The efficacy of antibiotics to prevent respiratory diseases in swine: A protocol for a systematic review

The treatment and prevention of infectious diseases in pigs is an important aspect of swine production worldwide. The prudent use of antimicrobials and other therapeutic drugs is a primary responsibility of swine producers and veterinarians and decisions surrounding the use of drug therapy include considerations such as cost, efficacy, and food safety. The World Health Organization has published numerous reports urging all stakeholders concerned with both food-producing animals and humans to establish recommended steps to enhance the prudent use of antimicrobials (WHO, 2015). Similarly, the Organization for Animal Health has also published recommendations and position statements regarding prudent use and risk management related to antimicrobial use in animals (OIE, 2017)

The efficacy of antibiotics to prevent collibacilosis in broiler poultry: A protocol for a systematic review and network meta-analysis.

Antibiotics are used in broiler poultry production both for the prevention and treatment of infectious diseases. However, antibiotic use is a driver of antibiotic resistance. The World Health Organization has published numerous reports urging all stakeholders concerned with both food-producing animals and humans to establish recommended steps to enhance the prudent use of antimicrobials (WHO, 2015). Similarly, the World Animal Health Organization has also published recommendations and position statements regarding prudent use and risk management related to antimicrobial use in animals (OIE, 2017). Colibacillosis is an important bacterial pathogen of poultry, and a costly disease for the industry resulting in multimillion dollar losses annually through morbidity, mortality or carcass condemnation at slaughter. Colibacillosis refers to any localized or systemic infection caused entirely or partly by the organism avian pathogenic Escherichia coli (APEC). These bacteria may be isolated as the sole pathogen or contribute to a disease complex with mixed viral and bacterial infections (Guabirara and Schouler, 2015). Two main disease processes important in the broiler industry are early mortality and cellulitis. Early mortality is defined by chicks under a week of age experiencing a higher than normal percentage of deaths in a flock. Early mortality can be caused by many things, for example chilling, overheating, or dehydration, however E.coli infection, or colibacillosis, is one of the main culprits. Colibacillosis can present with omphalitis, yolk sacculitis, enteritis, pasty vents, pericarditis, perihepatitis, polyserositis, congested lungs, splenomegaly and darkened proventriculus or any these combinations (Guabiraba and Schouler, 2015; Geetha and Palanivel, 2018). Many chicks succumb to an early and severe infection or are culled due to excessive morbidity. Antibiotics are typically used to reduce early mortality (Chauvin et al., 2005; Dziva and Stevens, 2008). Those with severe infection are unlikely to survive, however appropriate treatment reduces transmission between birds and improves the suitability of those with a mild infection. Not every labelled drug for E.coli is efficacious, resistance is common (Kabir, 2010) and effectiveness can vary from flock to flock, even within a flock, with more than one strain and more than one treatment. Understanding the efficacy of antibiotics used to prevent colibacillosis in broiler chickens is essential to optimizing their use; ineffective antibiotics should not be used for prevention or, if there are multiple efficacious antibiotics, their importance to human medicine should be considered when making decisions on antibiotic use. Systematic reviews of randomized controlled trials, and network meta-analysis to provide input on relative antibiotic efficacy, will yield the highest level of evidence for efficacy of treatments under field conditions (Sargeant and O’Connor, 2014)

Invited review: Completeness of reporting of experiments: REFLECTing on a year of animal trials in the Journal of Dairy Science

Reproducibility is an essential element of the scientific process, and it requires clear and complete reporting of study design, conduct, and analysis. In the human and animal health literature, incomplete reporting is associated with biased effect estimates. Moreover, incomplete reporting precludes knowledge synthesis and undervalues the resources allocated to the primary research. The Reporting Guidelines for Randomized Controlled Trials for Livestock and Food Safety (REFLECT) statement, published in 2010, is a checklist developed by expert consensus to provide guidance on what study elements should be reported in any intervention trial (designed experiment) involving livestock. The Journal of Dairy Science (JDS) has recently endorsed the use of reporting guidelines. To assess the status of reporting of controlled experiments in JDS and to provide a baseline for future comparison, we evaluated the reporting of 18 items from the REFLECT statement checklist in a sample of 137 controlled trials published in JDS in 2017. Two reviewers independently screened titles and abstracts for relevance and then evaluated a sample of 120 papers reporting controlled trials (experimental studies involving at least one intervention and one comparison or control group), using yes or no questions. Although some items, such as treatment details and statistical analysis, were well reported, other areas, including sample size justification, allocation concealment, blinding, study flow, baseline data, and ancillary analyses, were often not reported or were incompletely described. This work highlights the need for authors and reviewers to take advantage of guidelines and checklists for reporting. Adherence to reporting guidelines can help improve the completeness of reporting of research, expedite and better inform the peer-review process, increase clarity for the reader, and allow for knowledge synthesis, such as meta-analysis, all of which serve to increase the value of the work conducted

