Monitoring Antibiotic Usage in German Dairy and Beef Cattle Farms-A Longitudinal Analysis.

It is well-established that antimicrobial use is a major factor for the development of antimicrobial resistance. To analyze the associations between antimicrobial resistance and usage of antimicrobial agents, data from monitoring and surveillance systems are crucial. Within the project VetCAb (Veterinary Consumption of Antibiotics), antibiotic usage data in German livestock is regularly collected and evaluated. Based on a cross-sectional study in 2011, the project was continued as the longitudinal study VetCAb-Sentinel with ongoing participant recruitment and data collection from 2013. The data collection is based on official German application and delivery forms (ADF), voluntarily provided by veterinarians and farmers. In this study the results of antibiotic usage data of dairy cows, dairy calves and beef cattle were described, using a semi-annual treatment frequency, and 95,944 ADF issued between 2011 and 2015 were analyzed. Results show that the median of the treatment frequency in dairy calf and beef cattle holdings slightly decreased from 0.4 to 0.3 and from 0.2 to 0 days, respectively, whereas the median in dairy cow holdings ranged between 1.9 and 2.3 during the observed period. Temporal changes and the effect of the factors "farm size" and "region" on the treatment frequency were investigated, using multiple linear mixed and logistic regression models. Generally, the factor "time" has a statistically significant impact on the treatment frequency in all production types. In addition, a temporal trend test over the first six half-years shows that an increasing linear trend can be stated in dairy cows and dairy calves (p = 0.017; p = 0.004, respectively). If the time-period is extended to all eight half-years under study, this turns into a quadratic effect (dairy cows: p = 0.006; dairy calves: p < 0.001). In dairy calves and beef cattle the factor "farm size" also has a statistically significant impact. The factor "region," in contrast, shows no statistically significant impact at all. Compared to other livestock populations in Germany, the use of antimicrobials in dairy cows, dairy calves, and beef cattle appears to be low, but varies across several associated factors. Considering these effects, it is recommended that the size of dairy calf and beef cattle holdings is regularly considered in the evaluation of antimicrobial usage data over time.

Association of farm-related factors with characteristics profiles of extended-spectrum ß-lactamase- / plasmid-mediated AmpC ß-lactamase-producing Escherichia coli isolates from German livestock farms.

Resistance to ß-lactam antibiotics, including third-generation cephalosporins, is of major concern for animal and human health. In this study, extended-spectrum ß-lactamase (ESBL) / plasmid-mediated AmpC (pAmpC) ß-lactamase -producing Escherichia coli isolates from German livestock farms were characterised and associations of these isolate characteristics with farm-related factors were investigated across different types of livestock. A total of 469 isolates originating from 150 farms (34 broiler farms, 38 fattening pig farms, 43 dairy cattle farms, 35 beef cattle farms) was included in the analyses. ESBL-gene family, phylogroup and phenotypic antimicrobial susceptibility for several antimicrobial agents were determined. This data was used to define different profiles characterising the isolates. Multivariate analyses using a distance-based non-parametric approach were performed to investigate associations between the profiles of the isolates and farm-related factors (e.g. management, husbandry, and environment of the farms). Co-occurrence of ESBL-gene families were not found in any of the isolates analysed. Sixty-eight percent of the isolates carried blaCTX-M variant genes. The frequency of phylogroups was as follows: A (55%), B1 (35%), D (17%) and B2 (3%). The most frequent phenotypic non-wildtype profile was non-wildtype status of solely cefepime (27%). Profiles of isolates from broilers differed substantially from those of other isolates. Associations between farm-related factors and characteristics profiles differed, depending on the isolate characteristics included in the analyses. Some factors describing the farm environment, like waterfowl in the surrounding of the farm, were associated with all tested profiles. The epidemiological method applied defines distances between isolates on basis of isolate characteristics data and is capable of analysing associations between isolate characteristics and epidemiological factors. As additional data, such as plasmid characteristics, gene type, or sequence information could be included in future studies, the method is suitable to identify points of action to reduce the occurrence of antimicrobial resistant bacteria.

Antibiotic use on German pig farms - A longitudinal analysis for 2011, 2013 and 2014.

