Walter Obritzhauser

Genetic analysis of reproductive disorders and their relationship to fertility and milk yield in Austrian Fleckvieh dual-purpose cows

The objective of this study was to estimate genetic parameters for various reproductive disorders based on veterinary diagnoses for Austrian Fleckvieh (Simmental) dual-purpose cattle. The health traits analyzed included retained placenta, puerperal diseases, metritis, silent heat and anestrus, and cystic ovaries. Three composite traits were also evaluated: early reproductive disorders, late reproductive disorders, and all reproductive disorders. Heritabilities were estimated with logit threshold sire, linear sire, and linear animal models. The threshold model estimates for heritability ranged from 0.01 to 0.14, whereas the linear model estimates were lower, ranging from 0.005 to 0.04. Rank correlations among random effects of sires from linear and threshold sire models were high (>0.99), whereas correlations between any sire model (linear, threshold) and the linear animal model were lower (0.88-0.92). Genetic correlations among reproductive disorders, fertility traits, and milk yield were estimated with bivariate linear animal models. Fertility traits included interval from calving to first insemination, nonreturn rate at 56 d, and interval between first and last insemination. Milk yield was calculated as the mean from test-day 1 and test-day 2 after calving. Estimated genetic correlations were 1 among metritis, retained placenta, and puerperal diseases and 0.85 between silent heat-anestrus and cystic ovaries. Low to moderate correlations (-0.01 to 0.68) were obtained among the other disorders. Genetic correlations between reproductive disorders and fertility traits were favorable, whereas antagonistic relationships were observed between milk yield in early lactation and reproductive disorders. Pearson correlations between estimated breeding values for reproductive disorders and other routinely evaluated traits were computed, which revealed noticeable favorable relationships to longevity, calving ease maternal, and stillbirth maternal. The results showed that data from the Austrian health monitoring project can be used for genetic selection against reproductive disorders in Fleckvieh cattle.

Recording of direct health traits in Austria--experience report with emphasis on aspects of availability for breeding purposes.

A project to establish an Austria-wide health-monitoring system for cattle was launched in 2006. Veterinary diagnostic data subject to documentation by law [Law on the Control of Veterinary Medicinal Products (Tierarzneimittelkontrollgesetz)] are standardized, validated, and recorded in a central database. This Austria-wide project is a collaboration among agricultural and veterinary organizations as well as universities, and is also supported by the Austrian government. In addition to providing information for herd management and preventive measures, further objectives of the project include estimating breeding values for health traits and monitoring the overall health status of Austrias cattle. To ensure a high level of participation from farmers and veterinarians, data security issues are extremely important. Valid data are the prerequisite for the efficient use of health records. The challenge hereby is to distinguish between farms with low frequencies of diseases and incomplete documentation and recording. Measures were undertaken to establish a routine monitoring system for direct health traits. A routine genetic evaluation for direct health traits as part of the joint breeding value estimation program between Germany and Austria was introduced for Fleckvieh in December 2010, based on diagnostic data from 5,428 farms with 147,764 Fleckvieh cows. In 2010 to 2011, the reporting of direct health traits as a compulsory part of performance recording and the breeding program was introduced as well. The overall challenge is the availability of sufficient valid direct health data for reliable breeding values. Practical experience gained in Austria in setting up a health registration system, focusing mainly on the availability of direct health data for breeding purposes with its successes and difficulties, is described.

A systematic worldwide review of the direct monetary losses in cattle due to bovine viral diarrhoea virus infection

Bovine viral diarrhoea virus (BVDV) is an important infectious agent of cattle worldwide that affects herd productivity and reproduction. In this systematic review of the impact of BVDV, studies were analysed with a particular focus on the monetary implications and types of direct losses, the initial infection status of herds, production systems, time periods of assessment, calculation level, study types and whether or not country-specific assessments were published. A linear mixed model was applied to analyse factors that influence the level of monetary direct losses due to BVDV infection. The 44 studies included in this review covered 15 countries and assessed direct monetary losses due to BVDV incurred over the past 30 years. Direct losses between and within countries were largely heterogeneous with respect to the monetary level and types of direct losses, ranging from 0.50 to 687.80 US dollars (USD) per animal.1 Average direct losses per naïve dairy cow were USD24.85 higher than per beef cow. Country-specific assessments of direct losses due to BVDV were provided in 38/44 (86.4%) studies. Mortality, morbidity, premature culling, stillbirths, abortion, reinfection, country and study type had a significant influence on the monetary level of direct losses (r2 = 0.69). Countries recording direct losses were more likely to carry out voluntary or compulsory control and eradication programmes (odds ratio = 10.2; 95% confidence interval 1.7-81.9; P = 0.004).

