[Effect of monensin (USA, Czechoslovakia, Bulgaria) on fermentation of animal feed in an artificial rumen (Rusitec)]. / Efektívnost vplyvu monenzínu (USA, CSFR, Bulharsko) na fermentáciu krmnej dávky v umelom bachore (Rusitec).

An experiment was made with the Rumen Simulation Technique (Rusitec) in which the fermentation of a mixed ration of hay (12.8 g/d) and bruised barley (3.2 g/d) was compared with the fermentation of the same diet in the presence of 5 mg monensin/d from the USA, CSFR and Bulgaria. The fermentation of the mixed ration was significantly affected by all three kinds of monensin. The digestibility of dry matter (DM) in the rations declined in the presence of monensin from 48% to 40% (tab. I). The digestibility of detergent fibre, cellulose and hemicellulose also declined in the presence of monensin (tab. I). The production of methane decreased (-70%) and CO2 production dropped too, but this decrease could be accounted for by the changes in the production of volatile fatty acids and redistribution of metabolic hydrogen (tab. I). Monensin decreased the production of total volatile fatty acids (-21%), the production of acetic (-35%), n-butyric, n-valeric and isovaleric acids (tab. II) and increased the production of propionic acid (+60%). The production, utilization and recovery of metabolic hydrogen were significantly increased in the presence of all three kinds of monensin (tab. IV). The end products of fermentation were affected by an addition of monensin to the mixed ration. All three kinds of monensin increased energic efficiency of volatile fatty acids, decreased adenosinetriphosphate (ATP) production, the amounts of fermented hexose, organic matter fermented and utilization of glucose (tab. III).(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of salinomycin on lambs for fattening]. / Vliianie na salinomitsina vurkhu agneta za ugoiavane.

When applied to male Trakiiska tunkorounna lambs of initial weight 18.6 kg in the course of 90 days at concentrations of 6 g, 12 g, and 24 g per ton of forage slinomycin brought about a rise of liveweight and average weight gain in the treated animals (for the weight gain 12.2, 16.7, and 19.4 per cent, respectively, as against the controls). The conversion rate (intake per kilogram of weight gain) was by 9.7, 16.6, and 22.2 per cent, respectively, higher. The intake of forage progressively dropped when offering higher concentration of the antibiotic, particularly during the second half of the experimental period. Highest was the effect of adding 24 g salinomycin to a ton of forage. Salinomycin induced no essential changes in the slaughter indices and in the content of cyanocobalamin in the meat. However, cyancobalamin was found to be at a higher level in the liver.