COVID-19 Modeling with Caution in Relaxing Control Measures And Possibilities of Several Peaks in Cameroon

We construct a new model for the comprehension of the Covid-19 dynamics in Cameroon. We present the basic reproduction number and perform some numerical analysis on the possible outcomes of the epidemic. The major results are the possibilities to have several peaks before the end of the first outbreak for an uniform strategy, and the danger to have a severe peak after the adoption of a careless strategy of barrier anti-Covid-19 measures that follow a good containment period

Etude des systèmes d’élevage et description phénotypique des poules locales (Gallus gallus) en milieu rural de la zone forestière du Cameroun

Les systèmes d’élevage et la description phénotypique des populations de poules locales sont étudiés en milieu traditionnel camerounais (Lékié et Mfoundi) de la Région du Centre. Le but était d’établir la diversité génétique des poules locales et la diversité managériale pratiquée en milieu rural. Des 45 ménages et 650 poules échantillonnés, il ressort que l’élevage est du type divaguant (81%), caractérisé par une absence de logement spécifique, la non professionnalisation des éleveurs à majorité féminine (68%) et le manque d’un suivi vétérinaire. Bien que la valeur gustative des produits aviaires soit très appréciée et aux prix élevés, l’importante réduction du troupeau est due aux maladies (44,8%), à la prédation (33,9%) et aux accidents divers (21,3%). Phénotypiquement, le plumage est varié avec des couleurs dominantes telles le noir (41,5%), le blanc (21,3%) et le brun/rouge (16,3%). Les tarses sont blancs (54,8%), jaunes (27,3%), noirs (17,9%) ou verts (2,7%). La peau est blanche (76,1%) ou jaune (23,9%). La crête est rouge (96,3%) ou rouge sablé noire (3,75%), de type simple (89,9%), rosacé (9,0%) ou en pois (1,1%). Les phénotypes polydactyles (11,7 %), cous nus (7,0 %), huppés (6,1 %), barbus avec favori (5,6 %) et frisés (1,3 %) sont observés. Les longueurs et diamètres du tarse sont respectivement de 9,1 ± 0,18 cm et 1,7 ± 0,16 cm chez le coq, de 7,8 ± 0,06 cm et 1,5 ± 0,09 cm chez la poule. Les poids adultes des mâles et femelles sont respectivement de 2306 ±4,49 g et 1704 ± 12,08g. La maturité sexuelle est atteinte à 165 jours. La production annuelle moyenne sur 03 séries est de 47,2 ± 5,52 oeufs de couleur blanc crème (100%), avec un taux d’éclosion de 88,4%. La diversité génétique observée sur le terrain est un atout pour la création des souches adaptées en vue d’accroître la consommation protéique et les revenus des éleveurs en milieu rural.Mots clés : système d’élevage, phénotype, production, reproduction, poules locales, CamerounStudies were carried out on the production management and the phenotypic description of local fowl populations reared under the traditional systems of Lekié and Mfoundi divisions in the Centre Region of Cameroon. The aim was to establish the genetic diversity of local chickens and the management diversity practised in the rural area. Out of the 45 households and 650 chickens sampled, the free range system was the most practiced (81%), characterized by the absence of specific housing, untrained owners of whom women constituted the majority (68%), and poor health conditions. Although chicken meat and eggs are tasty and fetch higher market prices, flock size is substantially curtailed by factors such as diseases (44.8%), predation (33.9%) and various accidents (21.3%). Diversity in body feathers shows dominant colours like black (41.5%) or white (21.3%). Shanks are white (54.8%), yellow (27.3%), black (17.9%) or green (2.7%). The skin colour is either white (76.1%) or yellow (23.9%). The comb is either red (96.3%), or red spotted black (3.8%), being either single (89.9%), rose (9.0%) or pea (1.1%). Phenotypes such as polydactyly (11.7%), naked neck (7,0%), crested (6.1%), bearded and muffs (5.6%) and frizzled (1.3 %) are also found. Shank length and diameter show values of 9.1 ± 0.18 cm and 1.7 ± 0.16 cm for cocks and 7.8 ± 0.06 cm and 1.5 ± 0.09 cm for hens, respectively. Adult weights stand at 2306 ± 4.49 g for cocks and 1704 ± 12.08 g for hens. Age at sexual maturity is 165 days. About 47.2 ± 5.52 eggs of creamy colour spread in 3 clutches are laid yearly per hen for a hatchability rate of 88.4%. The observed major genetic diversity could help creating better adapted and more productive strains, likely to improve the dietary protein intake and potential income levels of the rural farmers

Comparative study of laying characteristics of Cameroon native (Gallus gallus) and label chickens

