Infection-interactions in Ethiopian village chickens

Chickens raised under village production systems are exposed to a wide variety of pathogens, and current or previous infections may affect their susceptibility to further infections with another parasite, and/or can alter the manifestation of each infection. It is possible that co-infections may be as important as environmental risk factors. However, in cross-sectional studies, where the timing of infection is unknown, apparent associations between infections may be observed due to parasites sharing common risk factors. This study measured antibody titres to 3 viral (Newcastle disease, Marek's disease and infectious bursal disease) and 2 bacterial (Pasteurella multocida and Salmonella) diseases, and the infection prevalence of 3 families of endo- and ecto-parasites (Ascaridida, Eimeria and lice) in 1056 village chickens from two geographically distinct populations in Ethiopia. Samples were collected during 4 cross-sectional surveys, each approximately 6 months apart. Constrained ordination, a technique for analysis of ecological community data, was used to explore this complex dataset and enabled potential relationships to be uncovered and tested despite the different measurements used for the different parasites. It was found that only a small proportion of variation in the data could be explained by the risk factors measured. Very few birds (9/1280) were found to be seropositive to Newcastle disease. Positive relationships were identified between Pasteurella and Salmonella titres; and between Marek's disease and parasitic infections, and these two groups of diseases were correlated with females and males, respectively. This may suggest differences in the way that the immune systems of male and female chickens interact with these parasites. In conclusion, we find that a number of infectious pathogens and their interactions are likely to impact village chicken health and production. Control of these infections is likely to be of importance in future development planning

Comparison of sesame cake and cottonseed as supplementary sources of protein to weaned N'Dama bull calves in The Gambia

Reports results of an experiment conducted to compare sesame cake with cottonseed when used as sources of supplementary protein in terms of their capacity to support increased growth rate of weaned N'Dama bulls. Observations were made of water intake and diurnal fluctuations in body temperature to compare with information published in earlier reports that N'Dama cattle may require less water and tolerate greater variation in body temperature than other breeds of cattle. Chemical composition of sesame cake and cottonseed cake, body weight gain and rectal temperature of cattle were also examined

Comparative studies on N'Dama and zebu cattle following repeated infections with Trypanosoma congolense

This study is designed to examine the nature of trypanotolerance, in particular to compare the clinical parameters of infected N'Dama with those of infected Zebu cattle and the variability and repeatability within the N'Dama breed of various disease parameters. Twenty N'Dama and light Zebu cattle were inoculated intradermally with bloodstream forms of a cloned strain of Trypanosoma congolense originating from East Africa. All inoculated cattle became parasitaemic. Zebus showed consistently higher levels of parasitaemia and lower PCV percentages than did N'Damas. Three of the eight Zebus required treatment. The variation in PCV values was large between individuals during the early stages of the disease and diminished as infection continued. After trypanocidal drug treatment and a recovery period of 14 months, the same animals were inoculated intradermally with T. congolense blood-stream forms isolated and cloned in the Gambia. Differences in susceptibility to the ensuing disease were apparent when comparing N'Dama and Zebu cattle. Five Zebu cattle needed trypanocidal drug treatment, while none of the N'Damas needed during intervention