The aim of this case series was to describe how the selective dry-off therapy affected the udder health of Bavarian dairy farms under field conditions as well as to record whether a long-term reduction in antibiotic dry-off therapy was feasible. Between 2016 and 2021, 90 herds participated. A subset of dairy herds participated over a period of several years. Quarter milking samples were taken annually from all lactating cows in the herds, and treatment and test day results were evaluated. Major pathogens were detected during the initial whole herd testing (e. g., Streptococcus agalactiae, Streptococcus canis) and the treatment regimen needed to be adjusted. Even though the median treatment risk decreased, at least numerically, from 63% to 50%, the treatment rate in individual herds could vary greatly between years (-60% to+40%). Selective dry-off therapy can be implemented without endangering the udder health of the herd.
Bei dieser Fallserie wurde die Umsetzung des selektiven Trockenstellens auf 90 bayerischen Milchviehbetrieben bezüglich der Reduktion von antibiotischen Behandlungen zum Trockenstellen sowie deren Auswirkung auf die Eutergesundheit untersucht. Zwischen 2016 und 2021 wurden die Betriebe teilweise für mehr als 3 Jahre hierbei begleitet und jährlich Viertelgemelksproben aller laktierenden Kühe der Herden genommen sowie Behandlungs- und Probemelkergebnisse ausgewertet. In einigen Herden wurden zu Beginn kontagiöse Erreger (Streptococcus agalactiae oder Streptococcus canis) nachgewiesen und durchschnittlich waren 62% der Kühe zu Beginn antibiotisch zum Trockenstellen behandelt worden. Die Häufigkeit von Trockensteherbehandlungen schwankte von Jahr zu Jahr bei den Betrieben, zeigte aber im Durchschnitt eine sinkende Tendenz. Die Eutergesundheit der Herden (Zellzahl) blieb über die Jahre annähernd gleich, die kuhassoziierten Erreger wurden weniger. Lediglich ab Jahr 3 stieg die Neuinfektionsrate während der Trockenstehphase.

The report describes an outbreak of Staphylococcus aureus mastitis in a dairy herd. The risk assessment included the analysis of data from milk recordings, bacteriological milk cultures, clinical mastitis records and influence of infected status on the culling risk of affected animals, as well as an evaluation of the milking routine. The milking routine and the treatment protocol of animals with Staphylococcus aureus infection were identified as possible risk factors. The implemented measures included changes to the milking routine, a different treatment protocol for infected animals, and culling and segregation of infected animals to reduce overall prevalence.
Der vorliegende Bericht beschreibt einen Fall gehäuften Auftretens von Staphylococcus-aureus-Mastitiden in einer Milchviehherde. Daten der Milchleistungsprüfung, bakteriologische Milchprobenergebnisse, Aufzeichnungen über das Auftreten klinischer Mastitiden einschließlich deren Verlauf und Einfluss auf den Verbleib in der der Herde betroffener Tiere sowie die Beurteilung der Melkroutine wurden zur Abklärung herangezogen. Die Melkroutine sowie das Behandlungsprotokoll für Tiere mit einer Staphylococcus-aureus-Infektion wurden als mögliche Risikofaktoren identifiziert. Umgesetzte Maßnahmen beinhalteten Veränderungen in der Melkroutine und dem Behandlungsprotokoll für infizierte Tiere sowie Keulung oder Abtrennung bereits infizierter Tiere.

Escherichia coli is one of the major pathogens causing mastitis that adversely affects the dairy industry worldwide. This study employed whole genome sequence (WGS) approach to characterize the repertoire of antibiotic resistance genes (resistome), virulence genes (virulome), phylogenetic relationship and genome wide comparison of a multi drug resistant (MDR) E. coli(SCM-21) isolated from a case of subclinical bovine mastitis in Bangalore, India. The genome of E. coli SCM- 21 was found to be of 4.29 Mb size with 50.6% GC content, comprising a resistome of 22 genes encoding beta-lactamases (blaTEM,blaAmpC), polymyxin resistance (arnA) and various efflux pumps (acr, ade, emr,rob, mac, mar, rob), attributing to the bacteria\'s overall antibiotic resistance genetic profile. The virulome of E. coli SCM-21 consisted of genes encoding different traits [adhesion (ecp, fim, fde), biofilm formation (csg) and toxin production (ent, esp, fep, gsp)], necessary for manifestation of the infection. Phylogenetic relationship of E. coli SCM- 21 with other global E. coli strains (n = 4867) revealed its close genetic relatedness with E. coli strains originating from different hosts of varied geographical regions [human (Germany) bos taurus (USA, Belgium and Scotland) and chicken (China)]. Further, genome wide comparative analysis with E. coli (n = 6) from human and other animal origins showed synteny across the genomes. Overall findings of this study provided a comprehensive insight of the hidden genetic determinants/power of E. coli SCM-21 that might be responsible for manifestation of mastitis and failure of antibiotic treatment. Aforesaid strain forms a reservoir of antibiotic resistance genes (ARGs) and can integrate to one health micro biosphere.