Laying performance of local chickens has been evaluated in a testing station in Cameroun, with a comparison to slow-growing label’s genotype imported from France. There were three ecotypes of local chickens (Center, South, North-West/West also called NO/OU) and two groups of label hens, either normal (DW*N) or dwarf (DW*DW). Label hens matured later, and were heavier than local ecotypes by 43%, 46%, and 48% as compared to NO/OU, Center, and South ecotypes, respectively. The dwarf gene decreased body weight of label hens by 20% (2083g versus 2604 g). Body weight of local ecotypes ranged from 1,362g (Center) to 1,481g (NO/OU). Egg weight was also higher for label hens (56g) than for local hens (46g) but the egg weight/body weight ratio was higher for local hens. At 52 weeks of age, egg number reached 85 (Center), 100 (South), 92 (NO/OU), 76 (DW*N) et 78 (DW*DW) and corresponding laying intensity was 68% (South), 63% (NO/OU), 62% (Center), 60% (DW*N) et 59% (DW*DW). Average egg mass recorded between 32 and 36 weeks of hens’ age were 875g (DW*DW), 803g (South), 722g (Center), 687g (NO/OU), and 672g (DW*N). The best food conversion ratio was obtained with local South ecotype (2.97). Residual feed intake was low for genotypes except for the NO/OU. The mean yolk percentage reached 30% in local hens as compared to label ones (27%). It could be concluded that, indigenous hens revealed a rather good laying ability in the controlled conditions of the testing station, the best performance being exhibited by the South ecotype. Crossbreeding between local ecotypes and label genotypes should be tested to improve egg weight

Études comparées de la croissance des poules locales (Gallus gallus) et d’une souche label au Cameroun

Chantier qualité GAThe growth of local chickens collected from the Western Highlands and the Forest zones of Cameroon was evaluated under intensive management alongside with a commercial label. The aim was to record the potentials of local chickens for developing appropriate genetic improvement strategies. Each genetic type was reared separately from hatching to week 52 of age and was subjected to the same health care, management and feeding. Results showed that normal commercial males (DW*N) were 48.75%, 49.55% and 41.98% heavier at 16th week than their counterparts from Centre, south and North-West/West (NO/ OU) ecotypes. Feed conversion ratios between 12 and 16 weeks of age were 3.16 for DW*N and varied from 3.92 to 4.16 for local ecotypes. Normal (DW*N) and dwarf (DW*N) local females weighed 1550g and 1260g, respectively and were heavier that the heaviest local hen (889g) from the NO/OU. Feed conversion ratios were 4.62 (DW*N and DW*DW), 4.94 (Centre), 4.31 (NO/OU) and 4.35 (South). At 18 weeks of age, normal females ‘DW*N’ (1792 g) were heavier than their dwarf ‘DW*DW’ counterparts (1453 g) while hens from NO/OU (964 g), Centre (960 g) and South (1047 g) were overall lighter. Mortality rate was highest in the growing phase; but less than 8% from 18 to 52 weeks of birds’ age. It was concluded that commercial labels could potentially be used for improving local chicken growing performances through crossbreeding.Les performances de croissance des populations de poules locales des hauts plateaux (Régions de l’Ouest et du Nord-Ouest) et des forêts ont été évaluées en station en présence des souches commerciales de type label. L’objet de l’étude a été d’avoir une meilleure connaissance des potentialités de ces deux types génétiques afin de développer des stratégies ultérieures de leur amélioration génétique. Chaque type génétique était élevé séparément de l’éclosion jusqu’à la 52ème semaine et était soumis aux mêmes soins de santé, de management et d’alimentation. Les principaux résultats montrent que les mâles labels normaux (DW*N) sont 48,75%, 49,55% et 41,98% plus lourds à 16 semaines d’âge que leurs homologues locaux respectifs du Centre, du Sud et du Nord-Ouest/Ouest (NO/OU). L’indice de consommation entre 12 et 16 semaines d’âge est de 3,16 pour le DW*N et varie de 3,92 à 4,16 chez les écotypes locaux. Les femelles normales ‘DW*N’ (1550g) et naines ‘DW*DW’ (1260 g) sont plus lourdes que la femelle locale la plus lourde (889g) du Nord-Ouest/Ouest. Les indices de consommation sont de 4,62 (DW*N et DW*DWW), de 4,94 (Centre), de 4,31 (NO/OU) et de 4,35 (Sud). Chez les femelles adultes à 18 semaines, la DW*N (1792 g) a un poids corporel supérieur à celui de la DW*DWW (1453 g) tandis que les femelles du NO/OU (964 g), du Centre (960 g) et du Sud (1047 g) sont plus légères dans leur ensemble. La mortalité en station a été élevée chez les jeunes mais inférieure à 8% de 18 à 52 semaines d’âge. Il est conclu que le label se présente comme le type le plus indiqué pour améliorer les performances pondérales et squelettiques des poules locales dans une stratégie utilisant le croisement