[Inhibition of methanogenesis in the rumen of sheep. I. Methanogenesis before administration of inhibitors].

Studies were carried out on 5 sheep aged 2-4 years of about 40 kg in body weight successively in summer and autumn. They were fed in 6 feeding groups in the morning between 6.30 and 7.30 and in the afternoon between 13.30 and 14.30. Gas samples were taken with an Orsat apparatus, Kiecka methanometer and a gas chromatograph from the rumen through a stable fistula directly before and after feeding and 0.5, 1, 2, 3, 4, 5, 6 hr after eating the morning food. The presence of CH4, CO2, N2, H2, O2, CO, CnHm, H2S and SO2 was found in the rumen gas samples analysed. The ratios of the following gases were also analysed: CO2:CH4, N2:O2, CO2:O2, H2:N2, CO2:N2 and CH4:N2. It was shown that the level of methane production in the sheep rumen depends on the composition of the food fed, the lapse of time from the last feeding and on the years season, whereas the amount of methane and its ratio to that of other gases of the rumen show a distinct dependence on the content of the food volume fed. The particular gas ratios, especially that of CO2 to CH4 may account for regular fermentation processes developing in the rumen of the sheep studied. The obtained results were mathematically analysed.