Association between herd management practices and antimicrobial resistance in Salmonella spp. from cull dairy cattle in Central California.

BackgroundIn this study cull dairy cows from six California dairy herds were sampled seasonally over the course of a year. The objectives were to determine the prevalence of antimicrobial resistant (AMR) Salmonella spp. shed in cull cow feces, and the factors associated with fecal shedding of AMR and multidrug resistant (MDR) Salmonella.MethodsSix dairy farms located in the San Joaquin Valley of California were identified and enrolled as a convenience sample. On each dairy, and once during each of the four seasons, 10 cull cows were randomly selected for fecal sampling on the day of their removal from the herd. In addition, study personnel completed a survey based on responses of the herd manager to questions related to the previous 4 month's herd management and the specific cattle sampled. Fecal samples were submitted to the California Animal Health and Food Safety laboratory for Salmonella isolation. Antimicrobial resistance was evaluated using broth microdilution method and a gram-negative assay plate following Clinical Laboratory Standards Institute (CLSI) guidelines and breakpoint references. All statistical models were survey adjusted for number of animals on sampling day.ResultsA total of 62 Salmonella were isolated from 60 of the 239 fecal samples collected. For 12% (95% confidence interval (CI) [3-20]) of fecal samples a multidrug resistant Salmonella was isolated. The survey-weighted results for the two most common drug classes for which isolates were resistant were tetracycline (39%; 95% CI [27-51]) and ampicillin (18%; 95% CI [9-27]). An important finding was the identification of cephalosporin as the third most common drug class for which isolates were resistant, with ceftriaxone (10%; 95% CI [2-17]) being the most common drug associated with resistance in that class. At the cow-level, reason for culling, prior treatment with antimicrobial drugs as the reason for culling was associated with higher odds of isolating an AMR Salmonella isolate. At the herd-level, percent of animals monthly culled on the farm as well as number of milking cows in the herd were associated with isolation of antimicrobial resistant Salmonella in cull cows.DiscussionSalmonella isolated from fecal samples from cull cows were resistant to important antimicrobials, such as ceftriaxone. The most common drug classes for which isolates were resistant were tetracyclines and beta-lactams, with ampicillin, ceftriaxone and ceftiofur being the three most common drugs within the latter. Cow and herd level factors were associated with isolating antimicrobial resistant Salmonella that should be further investigated for their potential role in promoting occurrence of AMR Salmonella. Our results also highlight the importance of monitoring dairy cattle sent to slaughter for shedding of Salmonella resistant to medically important antimicrobial drugs

Reproductive disorders in Portuguese Serrana goats and its effects on milk production

