Association of clinical respiratory disease signs and lower respiratory tract bacterial pathogens with systemic inflammatory response in pre-weaned dairy calves.

This study investigated the potential associations between 3 acute phase proteins (APPs) haptoglobin, serum amyloid A, and fibrinogen, clinical signs of respiratory disease, and the presence of bacterial pathogens in the lower respiratory tract (LRT) of pre-weaned dairy calves. This cross-sectional study included 150 pre-weaned calves (2-86 d old) from 15 large dairy herds in Estonia. Tracheobronchial lavage, blood, and fecal samples were collected from 5 calves showing clinical signs indicative of LRT disease, and samples from 5 calves without clinical signs of LRT disease per herd. All samples collected from these calves were analyzed for concentrations of systemic APPs, LRT bacteria, and intestinal pathogens. Heifer blood and bulk tank milk samples were collected for the detection of disease-specific antibodies against bovine herpesvirus 1, bovine viral diarrhea virus, bovine respiratory syncytial virus, and Mycoplasma bovis. Mixed-effects linear regression models were used to analyze the associations of clinical respiratory disease signs and LRT bacteria with APPs. Increased plasma fibrinogen concentrations in calves were associated with higher rectal temperature (>39.5°C), increased respiratory rate (>50 breaths/min), and coughing. Increased serum amyloid A concentrations were associated with higher rectal temperature (>39.5°C) and respiratory rate between 40 and 50 breaths/min. Calves with the presence of fecal Cryptosporidium spp. and rectal temperature of 39°C and above had increased serum haptoglobin concentrations. Increased fibrinogen concentrations were associated with the presence of Pasteurella multocida in the calf LRT, whereas increased concentrations of fibrinogen and serum amyloid A were associated with the presence of Trueperella pyogenes. In conclusion, APPs showed variable associations with clinical signs of respiratory disease and LRT bacteria. Plasma fibrinogen concentration could be used as a complementary calf-side test to assess systemic inflammation caused by LRT bacteria such as P. multocida and T. pyogenes in pre-weaned dairy calves.

Understanding Smallholder Pigkeepers' Awareness and Perceptions of African Swine Fever and Its Control Measures in Ukraine.

African swine fever (ASF) has posed a significant threat to Ukrainian pig farming since its identification in 2012. In this study, recognising the pivotal role of pigkeepers in disease control, we conducted ten focus groups involving 52 smallholders across eight regions in Ukraine. Using participatory methods, we revealed their awareness of ASF signs, transmission routes, preventive measures, and the perceptions of stakeholders involved in ASF control. Furthermore, we identified the smallholders' acceptance of eradication and restriction measures, the perceived impact of zoning consequences, and their main sources of ASF information. Smallholders identified fever and skin haemorrhage as the most indicative signs of ASF and highlighted rodents as a primary transmission concern. Disinfection was seen as the most effective measure for preventing the introduction of ASF. Pigkeepers who perceived their stakeholder role in ASF control showed more trust in themselves and veterinarians than in central veterinary authorities. Farm-level ASF eradication measures were generally accepted; however, culling within the protection zone was least accepted, with economic losses listed as the most impactful consequence for pigkeepers. For ASF information, pigkeepers favour web searches and veterinarians, as well as traditional media and word-of-mouth news. This study provides valuable insights into refining the ASF communication strategies in Ukraine.

Application of multiblock analysis to identify key areas and risk factors for dairy cow persistence.

