75 research outputs found
Effects of environmental factors on seed germination
Detailed understanding of the environmental conditions required for the germination
and growth of tree seeds is an important prerequisite for the formulation of comprehensive
and sustainable forest development strategies, which is of great significance for
afforestation and forest management. The germination and establishment of seeds under
different light intensity, different planting depth and different species types were studied.
Among all tested tree seeds, there was no significant difference in seed germination rates
in different planting depths. There was no significant three-way interaction between light
intensity, planting depth and tree species. There was a significant two-way interaction
between light intensity and tree species. Under the same light intensity, the germination
rate of black spruce was higher than that of Jack pine. Light, had significant effects on
germination rate. After comparing between groups, it was found that the germination rate
was higher under 60% light intensity
Phenotypic characteristics and Gene Frequency of the Banyo Gudali zebu (Bos indicus) variety in the high Guinean Savannah zone of Cameroon
This study is aimed at evaluating the phenptypic and genetic diversity of local cattle breeds in Cameroon. To this end, biometric data were collected randomly in six (6) localities of the Mayo-Banyo Division, on a sample of 321 adult Banyo Gudali zebu cattle (234 cows and 87 bulls) aged between 6 and 16 years and having a body condition score varying from 2 to 4. Results reveal a variability of the coat color i.e., 19,00% white coat and its derivatives (speckled, stoat, grey, truiture); 9.99% black coat and its derivatives (black list and black piebald); 18.06% piebald (4.67% black piebald and 13.39 red piebald); 52.94% red and its derivatives (red piebald and red list). The single-colored coats are less represented (38.94%)compared to double-colored coats (61.06%). The frequency of alleles S+, D, ED, Aa, E+, s, A+, e and P are respectively 0.315; 0.201; 0.140; 0.267; 0.859; 0.685; 0.733; 0.386 and 1.000. There is a predominance of white-black horns (50.2%) over grey horns (42.4%). This population is characterized by long hairs, straight-edged ears oriented laterally and with humps occupying a cervico-thoracic position. The facial and back profiles are straight. The neck has a horizontal curved profile, the rump with a low set tail. Crescent shaped horns predominate (73,5%) followed by the horns in low lyre (15,9%) with the other shapes (stump, lateral pointed tip, crown and asymmetrical deformed right or left) being the least represented. The raised horns (92.5%) are predominant. Erect and moderate humps (86.6%) are dominant over drooping ones (13.4%)
Comment calculer et distribuer équitablement la valeur ajoutée dans la chaîne de valeur (CV) ''lait frais'' de la région de l'Adamaoua (Nord Cameroun) ?
Interaction between Trypanosoma brucei and Haemonchus contortus infection in West African Dwarf Goats
In order to investigate the immunomodulatory influence of concurrent T. brucei and H. contortus infection in West African Dwarf (WAD) goats, 28 infected and 7 uninfected (control) of 8-9 months old male WAD goats were studied. The infected goats were separated into resistant (Class 1) and susceptible (Class 2) Faecal Eggs Count (FEC) phenotypes. They were infected with 3000 infective larvae (L3) of H. contortus and 5 x 106 T. brucei. Another group of these phenotypes received only the H. contortus challenge. The responses were measured by parasitological response through FEC and Worm Burden (WB), and by host immune response through IgG levels. Class 2 animals with or without T. brucei infection exhibited non-significant (P > 0.05) higher FEC compared to those of Class 1. Worm burdens were not significantly different between FEC classes but were different (P=0.038) in relation to T. brucei infection. There was an overall increase in worm burdens of T. brucei infected goats, more pronounced in Class 2 than in Class 1. There was a significant upward drift of antibody levels with time across all groups without significant interactions. However, there was a significant effect of FEC Class (P=0.017) and trypanosome infection (P=0.041) with no significant interaction. Animals in Class 1 had generally higher antibody levels than those in Class 2, irrespective of T. brucei infection. Infection status had a highly significant (P=0.0001) effect on IgG. H. contortus only infected goats had the highest antibody levels and trypanosome infection reduced this response, irrespective of FEC phenotype. There was a highly significant (P=0.001) positive correlation (r = +0.719) between FEC and total worm counts. This work showed that the two response phenotypes identified in earlier immunizing infections were still clearly recognizable following homologous challenge and dual infections. This suggests that under field conditions where repeated H. contortus challenge occurs and trypanosomosis is endemic, the phenotypes could remain unchanged.© 2016 International Formulae Group. All rights reserved.Keywords: Haemoparasite, Gastrointestinal parasite, concurrent infection, immune response, domestic animal
Amélioration génétique bovine par voie de croisement et de sélection en Afrique Tropicale : Expériences du Cameroun