To study antibiotic use in livestock in a temporal context with the development of antimicrobial resistance, long-term changes in antibiotic use must be mapped and their possible causes must be explored. Therefore, the present work assesses the changes in antibiotic use over time in German livestock husbandry. In addition, factors associated with antibiotic use were analyzed to identify possible strategies for further reducing antimicrobial usage. For 2011, 2013 and 2014, antibiotic usage data were collected and examined within the VetCAb project. Three hundred participating pig holdings provided information on their antibiotic use based on obligatory application and delivery forms (ADFs) filled in by their veterinarian as well as information on their current stabling capacities for each production type held. Data on sow, piglet, weaner and fattening pig holdings were described separately, using the semi-annual treatment frequency (TF) to measure antibiotic consumption. Multiple linear mixed models were used to investigate the effects of time, farm size, region and farm management category on the treatment frequency. The study yielded significant time changes with p-values below 0.001 in antibiotic administration with a decreasing median TF in piglets from 3.8 in the first half of 2011 (IQR = 1.1-10.6) to 1.7 in the second half of 2014 (IQR = 0.2-4.5) and in fattening pigs from 5.1 in the first half of 2011 (IQR = 0.2-15.4) to 0.7 in the second half of 2014 (IQR = 0.1-6.7). Meanwhile the TF fluctuated between 8.2 and 12.2 in weaners during the observational period (IQRs between zero (lower quartile) and 37.9 (upper quartile)). Piglet, weaner and fattening pig holdings belonging to the upper third of the holdings in size used significantly more antibiotics than the other holdings investigated. Particularly for weaner and fattening pig holdings, a higher TF was noted for farms without breeding units. The region was only a significant factor in weaners. In conclusion, for 2011, 2013 and 2014, the present study shows a clear reduction in antibiotic treatment frequency in German pig holdings. In addition, the association with various factors such as herd size and farm organization on the antibiotic usage frequency is indisputable. Therefore, these factors should be included in monitoring systems and considered when evaluating intervention measures.

Investigation of potential risk factors for the occurrence of Escherichia coli isolates from German fattening pig farms harbouring the mcr-1 colistin-resistance gene.

Within the scope of a cross-sectional investigation on fattening pig farms conducted in 2011 and 2012, 48 fattening farms in different agricultural regions of Germany were sampled. Primary cultures of boot swabs and collective faecal samples were stored at -80 °C and screened for the presence of the mcr-1 colistin-resistance gene. The laboratory results were linked to farm-related data collected via questionnaire. Logistic regression models were used to investigate the association between occurrence of mcr-1 and farm-related data. Escherichia coli carrying the mcr-1 gene were isolated from 26 of 216 (12.0%) mixed bacterial cultures originating from 12 of 48 (25.0%) farms. Results of the logistic regression analyses indicate that the transmission between pigs or their direct environment is crucial for the occurrence of these resistant bacteria. However, there was no statistically significant association between antimicrobial use and the occurrence of the mcr-1 gene.

Cefotaxime-resistant E. coli in dairy and beef cattle farms-Joint analyses of two cross-sectional investigations in Germany.

Resistance to third-generation cephalosporins and other beta-lactam antibiotics is of major concern for animal and human health. Knowledge of the prevalence of resistant bacteria in primary production is an important element to estimate transmission along the stages in the food production chain and the exposure of the human population. The primary objective of this study was to determine the prevalence of cefotaxime-resistant commensal E. coli in dairy and beef cattle production units throughout Germany. Secondarily, the association between management factors and the presence of cefotaxime resistance was investigated. In total, 60 beef cattle and 52 dairy cattle production units all over Germany were included. Cefotaxime-resistant E. coli were isolated from at least one sample in 70% (95% CI: 58-83%) of the farms keeping beef cattle and 85% (95% CI: 75-94%) of the farms keeping dairy cattle. The sample prevalence was 35% (161/455; 95% CI: 31-40%) and 48% (156/323; 95% CI: 43-54%), respectively. Most factors associated with resistance to cefotaxime indicate that less intensive production results in a lower number of positive samples. For beef cattle, antimicrobial treatment of the whole animal group was significantly associated with an increased proportion of samples containing cefotaxime resistant E. coli. In addition, our results indicate that better hygiene management could improve the resistance situation on cattle farms.

Frequent occurrence of nonprimate hepacivirus infections in Thoroughbred breeding horses - A cross-sectional study for the occurrence of infections and potential risk factors.

