, it is useful to consider how the aims and the benefits of future AHI programmes are framed and communicated to all stakeholders.

The impact of liver fluke infection on steers in Ireland: A meta-analytic approach.

Post-mortem liver inspection results together with production parameters are often used to estimate the impact of liver fluke infection on farm animal populations. However, post mortem liver inspection is an imperfect method of determining the liver fluke infection status of cattle. This work estimates the difference in mean lifetime weight gain at 819 days (ΔLWG819) between steers assigned liver fluke negative (LFN) and liver fluke positive (LFP) status at post-mortem meat inspection, quantifies the potential impact of imperfect sensitivity and specificity on these results and estimates the economic impact of these differences. The study population is 32,007 steers that never moved from their birth herd in the Republic of Ireland and were slaughtered in one of two Irish meat processors in 2014. Individual animal-level data are used to generate 46 county - processor level estimates of ΔLWG819. Standard errors and confidence intervals for these estimates are derived using bootstrapping. A meta-analytic approach is then used to obtain 3 overall estimates of the effect of liver fluke status on the ΔLWG819 in all the county - processor combinations, assuming post - mortem liver inspection Se = Sp = 1, 0.99 and 0.95. A random effects model is used and 95% prediction intervals (95% PI) are calculated. Assuming Se = Sp = 1 for post - mortem liver inspection, the random effects summary estimate of ΔLWG819 (ΔLWG819(RE)) is 36 kg (95% PI: -1, 73). There is a minor change in ΔLWG819(RE) (38 kg, 95% PI: -1, 77) when Se = Sp = 0.99 is assumed but this increases to 46 kg (95% PI: -2, 94) assuming Se = Sp = 0.95. The corresponding cost in euros of these differences between the LFN and LFP steers, assuming a price per kg of €3.90, are €77.01 (95% PI: -2.57, 156.37), €80.65 (95% PI: -3.43, 164.74) and €98.67 (95% PI: -5.15, 202.27) respectively. Our results demonstrate an association between liver fluke infection and reduced weight gain. We show that the effect of liver fluke infection on weight gain in cattle is underestimated due to misclassification resulting from imperfection in post mortem meat inspection. These findings will aid researchers, farmers and veterinary practitioners to make informed decisions on the control of liver fluke on farms.

Spatial and network characteristics of Irish cattle movements.

Our aim was to examine, for the first time, the spatial and network characteristics of cattle movements between herds in the Republic of Ireland (ROI), to inform policy and research of relevance to the surveillance and management of disease in Irish cattle. We analysed movements in 2016 as discrete herd to herd pairings (degree), herd to herd pairings by date of move (contacts) and herd to herd pairings by date and individual animal (transfers), and looked at each of these as movements out of a herd (out degree, out contacts, out transfers) and into a herd (in degree, in contacts, in transfers). We found that the frequency distributions, by herd, of these six move types were all heavily right skewed but in the case of the 'out' data types more closely followed a log-normal than the scale free distribution often reported for livestock movement data. For each distinct herd to herd contact in a given direction, over 90 % occurred only once, whereas the maximum number of occurrences was 62. Herd-level Spearman rank correlations between inward moves (represented as in degree, in contacts, in transfers) and outward moves (out degree, out contacts, out transfers) were weak or even negative whereas correlations between different measures of outward moves or inward moves (e.g. out degree vs. out contacts, in transfers vs. in degree) were stronger. Correlations between these variables and the network measure betweenness varied between r = 0.513 and r = 0.587. Some herds took part in a relatively large number of movements whilst also retaining their cattle for long periods (> 100 days) between moves. In and out degree, contacts and transfers were mapped across Ireland on a 5 km grid, and additionally normalized per 1000 animals and per herd. We found considerable variation in the number of movements by county. Approximately half of transfers were conducted within a single county, but the number and distance of between county movements varied considerably by county of origin and county of destination, with the proportion of moves completed within a single county correlated with its size. Herds exchanging cattle via a market were generally further apart than when moves were made directly herd to herd. For contacts, the distances moved away from the herd were on average greater for origin herds in the west of ROI whereas distances moved to a herd were generally greater for destination herds in the centre-east and the north-west.

Safety of combined use of local anesthetic infiltration and reinfusion drains in total knee arthroplasty.

Injection of local anesthetic during total knee arthroplasty (TKA) has been shown to aid postoperative pain relief. Reinfusion drains have also proven useful in decreasing allogenic blood transfusion. Combined use carries the risk of reinfusion of local anesthetic from drainage bag. We examined plasma ropivacaine concentrations from 20 patients undergoing TKA, who were treated with these 2 techniques. Samples were taken from a dedicated venous cannula and from the reinfusion drainage bag. The average amount of ropivacaine reinfused was 1.9 mg, a fraction of the injected dose (150 mg), and venous plasma concentrations reached peaks of 0.5 to 1.5 microg/mL, well below demonstrated levels of toxicity. Patients tolerated the treatment well, with no adverse outcomes. This study demonstrates the safety of combining these 2 techniques in TKA.

