Agriculture Reference
In-Depth Information
Table 10.8
Effects of supplemental copper on growth and immune function of growing kids.
Dietary Copper, ppm
P
- value
a
Item
0
100
200
SEM
Linear
Quadratic
Average daily gain, g
131
147
117
6.09
0.11
0.01
Average daily feed intake, kg
1.21
1.11
1.03
0.06
0.05
0.90
Gain:Feed (G:F)
0.11
0.13
0.11
0.01
0.67
0.02
Scrotal circumference, cm
23.1
22.3
20.4
0.31
0.0001
0.22
Serum copper, mg/dL
0.82
0.78
0.86
0.03
0.35
0.14
Liver copper, mg/kg DM
206
504
778
59.0
0.001
0.87
Immune response
b
Antibody titer to ovalbumin
Day 72
0.26
0.31
0.32
0.03
0.08
0.46
Day 98
0.19
0.29
0.26
0.01
0.005
0.003
a
Based on orthogonal contrasts for equally spaced treatments.
b
A greater titer refl ects an improved or greater immune response.
Source: Solaiman et al., 2007 .
safe procedures are available to biopsy the liver of cattle,
similar safety of biopsy procedures for goats is question-
able. A secondary measurement for assessing copper status
of goats is plasma or serum copper. Unfortunately, the
liver can be markedly depleted before plasma or serum
copper concentrations decline.
Copper can be supplemented through mineral mixes that
are high in copper. Mineral mixes that are labeled for both
sheep and goats should not be used for goats. Because
sheep are much more sensitive to high copper levels than
goats, mineral mixes appropriate for sheep do not have
adequate copper levels for goats, or they may have high
levels of molybdenum. Copper also can be supplemented
through slow release copper wire needles as copper boluses
(0.625-1.35 grams) given early to kids (2-4 weeks of age)
or 1 gram of copper oxide in bolus form per 10 kg of body
weight every 5-6 months in copper-defi cient areas. The
needles are deposited in the goat's stomach and release
copper slowly. Some feeds (wheat, barley, and oats) are
low in copper and some, like alfalfa, are rich in molybde-
num. Applying 1.5-3.0 kg of copper per hectare as an
organic compound such as copper EDTA, copper lignisul-
fonates, or copper polyfl avonoids has been recommended
and can increase soil copper levels for many years.
Selenium or iodine is defi cient in certain regions of the
U.S. Coastal areas usually have suffi cient iodine and are
defi cient in cobalt. The Dakotas are so rich in selenium
that selenium toxicity may occur; however, many other
places including California are selenium defi cient.
Selenium injections often are used for pregnant does
toward the end of the pregnancy and for young kids at
birth. However, both selenium and copper can be toxic if
overdosed. Feeding rather than injecting selenium is
recommended unless severe defi ciency is prevalent.
Feed Additives
Additives are products of nonfeed origin that may improve
feed effi ciency, growth, and health of animals. Many
herbal and natural remedies are used commonly by goat
producers in the U.S. with little if any scientifi c evidence
of their effectiveness. Only two additive classes are avail-
able commercially that have proven to be effective for
goats.
I
ONOPHORES
Ionophores are antibiotics produced by varieties of actino-
mycetes bacteria that alter the fl ux of ions across gram-
positive bacteria in the rumen and reduce their numbers.
This fermentation shift negatively affects methane, acetate,
and butyrate production, while increasing the molar pro-
portion of propionate; ammonia production is decreased
resulting in a “protein sparing” effect; protein degradation
is inhibited; and lactic acid formation associated with high
grain diets is reduced (Russell and Strobel, 1989). As a
result, feed effi ciency and the net energy available from
feed increases. Ionophores also may increase milk produc-
tion and milk protein synthesis and help to prevent ketosis
and reduce bloat. Lasolocid and monensin are the two
ionophores that are approved for prevention of coccidiosis
in meat goats in the U.S., but they are not approved for