Recently, several new hepaciviruses have been identified of which the nonprimate hepacivirus (NPHV) - the closest relative to hepatitis C virus (HCV) discovered to date - is highly prevalent in horses. However, potential risk factors for the transmission of NPHV among horses remain still unknown. Therefore, the objective of this study was to investigate the occurrence of NPHV infections in Thoroughbreds in northern and western Germany and to identify potential risk factors associated with NPHV infections. Using a cross-sectional study design, a total of 733 serum samples from Thoroughbred broodmares and stallions from northern and western Germany were analyzed for the presence of anti-NPHV nonstructural protein 3 (NS3) antibodies and NPHV RNA using the luciferase immunoprecipitation system (LIPS) and a quantitative real-time PCR, respectively. Information regarding signalment, stud farm, breeding history and international transportation history of each horse were collected and evaluated. A frequent occurrence of NPHV was found in the study population with 453 seropositive horses (61.8%) and 134 horses (18.3%) carrying NPHV RNA. Furthermore, statistical analysis revealed that the probability of being infected decreased for horses with a transportation history with increasing age by 20% each year. For horses that stayed in Germany no association between age and infection could be observed. In conclusion, the high occurrence of NPHV infections in breeding Thoroughbreds suggests circulating NPHV infections, endemic herds or persistent shedding in these animals and revealed the association of age and international transportation as risk factor for NPHV infections.

Simultaneous occurrence of MRSA and ESBL-producing Enterobacteriaceae on pig farms and in nasal and stool samples from farmers.

Methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum ß-lactamase (ESBL) producing enterobacteria (ESBL-E) have emerged in livestock. This study prospectively investigates the prevalence of MRSA and ESBL-E on pig farms and in nasal and stool samples from farmers and compares molecular characteristics of these ESBL-E isolates. In 2014, samples were derived at 51 pig farms in Germany. Per farm, five dust and five fecal samples were collected; one nasal and one stool sample were retrieved from farmers. ESBL-E isolates from humans and environmental isolates from the respective farms were characterized using whole genome sequencing for classical multilocus sequence typing (MLST), determination of ESBL-encoding genes and an ad hoc core genome MLST (cgMLST) analysis. MRSA and ESBL-E were detected on 49 (96%) and 31 (61%) of the farms, respectively; in most cases (59%) simultaneously. Nasal MRSA carriage was detected in 72 of 85 (84.7%) farmers and five of 84 (6.0%) farmers carried ESBL-E. ESBL-Escherichia coli isolates from farmers belonged to MLST STs/ESBL-genes ST10/CTX-M-1, ST196/TEM-52, ST278/TEM-52, ST410/CTX-M-15 and ST453/CTX-M-1. In one case, the human ESBL-E isolate was clonally identical to isolates from the farm environment; in the other four cases typing results indicated potential exchange of resistance determinants between human and environmental isolates, but, comparing the isolates within a minimum spanning tree indicated differences in cgMLST-patterns between the farms (p=0.076). This study demonstrated rectal ESBL-E carriage rates among farmers, which were similar to those in the general population. Molecular typing suggested that cross-transmission between the farmers and the farm environment is possible.

Antimicrobial-Resistant Escherichia coli Survived in Dust Samples for More than 20 Years.

In a retrospective study, 119 sedimentation dust samples stored between five and 35 years from various barns of intensive livestock farming were evaluated for the occurrence of cultivatable Escherichia coli. Growth of E. coli occurred in 54 samples. Successful cultivation was achieved in samples from as early as 1994. The frequency of detection increased from earlier to later time periods, but the concentrations, which ranged between 3.4 × 10(2) and 1.1 × 10(5) colony-forming units per gram, did not correlate with sample age (Spearman rank correlation; p > 0.05). We hypothesize that E. coli cells survived in dust samples without cell division because of the storage conditions. Dry material (dust) with low water activities (arithmetic mean < 0.6) and storage at 4°C in the dark likely facilitated long-term survival. E. coli were isolated on MacConkey agar with and without ciprofloxacin supplementation. For 110 isolates (79 from non-supplemented media and 31 from supplemented media), we determined the E. coli phylotype and antimicrobial resistance. Six phylogenetic groups were identified. Phylogroups A and B1 predominated. Compared to group A, phylogroup B1 was significantly associated with growth on ciprofloxacin-supplemented media (chi-square test, p = 0.003). Furthermore, the antibiotic resistance profiles determined by a microdilution method revealed that isolates were phenotypically resistant to at least one antimicrobial substance and that more than 50% were resistant to a minimum of five out of 10 antibiotics tested. A linear mixed model was used to identify factors associated with the number of phenotypic resistances of individual isolates. Younger isolates and isolates from fattening poultry barns tended to be resistant to significantly more antibiotics than older isolates and those from laying-hen houses (p = 0.01 and p = 0.02, respectively). Sample origin and storage conditions may have influenced the number of antimicrobial resistances. Overall, we found that under particular conditions, dust from farm animal houses can be reservoirs for antimicrobial-resistant E. coli for at least 20 years. The survival strategies that allow E. coli to survive such long periods in environmental samples are not fully understood and could be an interesting research topic for future studies.