BACKGROUND: Mastitis is the most common health concern plaguing the modern dairy cow and costs dairy producers estimates of two billion dollars annually. Staphylococcus aureus infections are prevalent, displaying varied disease presentation and markedly low cure rates. Neutrophils are considered the first line of defense against mastitis causing bacteria and are frequently targeted in the development of treatment and prevention technologies. We describe a case of naturally occurring, chronic mastitis in a Holstein cow (1428), caused by a novel strain of S. aureus that was not able to be cleared by antibiotic treatment.
METHODS: The infection was identified in a single quarter, 2 months into the cow\'s first lactation. The infection persisted for the following 20 months, including through dry off, and a second calving and lactation. This case of mastitis was associated with a consistently high somatic cell count, however presented with no other clinical signs. This cow was unsuccessfully treated with antibiotics commonly used to treat mastitis, consisting of two rounds of treatment during lactation and an additional round at the beginning of dry off. The chronic infection was also unchanged through an experimental mid-lactation treatment with pegylated granulocyte-colony stimulating factor (PEG-gCSF) and an additional periparturient treatment with PEG-gCSF. We isolated milk neutrophils from 1428 and compared them to two cows challenged with experimental S. aureus, strain Newbould 305. Neutrophils from 1428\'s milk had higher surface expression of myeloperoxidase compared to experimental Newbould challenged animals, as well as increased presence of Neutrophil Extracellular Traps. This suggests a heightened activation state of neutrophils sourced from 1428\'s naturally occurring infection. Upon postmortem examination, the affected quarter revealed multifocal abscesses separated by fibrous connective tissues. Abscesses were most common in the gland cistern and collecting duct region. Microscopically, the inflammatory reaction was pyogranulomatous to granulomatous and consistent with botryomycosis. Colonies of Gram-positive cocci were found within the eosinophilic matrix of the Splendore-Hoeppli reaction within granulomas and intracellularly within the acinar epithelium.
CONCLUSIONS: Collectively, we describe a unique case of chronic mastitis, the characterization of which provides valuable insight into the mechanics of S. aureus treatment resistance and immune escape.

The objective of this case-control study was to determine the herd- and cow-level risk factors associated with an outbreak of Mycoplasma bovine mastitis in the winter of 2014-2015 in Nemuro, Hokkaido, Japan. Two questionnaire surveys were sent to all 40 Mycoplasma-infected farms in the area and 73 non-infected farms for the farm-level analysis. Infected cows were matched to twice the number of non-infected cows in the same herds by parity and days after calving. Movement records, dairy herd test records, and clinical records of infected cows and matched non-infected cows were collected for the cow-level analysis. Risk factors for Mycoplasma infection were explored by multivariable analyses at both levels. In the herd-level analysis, tie stall housing for milking cows (odds ratio [OR] = 0.20, 95 % confidence interval [CI]: 0.07-0.60, p =  0.004), consciously wiping of teat openings before milking (OR = 0.15, 95 % CI: 0.02-0.76, p =  0.030), and use of paper towels to wipe teats (OR = 0.31, 95 % CI: 0.09-0.92, p =  0.045) were identified as preventive factors, whereas introduction of cattle (OR = 3.43, 95 % CI: 1.14-10.86, p =  0.030) was identified as a risk factor. In the cow-level analysis, a history of presence in livestock markets (OR = 10.80, 95 % CI: 1.12-104.38, p =  0.040), higher milk yield 2 months prior to Mycoplasma infection (OR = 1.09, 95 % CI: 1.02-1.18, p =  0.014), and previous diagnosis of acute mastitis without isolation of the causal pathogen (OR = 3.14, 95 % CI: 0.86-11.41, p =  0.082) were identified as risk factors. These results highlight the importance of proper milking hygiene control and quarantine of introduced cattle to prevent Mycoplasma infection.

