Fresh nacedero foliage is used as a protein supplement for sheep and goats, but data are lacking for cattle (Hess et al., 1998; Keir et al., 1997a; Nguyen Thi Duyen et al., 1996; Vargas, 1993). It has been evaluated for ruminant feeding in South America and South-East Asia since the 1990s with mixed and variable results, which is probably due to its highly variable nutritive value (Rosales et al., 1999; Hess et al., 1998; Rosales, 1997; Keir et al., 1997a; Nguyen Thi Duyen et al., 1996; Vargas, 1993). Its palatability is only moderate (Garcia et al., 2009; Garcia et al., 2008; Mejia et al., 1993). Animals appear to need a period of adaptation to nacedero (Rosales, 1996). Unlike other tropical plants, nacedero has poor anthelmintic properties (Rios de Alvarez et al., 2012).
The relative intake of nacedero foliage by goats and sheep was only moderate or low in comparison with other forage trees or shrubs in Colombia and Venezuela (Garcia et al., 2009; Garcia et al., 2008; Mejia et al., 1993). It was suggested that the lower palatability of nacedero leaves could be due to their slightly hairy surface (Keir et al., 1997b). In Colombia, the intake of nacedero by weaned African Hair sheep was much lower than that of gliricidia (Gliricidia sepium), but higher than that of leucaena (Leucaena leucocephala). Animals needed time to adapt to nacedero before being able to consume it in appreciable quantities (Mejia et al., 1993). In Venezuela, in a free-choice trial comparing 12 forage tree species, nacedero intake by dry Creole goats was intermediate (Garcia et al., 2008). Intake of nacedero by cattle, sheep and goats remained low in free-choice trials compared to that of Maclura tinctoria, Morus alba and Balizia pedicellaris, and high compared with that of Leucaena leucocephala, Moringa oleifera, Azadirachta indica and Albizia saman. Nacedero intake increased gradually during the first 3 days that the goats were offered this forage and then levelled off (Garcia et al., 2009).
A large variability in the nutritive value of nacedero, due to climate, soil and genetics has been observed (Rosales et al., 1999; Suarez Salazar et al., 2008). Nacedero forage has a high fermentation rate, due to its high concentration in carbohydrates, with most fermentation occurring during the first 12 hours (Rosales, 1996). Rumen degradation is characterized by high fractions of soluble and potentially degradable DM (Edwards et al., 2012; Naranjo et al., 2011; Nguyen Xuan Ba et al., 2003). However, the rumen degradation rate of the protein was relatively low compared to that of other forage tree species (Edwards et al., 2012; Naranjo et al., 2011). This could be explained by the presence of phenols, which can be significant though highly variable (Galindo et al., 1989; Rosales, 1997). There may be more hydrolysable than condensed tannins and, therefore, have a higher capacity to react with protein (Rosales, 1997). Thus, the relatively high level of rumen undegradable protein in nacedero foliage suggests that it may be a good source of bypass protein, though this was not confirmed in a comparative digestibility trial (Edwards et al., 2012).
Growing sheep and goats
In Vietnam, nacedero foliage gave poor results when it was used as the sole forage in diets for growing goats with access to multinutrient blocks. Nacedero had a similar protein content as jackfruit (Artocarpus heterophyllus) foliage. However, rumen degradability of DM, feed intake (9.8 g vs. 50 g DM /kg LW) and weight gain (-70 g/d vs. +69 g/d) were all lower with nacedero compared to jackfruit. The low DM content of nacedero leaves may have contributed to their low intake (Keir et al., 1997b). The need for a period of adaptation may explain the low intake and the loss of weight (Rosales, 1997).
Nacedero foliage can be used as a protein supplement in low quality forage-based diets. In Colombia, nacedero foliage (3 kg per 100 kg liveweight) as a supplement for young African Hair sheep, fed a basal diet of pressed sugar cane stalks and a multinutrient block (10% urea), increased feed intake similarly to Gliricidia sepium and Erythrina poeppigiana (Vargas, 1993). In African-type sheep, supplementation with 20 or 40% nacedero (DM basis) of a Dichanthium aristatum hay-based diet improved both intake and digestibility of the diet. In this experiment, the protein content of nacedero was much higher than that of the basal forage (16.6% vs. 3.4% of DM) (Hess et al., 1998).
In Vietnam, lactating goats were offered high levels (50% DM basis) of forage tree foliages such as nacedero, jackfruit (Artocarpus heterophyllus), banana plants (Musa spp.) and Acacia mangium as supplements to a basal diet of rice straw and sugarcane tops. Nacedero resulted in the lowest milk production even though intake of Acacia mangium was lower. However, the protein content of nacedero foliage used in this experiment was particularly low (less than 13% DM) (Nguyen Thi Duyen et al., 1996).