Sesbania grandiflora is a good source of fodder, particularly during drought periods (Cook et al., 2005). The leaves, the young branches and the pods are very palatable to cattle (Gutteridge et al., 1995; NAS, 1979). Sesbania grandiflora is a major component of ruminant diets in Eastern Indonesia where it may comprises up to 70% of total forage allowance during the dry season (Cook et al., 2005). For instance, in the Lombok Island, it is one of the most readily available feeds offered to goats both as a mixed or sole diet (Dahlanuddin, 2001). Sesbania herbage generally supplements low quality roughages such as straws, crop residues or dried grasses. This dilutes the effects of antinutritional factors and greatly improves the utilization of roughages (Gutteridge et al., 1995).
Digestibility and degradability
The digestibility and degradability of Sesbania grandiflora dry matter and nutrients are generally high and compare favourably to those of other common legumes species such as gliricidia and leucaena. Dry matter digestibility of Sesbania species is superior to that of most other tree and shrub legumes (Gutteridge et al., 1994). In northeast Thailand, the in vitro dry matter digestibility of Sesbania grandiflora (66%) was higher than that of 15 other tree legumes (Akkasaeng et al., 1989). The digestibility of crude protein, NDF, ADF and cellulose were significantly higher in rams fed Sesbania than in those fed other legumes (gliricidia and groundnut) (Muthukumar et al., 2005). Another trial found that DM, organic matter and crude protein digestibilities were high and similar for Sesbania grandiflora et Leucaena leucocephala (Nguyen Thi Hong Nhan, 1998a).
Many authors have reported high rumen degradability of Sesbania forage compared to other legumes: 72% effective DM degradability (Suchitra et al., 2008); 62% effective DM degradability (compared to 52% for leucaena and gliricidia, Muthukumar et al., 2005); 75% DM 12 h disappearance (Ash, 1990); 73% DM 24 h disappearance (compared to 65% and 73% for DM 48 h disappearance for leucaena and gliricidia, respectively, Rao et al., 1993).
In India, milk production of cows supplemented with Sesbania (5 kg/head/d) increased by 8% (9.2 to 10.0 L/d). Milk protein remained high up to 60 days after calving, whereas the percentage of fat was unchanged (Vijayakumar et al., 2000a). For cows in early lactation receiving a diet supplemented with Sesbania grandiflora leaves (5 kg/head/day for 45 days), there were significant increases in propionate, butyrate, and rumen microbial protein production in the experimental group, which showed that the Sesbania grandiflora had no deleterious effects and had been beneficial to the ecology of the rumen (Vijayakumar et al., 2000b).
In experiments in Java, cattle fed 1.8 kg/day of fresh Sesbania grandiflora leaves supplementing a rice straw diet showed growth increases comparable with those obtained with formulated diets (NAS, 1979).
Supplementation with Sesbania grandiflora dry leaf meal was able to promote economical and sustainable lamb production under a semi-intensive grazing system. The weight gain (49 g/day) was higher than with other legume leaf meals (leucaena, gliricidia) and groundnut haulms though lower than with a maize-groundnut cake concentrate. The feed cost/kg gain ratio was lower with Sesbania (Ravi et al., 2006).
In Vietnam, in a farm trial where tree foliages were given to goats as the sole diet, the highest live weight gains were obtained with Sesbania grandiflora (114 g/day) followed by Leucaena leucocephala (98 g/day), Ceiba pentandra (94 g/day) and Hibiscus rosa-sinensis (77 g/day). Feed intake of fresh foliage was in the range of 2.5-2.9 kg/day. Sesbania grandiflora gave a similar result when it supplemented (50% of the diet DM) a diet based on maize husks. It was found to be the most promising of these four foliages on the basis of high voluntary DM intake, high digestibility and growth rate (Nguyen Thi Hong Nhan, 1998a; Nguyen Thi Hong Nhan, 1998b). Also in Vietnam, the intake of Sesbania grandiflora leaves fed to 3-4 month-old growing goats was higher than the intake of sweet potato vines, and weight gain was also higher (64 g/d vs. 44 g/d) (Vo Lam et al., 2004).
However, there are limitations to using Sesbania forage, and in spite of generally higher in vitro digestibilities and nutrient content than many other browse trees, the live weight gains achieved are sometimes lower than expected (Gutteridge et al., 1995). In Indonesia, supplementing goats grazing elephant grass (Pennisetum purpureum) with 15% Sesbania grandiflora forage (diet DM) did not modify intake, and Gliricidia, Leucaena or Sesbania grandiflora gave the same weight gain (20 g/d) (Van Eys et al., 1986). In Western Samoa, goats failed to gain weight when supplemented with S. grandiflora, although the reasons for this poor result were not identified. The authors suggest that supplementation with S. grandiflora should be limited to 30% of the diet (Ash et al., 1992).
In Vietnam, farmer experience indicates that the main constraints to the widespread use of Sesbania grandiflora for feeding goats are its relatively low yield and slow rate of regrowth after pruning (Vo Lam et al., 2004).