| Sumario: | The low quality and slow fermenting roughage basal diets in sub-Saharan Africa (SSA) amply justifies the need to supplement such basal diets. Fodder trees have proved to attractive recently as energy, protein and mineral supplements when ruminants are fed such fibrous roughages. Unlike the morer uniform oil seed cakes, the high innter- and intra-specific variation among tree leaves confirms the need to evaluate tree leaves on their individual merit. The trials Reported here involved various types and formms of fodder trees (FTs) and the results indicated significant differences (P<0.05) between types and forms with reegard to degradability, in vitro gas production and rumen fermentation patterns (ammonia-nitrogen, pH. volatile fatty acids, isoacids and microbial protein synthesis). The fast degrading tree supplements eg. Sesbania elicited greater roughage intake response in sheep. Quantitive evidence suggest that Sesbania Sesban accounted for 0.73 of the variation attributed to roughage intake in growing sheep while Leucaena Leucocephala accounted for 0.53. The sum kinetic activities of rapid fermentation and movement out of the rumen by fast degrading FTs like Sesbania were rerasons assigned for the differences. This works and other trials confirmed the hypothesis that levels of supplementation that would optimise nitrogen balance may be the different from those that maximise intake. In other trials, the high roughage substitution rate recorded for the differences. This works and other trials confirmed the hypothesis that levels of supplementation that would optimise nitrogen balance may be the different from those that maximise intake. In other trials, the high roughage substitution rate recorded for fresh Leucaena or slow degrading FTs would suggest that bulkiness was important in the control of roughage intake. Intake, digestibility nitrogen utilisation and growth studies with menz sheep fed Eragrostis tef (teff straw) basal feed and high degrading sesbania supplement showed that the supplement could be offered either in the morning, evening or twice daily without any significant (P>0.05) differences. Addition of a readily available energy source improved roughag intake and nitrogen utilization. When FTs were fed. The presence of certain antinutritional factors in some FTs suppressed the growth of Ruminoccocus. High levels of tannins were found to reduce the efficiency of nitrogen utilization as evidences from the high faecal nitrogen output. Improved ruminant productivity was achieved when FTs, which provide certain critical nutrients, were fed as supplements. The increased roughage intake, digestion, kinetics and animal growth were attributed to the better rumen ecology created in such animals.
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