The present study analysed the importance of individual variables and different thematic blocks of production areas, management, and herd infectious disease status on cow persistence, characterised by herd on-farm mortality rate (MR), culling rate (CR), and mean age of culled cows (MAofCC) applying multiblock partial least squares (mbPLS) analysis. This study included 120 free-stall dairy herds with ≥ 100 cows. Data on the previous year's predominant cow housing system and management practices were collected, and on-farm measurements and cow scoring were performed. Bulk tank milk (BTM) and heifer blood samples (10 samples per herd) were collected and analysed for antibodies against the selected pathogens. In total, 172 variables were aggregated into 14 thematic blocks. The annual CR, MR, and MAofCC values were calculated for each herd. Thematic blocks with significant impact on cow persistence (included herd MR, CR and MAofCC) were 'infectious diseases' (block importance index out of all blocks = 13.6%, 95% CI 10.3; 20.5), 'fertility management' (16.3%, 95% CI 6.8; 26.9), 'lactating cow management' (11.5%, 95% CI 6.4; 17.8), 'milking' (11.3%, 95% CI 3.2; 17.1), 'herd characteristics' (10.1%, 95% CI 6.3; 14.2), 'close-up period management' (9.7%, 95% CI 2.7; 15.7), 'calving management' (7.9%, 95% CI 3.1; 11.4) and 'disease management' (7.3%, 95% CI 0.2; 12.0). Variable categories with the highest importance in explaining composite outcome including herd MR, CR and MAofCC were rear-end and udder lesions in ≥ 20% of the cows, BTM and heifers seropositive to bovine respiratory syncytial virus, vaccination against bovine herpesvirus 1, twice daily milking and herd location in Northwest region. Larger herd size, higher levels of milk yield, and rearing predominantly Holstein breed cattle were herd factors associated with poorer cow persistency. Grazing cows and having semi-insulated barns were associated with lower CR and MR, respectively. Heat detection and farm pregnancy testing strategies were significant factors in the fertility block. Using disposable dry papers for teat cleaning and not using any wet teat-cleaning tools were risk factors for high MR. A robotic milking system was protective for increased herd MR and CR. A high pre-calving body condition score and poor rear body cleanliness of ≥ 30% of cows were associated with inferior herd persistency outcomes. Calving in group pens with deep litter bedding was associated with a lower CR. Multiblock PLS model is innovative tool that helped to identify most influential farming areas but also single risk factors associated with cow persistency described by multiple parameters.

Calf care workers' attitudes and personality and their association with calf mortality in large-scale dairy farms.

Although calf mortality is a multifactorial problem, little is known about the attitudes and personalities of calf care workers (CCWs) and their association with calf mortality. This study aimed to describe the attitudes, satisfaction, and personality of CCWs in large Estonian dairy herds and to analyze their associations with herd calf mortality. A questionnaire registering CCWs' attitudes toward their work and calf mortality, personality characteristics, satisfaction and importance of different job-related factors was developed. In total, completed questionnaire data of 161 CCWs from 108 large (>100 cows) Estonian dairy farms were analyzed. Herd-level yearly calf mortality risk (MR) was calculated. Cluster analysis and variance partitioning analysis were applied to reveal the explanatory capacity of CCWs' attitudes and personalities on calf mortality. The mean yearly herd-level calf MR was 5.4% during the first 21 days of life and 2.7% during 22-90 days of life. Although good calf health and low calf mortality was important for CCWs, dead calves were often seen as inevitable. CCWs were generally doubtful regarding their capacity and available knowledge to influence calf mortality. In high-mortality herds, CCWs were dissatisfied with the calf health situation and farm working equipment and felt that the situation was out of their control. Despite striving, they had less faith that farmworkers could affect the outcomes, such as calf mortality. CCWs' personality domains explained <5% of the variance in the herd's calf MR, whereas their attitudes and satisfaction explained 20% of the variability in calf MR. The current study revealed the importance of the attitudes and satisfaction of CCWs on calf mortality and highlighted the need to allocate proficient assistance to herds with high calf mortality to mitigate calf health problems and the resulting consequences for CCWs.

Pigkeepers' knowledge and perceptions regarding African swine fever and the control measures in Estonia.

African swine fever (ASF) has been present in Estonia since 2014, and pigkeepers play a major role in controlling the spread of viral infection in domestic pigs. Participatory epidemiology may provide insight into livestock keepers' existing attitudes and compliance with implementing control strategies. By conducting focus group discussions and using participatory epidemiology tools, this study aimed to reveal pigkeepers' knowledge and awareness of ASF clinical signs, transmission routes, and preventive measures. Furthermore, opinions including trust in stakeholders in ASF control, acceptability of ASF eradication, and control measures by pigkeepers in Estonia were identified. The most indicative ASF signs in pigs were "increased mortality" and "fever, inappetence, lethargy". The highest risk of virus introduction into the herd was designated to "agricultural machinery, vehicles", "rodents, birds, insects", and "people". "Fencing" was the most liked ASF preventive measure, while "training of staff in biosecurity and informing the visitors" was considered the most effective measure. The least accepted ASF eradication measure was "culling of all animals on the farm". Generally, pigkeepers perceived that healthy animals should not be culled but only ASF-infected pigs. Additionally, healthy pigs could be slaughtered and used for the production of heat-treated canned meat. "Destroying the feed" of ASF-infected farms was not favoured because some pigkeepers proposed using it for other animal species. Regarding ASF territorial restrictions (zoning), "lower meat prices" and "economic losses" were regarded as consequences with the greatest impact. Pigkeepers ranked trust in "Veterinary Authority and Ministry of Rural Affairs" regarding their role in ASF prevention and control as high while perceiving themselves as the most trustworthy stakeholder within the ASF network. This study demonstrates a generally good level of awareness among the pigkeepers in Estonia concerning the clinical manifestation of ASF, the most relevant transmission routes of the virus for their farms, and preventive measures for ASF. Pigkeepers are aware of their own role in preventing ASF, and there is a high level of trust between them and government authorities. Additional efforts are needed from authorities to communicate better the purpose of some ASF control and eradication measures to the pigkeepers. Further incentives are required to support the implementation of costly biosecurity measures, assure compliance, and mitigate the consequences of these measures.