Ce travail passe en revue les résultats des travaux de recherches sur l’amélioration génétique des zébus locaux (Goudali, White et Red Fulani) par voie de sélection et de croisement avec les races exotiques (Holstein, Montbéliarde, Brahman américain, Jersiais, Tarentaise, Limousine et Charolaise). Ces travaux ont été conduits depuis 1952 dans les Centres de Recherches Zootechniques de Wakwa et Bambui par l’Institut de Recherches Zootechniques (IRZ, aujourd’hui connue sous le nom de l’Institut de Recherche Agricole pour le Développement) du Cameroun, en système d’élevage semi-intensif dans les zones des hautes savanes guinéennes et des hauts plateaux de l’Ouest Cameroun. Les données proviennent des rapports d’activité et de consultations, des publications scientifiques et des entrevues. L’objectif est de ressortir les résultats saillants utiles pour les décideurs politiques, les chercheurs et les éleveurs. Les principaux résultats montrent que le potentiel laitier des croisés est généralement supérieur (>4 litres) à celui des races locales (>3,5 litres). Les génotypes ayant moins de 75% de sang exotique sont les plus performants en lait et viande. Les causes de mortalité par ordre d’importance sont nutritionnelles (36,8%), accidentelles (29,6%), pathologiques (21,1%), parasitaires (7,7%) et reproductives (4,8%). Par rapport aux autres produits de croisement, les croisés Holsteins ont été plus lourds à la naissance (34,75 kg) avec une vitesse de croissance plus élevée (0,46 kg), une production laitière plus élevée (5,47 ± 0,17 litres), plus précoces (40,87 mois) et moins susceptibles au stress Nuenvironnemental. Pour la filière bovin-à -viande, les performances de viande de la race synthétique Wakwa sont légèrement supérieures à celles des zébus Goudali sélectionnés dans le cheptel local. Cependant, le taux de susceptibilité à la dermatophilose est estimé à 71,0%, 34,4% et 5,0% chez le pur, ½ et ¼ sang Brahman, respectivement. La sélection massale du zébu Goudali (variété Ngaoundéré) et la race synthétique Wakwa a permis d’obtenir des progrès génétiques significatifs, soient, respectivement, 8,60 kg et 20,40 kg. Cependant, les corrélations génétiques négatives entre les effets directs et maternels montrent que le progrès génétique serait davantage plus important si la sélection était concentrée sur les performances directes et maternelles. Les expériences d’insémination artificielle menées à la SODEPA et à « Tadu Dairy Cooperative Society»montrent que l’industrie laitière est une entreprise rentable avec un rapport bénéfice-coût de 4,21.
This work reviews the results of research on the genetic improvement of local zebus (Gudali, White and Red Fulani) through selection and crossbreeding with exotic cattle breeds (Holstein, Montbeliard, American Brahman, Jersey, Tarentaise, Limousine and Charolais). This work was started since 1952 by Institute of Animal Research (IRZ, now known as the Institute of Agricultural Research for Development) at the Wakwa and Bambui Research Centers, under semi-intensive management conditions in the high Guinea savannah areas of the Adamawa Plateau and the highlands of West Cameroon. Data were obtained from activity and consultation reports, scientific publications and interviews. The objective is to highlight salient findings that are useful for policy makers, researchers and livestock producers. The main results show that the milk potential of crosses is generally higher (>4 liters) than that of local breeds (>3.5 liters). Genotypes with less than 75% exotic blood had the best milk and meat production performance. The reported causes of mortality in order of importance are nutritional (36.8%), accidental (29.6%), pathological (21.1%), parasitic (7.7%) and reproductive (4.8%). Compared to the others crosses, Holstein crosses were found to be relatively heavier at birth (34.75 kg) with a higher growth rate (0.46 kg), higher daily milk production (5.47 ± 0.17 liters), earlier maturing (40.87 months), but more adapted to the breeding conditions and less susceptible to environmental stress. For the beef industry, the meat performance of the synthetic Wakwa breed is slightly better than that of the Gudali zebus selected from the local herd. However, the susceptibility rate to dermatophilosis was estimated at 71.0%, 34.4% and 5.0% in pure, ½ and ¼ blood Brahman, respectively. Individual selection of the Gudali zebu (Ngaoundéré subtype) and the synthetic Wakwa breed has resulted in significant genetic progress, 8.60 kg and 20.40 kg, respectively. However, the negative genetic correlations between direct and maternal effects showed that genetic progress would be more important if selection was concentrated on direct and maternal performance. Artificial insemination experiments conducted at SODEPA and Tadu Dairy Cooperative Society showed that the dairy industry is a profitable enterprise with a benefit-cost ratio of 4.21
Affections podales bovines dans la région de l'ouest du Cameroun
This study was carried out from November 2019 to May 2020 in Bangangte, a district in the West of Cameroon, with the aim of contributing to a better understanding of foot disorders in cattle. A total of 412 animals (Gudali (56.55%), Akou (40.78%), Red Fulani (2.43%) and Charolais (0.24%)) were examined. An overall prevalence of 34.47% was obtained. The main conditions encountered were: foot rot (23.06%), scissor nail (4.85%), cracking of the hoof (3.88%), nail asymmetry (2.43%), whitlow (1.7%), Morterallo's disease (0.97%), laminitis (0.49%), nail elongation (0.24%), and ergot elongation (0.24%). Three (3) % had cases of lameness caused mainly by whitlow (50%) and Morterallo's disease (33.3%). Cross-sorting revealed that 9.15% of the animals were affected by two conditions simultaneously, the combination of foot rot and scissor nail. Functional, infectious and metabolic foot disorders had prevalences of 3.88%, 25% and 7.73%, respectively. The risk factors associated with the occurrence of foot disorders were cleanliness, age of animals, soil type, manure disposal, and the type of husbandry system (p < 0.05). Therapeutic managements were general and specific.