[Prevalence and severity of lameness in early lactation in dairy cows and the effect on reproductive performance]. / Prävalenz von Lahmheiten unterschiedlichen Grades in der Frühlaktation von Milchkühen und deren Einfluss auf Fruchtbarkeitsparameter.

OBJECTIVE: To examine the impact of different degrees of lameness on the fertility of dairy cows. MATERIAL AND METHODS: Seven dairy herds housed in free stall barns with cubicles were visited at 4-week intervals and all cows were examined for locomotion characteristics using a locomotion scoring system. The cows received scores from 1 (normal gait) to 5 (severely lame). During the study period of 18 months, 893 cows in the first month of lactation and 944 cows in the second, third and fourth months of lactation were evaluated. Reproductive measures between non-lame cows (score 1), mild lame cows (score 2) and cows with clear lameness (score ≥ 3) were compared. RESULTS: Independent of parity and herd effects, cows with scores ≥ 3 in the first month of lactation displayed a 6 days longer calving to first service interval (CFSI) (86.2 ± 35.6 vs. 80.2 ± 34.1 days; p = 0.002) and a 16 days longer calving to conception interval (CCI) (119.7 ± 51.4 vs. 103.8 ± 55.5 days; p = 0.048) than non-lame cows. Additionally, the risk for non-conception was significantly higher in cows suffering from lameness in the first month of lactation (odds ratio: 2.1, 95% confidence interval: 1.095, 4.040; p = 0.026). Cows affected by mild lameness in the third month of lactation had a 4 days longer CFSI (84.7 ± 35.6 vs. 80.1 ± 30.5 days; p = 0.026) and a 18 days longer CCI (120.1 ± 55.4 vs. 102.3 ± 47.6 days; p = 0.016) than non-lame cows, while the CSFI in distinct lame cows was extended by 7 days compared to non-lame cows (87.2 ± 34.9 vs. 80.1 ± 30.5 days; p = 0.002). Cows with the score 1 in the first month and score 3 in the third month of lactation showed the longest CSFI (94.3 ± 33.9 vs. 76.5 ± 16.0 days in non-lame cows; p = 0.046). CONCLUSION AND CLINICAL RELEVANCE: This study suggests that both distinct and mild lameness in early lactation lead to a decline in reproduction in dairy herds. A regular determination of the lameness prevalence in dairy herds and optimizing claw health management, including early treatment of lame cows, will enhance animal welfare and reproduction efficiency.

[Possible causes of unspecific reduced productivity in dairy herds in SchIeswig-Holstein: an explorative case-control study]. / Mögliche Ursachen für unspezifische Leistungsminderung in Milchkuhherden in Schleswig-Holstein: eine explorative Fall-Kontroll-Studie.

Recently unspecific productivity losses were observed in dairy herds in Schleswig Holstein, Germany. This case-control study on cattle health investigated the possible association between a multifactorial event and the occurrence of unspecific productivity losses. 35 dairy farms were defined as cases and 65 farms as controls, when they met two out of three eligibility criteria, respectively (cell count, mortality and life production of cows). Case farms had relevantly more often problems with forage collection (too low cutting height), feed storage (no foil used), and energy supply of dairy cattle (insufficient feeding of corn silage and lowered energy content of grass silage). Case farms had relevantly more often dirty lying areas, feeding and walking alleys, feed bunks and watering places as well as more cows with dirty udders, flanks and legs than control farms. Farm individual self-control as well as veterinarian and agricultural consultancy should focus on these management areas. Furthermore, the health situation should be checked regularly on an individual animal level for diseases of the locomotor (especially by intensifying claw care), metabolic and reproductive systems. Additionally, 22 so-called intermediate farms with considerable herd health problem during the study period were investigated for possible exogenous influences on the farm performance. There were no indications for influences by the soil type, weather conditions at harvesting or wild bird occurrence on cropland, which might be as well due to the explorative nature of the study. However, herd health problems were apparent in case and intermediate farms more often and more diversely than in control farms.