A systematic review of financial and economic assessments of bovine viral diarrhea virus (BVDV) prevention and mitigation activities worldwide.

Infection with bovine viral diarrhea virus (BVDV) results in major economic losses either directly through decreased productive performance in cattle herds or indirectly, such as through expenses for control programs. The aim of this systematic review was to review financial and/or economic assessment studies of prevention and/or mitigation activities of BVDV at national, regional and farm level worldwide. Once all predefined criteria had been met, 35 articles were included for this systematic review. Studies were analyzed with particular focus on the type of financially and/or economically-assessed prevention and/or mitigation activities. Due to the wide range of possible prevention and/or mitigation activities, these activities were grouped into five categories: i) control and/or eradication programs, ii) monitoring or surveillance, iii) prevention, iv) vaccination and v) individual culling, control and testing strategies. Additionally, the studies were analyzed according to economically-related variables such as efficiency, costs or benefits of prevention and/or mitigation activities, the applied financial and/or economic and statistical methods, the payers of prevention and/or mitigation activities, the assessed production systems, and the countries for which such evaluations are available. Financial and/or economic assessments performed in Europe were dominated by those from the United Kingdom, which assessed mostly vaccination strategies, and Norway which primarily carried out assessments in the area of control and eradication programs; whereas among non-European countries the United States carried out the majority of financial and/or economic assessments in the area of individual culling, control and testing. More than half of all studies provided an efficiency calculation of prevention and/or mitigation activities and demonstrated whether the inherent costs of implemented activities were or were not justified. The dairy sector was three times more likely to be assessed by the countries than beef production systems. In addition, the dairy sector was approximately eight times more likely to be assessed economically with respect to prevention and/or mitigation activities than calf and youngstock production systems. Furthermore, the private sector was identified as the primary payer of prevention and/or mitigation activities. This systematic review demonstrated a lack of studies relating to efficiency calculations, in particular at national and regional level, and the specific production systems. Thus, we confirmed the need for more well-designed studies in animal health economics in order to demonstrate that the implementation and inherent costs of BVDV prevention and/or mitigation activities are justified.

A cost-benefit analysis and the potential trade effects of the bovine viral diarrhoea eradication programme in Styria, Austria

This study evaluated the voluntary and compulsory implementation of a bovine viral diarrhoea virus (BVDV) eradication programme in the Austrian Federal State of Styria, Austria, from an economic point of view using ex-post assessment of costs and benefits (disease losses avoided). An economic net benefit (benefit:cost ratio, BCR=1.18) of the programme was demonstrated during the voluntary programme phase (January 1998-July 2004). The break-even point was reached in 2003. If investments in the compulsory programme (August 2004-December 2016) were taken into account, a net economic loss (BCR=0.16) was demonstrated. In contrast to on-going annual testing of all cattle herds, annual testing in accordance with a revised sampling scheme could reduce total surveillance costs by more than 77%. A Bayesian structural time series model was applied to analyse a hypothesised positive impact of the compulsory BVDV programme on the Styrian cattle export market. The average number of exported cows and bulls increased significantly by 42% (P=0.03) and 47% (P=0.01), respectively, and the producer price increased by 14% (P=0.00) and 5% (P=0.16), respectively, during the compulsory programme period compared with the period prior to intervention. This equates to an average revenue increase of €29,754 for cows and €137,563 for bulls per month. These results justify the implementation of eradication programmes, which initially may not appear to be economically viable, particularly if trade effects are not included in the calculations.

The relationship between clinical signs and microbiological species, spa type, and antimicrobial resistance in bovine mastitis cases in Austria

