75 research outputs found

    Effects of environmental factors on seed germination

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    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

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    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%)

    Interaction between Trypanosoma brucei and Haemonchus contortus infection in West African Dwarf Goats

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    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

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    Ce travail passe en revue les rĂ©sultats des travaux de recherches sur l’amĂ©lioration gĂ©nĂ©tique des zĂ©bus locaux (Goudali, White et Red Fulani) par voie de sĂ©lection et de croisement avec les races exotiques (Holstein, MontbĂ©liarde, Brahman amĂ©ricain, Jersiais, Tarentaise, Limousine et Charolaise). Ces travaux ont Ă©tĂ© 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 DĂ©veloppement) du Cameroun, en système d’élevage semi-intensif dans les zones des hautes savanes guinĂ©ennes et des hauts plateaux de l’Ouest Cameroun. Les donnĂ©es proviennent des rapports d’activitĂ© et de consultations, des publications scientifiques et des entrevues. L’objectif est de ressortir les rĂ©sultats saillants utiles pour les dĂ©cideurs politiques, les chercheurs et les Ă©leveurs. Les principaux rĂ©sultats montrent que le potentiel laitier des croisĂ©s est gĂ©nĂ©ralement supĂ©rieur (>4 litres) Ă  celui des races locales (>3,5 litres). Les gĂ©notypes ayant moins de 75% de sang exotique sont les plus performants en lait et viande. Les causes de mortalitĂ© 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 croisĂ©s Holsteins ont Ă©tĂ© plus lourds Ă  la naissance (34,75 kg) avec une vitesse de croissance plus Ă©levĂ©e (0,46 kg), une production laitière plus Ă©levĂ©e (5,47 ± 0,17 litres), plus prĂ©coces (40,87 mois) et moins susceptibles au stress   Nuenvironnemental. Pour la filière bovin-Ă -viande, les performances de viande de la race synthĂ©tique Wakwa sont lĂ©gèrement supĂ©rieures Ă  celles des zĂ©bus Goudali sĂ©lectionnĂ©s dans le cheptel local. Cependant, le taux de susceptibilitĂ© Ă  la  dermatophilose est estimĂ© Ă  71,0%, 34,4% et 5,0% chez le pur, ½ et ÂĽ sang Brahman, respectivement. La sĂ©lection massale du zĂ©bu Goudali (variĂ©tĂ© NgaoundĂ©rĂ©) et la race synthĂ©tique Wakwa a permis d’obtenir des progrès gĂ©nĂ©tiques significatifs, soient, respectivement, 8,60 kg et 20,40 kg. Cependant, les corrĂ©lations gĂ©nĂ©tiques nĂ©gatives entre les effets directs et maternels montrent que le progrès gĂ©nĂ©tique serait davantage plus important si la sĂ©lection Ă©tait concentrĂ©e sur les performances  directes et maternelles. Les expĂ©riences d’insĂ©mination artificielle menĂ©es Ă  la SODEPA et Ă  « Tadu Dairy Cooperative Society»montrent que l’industrie laitière est une entreprise rentable avec un rapport bĂ©nĂ©fice-coĂ»t 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 ÂĽ blood Brahman, respectively. Individual selection of the Gudali zebu (NgaoundĂ©rĂ© 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

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    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 Ă©tude a Ă©tĂ© menĂ©e de novembre 2019 Ă  mai 2020 dans l'arrondissement de BangangtĂ© Ă  l'ouest Cameroun, dans le but de contribuer Ă  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 Ă©tĂ© examinĂ©s. Une prĂ©valence globale de 34,47% a Ă©tĂ© obtenue. Les principales affections rencontrĂ©es Ă©taient : le piĂ©tin (23,06%), l'onglon en ciseaux (4,85%), la seime (3,88%), la dissymĂ©trie 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) % prĂ©sentaient des cas de boiteries causĂ©es principalement par le panaris (50%) et la maladie de Morterallo (33,3%). Le tri croisĂ© rĂ©vèle que 9,15% des animaux Ă©taient atteints par deux affections simultanĂ©ment notamment l'association piĂ©tin et onglon en ciseaux. Les affections podales fonctionnelles, infectieuses et mĂ©taboliques avaient des prĂ©valences respectives de 3,88%, 25%, et 7,73%. Les facteurs de risque incriminĂ©s dans la survenue des affections podales Ă©taient l'Ă©tat de propretĂ©, l'âge des animaux, le type de sol, l'Ă©vacuation du fumier et le type d'Ă©levage. La prise en charge thĂ©rapeutique Ă©tait gĂ©nĂ©rale et locale. Mots clĂ©s: Bovins, affections podales, prĂ©valence, boiteries, BangangtĂ©, Camerou

    Haemaphysalis hoodi (Acari: Ixodidae) on a human from Yaoundé, Cameroon, and its molecular characterization

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    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

    Onchocerciasis (river blindness) – more than a century of research and control

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    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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