The Muscovy duck ( Cairina moschata ) is a vital poultry species for rural livelihoods in Benin, yet no prior scientific study has documented its phenotypic and morphometric characteristics in the country. This study presents the first comprehensive characterization of Muscovy ducks raised across three agroecological zones of southern Benin, aiming to establish a foundational reference for sustainable breeding and conservation. A total of 406 adult ducks (260 females and 146 males) from 93 smallholder farms were assessed for both qualitative and quantitative traits. Significant sexual dimorphism was observed, with males exhibiting larger body dimensions than females (P < 0.05). A wide range of plumage patterns was recorded, dominated by white (58%), along with black, ash, and the first report of rare blue eye coloration. Beak and skin colours were mostly pink (66%) and white (73%), respectively; traits that may serve as important identifiers for local genetic lines. Notably, most morphometric traits varied significantly across colour morphs and agroecological zones, reflecting rich phenotypic diversity. Ducks with spotted white and grey plumage had superior measurements, while other colour groups excelled in specific traits such as thoracic cage width and leg length. Strong positive correlations were found between body weight and body length (r = 0.73), and leg length and chest height (r = 0.80). These results offer valuable insights for local producers and lay the groundwork for targeted selection, genetic improvement, and future molecular research on indigenous duck populations in Benin.

Programmable genome editing enables heritable genetic modifications for livestock production, disease resistance, and animal welfare. However, its translational maturity across species and traits has not been systematically benchmarked against breeding-program standards. To address this gap, we conducted a systematic review following PRISMA 2020 guidelines. The Web of Science Core Collection (SCI-Expanded) was searched for peer-reviewed articles published between 2010 and 2026 using terms spanning ZFN, TALEN, CRISPR–Cas systems, base editors, prime editors, livestock, animal breeding, and biosafety. A total of 1,326 records were identified; 526 underwent full-text assessment, and 133 met eligibility criteria for qualitative synthesis. A quantitative subset of 28 primary experimental studies reporting editing efficiency, mosaicism, or multigenerational transmission was subjected to structured cross-study comparison. CRISPR–Cas9 was used in 24 of the 28 quantitative studies; notably, no primary livestock study reported founder-level quantitative data for base or prime editing. Across embryo-stage knockout studies, the median on-target efficiency was 84% (range: 45–100%). While SCNT-derived founders were uniformly non-mosaic by clonal design, mosaicism in zygote-edited animals ranged from 20 to 100%. Off-target analysis was reported in 43% of studies, but only 11% employed whole-genome sequencing (WGS). Multigenerational validation beyond founders was documented in 25% of studies, with three reaching the F2 generation or equivalent. Species-level maturity was highest for porcine CD163 editing, which demonstrated multigenerational, production-relevant validation for PRRSV resistance. No primary study identified in this review reported replicated parent–offspring trio-based WGS in directly zygote-edited livestock under contemporary methodological standards. For somatic cell nuclear transfer (SCNT)-derived founders, variant analysis was typically performed relative to the unedited donor cell line, and genome-wide assessments in this context have reported low off-target variant burdens relative to donor baselines, although cross-study comparability remains limited by heterogeneity in sequencing depth, variant-calling pipelines, and reporting thresholds. Finally, unintended on-target structural alterations, including plasmid backbone integration, were documented in SCNT-derived cattle. A robust proof-of-concept has been achieved for monogenic trait editing in pigs and cattle, yet the evidence base for breeding-scale deployment remains limited. Critical gaps include the absence of trio-based off-target baselines, a lack of cross-platform structural variant comparisons, and the unvalidated integration of computational tools within livestock editing pipelines. Responsible translation requires molecular validation depth proportional to dissemination intent as well as multi-generational, multi-environment performance data prior to commercialization. Graphical Abstract The alternative text for this image may have been generated using AI.

Climate change threatens livestock-dependent livelihoods across sub-Saharan Africa, yet National Adaptation Programmes of Action (NAPAs) and Nationally Determined Contributions (NDCs) rarely incorporate animal genetic resource management despite explicit mandates under the Convention on Biological Diversity's Global Plan of Action for Animal Genetic Resources. This study addresses this policy gap by investigating how environmental gradients shape phenotypic adaptation in Muscovy duck (Cairina moschata) populations across Benin's three agroecological zones, generating evidence to inform climate-responsive livestock policy. We surveyed 505 farmers and characterized 1,300 ducks across dry (Temperature-Humidity Index [THI]: 70-74), sub-humid (THI: 74-78), and humid (THI: 78-82) zones. Climate analysis confirmed accelerating thermal stress (+0.38 degrees C per decade in humid zones), exceeding IPCC West African projections and threatening Sustainable Development Goal 2 (Zero Hunger) targets. Principal component analysis revealed zone-specific phenotypic clustering (57.9% variance explained), with thermoregulatory traits showing coordinated adaptation: body volume-surface ratios 42.7% lower in humid zones (p = 0.002), limb proportions 72.7% higher (p < 0.001), and white feather coverage 31.3% greater (p = 0.019). Reproductive performance declined significantly along the thermal gradient (lifetime production: 40.7 vs. 37.1 eggs; p < 0.001), quantifying climate-driven productivity losses relevant to national food security assessments. Phenotype-climate associations demonstrated that locally adapted variants (black-white pied in dry zones; white-black-green pied in humid zones) maintain superior fitness under native conditions, providing critical evidence for the breed-for-environment approach advocated by FAO's Climate-Smart Agriculture framework. These findings provide an empirical foundation for incorporating animal genetic resource conservation into Benin's NDC implementation, ECOWAS regional livestock strategies, and the African Union's Comprehensive Africa Agriculture Development Programme (CAADP) climate resilience targets.