Cow culling patterns in eight commercial Estonian dairy herds and farmers' behaviour in reporting culling reasons.

The present study aimed to reveal the culling-related metrics, identify the culling reason patterns for cows by developing and implementing the cow culling form (CCF), and analyse the concordance of farmers' stated culling reasons with those identified based on the CCF. A CCF was developed to register the disease history and conditions of cows that were related to culling. CCFs were completed by farm managers and veterinarians in eight dairy herds over a one-year period for slaughtered (n = 686) and dead (n = 250) cows. Completed CCFs were interpreted by the study authors to identify underlying, intermediate, influential, and immediate culling reasons. The identified culling reasons were compared to those reported by producers. The mean annual cow culling rate of the study farms was 31.8%, and the average on-farm mortality was 9.3%. Of the 250 cows that died on the farms, 43.6% were euthanised. Only 2% of the cows were slaughtered due to low milk yield. In total, 260 and 119 unique three-reason culling codes were created for slaughtered and dead cows, respectively. Single disease or condition causing slaughter or death of cows was identified in 44.8% and 52.0% of the cases, respectively. Producers' reported culling reasons concurred with the underlying culling reason in 72.6% and 63.6% of slaughtered and dead cows, respectively. A high variety of agreements between the farmers' reported and CCF-based culling codes was identified across single culling reasons. Improved registration of culling reasons is required to support informed herd-based decisions.

Corrigendum: Overview of Cattle Diseases Listed Under Category C, D or E in the Animal Health Law for Which Control Programmes Are in Place Within Europe.

[This corrects the article DOI: 10.3389/fvets.2021.688078.].

Implementation of a pre-calving vaccination programme against rotavirus, coronavirus and enterotoxigenic Escherichia coli (F5) and association with dairy calf survival.

BACKGROUND: Diarrhea is one of the most common diseases and causes of death in calves during the first month of life. Pre-calving vaccination programme (PVP) against the most common diarrhea-causing pathogens could help to avoid this threat if hyperimmune transition milk (TM) is fed to calves throughout the whole susceptibility period. The aim of this retrospective cohort study was to reveal the implementation practices of PVPs in large commercial dairy farms and to compare calf-level mortality hazards during the first year of vaccination (V+ period) and a year before implementing the vaccination programme (V- period). A questionnaire was filled out in 15 large-scale dairy farms in Estonia that used PVP. The farms were assigned into three groups based on compliance with the vaccine directions for use and TM feeding practices. Calf-level time-to-event data was analyzed with an observation period of 21 days and on-farm mortality due to diarrhea being the event of interest. RESULTS: During the V+ period, a significant decline in diarrhea-induced calf mortality was identified in three out of six herds that followed vaccination instructions and fed TM for at least 14 days. On average, calf mortality hazard due to diarrhea decreased among these herds (hazard rate ratio (HR) = 0.72, 95% confidence interval (CI) 0.63; 0.81). In the group of correctly vaccinating herds where TM was fed for less than 14 days, diarrhea-induced calf mortality decreased in two herds and remained unchanged in two herds with average diarrhea-induced calf mortality hazard declining significantly during the vaccination period (HR = 0.24, 95% CI 0.14; 0.41). Among the three farms that deviated from the vaccination instructions, the average calf mortality hazard increased in the V+ period (HR = 1.61, 95% CI 1.21; 2.14). CONCLUSIONS: This study revealed that implementing a PVP might aid to reduce diarrhea-induced calf mortality in large commercial dairy farms. There is a need to increase veterinarians´ and farmers´ awareness about the importance of including pregnant heifers into the vaccination programme and emphasize the importance of prolonged feeding of hyperimmune TM to calves.