[Lactational incidences of common diseases in dairy herds in Schleswig-Holstein (Germany): effect of first test-day milk yield, herd milk yield and number of lactation]. / Erkrankungshäufigkeit von Milchviehherden in Schleswig-Holstein: Einfluss der Milchleistung bei der ersten Milchleistungsprüfung der Laktation, der Herdenmilchleistung und der Laktationsnummer.

It was the aim of this study to record common diseases in dairy cows in Schleswig-Holstein, Germany, and to describe associations between lactation number (LN: 1, 2, > 2), first test-day milk yield (TD1: < 30 kg, ≥ 30 kg) and herd milk yield (HM: ≤ 7500 kg, > 7500 kg), the latter parameter serving as a proxy for herd management (extensive vs. intensive). Data of 98 dairy herds (6439 lactations) were processed on cow level using mixed logistic regression models with LN< TD1, HM and calving season as fixed effects and herd as random effect. Lactational incidences were as follows: hypocalcaemia (5.0%), dystocia (13.2%), retained placental membranes (7.2%), clinical metritis/endometritis (4.9%), clinical mastitis (15.3%), subclinical mastitis (61.9%), ketosis (1.6%), displaced abomasum (0.4%), lameness (15.4%). Number of lactation (2, > 2 vs. 1) was a risk factor for hypocalcaemia (OR 3.715, 23.047), retained placental membranes (OR 1.764, 2.479), clinical mastitis (> 2 vs. 1 OR 2.118), subclinical mastitis (OR 1.668,4.397), ketosis (> 2 vs. 1 OR 3.936) and lameness (OR 1.275, 2.070). Older cows had a lower risk for dystocia (OR 0.373, 0.357). TD1 (≥ 30 kg) was not a risk factor of disease except for subclinical mastitis in first parity animals (OR 1.319). Herd milk yield (> 7500 kg) was a risk factor for clinical metritis/endometritis (OR 1.971), displaced abomasum (OR 7.764), lameness (OR 1.618) and hypocalcaemia (cows with high TD1 [OR 2.273]). In conclusion, not individual milk yield, but herd milk yield as an indicator of differences in intensity of herd management as well as number of lactation seemed to influence the frequency of common diseases in dairy cows.

[Statistical methods for description of phenotypic susceptibility data]. / Statistische Verfahren zur Beschreibung von phänotypischen Empfindlichkeitsdaten.

This paper summarizes statistical methods to describe susceptibility data. A frequent data basis in resistance studies are minimum inhibitory concentrations (MICs), measured for different antimicrobial agents. In the statistical context these (semi) quantitative MIC values are ordinal scaled. Therefore, they should be analysed with statistical tools appropriate for ordinal data. The resistance situation for each antimicrobial agent is often described using frequency distributions of MIC values. Resistance patterns can be described by frequencies of resistance profiles. More detailed insights into appearance and changes of simultaneous resistance against different agents are provided by a systematic analysis of dependency structure in susceptibility data. Furthermore, the calculation of differences between resistance profiles using appropriate distance measures enables the application of common methods of multivariate statistic for description and more complex analysis of susceptibility data. To improve the comparability of study results, it is desirable to present as much information as possible in a uniform way.

Epidemiology of influences on the performance in broiler flocks--a field study in Germany.

To establish which factors influence performance and bird welfare during a fattening period and to identify those factors to be investigated during routine monitoring of farms by veterinary authorities, a questionnaire-based field study was conducted in districts of Lower Saxony, Germany, with the highest density of broiler chickens. Mortality and BW of farms with different stocking densities (≤33, 33.1-39, and >39 kg/m(2)) were investigated. Analyses of 79 farms with 176 stables and 634 fattening periods revealed that flock mortality and BW appeared to be greatly influenced by weather conditions and litter material. In general, it is an advantage to grow broilers under warm weather conditions. However, the longer the fattening period lasts the more important it becomes that the outside weather conditions are not too warm. Therefore, weather conditions should be considered when determining the length of the fattening period, especially before the background of the growing demands of broilers regarding ventilation, absorption of feces by the litter material, and so on. Apart from the length of the fattening period, the weather conditions determine the choice of the litter material, as well. Under cold-humid weather conditions, it is better to use litter material other than wood shavings. In particular in older buildings it is not possible to provide the required conditions, which results in a lower weight gain the longer the fattening period lasts. The study identified differences in the final BW of flocks, which indicate different (farm) management policies. Regardless of the underlying policy, the performance of a fattening period can be improved by optimizing the farm management according to the prevalent conditions. Future routine monitoring, which should be cost effective regarding personnel and finance, should be generally risk based and consider weather conditions, litter material, the age of the building, and the length of the fattening period.