The study was conducted to describe the dynamics of ST398 methicillin-resistant Staphylococcus aureus (MRSA) on a dairy herd in northeastern Italy. MRSA was first identified in this herd of 120 cows in 2016, after which the herd was sampled once every 3 months for 1 year (April 2016-May 2017). Samples collected included nasal swabs and milk samples from cows and nasal swabs from farmworkers. In addition, pen fencing and teat milk liners were swabbed and air samples from cow pens and the milking parlor were collected. All samples were tested for MRSA using a selective medium; positive isolates were confirmed by mecA PCR. A representative set of MRSA isolates was genotyped using spa typing and multilocus sequence typing. Overall, 34 (mean 23%, range 16-30%) milking cows were found harboring MRSA in the mammary gland and only 6 recovered from infection or colonization. The mean incidence rate was 14% (range 8-20%), mean cure rate was 23% (range 13-43%), and estimated basic reproduction number (R0) was 1.08. The average of positive quarters found was 35.1% and most of the positive quarters (82.4%) developed subclinical mastitis. The mean duration of MRSA colonization in quarters during the study was 247 days, but quarters affected by subclinical mastitis harbored MRSA for a longer time than healthy ones (285 days vs. 131 days). After the second sampling, the farmer segregated MRSA-positive cows from the uninfected cows and milked them last. Despite segregation, 25 newly infected or colonized cows were detected. MRSA isolates from cows, environment, and two farmworkers belonged to the same sequence type (ST398) and spa type (t034). This study highlights the ability of ST398 MRSA to cause a persistent infection of the mammary gland and to survive in the farm environment.

The increasing attention for global warming is likely to contribute to the introduction of policies or other incentives to reduce greenhouse gas (GHG) emissions related to livestock production, including dairy. The dairy sector is an important contributor to GHG emissions. Clinical mastitis (CM), an intramammary infection, results in reduced milk production and fertility, increases culling and mortality of cows and, therefore, has a negative impact on the efficiency (output/input) of milk production. This may increase GHG emissions per unit of product. Our objective was to estimate the impact of CM in dairy cows on GHG emissions of milk production for the Dutch situation. A dynamic stochastic simulation model was developed to simulate the dynamics and losses of CM for individual lactations. Cows receive a parity (1 to 5+), a milk production and a calving interval (CI). Based on the parity, cows have a risk of CM, with a maximum of three cases in a lactation. Pathogens causing CM were classified as gram-positive bacteria, gram-negative bacteria, or other. Based on the parity and pathogen combinations, cows had a reduced milk production, discarded milk, prolonged CI and a risk of removal (culling and mortality) that reduce productivity of dairy cows and therefore increase GHG emissions per unit of product. Using life cycle assessment, emissions of GHGs were estimated from cradle to farm gate for processes along the milk production chain that are affected by CM. Processes included were feed production, enteric fermentation, and manure management. Emissions of GHGs were expressed as kg CO2 equivalents per ton of fat-and-protein-corrected milk (kg CO2e/t FPCM). Emissions of cows with CM increased on average by 57.5 (6.2%) kg CO2e/t FPCM compared with cows without CM. This increase was caused by removal (39%), discarded milk (38%), reduced milk production (17%) and prolonged CI (6%). The GHG emissions increased by 48 kg CO2e/t FPCM for cows with one case of CM, by 69 kg CO2e/t FPCM for cows with two cases of CM and by 92 kg CO2e/t FPCM for cows with three cases of CM compared with cows without CM. Preventing CM can be an effective strategy for farmers to reduce GHG emissions and can contribute to sustainable development of the dairy sector, because this also can improve the income of farmers and the welfare of cows. The impact of CM on GHG emissions, however, will vary between farms due to environmental conditions and management practices.

