Probabilistic risk model to assess the potential for resistance selection following the use of anti-microbial medicated feed in pigs

The cross-contamination of non-medicated feed with residues of anti-microbials (AM) causes a public and animal health concern associated with the potential for selection and dissemination of resistance. To analyse the associated risks, a probabilistic model was built using @Risk (R) (Palisade Corporation (R)) to show the potential extent of the effect of cross-contaminated pig feed on resistance selection. The results of the model include estimations of the proportion of pigs per production stage with residues of doxycycline, chlortetracycline, sulfadiazine and trimethoprim in their intestinal contents, as a result of exposure to cross-contaminated feed with different carryover levels, in Belgium. By using a semi-quantitative approach, these estimations were combined with experimental data on AM concentrations associated with potential for resistance-selection pressure. Based on this model, it is estimated that 7.76% (min = 1.67; max = 36.94) of sows, 4.23% (min = 1.01%; max = 18.78%) of piglets and 2.8% (min = 0.51%; max = 14.9%) of fatteners in Belgium have residues of doxycycline in their intestinal tract due to consumption of feed with at least 1% carry-over. These values were estimated to be almost triple for sulfadiazine, but substantially lower for chlortetracycline and trimethoprim. Doxycycline concentrations as low as 1 mg/L (corresponding to consumed feed with at least 1% carry-over) can select for resistant porcine commensal Escherichia coli in vitro and in vivo. Conclusions on this risk could not be drawn for other AM at this stage, due to the lack of data on concentrations associated with resistance development. However, since the possibility of resistance mechanisms (e.g. co-selection) occurring cannot be excluded, the results of this model highlight that the use of AM medicated feed should be minimised where possible. In case of medicated feed production, good practice should be followed thoroughly at all levels of production, distribution, storage and administration, with a special focus on the feed distributed to piglets and sows

Antimicrobial resistance prevalence of pathogenic and commensal Escherichia coli in food-producing animals in Belgium

In this article, detailed studies on antimicrobial resistance to commensal E. coli (in pigs, meat-producing bovines, broiler chickens and veal calves) and pathogenic E. coli (in pigs and bovines) in Belgium are presented for 2011. Broiler chicken and veal calf isolates of commensal E. coli demonstrated higher antimicrobial resistance prevalence than isolates from pigs and bovines. Fifty percent of E. coli isolates from broiler chickens were resistant to at least five antimicrobials, whereas sixty-one percent of bovine E. coli isolates were susceptible to all antimicrobials tested. On the other hand, bovine pathogenic E. coli isolates showed an extended resistance profile with more than half of the isolates being resistant to ten or more antimicrobials. The results are not significantly different from the results from previously published studies on commensal bacteria in pigs in Belgium, although different methodologies of sampling and susceptibility testing were used

Voorkomen van resistentie tegen de ‘meest kritisch belangrijke antimicrobiële geneesmiddelen’ bij Escherichia coli-isolaten van hond en kat

A descriptive retrospective analysis of 811 antibiograms in dogs and cats was carried out in order to get a better insight into the prevalence of antimicrobial resistance against 'critically important antimicrobials with highest priority for human medicine' in dogs and cats. A veterinary diagnostic laboratory performed antimicrobial susceptibility testing on 811 Escherichia coli isolates obtained from veterinary clinical samples from dogs and cats in Flanders, Belgium. These isolates were mainly from fecal ( 62.5%) or urogenital (30.5%) origin. A disk diffusion method with breakpoints provided by the supplier of the antibiotic disks was used for antimicrobial susceptibility testing. The results indicated that 9.5% of the Escherichia coli isolates were resistant against or intermediate susceptible to marbo-floxacine, 16.7% to enrofloxacine and 15.7% to cefovecin. The unexpected difference in resistance between marbofloxacine and enrofloxacin may be, at least partially, explained by the different clinical breakpoints used to interpret the results of sensitivity tests for dog and cat isolates in both agents. The observed resistance in this study might be related to the regular use of fluoroquinolones and third generation cephalosporins. Therefore, the use of 'critically important antimicrobials with highest priority for human medicine' remains an important issue in small animal veterinary medicine

Prophylactic use of meloxicam and paracetamol in peripartal sows suffering from postpartum dysgalactia syndrome

Postpartum dysgalactia syndrome (PPDS) is a major economic problem in modern sow farms. General treatment of PPDS consists of the use of oxytocin to promote milk ejection and non-steroidal anti-inflammatory drugs (NSAIDs) to alleviate inflammatory processes. So far, studies investigated the use of a single administration of NSAIDs after parturition in healthy and non-healthy sows. The current study investigated whether administration of meloxicam or paracetamol in sows prior to parturition improves sow and piglet health as well as performance in a farm with PPDS problems in sows. Sixty sows and 978 piglets from a Belgian farrow-to-finish farm were enrolled. Sows were randomly divided into three groups: a non-treated control group, a meloxicam-treated group and a paracetamol-treated group. Treatment was administered orally for 7 days from gestation day 113 onwards. Performance and health parameters investigated in sows were gestation length, farrowing duration, litter characteristics, colostrum yield and quality (Immunoglobulin G), litter weight gain, weaning-to-estrus interval, pregnancy rate, rectal temperature, acute phase proteins and inflammatory markers serum amyloid A, haptoglobin, interferon γ, interleukin 1β and 6 backfat, constipation and feed refusal. Performance and health parameters in piglets were birthweight, average daily weight gain, colostrum intake and mortality. Paracetamol-treated sows showed a significantly (P = 0.04) lower rectal temperature (mean ± SD: 38.09 ± 0.18°C) than the meloxicam-treated sows (38.24 ± 0.18°C), but not than the control group (38.22 ± 0.18°C). Sows of the paracetamol-treated group had a significantly (P = 0.001) longer gestation length (116.3 ± 0.9 days) than sows of the control group (115.3 ± 0.6 days), but not than meloxicam-treated sows (115.9 ± 0.9 days). No significant differences between the three groups were found for all the other parameters. In conclusion, the prophylactic oral administration of either meloxicam or paracetamol for 7 days starting 2 days prior to farrowing did not show beneficial effects on both health and performance parameters of sows and piglets