Investigation of the potential for sera from cattle persistently infected with bovine viral diarrhea virus to generate false-negative antibody ELISA results in pooled serum from seropositive and seronegative cattle.

We investigated the potential for viremic sera from cattle persistently infected with bovine viral diarrhea virus to create false-negative antibody results when testing pools of 10 sera by indirect or blocking ELISAs. Seronegative viremic sera ( n = 23) were each added to a series of artificially constructed pools containing various percentages (0-90%) of antibody-positive sera, and the resulting pools were assayed for antibody. In all 23 cases, a negative antibody result was obtained in the pool containing no seropositive sera. In contrast, all pools containing ≥10% seropositive serum, representing a single seropositive animal in a pool of 10 samples, returned a positive result in both antibody ELISAs. We concluded that the likelihood of a false-negative antibody result occurring as a result of the presence of serum from a viremic animal was low, and therefore did not preclude the use of pooled sera for serosurveillance.

Genetic parameters for variability in the birth of persistently infected cattle following likely in utero exposure to bovine viral diarrhea virus.

Genetic selection is an inexpensive and complementary strategy to traditional methods of improving animal health and welfare. Nonetheless, endeavors to incorporate animal health and welfare traits in international breeding programs have been hampered by the availability of informative phenotypes. The recent eradication program for bovine viral diarrhea (BVD) in the Republic of Ireland has provided an opportunity to quantify the potential benefits that genetic selection could offer BVD eradication programs elsewhere, as well as inform possible eradication programs for other diseases in the Republic of Ireland. Using a dataset of 188,085 Irish calves, the estimated direct and maternal heritability estimates for the birth of persistently infected calves following likely in utero exposure to BVD virus ranged from not different from zero (linear model) to 0.29 (SE = 0.075; threshold model) and from essentially zero (linear model) to 0.04 (SE = 0.033; threshold model), respectively. The corresponding genetic SD for the direct and maternal effect of the binary trait (0, 1) ranged from 0.005 (linear model) to 0.56 (threshold model) units and ranged from 0.00008 (linear model) to 0.20 (threshold model) units, respectively. The coefficient of direct genetic variation based on the linear model was 2.56% indicating considerable genetic variation could be exploited. Based on results from the linear model in the present study, there is the potential to reduce the incidence of persistent infection in cattle by on average 0.11 percentage units per year which is cumulative and permanent. Therefore, genetic selection can contribute to reducing the incidence of persistent infection in cattle. Moreover, where populations are free from persistent infection, inclusion of the estimated genetic merit for BVD in national breeding indexes could contribute to a preservation of a BVD-free status. Results from the present study can be used to inform breeding programs of the potential genetic gains achievable. Moreover, the approaches used in the present study can be applied to other diseases when data become available.

Cerebral oximetry does not correlate with electroencephalography and somatosensory evoked potentials in determining the need for shunting during carotid endarterectomy.

OBJECTIVE: Several reports in the literature have described the value of regional cerebral oximetry (rSO(2)) as a neuromonitoring device during carotid endarterectomy (CEA). The use of rSO(2) is enticing because it is simpler and less expensive than other neuromonitoring modalities. This study was performed to compare the efficacy of rSO(2) with electroencephalography (EEG) and median nerve somatosensory evoked potentials (SSEP) in determining when to place a shunt during CEA. METHODS: From October 2000 to June 2006, 323 CEAs were performed under general anesthesia by six surgeons. Shunting was done selectively on the basis of EEG and SSEP monitoring under the auspices of an intraoperative neurophysiologist. All patients were retrospectively reviewed to see if significant discrepancies existed between EEG/SSEP and rSO(2). RESULTS: Twenty-four patients (7.4%) showed significant discrepancies. Sixteen patients showed no significant EEG/SSEP changes, but profound changes occurred in rSO(2), and no shunt was placed. In seven patients there was no change in rSO(2) but a profound change occurred in EEG/SSEP, and shunts were placed. In one patient early in the series, the EEG and SSEP were unchanged but the rSO(2) dropped precipitously, and a shunt was placed. In the 299 patients who showed no discrepancies, 285 were not shunted and 14 required a shunt. Two strokes occurred in the entire series (0.6%), none intraoperatively. Shunts were placed in 23 patients (7%). The sensitivity of rSO(2) compared with EEG/SSEP was 68%, and the specificity was 94%. This gave a positive-predictive value of 47% and a negative-predictive value of 98%. CONCLUSIONS: Relying on rSO(2) alone for selective shunting is potentially dangerous and might have led to intraoperative ischemic strokes in seven patients and the unnecessary use of shunts in at least 16 patients in this series. The use of rSO(2) adds nothing to the information already provided by EEG and SSEP in determining when to place a shunt during CEA.