Diversité, structure et régénération de la végétation ligneuse de la Station Sahélienne Expérimentale de Toukounous, Niger

A la Station Sahélienne Expérimentale de Toukounous, le bétail est nourri essentiellement sur pâturage naturel. En saison sèche, l’herbe devient rare et subsiste à l’état de paille. Les animaux ont recours aux ligneux pour combler le déficit alimentaire. L’état de la végétation ligneuse a été établi à travers la détermination de la diversité, la structure et la régénération des espèces ligneuses par la méthode des transects. L’inventaire floristique a permis de recenser 15 espèces réparties entre 11 genres et 10 familles. La famille des Capparaceae et celle des Leguminosae-Mimosoïdeae sont les plus  représentées. Le peuplement est une formation arbustive à Maerua crassifolia avec comme espèces compagnes Balanites aegyptiaca et Acacia raddiana. La densité moyenne est de 172 pieds à l’hectare. La distribution par classes de diamètre montre une prédominance d'individus de petit diamètre. La majorité des ligneux a une hauteur inférieure à 2 mètres (46,4%). Le degré de couverture de la strate ligneuse, estimé à 12,67% est globalement faible. Le taux de renouvellement varie selon l’espèce. Maerua crassifolia (47,9%), Balanites aegyptiaca (17,4%) et Acacia raddiana (14,1%) ont les plus forts peuplements juvéniles. L’effectif de Maerua crassifolia est en baisse. La structure du peuplement fait état d’un milieu perturbé. La protection des jeunes plants devrait permettre de diversifier les sources d’aliments pour le bétail en période de soudure.Mots clés : Peuplement ligneux, parcours, caractéristiques structurales, Sahel, Niger

Bovine Tuberculosis Prevalence Survey on Cattle in the Rural Livestock System of Torodi (Niger)

BACKGROUND: Bovine tuberculosis (BTB) is a widespread zoonosis in developing countries but has received little attention in sub-Saharan Africa, especially in Niger. Recent investigations confirmed the high incidence of the disease in cattle slaughtered in an abattoir in Niamey. The fact that most of the animals in which M. bovis has been identified were from the rural area of Torodi implied the existence of a probable source of BTB in this region. This study aimed to determine the prevalence of BTB infection in cattle and to identify risk factors for infection in human and cattle populations in Torodi. METHODS AND PRINCIPAL FINDINGS: A survey was carried out at the level of households keeping livestock (n = 51). The questionnaire was related to the potential risk factors and the presence of clinical signs of TB both in animals and humans. Comparative Intradermal Tuberculin Test was conducted to determine the TB status in cattle (n = 393). The overall apparent individual animal prevalence of tuberculin reactors was 3.6% (CI: 95%, 1.9-5.9), whereas the individual true prevalence was estimated at 0.8% (CI: 95%, 0.0-5.0). Using a multivariate logistic regression analysis and a classification tree analysis, the only household level risk factor that significantly influenced the presence of BTB in cattle was the presence of animals coughing in the herd (OR = 4.7, 95% CI: 1.12-19.71, p-value = 0.034). The lack of the practice of quarantine was borderline significant (OR = 4.2, 95% CI: 0.96-18.40, p-value = 0.056). CONCLUSION/SIGNIFICANCE: The study confirmed that BTB is endemic in cattle in Torodi and the risk of the transmission of the disease to humans is potentially high. For the control of the disease in livestock, slaughtering of infected animals and the compensation of the owners is needed. Collaboration between the veterinary and the medical sectors, in the diagnosis, monitoring, prevention and control of BTB is strongly encouraged

Variations annuelles du comportement d'oestrus, du taux et des possibilités d'ovulations chez la brebis Peulh du Niger

Exterior, rear view with sculpture by Michael CalliganEnlarged by Taliesin Associated Architects, 1969-197

Variations annuelles du comportement d'oestrus, du taux et des possibilités d'ovulations chez la brebis Peulh du Niger

International audienc

Projet régional de recherche sur les petits ruminants. Rapport de synthèse. Fin de première phase. Programmation 1995-96

Ce document présente les acquis majeurs du Projet Régional de Recherche sur les Petits Ruminants sur les trois premières années de fonctionnement (1991-1994). La programmation des activités au Cameroun, Niger et Tchad pour les années 1995 et 1996 figurent à la fin de ce documen

Follicular growth during the oestrous cycle in Peul sheep

International audienc

Spermogram of Bicolor Peul and Touareg Rams: Genetic Type and Seasonal Influence

A study on the morphological parameters of ram sperm was carried out in an experimental station in Niger during three years. Six bicolor Peul rams and five Touareg rams were used. Sperm from each ram was collected after two consecutive ejaculations once a month with an artificial vagina. Means (± SE) of the various parameters studied in Peul and Touareg rams were, respectively: live weight 47.75 ± 3.75 kg and 49.98 ± 2.99 kg; sperm volume 1.73 ± 0.36 ml and 1.78 ± 0.33 ml; sperm gross motility 4 ± 0.61 and 3 ± 0.49; spermatozoon concentration 4265 x 106 ± 762 x 106 spz/ml and 4953 x 106 ± 583 x 106 spz/ml; total number of spermatozoa 7469 x 106 ± 2382 x 106 spz and 8877 x 106 ± 2323 x 106 spz; percentage of dead spermatozoa 12 ± 10% and 19 ± 19%; percentage of abnormal spermatozoa 13 ± 12% and 17 ± 11%. The mean weight of Touareg rams was significantly higher (p < 0.05) than that of Peuls. The dry cool season significantly (p < 0.05) and negatively affected the live weights of both breeds. Mean volumes of ejaculated sperm were not significantly (p < 0.05) different between the two breeds, except during the months of July and August. Significant (p < 0.05) differences were found between the two breeds with regard to the other parameters studied. Peul rams appeared more sensitive to Sahelian climate variations than Touaregs. Under the experimental conditions of the study (i.e. in station and under good management), ram fertility of both breeds was maintained in line with the established norms throughout the year, thus suggesting that rams might be mated with ewes year-round. Further studies would help determine the impact of traditional breeding conditions, season, individual characteristics on male and female fertility parameters, and consequently on the flock size