Keywords: Cattle, foot disorders, prevalence, lameness, Bangangte, CameroonCette étude a été menée de novembre 2019 à mai 2020 dans l'arrondissement de Bangangté à l'ouest Cameroun, dans le but de contribuer à une meilleure connaissance des affections podales chez les bovins. Au total 412 animaux (Goudali (56,55%), Akou (40,78%), Red Fulani (2,43%) et Charolais (0,24%)) ont été examinés. Une prévalence globale de 34,47% a été obtenue. Les principales affections rencontrées étaient : le piétin (23,06%), l'onglon en ciseaux (4,85%), la seime (3,88%), la dissymétrie de l'onglon (2,43%), le panaris (1,7%), la maladie de Morterallo (0,97%), la fourbure (0,49%), l'allongement des onglons (0,24%) et l'allongement de l'ergot (0,24%). Trois (3) % présentaient des cas de boiteries causées principalement par le panaris (50%) et la maladie de Morterallo (33,3%). Le tri croisé révèle que 9,15% des animaux étaient atteints par deux affections simultanément notamment l'association piétin et onglon en ciseaux. Les affections podales fonctionnelles, infectieuses et métaboliques avaient des prévalences respectives de 3,88%, 25%, et 7,73%. Les facteurs de risque incriminés dans la survenue des affections podales étaient l'état de propreté, l'âge des animaux, le type de sol, l'évacuation du fumier et le type d'élevage. La prise en charge thérapeutique était générale et locale.
Mots clés: Bovins, affections podales, prévalence, boiteries, Bangangté, Camerou
Haemaphysalis hoodi (Acari: Ixodidae) on a human from Yaoundé, Cameroon, and its molecular characterization
The genus Haemaphysalis Koch, 1844 (Acari: Ixodidae) is the second-largest genus, with more than 170 described species that primarily parasitize mammals and birds (Guglielmone et al. 2014, Guglielmone et al. 2020). Haemaphysalis species are three-host ticks, mainly distributed in southern and southeastern Asia and tropical Africa (Guglielmone et al. 2014). The present study identified a tick, Haemaphysalis hoodi Warburton & Nuttall, 1909, collected from a human in Yaoundé, Cameroon. This tick species feed on birds in sub-Saharan Africa. To the best of our knowledge, this is the second record of H. hoodi from humans. In addition, 16S ribosomal RNA and cytochrome oxidase I sequences were generated for this species for the first time. Screening pan-Rickettsia-PCR infection gave a negative result.Open Access funding enabled and organized by Projekt DEAL.https://link.springer.com/journal/436hj2023Veterinary Tropical Disease
Seroprevalence and Associated Risk Factors of Brucellosis among Indigenous Cattle in the Adamawa and North Regions of Cameroon
Onchocerciasis (river blindness) – more than a century of research and control
This review summarises more than a century of research on onchocerciasis, also known as river blindness, and its control. River blindness is an infection caused by the tissue filaria Onchocerca volvulus affecting the skin, subcutaneous tissue and eyes and leading to blindness in a minority of infected persons. The parasite is transmitted by its intermediate hosts Simulium spp. which breed in rivers. Featured are history and milestones in onchocerciasis research and control, state-of-the-art data on the parasite, its endobacteria Wolbachia, on the vectors, previous and current prevalence of the infection, its diagnostics, the interaction between the parasite and its host, immune responses and the pathology of onchocerciasis. Detailed information is documented on the time course of control programmes in the afflicted countries in Africa and the Americas, a long road from previous programmes to current successes in control of the transmission of this infectious disease. By development, adjustment and optimization of the control measures, transmission by the vector has been interrupted in foci of countries in the Americas, in Uganda, in Sudan and elsewhere, followed by onchocerciasis eliminations. The current state and future perspectives for control, elimination and eradication within the next 20–30 years are described and discussed. This review contributes to a deeper comprehension of this disease by a tissue-dwelling filaria and it will be helpful in efforts to control and eliminate other filarial infections
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