Attitudes and personality of farm managers and association with cow culling rates and longevity in large-scale commercial dairy farms.

The farmer has the central role in determining cow culling policies on their farm and thus affecting cow longevity. The present study aimed to examine farm managers´ satisfaction, attitudes, personality traits and analyse the associations with dairy cow culling and longevity in large commercial dairy farms. Farm managers of 116 dairy herds rearing at least 100 cows in freestall barns were included. A questionnaire for the farm managers registered personal background information of respondent and included statements capturing their satisfaction, opinions and attitudes regarding dairy cow culling and longevity, farming in general, and a Ten Item Personality Inventory scoring. For each herd, the last 12 months cow culling rate (CR, excluding dairy sale) and herd mean age of culled cows (MAofCC) was obtained from the Estonian Livestock Performance Recording Ltd. A K-mean clustering algorithm was applied to subgroup farm managers based on their attitudes, opinions and personality traits. The yearly mean herd CR was 33.0% and MAofCC was 60.6 months. Farm managers´ were mostly dissatisfied with cow longevity and culling rates in their farms. Dissatisfaction with culling rates and longevity, priority for producing high milk yields over longevity and production-oriented attitude was associated with high culling rates and poor longevity. Farm managers' personality had an effect on herd culling rates and their attitudes explained one third of the variability of culling rates and longevity. Explaining the economic consequences of high culling rates and decreased longevity, improving the visibility of these parameters together with benchmarking could bring these issues into focus.

Overview of Cattle Diseases Listed Under Category C, D or E in the Animal Health Law for Which Control Programmes Are in Place Within Europe.

The COST action "Standardising output-based surveillance to control non-regulated diseases of cattle in the European Union (SOUND control)," aims to harmonise the results of surveillance and control programmes (CPs) for non-EU regulated cattle diseases to facilitate safe trade and improve overall control of cattle infectious diseases. In this paper we aimed to provide an overview on the diversity of control for these diseases in Europe. A non-EU regulated cattle disease was defined as an infectious disease of cattle with no or limited control at EU level, which is not included in the European Union Animal health law Categories A or B under Commission Implementing Regulation (EU) 2020/2002. A CP was defined as surveillance and/or intervention strategies designed to lower the incidence, prevalence, mortality or prove freedom from a specific disease in a region or country. Passive surveillance, and active surveillance of breeding bulls under Council Directive 88/407/EEC were not considered as CPs. A questionnaire was designed to obtain country-specific information about CPs for each disease. Animal health experts from 33 European countries completed the questionnaire. Overall, there are 23 diseases for which a CP exists in one or more of the countries studied. The diseases for which CPs exist in the highest number of countries are enzootic bovine leukosis, bluetongue, infectious bovine rhinotracheitis, bovine viral diarrhoea and anthrax (CPs reported by between 16 and 31 countries). Every participating country has on average, 6 CPs (min-max: 1-13) in place. Most programmes are implemented at a national level (86%) and are applied to both dairy and non-dairy cattle (75%). Approximately one-third of the CPs are voluntary, and the funding structure is divided between government and private resources. Countries that have eradicated diseases like enzootic bovine leukosis, bluetongue, infectious bovine rhinotracheitis and bovine viral diarrhoea have implemented CPs for other diseases to further improve the health status of cattle in their country. The control of non-EU regulated cattle diseases is very heterogenous in Europe. Therefore, the standardising of the outputs of these programmes to enable comparison represents a challenge.

Existence and Quality of Data on Control Programs for EU Non-regulated Cattle Diseases: Consequences for Estimation and Comparison of the Probability of Freedom From Infection.