Implementation and evaluation of different eradication strategies for Brachyspira hyodysenteriae

Background: Brachyspira infections are causing major losses to the pig industry and lead to high antimicrobial use. Treatment of Brachyspira (B.) hyodysenteriae infections may be problematic due to the high level of antimicrobial resistance. The present study implemented and evaluated farm-specific eradication programmes for B. hyodysenteriae in 10 different infected pig farms in Belgium. Results: Ten pig farms clinically infected with B. hyodysenteriae volunteered to implement a farm-specific eradication programme. The programme depended on the farm and management characteristics, antimicrobial susceptibility of the B. hyodysenteriae strain and the motivation of the farmer. Two farms practiced total depopulation, six farms partial depopulation and two farms antimicrobial medication without depopulation. In addition, all farms implemented biosecurity measures, and faeces samples were tested for the presence of B. hyodysenteriae at 6, 9 and 12 months after the start of the program. Single Brachyspira isolates from before and after the programme were typed using multilocus sequence typing (MLST). Eradication was successful in four farms. Two of them (farrow-to-finish and finishing herd) had applied total depopulation and respected a vacancy period of at least 3 weeks. A third farm (gilt farm) practised partial depopulation, the rooms remained empty for 28 days and changed the source of breeding gilts. The fourth farm practised partial depopulation, the stables remained empty for 3 weeks, and used antimicrobial medication. The eradication programme was not successful in six farms. Two of the latter farms only used medication without partial depopulation. Four farms practiced partial depopulation, one of them combined it with antimicrobial medication. The cleaning and disinfection procedures, rodent control, stand-empty period and/or other biosecurity measures in the six farms were not always implemented properly. In two of three farms, isolates belonging to the same MLST type were found before and after eradication. Conclusions: Total depopulation or partial depopulation combined with implementing strict biosecurity measures allowed eradication of B. hyodysenteriae from clinically infected pig farms. Programmes based on antimicrobials without depopulation or partial depopulation without strictly adhering to all suggested biosecurity measures were not successful. Stockmanship and motivation of the farmer to permanently maintain high biosecurity standards are essential for success

Risk factors for poor health and performance in European broiler production systems

Background Conventional broilers are currently one of the most efficient protein converters. Although decades of progress in genetic selection and feed formulation have lead to high standards of efficient broiler production, still a lot of variability is found between farms and between successive flocks. The aim of this study was to investigate risk- and/or protective factors for poor health and performance in conventional broiler-farms in Europe by developing eight multivariable linear mixed models. Three different models were used to investigate mortality (overall, first week, after first week), three models for performance variables (growth, feed conversion, European production index) and two models were related to slaughterhouse data (i.e. dead on arrival and condemnation rate). Results Several factors related to management and housing were significantly associated with health and performance of broilers. The following factors were associated with increased mortality: floor quality, neonatal septicemia, ventilation type and other professional activities of the farmer. The factors associated with performance were chick sex, coccidiosis infections, necrotic enteritis, dysbacteriosis, light intensity adaptations, ventilation type, comparing daily flock results with previous flock results by farmer, daily check of feed and water system and type of feed. For dead on arrival three risk factors were identified i.e. daily growth, type of light adaptation and type of drinkers system. For condemnation rate seven risk factors were found, i.e. type of drinking system, daily growth, feed withdrawal time, type of ventilation, house size, septicemia after seven days and type of feed. Conclusions These results imply that a multifactorial approach is required with adaptations involving both improvements in management, housing, health programs and an increasing level of professionalism of the farmer in order to improve broiler performance and health

The economic costs of production diseases in pigs

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Scanning European Needs and Expectations Related to Livestock Biosecurity Training by Using the World Café Method

The European Union Animal Health Law (2016/429) emphasizes disease prevention, underpinned by livestock biosecurity, surveillance, and traceability, as key aspects to minimize the risk of animal diseases. An important element of biosecurity is the training of key actors involved in implementing it. However, their needs and expectations regarding this training are poorly known. Under the COST action BETTER (CA20103), a World Café was organized to identify the needs and expectations of biosecurity training for farmers, veterinary practitioners, veterinary students, and other actors. A total of 78 participants distributed in four groups participated in the World Café. Needs and expectations were identified and ranked in decreasing order of importance. For farmers, the most important aspects were training focusing on practical aspects, the planning of training sessions in the day to accommodate workload, the need to prepare multiple reminders of upcoming training, and the short duration of events. For veterinary practitioners, it was considered that a mixed approach, including a theoretical and a practical part where people are invited to create a biosecurity plan and a follow-up report, were the most important features of training. For veterinary students, creating a good knowledge of the main principles of biosecurity was found as an essential element of training. Regarding other actors, gaining an understanding in the spread of pathogens and the repercussions on the cost of animal products that diseases might have (consumers), training on good/best practices of cleaning and disinfection and the development of clear protocols (transporters), and a mixture of formal and informal training and training on communication skills (other actors) were considered important. The World Café was a useful method to have a first identification, discussion, and differentiation on livestock biosecurity training needs and expectations of the key actors, although additional follow-up research involving more participants from more diverse countries with different coverage of cultures and education would be beneficial. These needs and expectations are relevant and should be considered when designing new training courses