Jimmy W. Smith

Chemical composition, rumen degradation, and gas production characteristics of some multipurpose fodder trees and shrubs during wet and dry seasons in the humid tropics

Abstract Seasonal variations in chemical composition, dry matter (DM) and nitrogen (N) degradation, and gas production characteristics of 18 multipurpose trees and shrubs (MPTs) from the humid lowlands of West Africa were evaluated. The MPTs have potential for the development of integrated crop and livestock agroforestry technologies in the region. The experiment was conducted in Ibadan, southwestern Nigeria during the main-wet (April–August) and dry (December–March) seasons. The MPTs were ranked by their degradation and gas production characteristics, and these were found to be related to chemical composition. There were wide variations among MPTs in crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and proanthocyanidin contents, DM and N degradation, and gas production characteristics. Dry matter degradation during the dry season ranged from 416 to 868 g kg−1 and for N 508 to 950 g kg−1. Crude protein, and rates of DM and N degradation were significantly correlated (r=0.48, P=0.037 for DM and r=0.56, P=0.032 for N). The rates and extents of DM and N degradation were significantly correlated with NDF and ADF during the wet season (r=−0.47 to −0.63). The volume of gas produced (r=−0.48 to −0.67) and initial gas production (r=−0.64 to −0.73) were highly correlated with the NDF and ADF in both seasons. The rate of DM degradation was significantly correlated with gas production variables in the minor-wet season. Ranking of the MPTs based on extent of DM and N degradation, and volume of gas produced for the main-wet and dry seasons were highly correlated. Based on degradation and gas production characteristics in the main-wet and the dry seasons, F. exasperata, S. nodosa, S. siamea, S. spectabilis, G. sepium, L. leucocephala and L. diversifolia were superior in quality to M. thonningii, A. angustissima and P. pterocarpum.

Studies on multipurpose fodder trees and shrubs in West Africa: Variation in determinants of forage quality in Albizia and Paraserianthes species

We investigated variation in forage production, in sacco dry matter (DM) and nitrogen (N) degradations, and in vitro gas production characteristics of four Albizia (A. lebbeck N 864, A. procera N 865, A. saman N 825) and Paraserianthes falcataria (N 783) provenances obtained from The Nitrogen Fixing Tree Association. After one year of establishment forage production was assessed by harvesting trees at 0.5 m above ground in the main wet (April–August) minor-wet (September–November) and dry (December–March) seasons at Ibadan, southwestern Nigeria. Forage samples from the main-wet and dry seasons were incubated for 6, 12, 48, 72 and 96 h in rumen-fistulated cattle to estimate in sacco DM and N degradation characteristics. In vitro gas production was estimated over 3, 6, 12, 24, 48, 72 and 96 h of incubation. Forage production of A. procera was significantly higher than the other species in all seasons. Cell-wall components were comparatively higher in A. procera than the other species. Potential DM and N degradations of A. lebbeck and A. saman were significantly higher than P. falcataria and A. procera. The results suggest that A. lebbeck and A. saman provenances used in this study have relatively higher feed value than A. procera and P. falcataria.

Seasonal dynamics in dry matter degradation of browse in cattle, sheep and goats

Rumen degradation characteristics of DM in edible forage of 25 multipurpose tree and shrub fodders (MPTS) harvested at the end of the main-wet (April–August 1992), minor-wet (September–November 1992) and dry (December 1992–March 1993) seasons were determined in rumen-fistulated Bunaji cattle (BC), West African Dwarf (WAD) sheep (WS) and WAD goats (WG) in Ibadan, southwestern Nigeria. Air dry samples of edible forage were incubated for 3, 6, 12, 36, 48, 72 and 96 h in three each of BC, WS and WG castrates fed a basal diet of Panicum maximum supplemented with Gliricidia sepium leaves. Dry matter degradation constants were estimated from non-linear regression. Concentrations of crude protein, neutral detergent fibre and insoluble proanthocyanidins varied widely among seasons. Classification of the MPTS based on a (soluble fraction), b (rumen degradable fraction), c (rate of degradation)) and PD (potential degradation) varied among BC, WS and WG within season. Using PD as an index of forage quality, the MPTS were classified into high, medium and low groups. The b and PD in BC during the dry season were significantly higher than in WS and WG. The results suggested the existence of intraspecies and interspecies variation in rumen degradation characteristics of DM of the MPTS in BC, WS and WG. The PD in BC was highly correlated to WS and WG in the wet seasons. Thus, rumen degradation could be useful in the initial screening of MPTS for further nutritional studies.

