The value of acacia brevispica and leucaena leucocephala seedpods as dry season-supplement for calves in arid areas of Kenya

Abstract

Two feeding experiments were conducted to evaluate Acacia brevispica and Leucaena leucocephala seedpods as dry season supplements in terms of nutrient composition and liveweight performance. In feeding experiment one (FE-I), 18 calves were used. The treatments comprised of A1 (control-I), B (Acacia seedpod meal-ASM) and C1 (Leucaena seedpod meal-LSM-l). Each treatment was allocated 6 calves. In feeding experiment two (FE-2), 16 calves were used. The treatments were A2 (control- 2) and C2 (LSM-2). Each treatment was allocated 8 calves. Experimental diets were designed to supply isonitrogenous levels. A daily intake of 1.5 kg ASM diet and 1.2 kg LSM diet and at least 2.5 kg of basal hay would supply 60% (265 g) of the total CP requirement for growth rate of 500 g d-1. Control calves were given 0.6 kg wheat bran equivalent to the amount used in formulating ASM and LSM diets. Calves were weighed weekly over five and four weeks in FE-l and FE-2 respectively. Computed average daily gain (ADG) and intake data were subjected to analysis of variance and F-test was used to compare experimental groups with the controls. Seedpods at four phenological stages were analysed for DM, Ash, CP, NDF and ADF to monitor nutrient profile with maturity. Separated seedpods were analysed for DM, Ash, CP, EE, NDF, ADF, in vitro digestibility and tannin contents to determine the contribution made by seed and pod (carpel) to the nutritive value of the whole seedpod. Chemical analyses were done in duplicate following conventional procedures. Contents of CP declined and fibre (NDF and ADF) increased wit h maturity . The decline in CP was more drastic in ~ brevispica than in ~ leucocephala as the seedpods dry. Seeds contained higher CP, EE and IVDMD, but lower fibre than empty pods. Dry leucocephala seedpods had appreciable amounts of tannins than A. brevispica, more of which were located in empty pods. In FE-1, ADG (gd-1) was 486, 250 and 239 for calves on LSM-1, ASM and control-1 respectively. Calves supplemented with LSM-1 diet had significantly (P < 0.01) better ADG than control-l and those on ASM diet. Calves on ASM had superior growth rate than control-1, though not significantly (P<0.05) . Using hay from an arid enviroment in FE-2, calves on LSM-2 had significantly (P<0.01) higher ADG (559gd-1) than control-2 (276gd-1) confirming the results of both legume plants obtained in FE-1. Intact seedpods had similar contents of Digestible energy (DE). However, seedpods of abrevispica used in FE-1 contained only 65% of their seeds and thus had lower contents of DE. The ADG of calves on ASM diet did not reflect the true nutritive value of intact seedpods. It was concluded that if seeds are retained, both seedpods are suitable feeds for ruminants, at least for strategic supplementation by agropastoralists and farmers who have financial limitations when other feeds are unavailable in the dry season. However, further research was proposed to determine the effect and level of feeding A. brevispica seedpods when seeds are retained.