Some European countries have successfully implemented country-specific control programs (CPs) for infectious cattle diseases that are not regulated or are regulated only to a limited extent at the European Union (EU) level. Examples of such diseases include bovine viral diarrhea (BVD), infectious bovine rhinotracheitis (IBR), and Johne's disease (JD). The CPs vary between countries in the design and quality of collected data as well as methods used to detect infection and estimate prevalence or probability of freedom from infection. Differences in disease status between countries and non-standardized approaches to assess freedom from infection pose a risk for countries with CPs for non-regulated diseases as infected animals may influence the progress of the disease control or eradication program. The implementation of output-based standards allows estimation and comparison of the probability of freedom for non-regulated cattle diseases in European countries. The aim of the current study was to assess the existence and quality of data that could be used for estimating freedom from infection in European countries. The online data collection tool was sent to 32 countries participating in the SOUND control COST Action and was completed by 24 countries. Data on cattle demographics and data from CPs of IBR and BVD exist in more than 50% of the response countries. However, data describing risk factors and CP of JD was reported as existing in <25% of the countries. The overall quality of data in the sections on demographics and CPs of IBR and BVD were evaluated as "good", but risk factors and JD data were mostly evaluated as "fair." Data quality was considered less good mainly due to two quality criteria: accessibility and accuracy. The results of this study show that the quantity and quality of data about cattle populations and CPs are relatively similar in many surveyed countries. The outcome of this work provides an overview of the current situation in the European countries regarding data on EU non-regulated cattle diseases and will further assist in the development and implementation of output-based standards.

Seroprevalence of selected endemic infectious diseases in large-scale Estonian dairy herds and their associations with cow longevity and culling rates.

Herd culling rates and longevity represent herd health and welfare status as well as farm economic performance. The contribution of endemic circulation of the main cattle pathogens to herd performance has not been previously analysed. The aim of this study was to estimate the herd prevalence of selected endemic bovine pathogens among large commercial dairy herds and to analyse their associations with herd culling rates and longevity. Bulk tank milk (BTM) samples and 10 heifer serum samples were collected from 120 Estonian dairy herds with at least 100 cows, between August 2019 and July 2020. All samples were tested for antibodies against bovine herpesvirus 1 (BHV-1), bovine viral diarrhoea virus (BVDV), bovine respiratory syncytial virus (BRSV), Mycoplasma bovis, Mycobacterium avium spp. paratuberculosis (MAP) and Salmonella Dublin using commercial ELISA. Data on herd size, milk yield, culling rate (CR) and mean age of the culled cows (MAofCC) were collected from the Estonian Livestock Performance Recording Ltd. The apparent herd and animal prevalences were calculated, and linear regression models were used to identify associations between the herd status of six tested pathogens and CR and MAofCC. The herd seroprevalences for antibodies based on BTM and heifer serum sample testing were BHV-1 56.7 % (95 % CI 47.3; 65.7), Mycoplasma bovis 48.3 % (95 % CI 39.1; 57.6), MAP 2.5 % (95 % CI 0.5; 7.1) and S. Dublin 24.2 % (95 % CI 16.8; 32.8) in all tested herds. Excluding vaccinated herds, herds prevalence for BVDV was 27.0 % (95 % CI 19.0; 36.3) and for BRSV 94.7 % (95 % CI 88.1; 98.3). Herd seropositive status for BRSV was associated with lower MAofCC, and herds with BSRV-seropositive youngstock had increased CR. Herds with positive BTM test results for S. Dublin culled cows at an older average age (Coef = 3.79 months, 95 % CI 0.52; 7.07, p = 0.023). MAP-positive herds had somewhat lower herd MAofCC (Coef = -6.18 months, 95 % CI -12.98; 0.63, p = 0.075). There was also a tendency of BVDV-negative herds to have a lower CR than BVDV-positive herds (Coef = -3.03 %, 95 % CI -6.54; 0.49, p = 0.090), and vaccination against BVDV tended to be protective against high CR (Coef = -6.26 %, 95 % CI -12.61; 0.09, p = 0.053 compared to infected herds). This study shows that Estonian large-scale dairy herds are endemically infected with several important cattle pathogens. Most of the studied pathogens influence longevity and culling rates, thus entailing health and economic consequences.

The Use of Colistin in Food-Producing Animals in Estonia-Vaccination as an Effective Alternative to Consumption of Critically Important Antimicrobials in Pigs.

Reducing the use of critically important antimicrobials in veterinary medicine is increasingly important to avoid the development and spread of antimicrobial resistance. The aim of this study was to analyse ten-year trends of colistin consumption in Estonia and to ascertain the possible association between Escherichia (E.) coli vaccination and colistin consumption in pig production. Colistin sales data (2010-2019) were collected from the wholesalers, allowing differentiation of target species. In Estonia, the amount of sold colistin increased constantly and almost doubled from 2010 to 2013, and decreased from 2013 to 2019 by 92.5% in total. On average across a ten-year study period, 89.7% of colistin was used in pig production. The number of sold doses of E. coli vaccines for pigs was very low before 2014 (<2000) and increased drastically to 2019 (362,000). According to linear time-series model with autoregressive integrated moving average (ARIMA) the consumption of colistin in pigs decreased on average by 0.23 mg/PCU for every 10,000 E. coli vaccine doses (95% CI -0.39, -0.06; p = 0.006) over ten years. This study revealed that in pig production, vaccination against E. coli strains contributes to the expected downward trend in colistin consumption.

