Research Results - (PDF, 101 mb) - USAID

Greater efficiency of digestion in South
America camelids (SAC) may be due to more
frequent contractions of the forestomach, the
rumination cycle, and the ratio of salivary flow
to forestomach size. These attributes provide
for more efficient maceration, mixing, and
absorption of digesta. Greater digestibility
values in SAC on low nitrogen feed could be
explained by the ability to maintain higher NH ,
concentrations in CI-C2 compared to sheep,
which provides llamas with more nitrogen for
microbial synthesis, thus improving digestibility.
Our studies in Peru showed that alpacas
consumed mainly tall grasses in the wet season
and short grasses in the dry season. Preferred
species were Festucadolichophylla, Distichia
muscoides, Trifolium amabile,and Bromus
unioloides.
SR-CRSP research reported grass consumption
was highest during the driest months
and consumption of grass-like species was
inversely related to grass in the diet. Forbs in
the diet increased in the early wet season.
Alpaca ate more leaf material as the rainy
season progressed. Tuis consumed more grasslike
plants, forbs, and seeds than adults.
Researchers noted that alpacas are
highily adaptable grazers; where grass was
available, it comprised the bulk of the alpaca
diet, but on a site with low grass availability and
abundant sedges, diets were dominated by
sedges. Although forbs did not contribute a
large portion to the animal diet, they were
consistently eaten. As the dry season progressed,
the diet of "bofedal" alpaca (those
occupying perennially green areas) became
largely sedges and reeds (78%), while Altiplano
alpaca diets were dominated by grass (60%).
In the Peruvian Altiplano, 80%of the
total livestock are produced by small holders
and small communities; llamas and alpacas are
mixed with sheep and managed together. Few
studies have compared dietary composition
between these herbivores to understand how
they partition the forage resource. Researchers
found that alpacas selected more tall grasses
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and less short grasses than sheep. Grass-like
plants were important to alpacas in the early
rainy season. Highest index (70%) of diet
similarity was during intermediate months
between the dry and rainy seasons.
A Peruvian Ph.D. student sponsored by
the SR-CRSP, Felipe San Martin, studied the
dietary composition of llamas, alpacas, and
sheep under grazing conditions on three different
pastures: an improved pasture (Festuca
rubra,Lolium perenne,and Trifolium repens);a
Festucadolichophyllarange site (Fedo); and a
Festucarigidarange site (Feri). On the improved
pasture, sheep ate at least 2.6 times more legumes
than SAC. This lower selectivity for
legumes by SAC might explain why bloat has
not been reported in SAC. On the rangeland,
llamas selected for tall, coarse bunchgrasses and
ate more stems and less leaves than alpacas and
sheep. This selection by llamas suggests that
they can be classified as bulk and roughage
eaters of dry regions, as Van Soest (1982) classifled
old world camelids.
Sheep showed less selection for tall
grasses and more selection for leaves than
alpacas and llamas. Alpacas exhibit intermediate
selectivity between llamas and sheep. This
suggests that alpacas are more grazer-selectors
than llamas. San Martin showed that alpacas
are more opportunistic and appear to be able to
use a wide variety of forage types.
In the dry season, diet similarity was
high between llamas and alpacas on the Feri
range site, and between alpacas and sheep on
the Fedo range site. In a complementary grazing
system, llamas and sheep offer the most
efficient way for harvesting available forage,
while alpacas seem to be adequate for singlespecies
use of rangelands.
Domesticated SAC seem to be adapted to
areas where more coarse forage is available and
nutrients are diluted by structural carbohydrates
that are difficult to digest. These characteristics
are present in the Altiplano region,
where long dry periods (four months of every
normal year) and cyclic years of drought are not
uncommon. These climatic variations contrib­