Ticks on pastures and on two breeds of cattle in the Eastern Cape province, South Africa.

Many studies on the population dynamics of questing ticks on pastures and of parasitic ticks on cattle have been conducted. Few, however, have attempted to link the two in a single study. This study aimed to assess the population dynamics of questing ixodid ticks on pastures and of adult ticks on two breeds of cattle with different levels of susceptibility to tick infestation on the same pastures. Between January 2005 and December 2009 questing ixodid ticks were collected monthly from natural pastures at the Döhne Agricultural Development Institute and at the adjacent Campagna Production System in the Amahlathi District, Eastern Cape province, South Africa. Between February 2007 and January 2010 adult ticks were collected monthly from Bonsmara and Nguni cattle grazing these pastures. Ten tick species were collected from the pastures and 12 from the cattle. Significantly more questing larvae of Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus evertsi evertsi and Rhipicephalus microplus were recovered from the pastures grazed by Bonsmara cattle than from those grazed by Nguni cattle (p ≤ 0.05). Significantly more adult Hyalomma rufipes, Rhipicephalus follis, R. appendiculatus, R. decoloratus, R. evertsi evertsi and R. microplus were collected from the Bonsmara cattle than from the Nguni cattle (p ≤ 0.05). The study showed that Nguni cattle are less susceptible to tick infestation than are Bonsmara cattle and fewer questing ticks are collected from pastures grazed by Nguni cattle than by Bonsmara cattle.

Village livestock population and sampling strategies in communal areas in the Eastern Cape Province, South Africa.

There is an urgent need for a livestock census in communal areas of the Eastern Cape Province, South Africa. This study focuses on the description of the cattle, sheep, and goat populations with emphasis on the livestock distributions and population characteristics in a pilot study in two wards in communal farm land. In one of the wards, sample homogeneity was found in the cattle and goat populations. In contrast, in the second ward sheep and goat populations were found heterogeneous, and only cattle showed homogeneity. As a consequence, the use of a simple random sampling strategy for the livestock population can be recommended in one ward whereas a more complex stratified random sampling strategy is recommended for the other. The organization and logistics costs must be taken into consideration when organizing a livestock census. Therefore, the observations of this study prepare the decision on sampling schemes for future census activities. The possibility of using a complete enumeration census should not be discarded especially in areas with heterogeneous livestock populations where the organization of a complex sampling strategy can prove to be time-consuming and complicated to be executed in the field.

Influence of animal, herd and management factors on perinatal mortality in dairy cattle--a survey in Thuringia, Germany.

It was the aim of this study to identify cow/calf, herd and management risk factors on perinatal mortality (PM) in dairy herds from the German federal state of Thuringia. Perinatal mortality was defined as cases of stillborn calves or calves having died within 24 h after birth. From a representative sample of 53 herds (breeds: Holstein Friesian and crossbreedings between Holstein Friesian and Blackpied Dairy Cow), dairy herd improvement (DHI) records were obtained providing information about number of calvings, frequency of PM, parity, calving ease, gender, twin calvings and herd milk yield. Management practices (farm organisation, breeding policies, calving management, hygienic measures, feeding, status of infectious diseases) were recorded using a questionnaire filled in whilst interviewing the herd owner. Data of one year from 46 herds with 13 158 calvings were analysed using logistic regression models applying generalised estimation equations (GEE). The overall frequency of PM was 9.3%. The odds ratio for PM was 5.89, 1.73, 1.68 and 1.67 in cases of dystocia, heifer calving, twin and male calves, respectively. None of the management factors examined in this study remained as significant effects for PM in the final logistic regression model. In conclusion, the results of this study suggest that cow/calf related factors reported as risk factors for PM in many studies in the past such as dystocia, number of lactation, gender and twins were also major determinants of PM in commercial dairy herds in Thuringia. Besides applying appropriate breeding policies herd owners should primarily consider ways of further improving calving management with proper calving supervision and correct calving assistance in order to reduce the risk of PM.