Antimicrobial Selection for the Treatment of Clinical Mastitis and the Efficacy of Penicillin Treatment Protocols in Large Estonian Dairy Herds.

Clinical mastitis (CM) is the most common microbial disease treated in dairy cows. We analyzed the antimicrobial usage in cows with CM (n = 11,420) in large dairy herds (n = 43) in Estonia. CM treatment data were collected during a 12-month study period. The antimicrobial usage was observed during the 21 days from the initiation of treatment, and the incidence of antimicrobial-treated CM was calculated for each study herd. The effect of intramammary (IMM), systemic, and combined (systemic and IMM) penicillin treatment of CM on the post-treatment somatic cell count (SCC) was analyzed using the treatment records of 2222 cows from 24 herds with a mixed multivariable linear regression model. The median incidence of antimicrobial-treated CM was 35.8 per 100 cow-years. Procaine benzylpenicillin and marbofloxacin were used in 6103 (35.5%, 95% CI 34.8-36.2) and 2839 (16.5%, 95% CI 16.0-17.1) CM treatments, respectively. Post-treatment SCC was higher after IMM penicillin therapy compared to systemic or combination therapy. Treatment of CM usually included first-choice antimicrobials, but different antimicrobial combinations were also widely used. The effect of procaine benzylpenicillin to post-treatment SCC was dependent on the administration route, cow parity, and days in milk. Further studies should evaluate the factors affecting veterinarians' choice of antimicrobial used in the treatment of CM.

Biosecurity Levels and Farm Characteristics of African Swine Fever Outbreak and Unaffected Farms in Estonia-What Can Be Learned from Them?

Risk factors related to external biosecurity have been considered to play a major role in the introduction and spread of African swine fever (ASF) in domestic pig populations. The aim of the study was to describe the biosecurity levels and management practices of ASF outbreak and uninfected herds and to identify potential risk factors for ASF introduction. Data collected from the outbreak herds during outbreak investigations and from the randomly selected uninfected herds were analyzed. The biosecurity score in ASF outbreak herds was significantly lower compared to uninfected herds. However, this may reflect general improvement in the application of biosecurity measures in pig farms over time as the data on uninfected herds were collected later, at a time when intensified official controls may have had their effect. Larger herds were more at risk of being outbreak herds compared to smaller herds. The biosecurity parameters significantly associated with the outbreak herd status in multiple correspondence analysis were mostly related to indirect contacts with the outside farm environment. The biosecurity barriers applied in Estonian pig farms have not been sufficient to avoid ASF introduction and need critical evaluation and improvement. Reduction of all contacts between the farm and the external environment should be emphasized in a situation where ASF is circulating in wild boar populations close to pig farms.

Hunters' Acceptance of Measures against African Swine Fever in Wild Boar in Estonia.

African swine fever (ASF) was first identified in Estonia in 2014, initially detected in wild boar and spreading to affect almost the whole country from late 2016 onwards. Passive surveillance and the control measures applied in Estonia are the main actions in the attempt to control the wild boar population and therefore limit the spread of ASF. Implementation and success of both activities depend mainly on the involvement and commitment of the executing force: the Estonian hunters. Thus, their acceptance of the measures is of utmost importance and with the help of participatory methods, their acceptability can be assessed. Participatory epidemiology allows the involvement of key stakeholders in planning control measures and surveillance strategies and gathering information otherwise inaccessible. By conducting focus group discussions and utilizing participatory tools, this study aimed to assess the acceptance of ASF control measures by hunters in Estonia. Furthermore, the study aimed to detect means to improve the motivation of hunters to support passive surveillance. Among hunters, the results ranked the trust in lower authorities (e.g. local official veterinarians) towards implementing control measures as high (in contrast to higher officials e.g. 'Ministry of Rural Affairs'), while perceiving themselves as the most trustworthy group among those implementing ASF control measures. Hunting and every measure supporting increased hunting, for example selective hunting, bait feeding and incentives for hunting wild boar, were deemed favourable for hunters. These measures also received the highest trust for controlling ASF. All measures hindering hunting and the movement of wildlife, for example fencing or involvement of the army in ASF control, were described as unpleasant or even unethical and trust in these measures to control the disease successfully was lacking. When assessing the perceived consequences for hunters of finding a dead wild boar, arising financial costs, additional workload and time consumption were highlighted. In line with these results, the two tools with the strongest motivational effect for taking part in passive surveillance were: (1) higher monetary incentives as compensation for the hunters' work, and (2) the reduction of the negative consequences by limiting the hunters' duties to solely reporting found dead wild boar. In conclusion, participatory methods can be used as a highly suitable tool for the evaluation of acceptance of measures and surveillance systems. Potentially, the results can help to improve control and passive surveillance in Estonia, as well as functioning as an example for other countries battling or awaiting ASF.