Voluntary intake by sheep and goats ofGliricidia sepium fed in three states and at three levels of supplementation to a basal diet ofPanicum maximum

Crude protein content andin sacco dry matter (DM) loss after 72 h of incubation in West African dwarf (WAD) sheep and goats of fresh, wilted and dried leaves ofGliricidia sepium were compared. Additionally, voluntary DM intakes by WAD sheep and goats ofG. sepium leaves presented in the fresh, wilted and dried states at 10, 20 and 30% levels of supplementation were investigated in two separate experiments. The crude protein content and DM loss from dried leaves were relatively lower than fresh and wilted leaves. At all levels of supplementation, the voluntary DM intakes of fresh and wilted leaves by WAD sheep and goats were relatively higher than dried leaves. The results suggest thatG. sepium leaves should be fed either in the fresh or wilted states to WAD sheep and goats, at levels between 20 and 30% of the total daily DM allowance.

Influence of minerals on the aetiology of geophagia in periurban dairy cattle in the derived Savannah of Nigeria

The aetiology of geophagia in periurban dairy cattle in Nigeria was assessed in relation to the mineral status of the serum, the herbage consumed, and the soil from where the herbage was consumed. The study was carried out using nine herds in the derived savannah zone during both the wet and dry seasons. Generally, the Na, Ca, Fe, Zn and Cu levels in the samples were adequate. However, the forages were low in Ca and the serum was deficient in P. Forage, soil and termite hill samples were also deficient in P. The low levels of P in the soil and termite hill samples showed that the consumption of sand by the cattle did not have any positive impact on their P intake. A seasonal effect was apparent (p<0.05) on the serum Na+, PO43–, Cu2+ and Fe2+ concentrations but not on Ca2+ and Zn2+ concentrations. A seasonal effect was also significant (p<0.05) on the minerals in the forage. There were also seasonal differences in most of the soil and termite hill minerals. Most samples had higher (p<0.05) mineral levels in the dry season. Herd size and farming activity had no apparent influence on the aetiology of geophagia as they did not affect (p>0.05) the concentration of P in the serum, the reported cause of geophagia. Geophagia is probably caused by a marginal level of P in the serum and low levels in the forage and soil. Experimental trials will be required to confirm these observations.

Rumen degradation in sheep, goats and cattle and voluntary intake by sheep of four browse species

Two experiments were conducted using dried leaves ofAlchornea cordifolia, Ficus capensis, Manniophytum fulvum andAlbizza niopoides. In Experiment 1, dry matter (DM) degradation characteristics were investigated using thein sacco nylon bag technique in West African Dwarf (WAD) sheep, WAD goats and Bunaji steers. In Experiment 2, voluntary intake of the browse forage when fed as supplements to sheep at 0, 10 and 30% levels was measured. In Experiment 1,A. cordifolia andM. fulvum had significantly higher rapidly degradable DM fraction thanA. niopoides andF. capensis. Averaged across browse species, the extent of DM degradation for sheep (58.3%) was significantly higher than for goat (47.7%) or cattle (44.1%). Ranking order of browse species for the extent of DM degradation was:F. capensis>A. cordifolia=M. fulvum=A. niopoides. In Experiment 2, as the level of supplementation increased from 10 to 30%, voluntary intake ofA. niopoides andM. fulvum increased while voluntary intake ofA. cordifolia andF. capensis declined. The results suggest that dried leaves ofA. niopoides andM. fulvum are more acceptable to WAD sheep than those ofA. cordifolia andF. capensis.

