RUMEN FERMENTATION PATTERN IN GOATS AND SHEEP GRAZING PASTURES FROM SEMIARID SPANISH LANDS UNSUPPLEMENTED OR SUPPLEMENTED WITH BARLEY-GRAINOR BARLEY GRAIN-UREA
Ma. Garcia et al., RUMEN FERMENTATION PATTERN IN GOATS AND SHEEP GRAZING PASTURES FROM SEMIARID SPANISH LANDS UNSUPPLEMENTED OR SUPPLEMENTED WITH BARLEY-GRAINOR BARLEY GRAIN-UREA, Livestock production science, 39(1), 1994, pp. 81-84
An experiment following a 2 (animal species) X 3 (phenological state)
X 3 (feed supplementation) factorial design was carried out with sheep
and goats grazing on semiarid lands in the south-east of Spain. Anima
ls consumed, from early spring to late summer, pasture alone or pastur
e supplemented with barley grain (88 g DM/an/d) or with barley grain p
lus 1% urea. The animals were on a semiextensive management system. Ce
ll wall content was always slightly higher in the pasture selected by
sheep. Significant (P < 0.05) interspecies differences in ruminal pH,
ammonia nitrogen (NH3-N) and total volatile fatty acids (VFA) concentr
ations and in molar proportions of acetic, n-butyric, isobutyric, iso-
valeric and n-valeric acids were found in samples taken just before gr
azing. The contents of NH3-N, total VFA, acetic, propionic and n-butyr
ic acids at the highest microbial activity times were similar. The phe
nological state of the pasture had a significant effect (P < 0.05) on
rumen NH3-N and total VFA contents. Supplementation with barley grain
did not significantly change the rumen fermentation pattern, except fo
r the n-valeric acid molar proportion which increased (P < 0.05) when
barley was offered. This effect was not found when urea was added. It
is concluded that there are differences in rumen fermentation pattern
between sheep and goats. Those differences are influenced by the pheno
logical state of the pasture but they are not affected by supplementat
ion.