Beef/Cattle Extension Program
Life Cycle Trace Mineral Needs for Reducing Stress
in Beef Production
Connie Swensonb, Bruce Johnsonb
and Ray AnsoteguiaaMontana State University
and b Zinpro Corporation
trace minerals have been shown to have positive
effects on reproduction, immune status, disease
resistance and feed intake of incoming feeder
Trace minerals are needed for vitamin
synthesis, hormone production, enzyme activity, collagen
formation, tissue synthesis, oxygen transport, energy
production, and other physiological processes related
to growth, reproduction and health. The priority
of use for these physiological processes varies.
For example, growth, feed intake, and feed efficiency
may not be altered during sub-clinical deficient states,
although impairment of reproduction or immune-competence
may occur. The requirement of trace minerals is
often based upon the ability of the animal to maintain
desired production performance parameters. Table
1 shows the trace mineral requirements for growing and
finishing cattle, and cows (NRC, 1996). These
requirements are based upon average cattle consuming
average diets. Copper requirements are suggested to
be 10 mg/kg of DM intake but can vary depending upon
other dietary components.. Because copper utilization
can be low in ruminant diets, especially when the antagonists
Mo and S are present in moderate
to high levels, the NRC recommendations
may require adjustment.
Molybdenum and sulfate form thiomolybdates
in the rumen when fed in excess. Thiomolybdate
complexes with Cu at both the gastrointestinal and tissue
level rendering it unavailable to the animal (Allen
and Gawthorne, 1987; Gooneratne et al., 1989; Suttle,
1991). Disorders associated with a simple or induced
(high Mo and S) Cu deficiency include anemia, diarrhea,
depressed growth, change of hair color, neonatal ataxia,
temporary infertility and weak, fragile long bones which
break easily (Underwood, 1981). Recently, Herd (1997)
indicated that there is concern that trace elements
may be limiting production in better-managed herds to
a much greater extent than previously recognized. Sub-clinical
trace mineral deficiencies in cattle may be a larger
problem than an acute deficiency, because specific clinical
symptoms are not evident to allow the producer to recognize
the deficiency (Wikse, 1992). Animals with a sub-clinical
status can continue to reproduce or grow, but at a reduced
rate, with decreased
feed efficiency, and a depressed immune system (Nockles,
1994). Correcting sub-clinical mineral deficiencies
in animals that have been nutritionally stressed may
have a positive economic impact on cattle production
efficiency. Factors which may contribute to trace mineral
requirements when animals experience stress include
deficiencies of trace minerals in the forage, antagonistic
effects of other minerals found in water or diet, fetal
growth of the calf, calving, weaning and even
expected level of animal productivity.
Assessing Trace Miniteral Status in
In reviewing the responses to trace mineral
supplementation, we have asked the question "Were the
responses due to level of intake, form of mineral intake
(inorganic vs organic) or a response to overcoming antagonistic
effects caused by Mo, S or Fe?" The approach that
we have followed with producers is to first test the
forages, then the water and finally conduct a liver
biopsy to make recommendations. The easiest and
least expensive are the first two.
Forage mineral content and bio-availability
varies because of factors such as soil mineral level,
soil pH, climatic conditions, plant species and even
stage of plant maturity (Spears, 1996). When comparing
grasses to legumes grown in the same location, legumes
have been shown to be higher in Ca, Cu, Zn and Co than
grasses (Greene et al. 1998). Distribution of
the mineral in the plant, chemical form and mineral
interactions can also influence bioavailability.
2 describes average values obtained from grass,
grass-legume and legume hay samples collected over the
past two years in Montana.
The most noticeable and consistent deficiencies were
for Cu and Zn.
Current NRC dietary recommendations are
10 ppm for Cu and 30 ppm for Zn. Of the forages
analyzed, all had average Cu and Zn values much lower
than these recommendations, indicating that supplementation
would be warranted. Although, fewer samples were analyzed
for Mo, concentration in grass hays were high enough
to consider antagonistic effects on the utilization
of Cu; (Cu:Mo ratio of less than 5:1). These results
would be in agreement with those reported by Corah and
Dargatz (1996) who reported that 64% of forages analyzed
were deficient to marginal in Cu and 97.5% were deficient
to marginal in Zn. Similar to MT data, Herd (1997)
published trace mineral values for native grasses from
Texas and Davis et
al. (1999) published results for Arkansas forages
The TX data for native grass suggests
that P, Mg, Cu, Mn and Zn would all be deficient for
a lactating cow. The AR data for mixed grass hay
indicates that P, Cu and Zn could also be deficient
on certain ranches.