The efficacy of teat sealants in dairy cows at dry-off to prevent new intra-mammary infections during the dry-period or clinical mastitis during early lactation: A protocol for a systematic review

Rationale: The majority of antibiotic use in the dairy industry is for intramammary infections (IMI), with a large portion of this aimed at treating and preventing IMI during the dry period (Lam et al., 2102). During dry off, formation of the teat-canal keratin plug plays an important role in susceptibility to IMI (Huxley et al., 2002), but there is wide variation between cows on time to complete closure of the teat-canal, or indeed if closure occurs at all (Dingwell et al., 2003). In heifers, pre-partum IMI is an important risk factor for the development of clinical mastitis in early lactation, and the impact of this disease on future udder health and productivity is far greater than in multiparous animals (Piepers et al., 2009). Moreover, the incidence of clinical mastitis at freshening in heifers is roughly double that of multiparous cows (Ali Naqvi et al., 2018). Teat sealants provide a non-antibiotic strategy to prevent IMI in the pre-calving period, which is of increasing importance due to concern for antimicrobial use and its relationship with the development of antimicrobial resistance (WHO, 2015). Understanding the efficacy of these products is essential to optimizing their use in order to decrease reliance on antibiotics for both treatment and prevention. Systematic reviews of randomized controlled trials in these areas will yield the highest level of evidence for efficacy of treatment under field conditions (Sargeant and O’Connor, 2014). Establishing the efficacy of teat sealants at dry-off, and pre-partum in heifers, to reduce the incidence of both clinical mastitis and/or IMI, will serve to improve decision makers’ ability to engage in effective stewardship of antibiotics thorough the strategic use of non-antibiotic alternatives

The efficacy of antibiotic treatments in dairy cows at dry-off to prevent new intramammary infections during the dry-period or clinical mastitis during early lactation: A protocol for a systematic review

Rationale: The majority of antibiotic use in the dairy industry is for the treatment and prevention of intramammary infections (IMI); in the Netherlands, approximately 60 % of all antimicrobial use in dairy is for this purpose, with two-thirds being dry cow therapy (Lam et al., 2012). In the United States, over 90 % of dairy cows receive dry cow therapy after every lactation (USDA-APHIS, 2016), with the goal of treating or preventing IMI during the dry period. These infections are strongly associated with risk of development of clinical mastitis in the first two weeks post-calving, which represents the highest risk period for this disease (Green et al., 2002). To combat this, blanket dry cow therapy (intramammary antimicrobial treatment of all quarters of all cows after the last milking of the lactation) was recommended for decades as part of a comprehensive strategy to reduce IMI in the dry period (Neave et al., 1969), and has been widely adopted in North America and the United Kingdom (Ruegg, 2017). Although cow2 level selective dry cow therapy has been in use in some regions for several decades (Schultze, 1983), interest has more recently increased worldwide, in part driven by concern for antimicrobial use and its relationship with the development of antimicrobial resistance between species (WHO, 2015), including nation-specific regulations (Santman-Berends et al., 2016). Selective dry cow therapy has been employed because it is a means to rapidly reduce the amount of antimicrobials used in dairy cattle (Vanhoudt et al., 2018), rather than because it is known to contribute importantly to antimicrobial resistance (Oliver et al., 2011). With a greater concern for prudent antibiotic use in the dairy industry, it is important that decision making with regards to dry cow therapy at both the cow and herd levels be evidencebased. Choosing ineffective antibiotics, or using antibiotic when not warranted, unnecessarily contributes to use while having little impact on controlling disease, which has substantial bearing to both profitability and animal welfare (Leslie & Petersson-Wolfe, 2012). Systematic reviews of randomized controlled trials yield the highest level of evidence for efficacy of treatment under field conditions (Sargeant and O’Connor, 2014), and comparative efficacy can be examined using network meta-analysis for multiple comparisons. Establishing the efficacy of both cow-level antibiotic therapy and herd-level dry cow antibiotic protocols for the prevention of IMI will serve to improve decision makers’ ability to engage in effective stewardship of antibiotics

Systematic reviews and meta-analyses in animal health, performance, and on-farm food safety: a scoping review