Our objective was to evaluate a 200,000 cells/mL somatic cell count (SCC) cut-point on both the quarter and composite level to determine its effectiveness at identifying subclinical mastitis infections in one commercial dairy herd in Central New York. Milk samples from 107 Holstein cows were used for analysis. All cows were eligible for enrollment provided they had 4 working udder quarters, were >14 and <365 d in milk, and had no clinical mastitis event or treatment with intramammary antibiotics ≤14 d prior to d of sampling. A total of 428 quarter and 107 composite samples from 34 primiparous and 73 multiparous animals were analyzed for total SCC and aerobic culture. Performance of SCC for identification of subclinically infected animals was evaluated against the gold standard aerobic culture. Sensitivities for a 200,000 cells/mL cut-point on both the quarter and composite basis were 28.6%, and specificities were 91.5% and 87.3% on the quarter and composite basis, respectively. Receiver operating characteristic (ROC) curves determined on a quarter basis found the cut-point that optimized the sensitivity and specificity of a positive culture was 32,000 cells/mL, with a sensitivity of 76.2%, a specificity of 62.4%, and an area under the curve (AUC) of 0.73. The ROC curve cut-point that optimized the sensitivity and specificity for the composite samples was 75,000 cells/mL, with a sensitivity of 57.1%, a specificity of 78.9%, and an AUC of 0.67. A large proportion of culture positive primiparous cows (38%) had low SCC (median of 101,000 cells/mL on the quarter and 80,000 cells/mL on the composite level), and therefore, when multiparous cows were examined separately, the cut-point that optimized sensitivity and specificity on the quarter basis increased to 645,000 cells/mL with a corresponding sensitivity of 34.8%, specificity of 97.5%, and AUC of 0.65. On the composite basis, the cut-point based on multiparous cows only was 152,000 cells/mL, with a corresponding sensitivity of 60.0%, and specificity of 82.0%, and an AUC of 0.65. Our data indicate that the 200,000 cells/mL cut-point was inefficient in identifying subclinically infected animals, regardless of whether quarter or composite sampling was used. The low prevalence of subclinical infections as well as the large proportion of minor pathogens, especially in primiparous animals, contributed to this inefficiency. This case study provides evidence that, with continued improvement upon mastitis control and reduction in major mastitis pathogens, blanket cut-points may no longer provide the same diagnostic usefulness as they once did.

Diseases caused by livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) are an important global public health concern, and MRSA is increasingly being isolated in bovine milk. However, information on the genotype and antimicrobial resistance of MRSA in bovine milk in Xinjiang is limited. The objective of this study was to determine the antimicrobial-susceptible phenotypes and genotypes of the circulating MRSA clone isolated in bovine mastits milk samples in Xinjiang, China.
Fifty six MRSA isolates collected from milk of bovine mastitis were investigated by multilocus sequence typing (MLST), staphylococcal protein A (spa) typing, and a minimum inhibitory concentration test with 21 antimicrobial agents.
Antibiotic resistance results showed that 47.4% of the isolates were resistant to 16 or more antibiotics. Twelve MLST types were defined in this study, and ST398 (n = 7) and ST2393 (n = 2) were found to be the most prevalent types. Seven spa types (t034, t269, t4030, t114, t35, t189, and t7589) were identified, of which t034 (n = 7), t189 (n = 3), and t4030 (n = 3) were predominant. Here, 3 MRSA ST188 is reported among human MRSA isolates in China, and this is the first time that it is reported in bovine MRSA strains.
The antimicrobial susceptibility of MRSA in this area exhibited multidrug resistance, and clonal complexes CC398 and CC188, which have been reported among human MRSA isolates, do occur in Xinjiang dairy cows. This study provides a foundation for further MRSA monitoring.

