Andrew Raymond Peters

The concept of resource extraction in the context of antimicrobial resistance (AMR) is rarely explored. In this framework, antimicrobial susceptibility is viewed as a finite resource that is depleted through the use of antimicrobials —thus, AMR represents the exhaustion of this resource. In this conceptual study, we examine the system dynamics of AMR using causal loop diagrams to define both the structure and behaviour of two variants of the system. We then evaluate the robustness of the System Dynamics models through sensitivity testing. The first model is inspired by a classic “Limits to Growth” structure, in which antimicrobial use practices depend on recent observations of treatment success or failure. The second differs by including AMR surveillance informing antimicrobial prescribing instead of anecdotal experience. The models consider one “bug-drug-mutation-context” combination at a time, but can be applied to different microbes, antimicrobials, and host populations in human or veterinary contexts. Multiparameter sensitivity analyses of relative fitness and timescale parameters were carried out on both model variants. Several key differences in model behaviour over time were observed between the socio-ecological Limits to Growth structure and the modified version in which human judgment, with its associated time lag, is bypassed. The models help explore the effects of human behaviour and associated time lags on patterns of population-level antimicrobial susceptibility over time, applying an established modelling technique in a novel context to generate new hypotheses – notably that plateaux in AMR observed in the field could be in part due to human behaviour rather than purely evolutionary forces. The framing of antimicrobial susceptibility as a variably renewable natural resource is valuable not only as an avenue for alternative modelling approaches, but also as a more collaborative framing for public and policy engagement to promote sustainable management of this common pool resource.

The concept of resource extraction in the context of antimicrobial resistance (AMR) is rarely explored. In this framework, antimicrobial susceptibility is viewed as a finite resource that is depleted through the use of antimicrobials —thus, AMR represents the exhaustion of this resource. In this work, we examine the system dynamics of AMR using causal loop diagrams to define both the structure and behaviour of two variants of the system. We then evaluate the robustness of the system dynamics models through sensitivity testing. The first model is inspired by a classic “Limits to Growth” structure, in which antimicrobial use practices depend on recent observations of treatment success or failure. The second differs by including AMR surveillance informing antimicrobial prescribing instead of anecdotal experience. The models consider one “bug-drug-mutation-context” combination at a time, but can be applied to different microbes, antimicrobials, and host populations in human or veterinary contexts. Multiparameter sensitivity analyses of relative fitness and timescale parameters were carried out on both model variants. Several key differences in model behaviour over time were observed between the socio-ecological Limits to Growth structure and the modified version in which human judgment, with its associated time lag, is bypassed. The models help explore the effects of human behaviour and associated time lags on patterns of population-level antimicrobial susceptibility over time, applying an established modelling technique in a novel context to generate new insights – notably that plateaux in AMR observed in the field could be in part due to human behaviour rather than purely evolutionary forces. The framing of antimicrobial susceptibility as a variably renewable natural resource is valuable not only as an avenue for alternative modelling approaches, but also as a more collaborative framing for public and policy engagement to promote sustainable management of this common pool resource.

Mastitis remains a significant health challenges affecting dairy cows, with implications for animal welfare, milk production, and farm profitability. In Nigeria, there are limited large-scale studies that have systematically investigated the multifactorial risk factors for mastitis across diverse production systems and geographical locations. This study aimed to assess the prevalence of mastitis and identify its risk factors using a hierarchical mixed effects logistic regression, block-wise analytical approach. A cross-sectional survey was conducted across 298 dairy farms in North-Central Nigeria. Data were collected on farm demographics, animal characteristics, housing and management practices, water and feeding routines, milking hygiene, and mastitis management. Mastitis was diagnosed based on farmer-reported cases within the current year. Univariable and multivariable mixed-effects logistic regression models were fitted for each conceptual block of variables, accounting for clustering at the local government area (LGA) level using random intercepts. Model performance was evaluated using likelihood ratio tests, intraclass correlation coefficients (ICC), and diagnostic plots of residuals. The prevalence of reported mastitis in the current year was 59.4% (95% CI: 53.7–64.9). Final multivariable models revealed significant associations between mastitis and herd size, presence of working bulls, milking hygiene (e.g., teat dipping and use of separate cleaning cloths), and mastitis treatment practices. Notably, large cattle herds had significantly higher odds of mastitis (adjusted OR = 6.56, 95% CI: 1.99–21.62), while post-milking teat dipping (OR = 0.013, 95% CI: 0.000–0.797) was strongly protective. The ICC values across models ranged from 0.58 to 0.83, indicating substantial variation at the LGA level. Mastitis is highly prevalent in Nigerian dairy farms, with multivariable risks: herd demographics, management practices, and hygiene behaviours. Interventions promoting evidence-based milking hygiene and targeted herd-level management could substantially reduce mastitis burden. The hierarchical modeling approach provides a comprehensive framework for identifying context-specific risk factors and guiding regionally appropriate control strategies.