Abstract Background: Abortions and parturitions with stillbirths are frequent in goat herds. However, the incidence of these events should remain low and their effects on subsequent lactation need to be assessed at breed level. Objective: To evaluate the incidence of abortions and parturitions with stillbirths (APS) in Portuguese Serrana goats breed ecotype Transmontano, and their association with milk production in subsequent lactation. Methods: Records of Serrana goats ecotype Transmontano from the pedigree book between 1997 and 2014 were used in order to determine the occurrence of APS. Goat level information, such as normal parturition and/or APS dates, number of fetuses, parity, and 150-d normalized milk production for each subsequent lactation, was considered. Results: The average incidence of APS was 8.7% (19,351/223,798). According to a multivariable logistic analysis, the year, month, parity, gemelarity, and their interactions were factors significantly (p<0.001) associated with APS. In overall, a higher APS incidence was observed in single births and primiparous goats. The 150-d normalized milk production was lower (p<0.001) in the APS group than in goats with normal parturitions. Conclusion: The APS incidence in Serrana goats ecotype Transmontano was higher than other ruminants, and APS had a negative effect on milk production considering the 150-d normalized lactation.Resumo Antecedentes: O aborto e os partos com nado-mortos são ocorrências normais nos rebanhos de caprinos. No entanto, a sua incidência deve manter-se em níveis baixos e a sua influência sobre a lactação subsequente deve ser determinada ao nível de cada raça. Objetivo: Determinar a incidência de abortos e/ou partos com nado-mortos (APS) em cabras da raça Serrana ecótipo Transmontano, e a sua associação com a produção de leite na lactação subsequente. Métodos: Foram usados todos os registos constantes na base de dados do livro genealógico da raça caprina Serrana, entre 1997 y 2014. Como variáveis, identificaram-se as datas de parto normal e/ou APS, número de fetos, número de parições, e a lactação subsequente normalizada aos 150 d de cada cabra. Resultados: Observou-se uma incidência média de APS de 8,7% (19.351/223.798). Ao aplicar um modelo de análise logística multivariada para os fatores ano, mês, paridade e gemelaridade, observou-se um efeito significativo (p<0,001) destas variáveis, quer das suas interações, sobre a incidência em estudo. Globalmente, os partos provenientes de gestações simples, com ligeiro destaque para as cabras primíparas apresentaram incidências mais elevadas. De igual modo, lactações consecutivas a partos com nado-mortos ou abortos apresentaram uma lactação acumulada aos 150 d menor (p<0,001) que de lactações provenientes de partos normais. Conclusão: A incidência apresentada foi maior que os limites normais para a espécie. Os APS tiveram um efeito negativo na produção de leite da lactação normalizada aos 150 d.Resumen Antecedentes: El aborto y nacimiento de mortinatos son hechos frecuentes en rebaños de cabras. Sin embargo, su impacto debe mantenerse en niveles bajos y su influencia en la siguiente lactación debe determinarse para cada raza. Objetivo: Determinar la incidencia de abortos y/o partos con muerte fetal (APS) en cabras Serrana ecotipo Transmontano, y su asociación con la producción de leche en la lactancia subsiguiente. Métodos: Se utilizó la información proveniente de la base de datos del registro genealógico de la raza Serrana ecotipo Transmontano entre 1997 y 2014. Como variables se incluyeron las fechas de partos normales y/o APS, el número de fetos, paridad, y la lactancia normalizada a los 150 d de cada cabra. Resultados: La incidencia promedio de APS fue del 8,7% (19.351/223.798). Mediante la aplicación de un modelo de análisis de logística multivariada para los factores año, mes, paridad y nacimientos múltiples, se observó un efecto significativo (p<0,001) de estas variables o sus interacciones en la incidencia de APS. En general, los partos no gemelares tuvieron una mayor incidencia, con un ligero énfasis en las cabras primíparas. Del mismo modo, las lactancias consecutivas a APS mostraron una menor producción de leche normalizada a 150 d que lactancias de partos normales (p<0,001). Conclusión: La incidencia observada fue mayor que el rango normal para la espécie. Los APS tuvieron un efecto negativo en la producción de leche en lactancia normalizada a 150 d

Reproductive disorders in Portuguese Serrana goats and its effects on milk production

Abstract Background: Abortions and parturitions with stillbirths are frequent in goat herds. However, the incidence of these events should remain low and their effects on subsequent lactation need to be assessed at breed level. Objective: To evaluate the incidence of abortions and parturitions with stillbirths (APS) in Portuguese Serrana goats breed ecotype Transmontano, and their association with milk production in subsequent lactation. Methods: Records of Serrana goats ecotype Transmontano from the pedigree book between 1997 and 2014 were used in order to determine the occurrence of APS. Goat level information, such as normal parturition and/or APS dates, number of fetuses, parity, and 150-d normalized milk production for each subsequent lactation, was considered. Results: The average incidence of APS was 8.7% (19,351/223,798). According to a multivariable logistic analysis, the year, month, parity, gemelarity, and their interactions were factors significantly (p<0.001) associated with APS. In overall, a higher APS incidence was observed in single births and primiparous goats. The 150-d normalized milk production was lower (p<0.001) in the APS group than in goats with normal parturitions. Conclusion: The APS incidence in Serrana goats ecotype Transmontano was higher than other ruminants, and APS had a negative effect on milk production considering the 150-d normalized lactation

Assessment of the knowledge and behavior of backyard and small-scale producers in California regarding disease prevention, biosecurity practices and antibiotics use.

The number and popularity of backyard poultry and livestock farming have rapidly increased in California as well as other states in the United States following consumers' preference for local and organic products in the last few years. This study aimed to investigate current on-farm management and farmers' understanding of Veterinary Feed Directive (VFD) and California Senate Bill (SB) 27 implications for disease prevention, biosecurity procedures, and antimicrobial use in small-scale and backyard farms in California. The survey consisted of 38 questions. The responses of 242 backyard and small-scale livestock owners were investigated in this study. Descriptive statistics summarized survey responses, and multivariable logistic regression evaluated the association of antibiotics purchase and use, and the impact of VFD and SB27 on antibiotic use with demographics and on-farm management. Backyard and small-scale farmers in California mostly raised chickens or small ruminants with small herd sizes kept for personal use. Antibiotics were generally used for individual treatment of a sick animal with the guidance of a veterinarian. VFD and SB27 implementation promoted the judicious use of antibiotics, specifically, by enhancing the relationship between backyard and small-scale farmers with veterinarians and treating fewer animals with antibiotics under veterinary oversight. Therefore, better access to veterinary service in backyard and small-scale farms will improve the farmer's knowledge of good husbandry practices with judicious antimicrobial use in livestock and finally contribute to reducing the risk of antimicrobial resistance in California

