Agriculture Reference
In-Depth Information
performance should be monitored closely. Condensed
tannin-containing browse can help control anthelmintic-
resistant gastrointestinal parasites. Tannins decrease fecal
egg counts in sheep and goats and may decrease hatch
(Min and Hart, 2003). Mimosa, fed as a cut-and-carry
forage, had no anthelmintic activity when fed for 21 days
to goats as compared to fresh soybean leaves. However,
when goats browsed on mimosa fi elds, they required less
parasite control than when they grazed bahaigrass pastures
(Solaiman et al., 2006).
The value of browse as a partial fulfi llment of a goat's
diet is not fully understood. Several factors can infl uence
its effectiveness as a part of a feeding system including
selection opportunity, nutritional quality, diversity of
browse to keep goats entertained, and the height where
parasite larvae cannot reach. Availability of browse should
be managed closely by monitoring the percentage of plant
defoliation that can secure rejuvenation rather than elimi-
nation of plants; each plant can tolerate a certain percentage
of defoliation before it is eliminated. Goats tend to have
higher blood urea nitrogen when allowed to browse. This
might refl ect insuffi cient consumption of carbohydrates or
carbohydrates and protein being bound by tannins. Also,
the size of animals in comparison to height of the canopy,
and number of animals per unit area must be considered
when considering the availability of browse plants.
Obtaining reliable browsing data requires an extensive
commitment of time with very limited applicable informa-
tion. Browsing studies are rare, and variation in the browse
species and in their composition within season and between
years complicates application to other conditions.
and produced less milk than when fed either palatable
green or pelleted forage. Corn silage is a good source of
energy, but its intake must be limited to avoid excessive
fat deposition. Supplying hay with silage helps reduce
digestive and metabolic problems, and increases feed
intake and milk production.
O THER R OUGHAGE
Goats readily consume garden by-products. Later discus-
sion is based on experience with limited scientifi c docu-
mentation but may provide some guidance for goat
producers.
Rape, kale, or beets commonly are added to diets for
goats. Under controlled feeding, goats adapt well to by-
products and surplus feeds including discarded produce.
Some surplus or damaged produce like carrots, artichokes,
and turnips should be used with caution. Because crucifers
like cabbage contain goitrogens that interfere with thyroid
hormones, their use in diets for goats should be limited.
Avoid feeding clippings from rhododendron or branches
pruned from cherry, apricot, or peach trees because when
wilted, they may prove toxic to goats. Sweet potato forage
and its mixture with grasses provide an inexpensive source
of nitrogen in the diet for growing goats (Aregheore,
2004). Little is known about the effects of pine needles in
grazing species other than cattle where they may prove
toxic. Sheep and goats may not abort if they consume pine
needles (Short et al., 1992).
Grains and Concentrates
Concentrate feeds are low in fi ber but rich in energy,
protein, or both. In addition to the roughage, grain mixes
typically are added to diets for growing and nursing goats.
This is the most expensive portion of the diet to purchase
from outside the farm or ranch. Concentrate mixes are
composed from high energy or high protein feeds. Although
the majority of a goat's required nutrients often come from
forage, when forages are not available or when forages are
insuffi cient in protein and energy to support desirable per-
formance, supplements should be provided. Supplements
should be designed specifi cally to match dietary shortages.
When protein is defi cient, feeding a low-protein, high-
energy supplement will not increase total nutrient intake,
but a relatively small amount of a high-protein supplement
may prove benefi cial. Feeding grain often decreases both
forage consumption and digestibility; however, with low
quality forage, a grain concentrate may have a positive
associative effect on forage intake (Huston, 1994). Goats
may refuse to eat concentrates in an abnormal physical
form, particularly if the feed is dusty. Goats prefer cubed,
S ILAGE
Silages include partially fermented grass or legume forage,
and they should be free of molds. Silage or haylage pro-
duced from legumes has a higher DM and protein content
and a lower cell wall content than silage produced from
grasses. High dietary concentrations of silage have been
associated with metabolic and other problems (acidosis,
demineralization, cortical necrosis, enterotoxemia, and
listeriosis) of goats. Silage should be introduced into the
goat's diet gradually. However, grass silage has been used
successfully in the goat diet (Trodahl et al., 1981). Also
many food industry by-products such as waste from beets,
apples, potatoes, banana leaves (Pieltain et al., 1998), and
cassava leaves (Marjuki et al., 2008) have been success-
fully used as silage for goats. Ensiling cassava leaves
reduced the content of cyanide (HCN), a poisonous com-
pound for livestock normally found in cassava leaves
(Tewe, 1992). When fed silage, goats tended to eat less
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