This study investigated the presence of contagious bovine pleuropneumonia (CBPP) and contagious caprine pneumonia (CCPP) in ruminants to confirm and identify the mycoplasma species present. A comprehensive approach was employed, involving serological and molecular assays. A total of 342 cattle and 319 goats were tested, with 42 cattle and 23 goats showing positive serum samples, along with six stored cultures. These samples were analyzed using various serological assays, including IDEXX CBPP and CCPP cELISAs, Immunoblot, CapriLAT, BoviLAT, and the Complement Fixation Test (CFT). Molecular techniques such as PCR-DGGE, species-specific PCRs, and real-time PCR kits were also utilized. The results indicated serological evidence of CCPP and CBPP infections, with some samples positive for M. agalactiae and M. ovipneumoniae. Due to culture contamination, the real-time PCR results were often borderline. However, the study suggests mixed infections in goats and highlights the importance of storing purified colony isolates and expanding sampling regions to identify diagnostic biomarkers and potential vaccine traits for mycoplasmas in Nigerian isolates.

CBPP is a highly contagious and economically significant respiratory disease of cattle. A systematic search of databases from 1987 to 2024 was conducted. This review assesses the history of CBPP in Africa. CBPP is caused by Mycoplasma mycoides subsp. mycoides. The disease’s spread across the African continent has been facilitated by factors such as colonial trade routes, cattle movements, nomadic pastoralism, and environmental conditions. The introduction of CBPP into Nigeria marked a pivotal moment in the country’s agricultural history. This review traces the early documentation of CBPP outbreaks, highlighting the disease’s influence on traditional cattle-rearing practices and the subsequent social and economic consequences. It further examines the role of vaccination efforts, disease monitoring, and government policies in controlling the disease. In Nigeria, CBPP has disrupted cattle herd compositions and cattle movement patterns, with financial costs incurred. This review underscores the importance of continued research as a way out of CBPP.

Livestock provide meat, milk, draught labour, are used for breeding, and act as a store of value for smallholder farmers. High young stock mortality (YSM) has the potential to cause significant financial loss. The Young Stock Mortality Reduction Consortium collaborated on a project to deliver a package of basic health and husbandry interventions to reduce YSM for cattle and small ruminants in mixed and pastoral production systems in Ethiopia. Prior to the intervention, YSM rates ranged from 9.8% for calves in mixed systems, to 35.6% for small ruminants in pastoral systems. Proportional reductions YSM from the intervention ranged from 60% for calves and for small ruminants in mixed systems, to 72% for calves in pastoral systems. This brief research report assesses the costs and benefits of the intervention ex-poste to determine its efficiency. NPVs for the intervention (per household) were calculated for a range of benefit periods (from 1 to 20 years), based on the cost of training enumerators and farmers and the net annual household benefits realised within each benefit period. We found in both pastoral and mixed systems the net annual household benefit for the intervention was positive. For pastoral households the intervention achieves a positive NPV after 2 years. For mixed households the intervention achieves a positive NPV after 11 years. Overall, we found the benefits of the intervention exceed the costs, by a very large amount in pastoral systems, and that benefits were larger for households that kept larger numbers of breeding females.

Good cattle reproductive performance is essential for livestock productivity. Farmers are highly dependent on the success of productive outputs to support their livelihoods. In low- and middle-income countries (LMICs), however, optimal reproduction of cows and bulls is comparatively less well defined, with information on key reproductive parameters and reproductive management often not available. The aim of this study was to collate and synthesise the recent published evidence on cattle reproductive performance in selected sub-Saharan countries.Systematic mapping methodology was used, with searches conducted for both cow and bull reproductive performance in Eritrea, Ethiopia, Kenya, Nigeria, Somalia, South Sudan, Sudan, Tanzania and Uganda, for the period 2012–2022, in English language. Search returns were screened for relevance at title and abstract, and full-text levels, based on the research question criteria.A substantial number of studies were identified for cows (n = 133), but only very few for bulls (n = 11). A large proportion of reported studies have been conducted in Ethiopia, with relatively few from the other countries, and most studies published between 2014 and 2016, and in 2021. Certain reproductive parameters received more attention than others; calving interval was reported in 86 studies, while culling due to infertility was reported in eight studies.The study highlights where research is being conducted in this area, and importantly where there is a gap, in particular on bull reproductive performance. While there were a range of values reported for cow reproductive parameters, the values were reasonable, indicating that it is possible to have good reproductive performance in LMICs. The synthesis of studies in the map should help to inform farmers and their advisors, at farm and national levels.

