Agriculture Reference
In-Depth Information
an adequate amount of copper can eliminate most symp-
toms of defi ciency. Copper defi ciency is sporadic through-
out the U.S. Soils in and feeds from the upper coastal areas
on the West Coast (including California) tend to have
higher copper and other trace minerals than the East Coast;
the Southeast and major parts of the Midwest are defi cient
in copper and many other trace elements according to
U.S. geochemical soil maps. However, animals raised in
Western states often have lower serum copper than those
raised in Southeastern and Midwestern states. In some
states, copper levels in soil may be suffi cient, but other
minerals present in feeds (molybdenum or sulfur) may
reduce copper availability. The addition of 5 or 10 mg of
molybdenum to the diet can deplete copper in the liver and
negatively impact immune response in goats (Solaiman et
al., 2008 ; Table 10.7 ).
Soil copper concentrations may vary from location to
location within a state. Therefore, it is recommended to
check soil or forage mineral levels for copper, molybde-
num, and sulfur. Copper defi ciency symptoms vary
depending on the severity of the condition. Symptoms can
include frequent staphylococcus lesions on the body, a thin
and faded hair coat, bald tail tips, twisting and bending of
the front legs, spinal cord injuries, and anemia. Generally,
the immune system loses effectiveness with a copper defi -
ciency leaving animals more vulnerable to diseases and
parasites. Although most symptoms of copper defi ciency
can be reversible by feeding adequate copper, other symp-
toms like swayback in young kids (caused by copper defi -
ciency in pregnant does), and spinal cord injuries are not
reversible. Goats are more tolerant to high levels of copper
than sheep or cattle (Solaiman et al., 2001). Feeding as
high as 100 mg of copper per day for 100 days improved
daily weight gain and immune function of goats (Table
10.8; Solaiman et al., 2007). This confi rms previous rec-
ommendations of other producers and goat experts.
However, copper is accumulative, and high levels of
copper are not recommended for long-term use. Dietary
levels of copper above 40 ppm are not recommended for
dairy goats. For more information on soil copper, the
reader is directed to the USGS map for copper at http://tin.
er.usgs.gov/geochem/doc/averages/cu/usa.html .
Internal parasites, either through altering GI pH and
copper absorption or by increasing blood loss, can contrib-
ute to copper defi ciency; conversely, parasites are more
prevalent in copper-defi cient animals, and parasite infesta-
tion can be managed more readily when animals are kept
at optimum copper status. Other minerals can interfere
with copper status. These include diets with high levels of
either sulfur (
0.35% of diet dry matter), molybdenum
(more than 2 ppm in feed), iron (more than 250 ppm),
calcium, zinc, manganese, or cobalt. Such diets can reduce
copper absorption and deplete liver copper. Soils that are
heavily limed or have a high pH will render the copper
unavailable. The concentration of copper in the liver is the
most reliable index of copper status of the animal. Although
>
Table 10.7
Mineral concentration in the liver and immune response of goats fed high amounts of
molybdenum.
P
- value
a
Added Molybdenum, mg
Item
0
5
10
SEM
Linear
Quadratic
L i v e r , D M
Copper, ppm
380.0
152.1
120.0
5.24
0.003
0.15
Molybdenum, ppm
5.17
4.93
6.03
0.32
0.07
0.11
Iron, ppm
190.0
136.7
131.7
10.9
0.002
0.09
Zinc, ppm
94.7
88.3
101.7
7.24
0.50
0.28
Humoral Immune Response
Antibody Titer
b
86.7
46.7
33.5
11.5
0.002
0.35
Cell - Mediated Immune Response
Skin Fold Thickness
c
, cm
4.63
4.06
3.84
0.14
0.002
0.30
a
Based on orthogonal contrasts for equally spaced treatments.
b
Antibody titer to ovalbumin injection; a higher titer refl ects a stronger immune response.
c
Skin fold thickness in response to PHA injection; greater thickness refl ects a stronger immune response.
Source: Solaiman et al., 2008 .