Antimicrobial resistance trends in fecal Salmonella isolates from northern California dairy cattle admitted to a veterinary teaching hospital, 2002-2016

Nontyphoidal Salmonella infections contribute to approximately 1.2 million annual illnesses in the United States. Historical and recent outbreaks have been associated with dairy products, ground beef, and direct contact with cattle. Salmonella antimicrobial resistance (AMR) is a serious concern that can reduce successful treatment of infections, increasing recovery time, medical costs, and mortality rates in humans and animals. This highlights the need to track AMR in Salmonella isolated from cattle to improve treatment plans, manage trends in AMR, and prevent future AMR development. A total of 242 Salmonella isolates were retrieved from 9,162 cattle fecal samples submitted to the University of California, Davis Veterinary Medical Teaching Hospital from 2002 to 2016. These isolates were tested for antimicrobial susceptibility using a standardized broth dilution panel. Multidrug resistance (MDR) to three or more classes of antimicrobials was observed in 50.8% of isolates, and the most common MDR pattern was amoxicillin-ampicillin-cefoxitin-ceftiofur-ceftriaxone-chloramphenicol-streptomycin-tetracycline (23.2%). There were significantly greater odds for antimicrobial resistance to aminoglycosides (OR: 2.03, 95% CI: 1.1-3.7), penicillins (OR: 1.87, 95% CI: 1.007-3.5), and tetracyclines (OR: 1.87, 95% CI: 1.017-3.4) for the 2002-2009 period when compared to the 2010-2016 period. The most prevalent MDR serotypes were Newport (100% MDR, n = 52), Typhimurium (100%, n = 20), and Dublin (71% MDR, n = 46). Risk factors associated with higher odds for isolating MDR Salmonella included isolates from calves when compared to adult cattle (OR: 22.0; 95% C.I.: 3.9-125.7), and isolates obtained from cattle suspect of having salmonellosis versus from the infectious disease control surveillance program (OR:13.7; 95%C.I.: 2.8-66.8). Despite a temporal trend for reduced AMR to most antimicrobial drug classes, a lack of this observed in the 2002-2009 period when compared to the 2010-2016 period for important drug classes such as cephalosporins (OR: 1.6, 95% CI: 0.87-3.1), and a trend for temporal increase in resistant to quinolones drugs (P value 0.004) highlight the relevance of AMR surveillance in cattle with Salmonella infections with the aim of targeting future prophylactic interventions

Improving Biosecurity Procedures to Minimize the Risk of Spreading Pathogenic Infections Agents After Carcass Recycling.

Animal proteins are essential elements of human and animal feed chain and improving the safety of human and animal feed requires understanding and controlling of the transmission of infectious agents in food chain. Many pathogenic infectious agents, such as prion protein is known to damage the central nervous system in the cattle. Bovine spongiform encephalopathy (BSE) results from infection agent (prion), and affects number of species such as cattle, human, and cats. In addition, Salmonella, pathogenic E. coli O157:H7, and Listeria monocytogenes were found in animal by-products used in the human and animal feed production. Increased interest in controlling microbial risks in human and animal feed is evidenced by a large number of publications, which highlights the need for examining the animal disposal method such as rendering process and provides a broader perspective of rendering process. While existing practices help greatly in controlling microbial contamination, this overview study showed that additional biosafety measures are necessary to ensure microbial safety in animal feed

Role of soil in the regulation of human and plant pathogens: soils' contributions to people

Soil and soil biodiversity play critical roles in Nature's Contributions to People (NCP) # 10, defined as Nature's ability to regulate direct detrimental effects on humans, and on human-important plants and animals, through the control or regulation of particular organisms considered to be harmful. We provide an overview of pathogens in soil, focusing on human and crop pathogens, and discuss general strategies, and examples, of how soils' extraordinarily diverse microbial communities regulate soil-borne pathogens. We review the ecological principles underpinning the regulation of soil pathogens, as well as relationships between pathogen suppression and soil health. Mechanisms and specific examples are presented of how soil and soil biota are involved in regulating pathogens of humans and plants. We evaluate how specific agricultural management practices can either promote or interfere with soil's ability to regulate pathogens. Finally, we conclude with how integrating soil, plant, animal and human health through a 'One Health' framework could lead to more integrated, efficient and multifunctional strategies for regulating detrimental organisms and processes. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People'