Neonotonia wightii has a good palatability. In Brazil, its palatability improved as the plant became more vigorous in mid-season and was maintained into the autumn (Lychatchynsky et al., 1968 cited by FAO, 2011). Perennial soybean was found to be as palatable as other legumes, including Stylosanthes guianensis, Centrosema molle, Pueraria phaseoloides and Macroptilium atropurpureum (Souto et al., 1975), though the latter was found more palatable in one trial (Kretschmer et al., 2001).
The digestibility of Neonotonia wightii compares favourably with that of alfalfa and other legumes forages (FAO, 2011). Organic matter digestibility is generally in the 55-65% range (Mero et al., 1998a; Mero et al., 1998b; Ribeiro et al., 1980a; Ribeiro et al., 1980b). It has been estimated that the digestibility of perennial soybean was about 10 units lower than that of a temperate legume at an equivalent stage of growth (Holder, 1967).
Digestibility decreases with the stage of growth. The DM digestibility of fresh forage measured in cattle varied from 62% when leafy to 56% DM when seeded. The digestibility of crude protein reached 80% in young forage (Holder, 1967). In sheep fed Neonotonia wightii hay, DM and protein digestibility decreased from 53 to 44% and from 66 to 52%, respectively, between pre-bloom (71 d) and late flowering (112 d) (Vera et al., 1989).
In Cuba, cows grazing pastures of Neonotonia wightii and Pennisetum purpureum yielded significantly more than cows grazing grass (Brachiaria mutica or Pennisetum purpureum/Digitaria eriantha) (10.6 vs. 8.1 and 7.0 kg milk, respectively) (Perez Infante et al., 1979). In Bolivia, access by dairy cows and their calves to legume pasture (Neonotonia wightii, Macrotyloma axillare and Stylosanthes guianensis) during the dry season increased milk yield and milk fat percentage. Calf growth was poor but tended to improve with access to legumes (Paterson et al., 1983).
Most of the feeding trials with Neonotonia wightii concern growing cattle and the benefits of its association with grasses. These trials (see table below for a summary) usually demonstrate the superiority of grass/legume mixtures containing Neonotonia wightii:
||Crossbred female calves (8-12 months)
||- Star grass (Cynodon nlemfuensis) + mixture of legumes including Neonotonia wightii (supplemented with 1 kg/d of concentrate during the dry season)
- Star grass alone (supplemented with 0.5 kg/d of concentrate in the rainy and dry seasons)
|- Better growth (452 vs. 336 g/day) and development (thorax circumference) on animals grazing the grass/legumes pasture
- Higher weight gains made the grass/legume association more profitable
|Mejias et al., 2003
||Crossbred heifers (12 months to reproduction)
||Identical to the trial above but with Pennisetum purpureum instead of star grass in the grass/legumes mixture
||Gains higher than 500 g/d, better development
||Mejias et al., 2004
||- All trials: rotational grazing for 1 year (28 day periods), 3.3 head/ha
- Pangola (Digitaria eriantha) alone
- Pangola + Neonotonia wightii
- Pangola + Centrosema molle
- Pangola + Leucaena leucocephala
|- Highest average daily gain on the pangola/Neonotonia wightii pasture
- Higher gains on mixed pastures: 538 g/d (Neonotonia wightii), 529 g/d (Centrosema molle), 488 g/d (Leucaena leucocephala) vs. 390 g/d for pangola
|Garza et al., 1978
||Nelore and Santa Gertrudis cattle
||- Neonotonia wightii
- Green panic (Megathyrsus maximus var. trichoglumis)
|- Higher growth on perennial soybean (410-469 g/d vs. 331-303 g/d)
- Daily gain decreased over the years (from 544 to 375 g/d for perennial soybean)
|Lourenço et al., 1998
||- Guinea grass/legume pastures (Neonotonia wightii, Centrosema molle, Macroptilium atropurpureum), 3.2 head/ha
- Guinea grass alone, 1 head/ha
|Live-weight gains per animal and per ha on mixed pasture higher than on grass alone. Steers on mixed pasture could attain 500 kg live-weight at an age of 2.5 yr without protein or energy supplementation
||Andrade et al., 1979
||- Guinea grass/legume pastures (Neonotonia wightii, Macroptilium atropurpureum, Stylosanthes guianensis)
- Guinea grass alone
|Live-weight gain/ha increased by 3.45 times and average daily gain by 2.64 times on mixed pasture. Contents of crude protein, P and Ca were higher in grass/legume mixture than in grass alone
||Vilela et al., 1976
||- Guinea grass fertilized with 75 kg N/ha/yr
- Guinea grass + Neonotonia wightii
|Comparable average daily gains (about 460 g/d) for both pastures
||Lourenço et al., 1992
||- Green panic + Neonotonia wightii pasture
- 1.2, 1.7 and 2.2 head/ha
|The animals selectively grazed the available forage. Intake of perennial soybean was higher in autumn/winter than in spring/summer. Neonotonia wightii improved the quality of DM intake
||Lourenço et al., 1984
||Neonotonia wightii + other grasses (Guinea grass, Cenchrus ciliaris, Setaria sphacelata, Chloris gayana) + legumes (Stylosanthes humilis, Centrosema molle, Macroptilium atropurpureum)
||Average daily gains of 120-470 g/d
||Brahman cross bullocks
||- Guinea grass + Neonotonia wightii + Centrosema molle pasture
- Guinea grass + Centrosema molle
|The grass/legume mixture including Neonotonia wightii gave greater live-weight gains in autumn and winter
||Mellor et al., 1973
||Cenchrus ciliaris hay + cassava meal + Neonotonia wightii dried leaves
||Enhanced the digestible organic matter and the nitrogen balance. Dried legume forages such as Neonotonia wightii can replace fish meal as a protein source and supplement low quality roughages when fed with a source of readily fermentable carbohydrate such as cassava
||Mero et al., 1998c
In Hawaii, intake by adult sheep of a dried 1:3 mixture of Neonotonia wightii and Guinea grass (Megathyrsus maximus) was around twice that of pure Guinea grass. The grass-legume mixture also had a better nutritive value than grass alone (Campbell et al., 1980).
In Kenya, male kids that lost weight when fed on natural pastures (Pennisetum purpureum and other grasses) had positive weight gains when supplemented with legume forages (fresh, chopped, 30% of the feed requirement). The gain with Neonotonia wightii (16.4 g/d) was higher than with Macroptilium atropurpureum (4.0 g/d) but much lower than with Leucanea leucocephala (31.3 g/d) (Njarui et al., 2003).
When goats were fed perennial soybean grass hay to excess, a reduction occured in the lignin intake, but not in the other cell wall components (da Silva et al., 1999).