Palatability
Breadnut trees provide forage during the dry season in many areas of Central America. The leaves, seeds and entire fruits are eaten by animals. Breadnut forage has been assessed in agroforestry systems with other woody species for cattle preference and was shown to be readily consumed by cows, though not as much as Albizia saman, Moringa oleifera or Leucaena leucocephala (Nelson Pérez et al., 2012).
Digestibility
Because of their high protein and low NDF and ADF content, breadnut leaves have a high dry matter digestibility (DMD):
The DMD measured in vivo with white tailed deer is medium, with 61% (Lopez-Coba et al., 2007).
The protein degradability in the rumen is very high (93-95%) (Ku Vera et al., 1998). This means that leaves are a good source of protein for the rumen microorganisms (Ramirez-Cancino et al., 2000).
Because breadnut leaves are a good source of protein and fibre supplement, they increased the DMD of a diet based on a forage of low nutritive value (4-5.6% CP) when supplemented at 15% to 23% of the DM (Ramirez-Cancino et al., 2000; Ku Vera et al., 1998).
Intake
Breadnut leaves are mostly offered with small and young branches (Göhl, 1982). When fed alone to sheep, breadnut leaves dry matter intake (DMI) reaches a high level: 5.9 % of body weight (Yerena et al., 1977). In several studies conducted for comparing different tree leaves offered to ruminants, breadnut leaves were almost always preferred: 1.7 to 9 times more by cattle (Sandoval-Castro et al., 2005), 1.4 to 2 times more by goats (Alonso-Diaz et al., 2008; Pech-Cervantes et al., 2016), 1.4 to 6.3 times more by sheep (Alonso-Diaz et al., 2009; Hernández-Orduño et al., 2015; Pech-Cervantes et al., 2016), and 1.2 to 6 times more by white tailed deer (Lopez-Coba et al., 2007; Plata et al., 2009). In several situations, the lower preference of the other tree species is a consequence of their high anti-nutritive factors contents like phenolic compounds and condensed tannins, and high lignin content.
Because of their good protein content (similar to legume forages), high DMD and protein digestibility, breadnut leaves are a good forage supplement which can be used during the dry season with low nutritive value forage. They may increase the DMD of the forage and would at least fulfill the maintenance requirements, or a low growth rate.
Cattle
Heifers
When fresh leaves of breadnut were offered ad libitum with fresh elephant grass (Pennisetum purpureum), heifers (about 350 kg BW) ate up to 3 kg DM of breadnut leaves and almost 6 kg DM of elephant grass (Sandoval-Castro et al., 2005).
Dairy cattle
When offered at 2 kg DM/d as a supplement to 450 kg crossbred (Bos taurus x Bos indicus) cows, suckling their calf and grazing Guinea grass, breadnut leaves allowed a total yield of 5.5 kg milk/d (Bobadilla-Hernandez et al., 2007). When breadnut leaves replaced up to 66% of the concentrate (2 kg/d of sorghum grain and soybean meal) to crossbred dairy cows (453 kg; 86 days in milk) the milk yield was no different: 7 vs. 8.2 kg/d (Sandoval-Castro et al., 2005).
Sheep
In Yucatan, Mexico, breadnut leaves were either offered ad libitum as a supplement to Pelibuey and Black belly sheep (13 kg) grazing medium quality pasture or as a sole forage supplemented with 200 g concentrate for more than 2 months. The daily weight gains were different (70 to 77 g/d) but in the same range, while it was shown that using breadnut leaves as sole forage resulted in a very lower daily weight gain (only 46 g/d) (Pérez et al., 1995). However, it was shown that using breadnut foliage alone yielded better DWG than mixing it with foliage of false tamarind (Lysiloma latisiliquum), which had deleterious effects on voluntary intake, nutrient digestibility and N balance in Pelibuey sheep fed on low quality grass (Sorghum halepense) hay (Castro-González et al., 2008).
Goats
While breadnut foliage was shown to be preferred by goat kids with a forage intake of 13 g DM/kg LW among 3 other tree foliages (Acacia pennatula, Piscidia pendula, Lysiloma latisiliquum), its intake rate per minute was the lowest (Alonso-Diaz et al., 2008). Lactating goats fed on elephant grass basal diet were supplemented with breadnut foliage or mucuna bean. Both supplements increased DM intake at the beginning. At the end of the experiment both supplements resulted in higher intake but breadnut showed a quadratic increase which suggested that animals fed on breadnut foliage had reached their digestive capacity since breadnut foliage is bulky. A linear increase in milk production was observed with breadnut foliage (Mendoza-Castillo et al., 2003).
