Five experiments were conducted to evaluate tree
forage as a feedstuff for small livestock, using the
foliage of black locust (Robinia pseudoacacia) and hybrid
poplar (Populus spp.). In the first trial, rabbits were
fed diets containing 40% alfalfa (control), and 10%, 20%
and 40% poplar leaves (PL) from untrimmed or uncoppiced
growth, and 10% and 20% PL from trimmed or coppiced
growth. At the 20% level, crude protein (CP) was better
digested for the coppiced PL than for the uncoppiced (p <
.05). No significant difference was evident between
treatments in the average daily gain (ADG) or feed
efficiency, but dry matter (DM) intake increased for all
the PL treatments compared to the control (p < .01). In
the second experiment, black locust (BL) leaves were
treated by various methods in an attempt to counter the
effect of tannins. Rabbits were fed diets containing 50%
alfalfa (control), 25% alfalfa and 25% black locust meal
(BLM) (BLM control), BLM + 1% polyethylene glycol (PEG),
BLM + 1% phytase, and BLM + 0.3% L-methionine and 0.3%
choline chloride. In general, nutrient utilization and
ADG were better for the control than for the BLM
treatments. The addition of PEG increased CP
digestibility (p < .01) and ADF (p < .03) compared to the
BLM control, partially alleviating the reduced nutrient
availability. The addition of L-methionine and choline
chloride increased ADF digestibility (p < .02). In the
third trial, black locust (BL) bark and other tree
products were used to study the possible toxic effects of
lectins in BL bark. Rabbits were fed diets containing 25%
BL bark, oak sawdust, red alder bark, or red alder sawdust
(all diets also included 25% alfalfa). A 50% alfalfa diet
served as a control. In general, nutrient digestibilities
and ADG were higher for the control than the treatments
and, also, higher for the BL bark diet than the alder bark
diet. The ADG with the BL bark diet was lower than for
the alder bark diet (p < .01), which indicated a possible
toxic effect of the BL bark. The fourth trial examined
the feeding value of poplar leaves for sheep. Sheep were
fed diets containing 50% PL or 50% alfalfa. Nutrient
digestibilities were lower for the PL diet (p < .01). In
the fifth experiment, BL leaves were fed to sheep and
goats in order to determine if goats, being browsers
instead of grazers like the sheep, are better equipped to
tolerate the anti-nutritive effects from BL forage. Sheep
and goats were fed diets composed solely of BL leaves or
alfalfa (control). Overall, the nutrient digestibilities
were higher for alfalfa than for BL leaves, and there was
no difference in terms of digestibility between species.
Although the leaves of black locust and poplar contain
anti-nutritive factors, it was concluded that the trees
have potential as multipurpose trees from which the leaves
could be harvested as animal fodder, particularly in
temperate areas of the developing world. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35929 |
| Date | 07 August 1992 |
| Creators | Ayers, Anne Christine |
| Contributors | Cheeke, Peter R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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