In addition to forage quality, livestock
water quality is often considered in making nutritional
recommendations. The following figure (Figure
1) shows the variation in sulfate concentration
of water for 12 ranches in Montana.
The target values above 400 ppm cause us to question
the effects on Cu utilization. Independent of
Mo, dietary S can also reduce Cu absorption (Suttle,
1974). Our concern has been the interaction
that molybdenum and sulfur consumption has on the utilization
of Cu. This concept is demonstrated by the work
of Arthington et al. (1996) who showed that copper levels
in the liver were significantly reduced when molybdenum
and sulfur were supplemented to beef cattle (Figure
These data show that supplementing both
S and Mo resulted in a reduction in liver stores of
Cu. Ward et al. (1992) also demonstrated that Mo and
S supplementation reduced plasma Cu concentrations in
steers after 21 days of feeding, and impaired Cu metabolism.
Liver Biopsy to Determine Cu, Zn, and Mn Status
In diagnosing Cu status, serum may not always be a
good indicator of status because not all Cu circulating
in the blood is available to the animal and can be influenced
by Mo, sulfate, infection, trauma and stage of production
(Puls, 1990). Serum Cu levels have not been shown to
have a high correlation to liver Cu levels (Clark et
al., 1993). For example, cattle with low plasma Cu levels
had adequate liver Cu levels (Mulryan and Mason, 1992).
Stoszek et al. (1986) found that animals with liver
Cu levels of 25 ppm had plasma Cu levels between
.07 to 1.0 ppm while animals with liver Cu levels between
100 and 400 ppm also had plasma Cu levels close to .9
ppm. Table 4 describes
the status levels for Cu, Zn, Mn and Fe in the
bovine the liver. For Cu and Zn, approximately
100 ppm (DM basis) is considered to be adequate
in the bovine, while 10 ppm is adequate for Mn.
To assess trace mineral levels on a regional basis,
a nine-state survey was conducted to determine the variation
in Cu, Zn, Mn and Mo levels of bovine liver. Twelve
hundred and forty three cows were sampled by the use
of a liver biopsy technique. States included in
the survey were CO, KS, MO, MT, NE, ND,
SD and TX. Table 5
presents the number of cows biopsied, and the average,
minimum and maximum liver concentrations for these trace
Evaluation of the average liver Cu concentrations suggests
that cows from CO, NE, ND and SD would be considered
to be deficient to marginal in status. Manganese
levels were marginal for MT, NE, ND, and SD.
Zinc levels appeared to be adequate based
on the recommendations from Table 4. The minimum and
maximum values indicate wide variation in liver copper
storage. The results were further sorted by state
to indicate the percentage of the cattle which were
considered to be deficient, marginal or adequate in
liver copper (Table
6) based on the recommendations from
Cows from CO, KS, NE, ND and SD had high percentages
of cows that were considered to be of marginal status.
Three questions arise from this survey; "When should
a liver biopsy be conducted, how does liver copper concentrations
change throughout the year and does a high level of
Mo in the liver influence availability of copper to
Swenson, (1998) repeatedly biopsied sixty spring-calving
cows starting 30 days precalving, at calving, at breeding,
at weaning and again just before calving the next year.
These results are presented in
Results from this experiment indicated that the cows
had adequate liver Cu stores pre-calving (110 ppm) but
became marginal by the time of parturition (80 ppm).
We interpreted these results to indicate a maternal
transfer of Cu to the fetus during the last trimester
of pregnancy. Copper reserves were increased during
the summer and fall and did not appear to decline until
just before calving the next year. Serum Cu changes
were not indicative of liver copper changes.