Systematic reviews and meta-analyses are used to summarize and interpret evidence for clinical decision-making in human health. The extent of the application of these methods in veterinary medicine and animal agriculture is unknown. The goal of this scoping study was to ascertain trends in the publication of systematic reviews and meta-analyses examining animal health, animal performance, and on-farm food safety. Online databases were searched for reviews published between 1993 and 2018 that focused on relevant outcomes in domestic livestock, companion animals, or wildlife species. In total 1787 titles and abstracts underwent data characterization. Dairy cattle, fish, and pigs were the most common target commodity groups. Few articles investigated both health and performance outcomes (only health: n = 418; only performance: n = 701; both health and performance: n = 103). Most of the reviews (67.6%, n = 1208/1787) described a meta-analysis but did not state in the title or abstract that a systematic review was also conducted, which is potentially problematic. Adherence to reporting guidelines is recommended for all systematic reviews and meta-analyses. For research areas with many reviews, an evidence repository is recommended. For less well-reviewed areas, additional investigation may be necessary to identify the reasons for the lack of synthesis research

Associations between Feeding Behaviors Collected from an Automated Milk Feeder and Neonatal Calf Diarrhea in Group Housed Dairy Calves: A Case-Control Study

The objective of this case-control study was to determine if feeding behavior data collected from an automated milk feeder (AMF) could be used to predict neonatal calf diarrhea (NCD) in the days surrounding diagnosis in pre-weaned group housed dairy calves. Data were collected from two research farms in Ontario between 2017 and 2020 where calves fed using an AMF were health scored daily and feeding behavior data (milk intake (mL/d), drinking speed (mL/min), number of rewarded or unrewarded visits) was collected. Calves with NCD were pair matched to healthy controls (31 pairs) by farm, gender, and age at case diagnosis to assess for differences in feeding behavior between case and control calves. Calves were first diagnosed with NCD on day 0, and a NCD case was defined as calves with a fecal score of ≥2 for 2 consecutive days, where control calves remained healthy. Repeated measure mixed linear regression models were used to determine if there were differences between case and control calves in their daily AMF feeding behavior data in the days surrounding diagnosis of NCD (−3 to +5 days). Calves with NCD consumed less milk on day 0, day 1, day 3, day 4 and day 5 following diagnosis compared to control calves. Calves with NCD also had fewer rewarded visits to the AMF on day −1, and day 0 compared to control calves. However, while there was a NCD status x day interaction for unrewarded visits, there was only a tendency for differences between NCD and control calves on day 0. In this study, feeding behaviors were not clinically useful to make diagnosis of NCD due to insufficient diagnostic ability. However, feeding behaviors are a useful screening tool for producers to identify calves requiring further attention

Comparative efficacy of antimicrobials for treatment of clinical mastitis in lactating dairy cattle: a systematic review and network meta-analysis

A systematic review and network meta-analysis were conducted to assess the relative efficacy of antimicrobial therapy for clinical mastitis in lactating dairy cattle. Controlled trials in lactating dairy cattle with natural disease exposure were eligible if they compared an antimicrobial treatment to a non-treated control, placebo, or a different antimicrobial, for the treatment of clinical mastitis, and assessed clinical or bacteriologic cure. Potential for bias was assessed using a modified Cochrane Risk of Bias 2.0 tool. From 14775 initially identified records, 54 trials were assessed as eligible. Networks were established for bacteriologic cure by bacterial species group, and clinical cure. Disparate networks among bacteriologic cures precluded meta-analysis. Network meta-analysis was conducted for trials assessing clinical cure, but lack of precision of point estimates resulted in wide credibility intervals for all treatments, with no definitive conclusions regarding relative efficacy. Consideration of network geometry can inform future research to increase the utility of current and previous work. Replication of intervention arms and consideration of connection to existing networks would improve the future ability to determine relative efficacy. Challenges in the evaluation of bias in primary research stemmed from a lack of reporting. Consideration of reporting guidelines would also improve the utility of future research

The efficacy of antibiotics to control colibacillosis in broiler poultry: a systematic review

The objective of this systematic review was to evaluate the efficacy of antibiotics to prevent or control colibacillosis in broilers. Studies found eligible were conducted controlled trials in broilers that evaluated an antibiotic intervention, with at least one of the following outcomes: mortality, feed conversion ratio (FCR), condemnations at slaughter, or total antibiotic use. Four electronic databases plus the gray literature were searched. Abstracts were screened for eligibility and data were extracted from eligible trials. Risk of bias was evaluated. Seven trials reported eligible outcomes in a format that allowed data extraction; all reported results for FCR and one also reported mortality. Due to the heterogeneity in the interventions and outcomes evaluated, it was not feasible to conduct meta-analysis. Qualitatively, for FCR, comparisons between an antibiotic and an alternative product did not show a significant benefit for either. Some of the comparisons between an antibiotic and a no-treatment placebo showed a numerical benefit to antibiotics, but with wide confidence intervals. The risk-of-bias assessment revealed concerns with reporting of key trial features. The results of this review do not provide compelling evidence for or against the efficacy of antibiotics for the control of colibacillosis