Paratuberculosis is an infectious disease that is not easily amenable to classical control methods such as treatment and vaccination. Experimental animal models suggest that there could be genetic factors responsible for susceptibility or resistance to infection with the causative agent, Mycobacterium avium subsp. paratuberculosis. The aim of this study was to estimate genetic variation in susceptibility to paratuberculosis in Dutch dairy cattle. Data collected during a vaccination trial, conducted from 1984 to 1994, was used. A total of 3020 cows, with complete pedigree records and infection status at slaughter, were available for analysis. A standard polygenic statistical probit model was used to estimate heritabilities. The estimated heritability of susceptibility to M. avium. subsp. paratuberculosis infection was 0.06 for the overall population. In the subpopulation of vaccinated animals the estimated heritability was 0.09. Other calculations based on the model used in this study argue against a prominent role for vertical transmission. Because the establishment of genetic variation is one of the first steps towards the exploration of the possible use of selection for genetic improvement, the present study provides evidence for the presence of genetic variation in the susceptibility of cattle to paratuberculosis. Because the economic impact of the disease is substantial, the development and application of genetic tools, along with other control methods, could be instrumental in the eradication of paratuberculosis.

No abstract

No abstract

No abstract

No abstract

Maize is attacked by more than sixty diseases and a number of species of insect pests in the field as well as in the storage. Fungi are among the principal causes of deterioration and yield loss on farmers' maize during the storage period. Among the storage fungal pathogens Aspergillus, Fusarium and Penicillium are the most predominant species attacking maize seed and resulting in reduction in seed germination. The study was conducted at the Jimma University College of Agriculture and Veterinary Medicine in plant pathology laboratory. Three maize varieties and two levels of disinfection were used and arranged in complete block design with five replications. The highest frequency of Aspregilus spp. (40.4%) at farmer preserved seed with surface disinfected kernels on agar plate were recorded. The highest relative density of Fusarium spp. (51%) was only recorded on agar plate test from the farmer preserved seed without. The lowest germination percentage (62%) were recorded on the farmer preserved seed which was not disinfected. The Aspregilus spp. are the most dominant fungi followed by Fusarium spp. isolated in this study as well as in Ethiopia. These fungi are important in producing secondary metabolites which are carcinogenic to both humans and animals.

No abstract

No abstract