UTILIZATION OF LEUCAENA-DIVERSIFOLIA, LEUCAENA-ESCULENTA, LEUCAENA-PALLIDA AND CALLIANDRA-CALOTHYRSUS AS NITROGEN SUPPLEMENTS FOR GROWING GOATS FED MAIZE STOVER

Three psyllid resistant Leucaena species (Leucaena esculenta sub-speci es paniculata (Oxford Forestry Institute, accession number 52/87), L. diversifolia sub-species stenorcarpa (Oxford Forestry Institute, acces sion number 53/88) and L, pallida offspring of Commonwealth Plant Intr oduction, number 85890)) and Calliandra calothyrsus (Oxford Forestry I nstitute, accession number 9/89) were evaluated for their potential as supplements for growing goats fed maize (Zea mays) stover, using chem ical analyses, in vivo digestibility and a growth trial. Leucaena escu lenta forage had the highest (P<0.001) content of nitrogen (38.3 g kg( -1) DM) compared to L. diversifolia, L. pallida and C. calothyrsus, wi th 36.3, 34.8 and 34.0 g kg(-1) DM, respectively. Levels of insoluble proanthocyanidins and soluble phenolics were highest (P<0.001) in C, c alothyrsus forage, moderate in L. esculenta and L. diversifolia and lo west (P<0.001) in L. Pallida, Soluble proanthocyanidin concentrations differed significantly (P<0.001) between fodder tree legumes and ranke d in the order L. esculenta and L. diversifolia > C. calothyrsus > L. pallida. Mean apparent digestibility coefficient of nitrogen for the d iets supplemented with C. calothyrsus, L. diversifolia and L. pallida was 0.56 and differed significantly (P<0.001) from that reported for g oats on L, esculenta (0.46). Highest (P>0.05) nitrogen retention was r eported for goats on the L. diversifolia supplement (0.45 g kg(-1) W-0 .75 per day) and the mean nitrogen retention for goats on C, calothyrs us, L. esculenta and L. pallida was 0.43 g kg(-1) W-0.75 per day. In t he growth trial, total dry matter intake was highest (P<0.05) with goa ts on the L. pallida and C. calothyrsus supplemented diets. Growth rat e during the last 35 days of the study was highest (P<0.001) for goats on the C. calothyrsus supplement (44.2 g per day) reflecting a high n itrogen use efficiency, while those fed the L. esculenta, L. diversifo lia and L. pallida gained 27.5, 37.8 and 40.6 g per day, respectively. The different impact of tree fodder proanthocyanidins on animal respo nses emphasises the need to identify and define their chemical and fun ctional structures in order to understand the biological effects of di fferent proanthocyanidins on ruminant performance. (C) 1998 Elsevier S cience B.V.