Culling reasons and risk factors in Estonian dairy cows.

BACKGROUND: Culling is a major cost for dairy farms but also an essential part in managing herd productivity. This study aimed to identify the culling rates of Estonian dairy cows, identify the farmers' stated reasons and risk factors for culling. This observational study used registry data of all cows from herds with ≥20 cow-years in 2013-2015. Cow lactation-level analyses included data of 86,373 primiparous cows from 409 herds and 177,561 lactations of 109,295 multiparous cows from 410 herds. Weibull proportional hazard regression models were used to identify risk factors for culling due to slaughter or death. RESULTS: The overall culling rate of Estonian dairy cows was 26.24 (95% CI 26.02; 26.46) per 100 cow-years. The most common reasons farmers stated for culling were feet/claw disorders (26.4%), udder disorders (22.6%), metabolic and digestive disorders (18.1%) and fertility problems (12.5%). Animal-level risk factors for culling were Holstein breed, older parity, lower milk yield breeding value, older age at first calving, longer previous calving interval, having assisted calving, stillbirth and birth of twins/triplets. Lower milk yield, somatic cell count over 200,000 cells/ml and fat/protein ratio over 1.5 at first test-milking after calving were associated with greater culling hazard during the lactation. Cows from larger herds, herds with decreasing size and higher milk yields had a higher culling probability. CONCLUSIONS: This study emphasises the need for improved management of hoof health and prevention of mastitis and metabolic diseases. It is essential to ensure easy calving and good health of cows around calving in order to lower the culling hazard.

Herd-level risk factors for cow and calf on-farm mortality in Estonian dairy herds.

BACKGROUND: On-farm mortality (unassisted death and euthanasia) is the unwanted loss of animals, and it comes with negative economic consequences. On-farm mortality rates reflect a herd's animal welfare status. The objective of this historical longitudinal single cohort study was to identify the associations between herd characteristics, animal housing conditions and management routines and within-herd calf and cow mortality rates in participating Estonian dairy herds. All farmers enrolled in the voluntary production recording system with a herd size of 20 or greater cow-years in 2015-2017 were contacted by mail or telephone between October 2017 and March 2018. The survey included questions about management routines and housing conditions of calves up to 3 months of age and of cows. In total, 214 completed questionnaires were returned, corresponding to a 63.3% response rate. The within-herd mortality rate of calves (aged 21-90 days) and cows (cattle over 24 months of age) in years 2017-2018 were calculated and used as outcome variables. Negative binomial and linear regression models were applied for risk factor analysis in calf and cow datasets, respectively. RESULTS: The median within-herd mortality rate for calves aged 21 to 90 days was 0.15 per 100 calf-months (quartiles 0.00; 0.36). The median within-herd mortality rate for cattle over 24 months of age was 4.57 per 100 cow-years (quartiles 2.44; 6.86). Factors significantly associated with increased mortality of calves were larger herd size, higher proportion of stillbirths and abortions in a herd, prophylactic administration of vitamins to all calves and housing pre-weaned calves in single pens only compared with housing in both single and group pens. Also, farmers who attended more frequent trainings had higher calf mortality rates. Calving in a group pen or in a tie-stall compared with calving in multiple systems was associated with higher calf mortality rates. Higher cow mortality rates were present in herds that had a higher proportion of stillbirths and on farms where employees handled cows. Housing cows in free-stall barns, grazing cows and more frequent hoof trimming were protective for cow on-farm mortality. CONCLUSIONS: This study identified the importance of housing conditions for on-farm cow and calf mortality rates. Our study results suggest that providing good care might ensure better health and welfare of dairy cows and calves.