Effect of Form of Supplemental Mineral
Traditionally, supplemental trace minerals have been
supplied to livestock in the form of inorganic salts,
sulfates, oxides and chlorides. The use of organic
trace minerals has increased due to reports of improved
feed efficiency, growth, reproduction and immune response
(Manspeaker et al., 1987; Chirase et al., 1991; Swenson,
1998). Power et al., (1994) showed bio-availability
of zinc proteinate to be 159% of the bio-availability
of zinc sulfate in rats while Lovell (1994) reported
that zinc methionine had 300-400% the potency of zinc
sulfate in young channel catfish. Spears et al. (1991)
reviewed the beneficial effects of feeding zinc
methionine to cattle, which resulted in improved performance,
carcass quality and immune response. The following table
(Greene et al., 1998) compares the bio-availability
of several trace elements from different sources (Table
Other work has suggested that the bioavailability of
Cu-lysine was similar to CuSO4 in chicks
(Baker et al., 1990) and steers (Ward et al., 1992).
But, Du et al., (1996) showed that the utilization of
Cu from either Cu-proteinate or Cu-lysine was higher
than Cu-sulfate based on rat liver Cu content.
Interestingly, these data also revealed that high dietary
Zn decreased the utilization of Cu, but this effect
could be overcome by increasing Cu in the diet.
Wellington et al. (1998) came to a similar conclusion
with beef heifers (Figure 4). In this study, heifer
calves were fed 5 ppm Mo and supplemented with either
Cu-amino acid complex (15 ppm in the diet) or Zn-amino
acid complex (90 ppm in the diet) to determine the effects
on liver Cu changes over 90 days. Data indicate
that Cu-supplementation alone increased liver
Cu by 24% while Zn supplementation alone decreased
liver Cu levels by 41%. But, supplementing both Cu and
Zn increased liver Cu by 103%.
Herd (1997) hypothesized that the usage of organic
forms of trace minerals may be of greater value when
an animal is under nutritional, disease or production
stress. Ward et al (1992) demonstrated that source
of trace minerals may result in differences with result
to ADG and feed intake. Their data showed improved performance
for incoming feedlot calves during the first two weeks
compared to feeding the sulfate form of trace minerals
Nockles et al. (1993) showed that Cu from Cu-Lysine
was better retained than from CuSO4 and
that significant changes occurred in both Cu and Zn
balance due to supplementation and stress. Eckert et
al., (1999) conducted a study with crossbred ewes comparing
copper sulfate to copper- proteinate fed at three levels
(10, 20 or 30 ppm of diet). Although no observable Cu
toxicity was measured, feeding Cu-proteinate resulted
in greater ceruloplasmin activity than CuSO4,
but liver Cu was greater when CuSO4 was fed.
In the presence of high dietary antagonists, we have
hypothesized that feeding a higher amount of Cu/day
may overcome these effects. However, we also hypothesized
that a combination of inorganic and amino acid complexed
forms of Cu fed at a lower level may give a similar
response as feeding a high level of Cu in the sulfate
form. Bailey et al. (1999) conducted an experiment
with growing heifers (average initial weight of
643 lbs) to determine if form and(or) level of
supplemental Cu and Zn in the presence of the antagonists
Mo, S and Fe influenced liver Cu level. This work
was conducted to determine if increasing the level of
supplemental Cu, or if a combination of inorganic and
amino acid complexed-Cu sources would result in similar
changes in liver Cu when animals were consuming diets
high in the antagonists Mo, S and Fe. Supplemental
trace mineral treatments were: 1) basal supplement with
no additional Cu or Zn (Control), 2) 250 mg/d Cu and
500 mg/d Zn in sulfate form (Lo-Sulfate), 3) same as
treatment 2 but 50% of the Cu and Zn were
provided from amino
acid complex form and 50% was from the sulfate
form (2-Way), 4) same as treatment 2 but the ratios
of Cu and Zn were 50% amino
acid complex form,
25% sulfate-form and 25% from the oxide form (3-Way)
and 5) 500 mg/day Cu and 1000 mg/day Zn in sulfate form
All animals were
individually fed the antagonists Mo (10 ppm), S (3,500
ppm) and Fe (450 ppm) of the
daily DM intake. The diets were formulated so that the
Cu:Mo ratios were .8:1 for the Control; 5:1 for the
Hi-sulfate and 2.5:1 for all other diets. The
basal diet was composed of chopped hay and a barley-based
concentrate formulated to achieve 1.5 lb/day gain. Liver
biopsies were taken on days 0, 50 and 100 and analyzed
for trace minerals. Copper loss from the liver