Background: The California mastitis test (CMT) is a simple cow-side indicator of the somatic cell count (SCC) in milk, providing a useful tool in identifying cases of subclinical mastitis in cattle. Mastitis, and in particular subclinical mastitis, is a major concern in Ethiopia and Nigeria, yet detection is challenging due to cost and access to commercial CMT reagents. Methods: Commercially available domestic detergents from Ethiopia and Nigeria were compared (n = 3 for each country) with the UK commercial CMT reagent in their ability to detect high SCC (>400,000 cells/ml milk). Sensitivity and specificity of the CMT test were calculated for the different detergents and positive and negative predictive values were established. Results: The average sensitivities of the tests ranged from 28-75% for the Ethiopian detergents and 68-80% for the Nigerian detergents, compared to 76% for the UK domestic detergent. Test specificities were 84-98%, 93-97% and 96%, respectively. Conclusions: Overall, the detergents demonstrated higher specificity than sensitivity. Nigerian detergents performed better than the Ethiopian products, however, the study identified suitable domestic detergents from both Ethiopia and Nigeria, comparable to the UK commercial CMT reagent, and we recommend their use as alternative CMT reagents for livestock-keepers to aid in cost-effective diagnosis of mastitis.

Evidence-based decision-making is now axiomatic in many sectors and has become increasingly important in prioritising development in low- and middle-income countries. In the livestock development sector, there has been a lack of data on health and production required to establish an evidence base. Thus, much strategic and policy decision-making has been based on the more subjective grounds of opinion, expert or otherwise. However, there is now a trend towards a more data-driven approach for such decisions. The Centre for Supporting Evidence-Based Interventions in Livestock was established in Edinburgh by the Bill and Melinda Gates Foundation in 2016, to collate and publish livestock health and production data, lead a community of practice to harmonise livestock-data-related methodologies, and develop and monitor performance indicators for livestock investments. La adopción de decisiones atendiendo a datos y criterios factuales, algo que ya es un axioma en muchos sectores, ha venido cobrando creciente importancia a la hora de fijar prioridades de desarrollo en los países de renta baja o de renta media. En el sector pecuario han faltado los datos de sanidad y de producción necesarios para establecer una sólida base factual. De ahí que buena parte de los procesos decisorios de carácter estratégico y normativo hayan discurrido por el terreno más subjetivo de las opiniones, ya provengan estas de expertos o de cualquier otro ámbito. Ahora, sin embargo, se tiende cada vez más a tratar de adoptar este tipo de decisiones a partir de una base más objetiva. En 2016, la Fundación Bill y Melinda Gates estableció en Edimburgo el Centre for Supporting Evidence-Based Interventions in Livestock [Centro de apoyo a las intervenciones basadas en datos factuales en ganadería], cuyos objetivos se cifran en reunir y publicar datos de sanidad y producción pecuarias, encabezar una dinámica de praxis colectiva para armonizar los métodos referidos a los datos de la ganadería y elaborar y seguir de cerca los indicadores de rendimiento utilizados para orientar las inversiones en el sector pecuario. La prise de décision fondée sur des données probantes est désormais une évidence pour de nombreux secteurs, et elle devient de plus en plus importante dans la priorisation des initiatives de développement dans les pays à revenus faibles et intermédiaires. Dans le secteur du développement de l’élevage, peu de données sont disponibles concernant la santé et la production animales, or ces éléments sont nécessaires pour établir une base de données probantes. De nombreuses décisions politiques et stratégiques sont donc prises sur la base d’éléments plus subjectifs – opinions d’experts ou autres. On observe cependant une tendance en faveur d’une approche davantage ancrée dans les données pour ce type de décisions. Le Centre for Supporting Evidence-Based Interventions in Livestock [Centre de soutien aux interventions basées sur des données probantes dans le domaine de l’élevage] a été établi par la Fondation Bill et Melinda Gates en 2016 à Édinbourg. Il a pour objectif de rassembler et de publier les données relatives à la production et à la santé du bétail, d’animer une communauté de pratiques en vue d’harmoniser les méthodologies relatives aux données sur le bétail et d’élaborer et de superviser les indicateurs de performance utilisés pour orienter les investissements dans le secteur de l’élevage.