A large part of the world\'s resources are used to produce animal products. Efficient use of these resources is important to improve social well-being. Endemic animal diseases decrease production efficiency, because they require a higher level of input to produce the same amount of output or result in a lower output with the same amount of input. The optimal level of production with and without disease differs from farm to farm and depends on varying economic circumstances. Given these difficulties, making an accurate theoretical estimation of the economic impact of endemic diseases is challenging. Current approaches towards the economic assessment of endemic diseases are, therefore, quite pragmatic. For on-farm decision-making, the total costs consist of failure costs and preventive costs. Failure costs are associated with production losses (i.e. decreases in milk production, mortality and culling), treatment costs (i.e. veterinary treatment, drugs, and discarded milk) and the use of other resources associated with the occurrence of disease (i.e. increased labour costs). Preventive costs are associated with preventive measures in terms of equipment, consumables (e.g. diagnostics and chemicals) and the use of other resources to prevent diseases (i.e. increased labour). There is a substitution relationship between failure costs and preventive costs. That means that, in order to maximise profit at the farm level, the amount of resources invested in prevention should be chosen in such a way that total costs are minimised. The most studied endemic disease in animal production is mastitis. Most publications on mastitis only assess failure costs, and studies on assessing the total costs and best methods to determine an optimal level of prevention are scarce. Future challenges lie in researching frameworks that can assist decision-makers to establish optimal prevention levels for endemic diseases.
Une grande partie des ressources mondiales est consacrée à la production de produits d’origine animale. Il est important d’utiliser rationnellement ces ressources si l’on veut améliorer le bien-être des sociétés. Les maladies animales endémiques réduisent la rentabilité des élevages car en cas de maladie il faut plus d’intrants pour maintenir le niveau de production, tandis que celui-ci décroît si la quantité d’intrants demeure inchangée. Le niveau optimal de production avec ou sans maladie varie d’une exploitation à l’autre et dépend du contexte et des fluctuations économiques. Ces facteurs complexes expliquent la difficulté de réaliser une estimation théorique exacte de l’impact économique des maladies endémiques. En conséquence, les approches actuelles en matière d’évaluation économique des maladies animales privilégient le pragmatisme. Au niveau décisionnel des élevages, les coûts totaux englobent les pertes d’exploitation et les coûts de la prévention. Les pertes d’exploitation sont liées aux pertes de production (baisse de la production de lait, mortalité et animaux sacrifiés), au coût des traitements (prestations vétérinaires, médicaments, perte de lait en raison des traitements) et à l’utilisation d’autres ressources en lien avec l’apparition de la maladie (augmentation des coûts de main-d’oeuvre). Les coûts de prévention sont liés aux mesures de prévention et couvrent les équipements, les consommables (les réactifs et matériels de diagnostic et les produits chimiques) et l’utilisation d’autres ressources pour prévenir les maladies (augmentation des coûts de maind’oeuvre). Les pertes d’exploitation et les coûts de prévention sont mutuellement substituables. Ainsi, pour optimiser la rentabilité à l’échelle de la ferme, il conviendra de choisir le montant des ressources investies dans la prévention de manière à minimiser les coûts totaux. La mammite est la maladie endémique la plus étudiée en production animale. La plupart des publications sur la mammite évaluent uniquement les coûts de perte d’exploitation, peu d’études ayant été consacrées à l’évaluation des coûts totaux ou aux méthodes permettant de déterminer le niveau optimal de la prévention. Les défis futurs consisteront à élaborer des cadres permettant d’aider les décideurs à déterminer les niveaux optimaux de la prévention des maladies endémiques.
Buena parte de los recursos del mundo se destinan a la obtención de productos de origen animal. Para alcanzar mayores cotas de bienestar social es importante pues utilizar esos recursos de modo eficiente. Las enfermedades animales endémicas merman la eficiencia productiva porque exigen una mayor cantidad de insumos para obtener el mismo nivel de producción o, alternativamente, reducen la producción obtenida por una misma cantidad de insumos. El nivel óptimo de producción, en presencia y en ausencia de enfermedades, difiere de una explotación a otra y depende de parámetros económicos que son variables. Estas dificultades explican por qué resulta tan arduo hacer una estimación teórica precisa del impacto económico de enfermedades endémicas. De ahí que los métodos actuales para evaluar en clave económica las enfermedades endémicas revistan un carácter bastante empírico. En lo que concierne a las decisiones adoptadas en el ámbito de la explotación, el costo total está formado por las pérdidas de explotación y los costos de prevención. Las pérdidas de explotación vienen determinadas por las pérdidas productivas (menor producción de leche, mortalidad y animales sacrificados), el costo de los tratamientos (servicios veterinarios, medicamentos y leche desechada a consecuencia del tratamiento) y el uso de otros recursos ligados a la aparición de la enfermedad (mayores costes laborales). Los costos de prevención, que son aquellos vinculados a las medidas profilácticas, corresponden al equipo empleado, los bienes consumibles (como productos químicos o de diagnóstico) y la utilización de otros recursos para prevenir enfermedades (mayores costes laborales). Existe una relación de sustitución entre las pérdidas de explotación y los costos de prevención. Ello significa que, para que una explotación rinda el máximo beneficio, conviene fijar la cantidad de recursos invertidos en prevención de tal manera que ello reduzca al mínimo los costos totales. La enfermedad endémica más estudiada en producción animal es la mastitis. En la mayoría de las publicaciones que se le han dedicado solo se evalúan las pérdidas de explotación, y en cambio escasean los estudios encaminados a evaluar los costos totales o a definir el mejor método para determinar el nivel óptimo de prevención. De cara al futuro, se trata de buscar modelos que puedan ayudar a las instancias decisorias a fijar los niveles óptimos de prevención de enfermedades endémicas.