Lentil straw tends to be more digestible and palatable for ruminants than cereal straws. Harvesting lentils leaves very few residues in the field, so it is recommended to allow animals to graze in order to salvage those residues (Lardy et al., 2009).
Several studies have concluded that lentil straw has a lower NDF content, a better rumen degradability and a better whole tract digestibility than cereal straws (Sehu et al., 1998; Lopez et al., 2005; Singh et al., 2011). There are few studies on the nutritive value of lentil straw for ruminants. Four studies reported in vivo OM digestibility values comprised between 47 and 55% (Dutta et al., 2004; Abreu et al., 1998; Alibes et al., 1990; Sehu et al., 1998). However, a comparison of in vitro methods (enzymatic method defined by Aufrère and the two-stage method of Tilley and Terry), resulted in higher values comprised between 54 and 57% (Denek et al., 2004). Such differences may be explained by the variable leaf:stem ratio, which depends on the harvesting method. For instance, using in vitro gas production, a stem-rich lentil straw was found to have an ME of 6.7 MJ/kg DM vs. 8.3 MJ/kg DM for a leaf-rich lentil straw (Lopez et al., 2005).
In Jordan, in Awassi ewe lambs supplemented with concentrate (0.55 kg/head/day), the palatability, nutrient digestibility and weight gain from lentil straw were comparable to those from alfalfa hay, and higher than those from bitter vetch (Vicia ervilia) straw or wheat straw (Haddad et al., 2001). In Chile, sheep fed for much of the dry period on lentil straw supplemented with a molasses-urea-minerals mix lost less than 10% of their body weight (Tima et al., 1991). In India, a synergistic interaction with positive effects on the dairy performance of buffaloes and in vivo digestibility was observed when lentil straw was combined with urea-treated wheat straw (Dutta et al., 2004). A DM intake of 70 g/kg for lentil straws in sheep has been reported (Abreu et al., 1998).
Comparison with other legume straws
Several studies have compared lentil straw with other legume straws. Lentil straw was found to have DM in sacco degradability and in vivo DM digestibility values higher than those of chickpea straw but lower than those of common vetch (Vicia sativa) straw (Sehu et al., 1998). In another study, in sacco DM degradability was found to be similar to that of the straws of chickpea (Cicer arietinum), faba bean (Vicia faba) and purple vetch (Vicia benghalensis), but lower than that of the straws of pea, common vetch (Vicia sativa) and hairy vetch (Vicia villosa) (Bruno-Soares et al., 2000). A study found similar protein and NDF in sacco degradability values for lentil straw and common vetch straw but the in vivo OM digestibility of lentil straw was lower than that of vetch straw (55% vs. 65%) (Abbeddou et al., 2011).
Lentil bran (hull, chuni)
In India, a trial with cross-bred calves fed lentil chuni and alfalfa hay (2 kg/d each) showed that lentil chuni was a valuable protein and energy supplement (Paliwal et al., 1987). In bulls, rumen fermentation benefited when animals were fed a diet of 50% lentil chuni and 50% wheat bran, compared to one of these two ingredients alone (Gendley et al., 2009).
The in vitro DM digestibility of lentil hulls (51%) was found to be lower than that of faba bean hulls (57%) and higher than that of pea hulls (48%) (Mekasha et al., 2002; Mekasha et al., 2003). In sacco degradability of DM was lower for poor-quality lentil bran than for lentil screenings (30% vs. 49%) (Yalçin et al.,1992).
Lentil seeds and screenings
Feeding trials in North Dakota suggest that lentil seeds are very palatable and calves fed lentils performed equally to animals fed field peas or chickpeas (Lardy et al., 2009). Lentil screenings were found to have a poor OM digestibility (55%) despite a fairly low NDF content (29% DM) and a high crude protein (23% DM) (Stanford et al., 1999). Organic matter digestibility and DM intake were similar in beef cattle receiving diets containing either lentils, chickpeas or field peas, in replacement of corn and canola meal as the grain component in the diet (Gilbery et al., 2007).