Comparative evaluation of biogas production from poultry droppings, cow dung and lemon grass.

The study explored the production of biogas from Lemon grass, Cow dung and Poultry droppings. The three substrates were pre-fermented according to standard methods. Six (6) kg of each pre-fermented substrate was mixed with water in ratio 1:1 v/v to form slurry and digested for 30days. A total of 0.125m(3), 0.191m(3) and 0.211m(3) of biogas were respectively produced from the Lemon grass, Cow dung and Poultry droppings with deviations of 0.00234m(3), 0.00289 m(3) and 0.00484 m(3) respectively. The cooking test carried out revealed that the scrubbed gas had higher cooking rates for water (0.12L/min, 0.085L/min and 0.079L/min for Lemon grass, Cow dung and Poultry droppings respectively) while the cooking rates for unscrubbed gas were 0.079L/min, 0.064L/min and 0.06L/min respectively. The pH of the medium fluctuated optimally between 6.5 and 7.8. The research demonstrated that Lemon grass produced less volume but better quality biogas compared to Cow dung and Poultry droppings.

Evaluation of the interferon-γ assay on blood collected at exsanguination of cattle under field conditions for surveillance of bovine tuberculosis.

Development of point of concentration (POC) surveillance strategies for bovine tuberculosis (bTB) would facilitate global efforts to eradicate bTB. The interferon-gamma (IFNγ) assay can detect IFNγ responses to Mycobacterium bovis in blood collected at commencement of exsanguination (COE) of experimentally challenged cattle but has not been evaluated under field conditions. The current study was aimed at determining (i) whether blood collected at COE of cattle at slaughter, under field conditions, is practical to obtain and useful for identifying cattle as IFNγ positive for bTB, (ii) whether the results of the IFNγ assay obtained at COE reliably compare with results obtained from live animals in the field, and (iii) whether the identified animal(s) originated from bTB-infected or bTB-exposed herds. Cattle from three risk groups were used: the highest risk group consisted of 49 cattle from 3 bTB-infected herds; the medium risk group consisted of 24 cattle from a potentially exposed herd; and the lowest risk group consisted of 60 cattle from herds with no known history of bTB exposure. The IFNγ assay was performed on blood collected both before stunning and at COE of cattle at slaughter. An enhanced slaughter inspection for gross lesions consistent with bTB was performed on all cattle. In addition, lymph nodes were cultured for M. bovis for cattle that tested positive for bTB via the IFNγ assay and for most cattle that tested negative for bTB. Cattle, both with and without lesions consistent with bTB, were identified as positive for bTB by the IFNγ assay using blood collected at COE, but none of the positive cattle originated from the lowest risk group. The current study demonstrates that blood collected at COE of cattle is both a practical and moderately reliable sample for accessing bTB infection using the IFNγ assay.