1.1 Background of the Study
Ruminant livestock have a unique digestive system that
allows them to use energy from fibrous plants materials better than other
herbivores. Their digestive system is designed to ferment feedstuffs and
provide precursors for energy for the animal to use (Parish et al., 2009).
Forages play an important role in ruminant animal nutrition. Ruminants are able
to ruminate or regurgitate ingested high forage diets to reduce particle size
for improving their digestibility (Ranjbar, 2007; Parish et al., 2009).
However, inadequate supply of all year round quality forage is a major
constraint to livestock production in the tropics (Ajayi et al., 2005;
Ogunbosoye and Babayemi, 2010a). Most available ruminant feeds/feedstuffs
the dry season are poor in nutrients which deteriorate
rapidly with increasing fibre and decreasing protein (Babayemi, 2007).
Sources of cheaper alternative forages of high quality for
ruminants have been a subject of research in recent years (Alan et al., 2013)
especially for farmers in the tropics. Browse plants have great potential as
source of high quality nutrient for ruminants, being high in protein, minerals
and Vitamins (Babayemi et al., 2003). They are available all year round
because of their drought resistance, persistence, vigorous
growth, re-growth and palatability (Reynolds and Atta-Krah, 2006). The use of
browse plants as supplement have been shown to enhance intake, improve growth
rate and increase reproduction in ruminants (Osakwe and Udeogu, 2007; Lamidi et
al., 2009; Okafor et al., 2012). However, most of these forage trees have not
been widely used because they often contain anti-nutritional compounds that
have deleterious effects on animal performance (Ghosh et al., 2007).
Moringa oleifera Lamarck which originated from India is widely
distributed and has become naturalized in many locations in the tropics (Fahey,
2005). It is a non-leguminous multipurpose tree and one of the fastest growing
trees of the world. Moringa is one of the promising plants which could
contribute to increased intake of some essential nutrients and
health-promoting phytochemicals (Alikwe and Omotosho, 2013;
Nweze and Nwafor (2014). It has a high crude protein content ranging from
20-26% CP in leaves (Kakengi et al., 2005; Ben Salem et al., 2004; Asaolu et al.,
2011) with negligible contents of anti- nutrients (Makkar and Becker, 1996).
Moringa has been reported for its unique nutrient profile (Ofoh et al., 2011).
Moringa can grow up to 12m in height at maturity, with a yield
up to 120 t/ha/yr when it is densely planted for use as
forage crop (Makkar and Becker, 1996).
Gmelina arborea Roxb. (Family verbenanceae) is a fast
growing deciduous tree that can grow up to 40 m tall and 140 cm in diameter
(Jensen, 1995). Even though Gmelina arborea can shed some of its leaves when
the dry season is approaching, the regrowth of new leaves could serve as animal
feed during this period. The leaves are high in nutrient. Previous records
(Okafor et al., 2012; Osakwe and Udeogu, 2007; Ahamefule et al., 2006) have
shown that the leaves contain as much as 10.01-38.4% crude protein and
3.10-30.46 % crude fibre with low level of anti nutritional compounds