Bovine mastitis, an inflammation of the udder usually caused by bacteria, is the most common disease in dairy cattle worldwide with a negative economic impact on the dairy industry. In this study 3020 quarter milk samples from 647 dairy cows on 166 Austrian farms were collected and microbial species, spa type for Staphylococcus (S.) aureus and antimicrobial susceptibility were analysed. A multinomial logistic regression model was applied to investigate the effect of possible categorical influencing covariates on the microbiological findings. Additionally, a generalized linear model was used to analyse the effects of genotype and pathogen species on the occurrence of antimicrobial resistance. Staphylococci were the most common (17% of samples) udder pathogens including 32 different S. aureus spa types. The occurrence of pathogen groups was significantly associated with the clinical mastitis score. Enterobacteriaceae isolates had a significantly higher probability of being present in severe mastitis cases compared to streptococci. Benzylpenicillin and tetracycline were the most common resistance in S. aureus including 14% and 11% resistant isolates. Whereas 16% and 13% of coagulase-negative staphylococci (CNS) isolates were resistant to tetracycline and clindamycin. Overall the proportion of Enterobacteriaceae isolates resistant to at least one antibiotic agents was high (55% of isolates), whereas only 3% benzylpenicillin resistant streptococci were detected. Associations were detected between antimicrobial resistance and particular species of Enterobacteriaceae, CNS and specific S. aureus spa types. In conclusion we present in this study data on causative udder pathogen species and their antimicrobial resistance, which are of great importance for mastitis management and prevention.

A meta-analysis of bovine viral diarrhoea virus (BVDV) prevalences in the global cattle population

A random effect meta-analysis was performed to estimate the worldwide pooled bovine viral diarrhoea virus (BVDV) prevalences of persistently infected (PI), viraemic (VI) and antibody-positive (AB) animals and herds. The meta-analysis covered 325 studies in 73 countries that determined the presence or absence of BVDV infections in cattle from 1961 to 2016. In total, 6.5 million animals and 310,548 herds were tested for BVDV infections in the global cattle population. The worldwide pooled PI prevalences at animal level ranged from low (≤0.8% Europe, North America, Australia), medium (>0.8% to 1.6% East Asia) to high (>1.6% West Asia). The PI and AB prevalences in Europe decreased over time, while BVDV prevalence increased in North America. The highest mean pooled PI prevalences at animal level were identified in countries that had failed to implement any BVDV control and/or eradication programmes (including vaccination). Our analysis emphasizes the need for more standardised epidemiological studies to support decision-makers implementing animal health policies for non-globally-regulated animal diseases.

Antimicrobial consumption on Austrian dairy farms: an observational study of udder disease treatments based on veterinary medication records

Background Antimicrobial use in livestock production is an important contemporary issue, which is of public interest worldwide. Antimicrobials are not freely available to Austrian farmers and can only be administered to livestock by veterinarians, or by farmers who are trained members of the Animal Health Service. Since 2015, veterinarians have been required by law to report antimicrobials dispensed to farmers for use in food-producing animals. The study presented here went further than the statutory framework, and collected data on antimicrobials dispensed to farmers and those administered by veterinarians. Methods Seventeen veterinary practices were enrolled in the study via convenience sampling. These veterinarians were asked to contact interested dairy farmers regarding participation in the study (respondent-driven sampling). Data were collected from veterinary practice software between 1st October 2015 and 30th September 2016. Electronic data (89.4%) were transferred via an online interface and paper records (10.6%) were entered by the authors. Antimicrobial treatments with respect to udder disease were analysed by number of defined daily doses per cow and year (nDDDvet/cow/year), based on the European Medicines Agency technical unit, Defined Daily Dose for animals (DDDvet). Descriptive statistics and the Wilcoxon rank sum test were used to analyse the results. Results Antimicrobial use data from a total of 248 dairy farms were collected during the study, 232 of these farms treated cows with antibiotics; dry cow therapy was excluded from the current analysis. The mean number of DDDvet/cow/year for the antimicrobial treatment of all udder disease was 1.33 DDDvet/cow/year. Of these treatments, 0.73 DDDvet/cow/year were classed as highest priority critically important antimicrobials (HPCIAs), according to the World Health Organization (WHO) definition. The Wilcoxon rank sum test determined a statistically significant difference between the median number of DDDvet/cow/year for acute and chronic mastitis treatment (W = 10,734, p < 0.001). The most commonly administered antimicrobial class for the treatment of acute mastitis was beta-lactams. Intramammary penicillin was used at a mean of 0.63 DDDvet/cow/year, followed by the third generation cephalosporin, cefoperazone, (a HPCIA) at 0.60 DDDvet/cow/year. Systemic antimicrobial treatments were used at a lower overall level than intramammary treatments for acute mastitis. Discussion This study demonstrated that Austrian dairy cows in the study population were treated with antimicrobial substances for udder diseases at a relatively low frequency, however, a substantial proportion of these treatments were with substances considered critically important for human health. While it is vital that sick cows are treated, reductions in the overall use of antimicrobials, and critically important substances in particular, are still possible.