Dynamics of the within-herd prevalence of Mycoplasma bovis intramammary infection in endemically infected dairy herds.

We aimed to identify the dynamics of the within-herd prevalence of Mycoplasma (M.) bovis intramammary infection (IMI) in four dairy herds, estimate prevalence of M. bovis in colostrum and clinical mastitis cases and compare M. bovis strains from calves' respiratory and cow clinical mastitis samples. Within a six-month study period, cow composite milk samples (CMS) were collected three times during routine milk recording, first milking colostrum samples from all calving cows and udder quarter milk samples from clinical mastitis cases. Calf respiratory samples were collected from calves with respiratory disease. Pooled milk samples were analysed for M. bovis with the Mastitis 4B polymerase chain reaction (PCR) test kit (DNA Diagnostic A/S). Prevalence estimates were calculated with Bayesian framework in R statistical programme. cg-MLST was used for M. bovis genotyping. In Herd I and II first testing M. bovis IMI within-herd prevalence (95 % credibility interval (CI)) was 4.7 % (2.9; 6.8) and 3.4 % (2.3; 4.6), changing to 1.0 % (0.1; 1.7) and 0.8 % (0.1; 1.4) in Herd I and 0.4 % (0.0; 0.7) in Herd II at the next samplings. In Herd III and IV first testing M. bovis IMI within-herd prevalence was 12.3 % (9.7; 15.2) and 7.8 % (6.2; 9.5), changing to 4.6 % (3.0; 6.4) and 3.2 % (1.9; 4.8) in Herd III and to 2.8 % (1.9; 3.8) and 4.9 % (3.6; 6.4) in Herd IV at the next samplings. The estimated prevalence of M. bovis in colostrum ranged between 1.7 % (0.2; 2.8) and 4.7 % (2.7; 7.1) and in clinical mastitis cases between 3.7 % (1.7; 6.4) and 11.0 % (7.5; 15.2) in the study herds. M. bovis strains isolated from cows and calves clustered within herds indicating possible transmission of M. bovis between dairy cows and calves. Prevalence of M. bovis in colostrum and clinical mastitis cases as well as the within-herd prevalence of M. bovis IMI was low in endemically infected dairy herds.

Epidemiological analysis of the 2015-2017 African swine fever outbreaks in Estonia.

African swine fever (ASF) was first detected in the Estonian wild boar population in September 2014, while the first domestic pig farm was affected in July 2015. In the present study, we aimed to analyse, retrospectively, the epidemiology of the disease in all 26 outbreaks in domestic pig herds that occurred in Estonia during the period 2015-2017. Formal interviews were conducted to estimate the high-risk period for every farm, and to identify the possible origin of the ASF virus and the mode of virus introduction. Furthermore, the clinical manifestation of the disease as well as the course of the disease within the farm were investigated. Survival analysis was used to calculate herd incidence and to estimate outbreak risk. A hierarchical Bayesian space-time model was used to analyse the associations between outbreaks and ASF occurrence in wild boar. The spatial and temporal distribution of outbreaks was analysed to characterise the ASF epidemic in the Estonian domestic pig population from 2015 to 2017. The estimated high-risk period varied from seven to 20 days with a median of 11 days. On most of the affected farms, the first clinical signs were mild and not specific to ASF despite the high virulence of the circulating virus. Morbidity and mortality were often limited to a single pen or unit of the farm. The highest mortality (29.7%) was seen on backyard farms with 1-10 pigs and the lowest (0.7%) on large commercial farms (>1000 pigs). The spread of the virus within affected farms has been slow and the contagiousness of the virus has been relatively low. Farms of all sizes and types have been at risk, including large commercial farms operating at a high biosecurity level. In none of the affected farms could the specific route of introduction be verified. However, the findings suggested that virus introduction occurred via indirect transmission routes due to insufficient biosecurity. The total herd incidence of outbreaks was similar across all three years, being 2.4% in 2015 and 2016, and 2.0% in 2017. All outbreaks occurred from June to September, during the warmest period of the year. The results suggest that the increase in ASF cases in local wild boar populations is the main risk factor leading to the infection of farms; 88% of outbreaks occurred in areas where ASF virus was detected in wild boar prior to the outbreak, within a radius of 15 km from the outbreak farm.