Edible forage production, chemical composition, rumen degradation and gas production characteristics of Calliandra calothyrsus (Messin) provenances in the humid tropics of West Africa

Two experiments evaluated variations in feed value among Calliandra calothyrsus provenances. In Experiment 1, edible forage production of four provenances were evaluated at Ibadan, southwestern Nigeria over a 2-year period in three seasons: main-wet (April–August), minor-wet (September–November) and dry (December–March). Forage samples from the main-wet and dry seasons were incubated for 6, 12, 48, 72 and 96 h in rumen-fistulated steers to estimate in sacco dry matter (DM) and nitrogen (N) degradation characteristics. In vitro gas production was estimated over 3, 6, 12, 24, 48, 72 and 96 h of incubation. In Experiment 2, DM degradation characteristics of 14 provenances of C. calothyrsus planted on an acid soil in Yaounde, Cameroon, were evaluated. Data were subjected to cluster analysis for grouping, and the 14 provenances were placed into four distinct cluster groups. Based on the potential extent of DM and, N degradation and gas production characteristics in Experiment 1, the four provenances of C. calothyrsus were classified into three forage quality groups: high (ILCA 16310), medium (ILCA 14891, ILCA 15166) and low (NFTA 896). In Experiment 2, using the extent of DM degradation as a forage quality index, C. calothyrsus provenances in clusters 3 and 4 (namely: 51/92, 11/91, 13/91, 45/92, 10/91, 15/91, 18/91, 134/91, 12/91, 62/92), were relatively higher in quality than their counterparts in clusters 1 and 2. The results suggested the existence of intra-species variation among the provenances, and confirmed earlier observations that forage quality of C. calothyrsus could be improved through provenance evaluation.

Feed value of multipurpose fodder trees and shrubs in West Africa: edible forage production and nutritive value of Millettia thonningii and Albizia lebbeck

Millettia thonningii (Schum. & Thonn.) Bak., a nitrogen fixing shrub native to Africa and Albizia lebbeck Benth, were harvested at 0.50 m above ground level after one year of establishment to determine edible forage production. Harvests were made at the end of the main (April–August) and minor (September–November) wet, and dry (December–March) seasons for two years. Dry season edible forage samples were analyzed for concentrations of crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (NDF), acid detergent lignin (ADL), cellulose (CL), soluble phenolics (SOPH) and proanthocyanidins (PAs). In sacco dry matter (DM) and nitrogen (N) degradation and in vitro gas production (GP) characteristics were also determined on dry season edible forage samples. Edible forage production of M. thonningii was significantly lower than A. lebbeck during the wet seasons. Millettia thonningii had relatively lower CP and PAs, but higher NDF, ADF, ADL, CL and SOPH than A. lebbeck. In sacco DM and N degradation and in vitro GP parameters of M. thonningii were significantly lower than A. lebbeck. Parameters of in sacco DM degradation and in vitro GP were highly correlated. Millettia thonningii appeared to be of lower feed value than A. lebbeck based on edible forage production, chemical composition, in sacco DM and N degradation and in vitro GP characteristics.

The Effect of Leaf-Pruning on Nutrient Intake and In Vivo Digestibility of Soybean Stovers by Sheep

ABSTRACT Nutrients of soybean stovers (SBS) from three soybean varieties: TGx 923-2E (SBS1), TGx 1660–19F (SBS2) and TGx 1019–2EN (SBS3) whole plant (WP) and leaf-pruned stem (LPS) were compared, and these SBS (WP and LPS) were offered to West African dwarf sheep to measure voluntary dry matter (DM) intake (VDMI) and apparent crude protein (CP) and cell wall constituent digestibility coefficients. Average DM, CP, ash and cell wall phenolics concentrations in WP were higher than in LPS by 1.53, 33.65, 1.47 and 96.15%, respectively. In contrast, average NDF, ADF, ADL, cellulose and hemicellulose concentrations of LPS were higher than in WP by 1.73, 1.87, 2.93, 1.19 and 1.44%, respectively. Daily DM intake by sheep fed SBS2 (WP; 36.2 g kg BW) was lower (P < 0.05) than other tested stovers with a similar (P >: 0.05) average intake value of 41.8 kg BW0.75. Corresponding (P > 0.05) average daily CP intake by sheep fed SBS1, SBS2 and SBS3 (WP; 5.1 g kg BW0.75) was higher (P < 0.05) than the CP intake of sheep fed SBS1, SBS2 and SBS3 (LPS). Neutral detergent fibre digestibility values of 3 SBS (WP) and N-retention coefficient of 3 SBS (WP) were significantly (P < 0.05) higher than the values obtained from the 3 SBS (LPS). It is concluded that leaf-pruning has no significant beneficial effect on the feeding of soybean stovers to sheep.