over the 100 day trial was slower (P<.05; Figure
5) for Cu-supplemented heifers compared to Control
heifers. The rate of Cu loss was not different between
the Hi-sulfate supplement vs the
supplements with half the amount of supplemental Cu
for the first 50-d of the experiment. But, by
day 100, heifers fed the high Cu-sulfate supplement,
did retain slightly more (P<.05) liver Cu than heifers
fed the lower levels. Daily gains were not different
among the treatments. In retrospect, all heifers
started the experiment with more than adequate liver
Cu (236 ppm). A different response may have been
observed if heifers had been deficient (<60 ppm)
at trial initiation. Over the 100 d study, there were
no differences in liver Cu retention for the treatments
in which the heifers were fed 250 mg/d supplemental
Cu. Other work has shown that when animals were in a
negative Cu balance due to stress, retention was
significantly greater when Cu-lysine was supplemented
compared with CuSO4 following a repletion
phase (Nockles et al., 1993; Figure 6). This work implies
that Cu from Cu-lysine was metabolized differently than
copper from copper sulfate. It ican be speculated
whether the differences in copper retention between
the Bailey et al. (1999) and the Nockles et al. (1993)
studies may be a result of differences in degree
of stress on the animals and(or) simply a result of
differences in antagonist consumption. Nockles
et al, did not feed the same high level of antagonists
as did Bailey et al.
Effects of Trace Minerals on Reproduction and Immunity
Reproduction. Table 9 describes effects
of Cu, Zn and Mn deficiencies on the fertility of cattle.
Copper, Zn and Mn have all been shown to have negative
effects on reproductive efficiency. As an example
of this, Doyle et al. (1988) conducted a
study in which Zn, Cu and Mn supplementation were compared
to no additional Cu, Zn or Mn. The average length
of time from the beginning of the breeding season to
conception was 22 days for trace mineral supplement
treatment vs. 42 days for non-supplemented cows.
Manspeaker (1987) compared no supplementation to supplementation
with Cu, Zn, Mn, Fe and Mg (chelated forms) for dairy
heifers. Results of this experiment are presented
in Table 10.
Supplementation reduced the percentage of infections,
embryonic mortality, endometrial scarring and improved
post-partum involution and tone of the pregnant horn.
Swenson (1998) supplemented Cu, Zn, Co and Mn in either
the inorganic-sulfate form or in an
amino acid complex
form to first calf heifers. Results from
these researchers showed that even though significant
structures and the percentage of cows exhibiting estrus
by day 45 was lower when complexed minerals were supplemented,
the percentage of cows bred by AI was improved (Table
11). In another study
(Swenson, 1998), days to conception were reduced by
10 days in first calf heifers supplemented with amino
acid complex forms of Cu, Zn, Mn and Co compared to
sulfate forms and controls with no additional trace
Ansotegui et al. (1999) utilized the same heifers (avg
wt. of 700 lbs) of Bailey et al. (1999) to determine
the influence of Cu and Zn supplementation on estrus,
ovulation rate and fertility. Supplemental trace mineral
treatments were: 1) basal supplement with no additional
trace minerals; 2) basal supplement plus 250 mg/d of
Cu and 500 mg of Zn/d in the sulfate form and 3) basal
supplement plus an additional 250 mg/d of Cu and 500
mg/d of Zn in which 50% were in the sulfate form and
50% were amino acid complexes. The number
of heifers responding to estrous synchronization and
ovulating at least one ova did not differ (P>.10)
among treatments. Heifers supplemented with the blended
forms of Cu and Zn (Treatment 3) produced more ova than
the control heifers, and heifers supplemented with the
blended supplement or the control supplement produced
more ova than the heifers fed the supplement containing
Cu and Zn in the sulfate form (Treatment 2). Numbers
of embryos did not differ (P>.10) between the control
and blended supplement treatments, but were higher (P<.05)
than for the sulfate-only supplemented heifers.
Phillipo et al. (1987) conducted two heifer studies
with barley grain- straw based diets containing 4 ppm
Cu and 5 ppm Mo (.80:1 Cu:Mo ratio). Molybdenum
supplementation resulted in the delayed onset of puberty,
decreased conception rate and caused anestrus in cattle
without accompanying changes in Cu status or in live-weight
gain. It was proposed that the effects of Mo were associated
with a decreased release of luteinizing hormone that
might be due to an altered ovarian steroid secretion.
Earlier work by Case et al. (1973) found that cattle
grazing pasture on soil with an elevated Mo content
had reduced fertility while Peterson and Waldern (1977)
described a negative association between the Cu:Mo ratio
of silage and fertility in dairy herds in Canada.
Immunity. Trace mineral requirements
are determined largely by animal growth or reproductive
response and not by the ability of the immune system
to respond to a challenge. There is increasing evidence
that the concentrations of trace elements required for
healthy animals are often below what is required for
animals experiencing an immunological challenge (Berger,
1997; Beisel, 1982.). Research (Stabel et al.,
1993) has indicated that Cu deficiency affects various
physiological characteristics that may be important
in immunological defense to pathogenic
et al. (1986) showed that Cu supplementation affected
the resistance of sheep to bacterial infections.
Genglebach and Spears (1998) showed that when Mo was
supplemented to a diet containing adequate Cu, no differences
were apparent in plasma or liver Cu. However, calves
fed Mo had a more severe Cu deficiency based on
depressed humoral-immune response and super-oxide dismutase
activity. In another study, Ward and Spears (1999) concluded
that Cu deficiency and 5 ppm Mo in the diet did not
dramatically alter the specific immunity of stressed
cattle. Genglebach et al. (1997) showed
that when diets were marginally deficient in Cu with
supplemental Fe, Mo added, body temperature and feed
intake responses to disease were affected. Ward et al.
(1997) concluded that Cu deficiency and Cu deficiency
coupled with high dietary Mo or Fe intake produced inconsistent
immune function responses, indicating at Cu deficiency
may not affect specific immune function in calves. Ansotegui
et al (1994; Figure 7) found that cell mediated immune
response was faster and significantly higher when complexed-forms
of Cu, Zn, Co and Mn were fed compared to sulfate forms
of the same minerals or to cows which were not supplemented.
This study was conducted with out additional antagonists
added to the diet. Subsequent responses have been
much more variable when antagonists have been provided.
Zinc has been
shown to have a positive impact on immunity in stocker
and feedlot cattle with limited research in beef cows.
Weaned calves normally experience stress due to transportation,
changes in feed and handling, which increase susceptibility
to infectious diseases. During this period of
stress, providing adequate dietary Zn may be critical,
because stress has been shown to have a negative impact
on Zn retention (Nockels et al., 1994). Infection
can also have a detrimental effect on Zn status in cattle.
Infecting cattle with a bovine rhinotracheitis challenge
increased urinary Zn excretion which caused a negative
balance (Orr et al., 1990). Feed intake is often
depressed when feeder cattle are stressed and the reduction
in intake results in a decrease of trace minerals ingested.
Supplying Zn to steer calves which had undergone stress
(weaning, transportation, exposure to new cattle and
vaccination) was shown to increase feed intake (Spears
and Kegley, 1991) while Chirase et al., (1991) showed
that dietary Zn enhanced the recovery rate of IBR-stressed
Data from MT, TX and AR indicate that copper and zinc
can be deficient in many of the forages cattle consume.
Coupled with the antagonistic effects of Mo and S, this
may require additional supplementation with copper because
it would also appear that there are a fairly large number
of cows who are deficient to marginal in liver Cu and
Mn stores. Experimental results do suggest that
single trace element supplementation can be antagonistic
(e.g. excessive Zn depressing liver Cu stores) or symbiotic
(Cu and Zn both supplemented). Supplemental trace
minerals have been shown to have positive effects on
reproduction, immune status, disease resistance and
feed intake of incoming feeder cattle. Although
the data is somewhat variable among experiments, it
has been shown that complexed minerals are more available
than inorganic minerals and have application in the
presence of dietary antagonists, and(or) when the animal
is under stress. Our present field recommendations
have been to use a blend of inorganic-organic minerals
in front of an expected stress (calving to breeding
and pre-weaning) and then use an inorganic based trace
mineral supplement the rest of the year. This approach
is only part of a program to provide balanced nutrition
with emphasis on supplying adequate protein, energy
and trace minerals to prevent loss of beef cattle productivity.
It is our opinion that providing adequate nutrition
prior to expected stress can result in reduced morbidity
of beef cattle; trace mineral supplementation is an
important part of this management approach.
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