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Cobalt deficiency atrticle, pt. two
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> *Acknowledgements:*
>
> I thank the breeders and researchers in New Zealand and world-wide who have
> been pestered for information.
>
> *Bibliography:*
> Black’s Veterinary Dictionary
>
> David Mackenzie: Goat Husbandry
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> Peter Dunn: The Goatkeeper’s Veterinary Book
>
> Max Merrall: The A-Z of Goat Diseases – recognition & treatment
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Cobalt In Ruminant Nutrition
Vol. 37 No. 2
Cobalt in Ruminant Nutrition
Larry L. Berger, Ph.D • University of Illinois
As early as 1935, Australian researchers
associated cobalt
with coast disease of sheep
When it was recognized that cobalt
was 4.4% of the molecular weight of
vitamin B12 and that rumen bacteria
could efficiently synthesize B12, these
differences started to make sense.
Cobalt deficiency in ruminants leads
to a vitamin B12 deficiency that is
corrected with cobalt supplementation.
Because monogastric animals
do not have a bacterial population in
the gut that can synthesize sufficient
vitamin B12, cobalt supplementation
is ineffective. Monogastric
animals must have vitamin B12 in
their diet or practice coprophagy to
prevent a deficiency. In the wild, ingestion
of feces is common among
monogastric animals. Many of the B
vitamins including B12 are synthesized
as a result of bacterial fermentation
in the large intestine, but B12 is
excreted because it must be bound
by an intrinsic factor produced in
the stomach before it can be absorbed.
Coprophagy is one means of
obtaining the B vitamins that are deficient
in the basal diet. Clear evidence
of a cobalt requirement
independent of the B12 requirement
has not been documented in monogastric
animals.
Ruminant feces are an excellent
source of vitamin B12. In the 1930s it
was observed that feeding pigs and
cattle together in the same pen improved
the health and performance
of the pigs, if they were not fed animal
proteins. We now know that
pigs on plant-based diets were deficient
in vitamin B12. When cattle
Summer 2005
continued on page 2
and wasting disease of cattle. However,
it wasn’t until 1948 that cobalt
was recognized as essential for vitamin
B12 synthesis. More recently results
of several studies suggest that
cobalt may improve fiber digestion
in the rumen independent of its role
as part of vitamin B12. Following is a
review of our current understanding
of the nutrient, cobalt.
Ruminants vs.
Monogastrics:
The reason ruminants responded to
cobalt supplementation and monogastric
animals showed no response
was a mystery for many years.
Introduction: A
Cobalt in Ruminant Nutrition (continued from page 1) Cobalt in Ruminant
Nutrition (continued from page 1)
and pigs were in the same pen, the
pigs pick up enough B12 from the
cattle feces to prevent the deficiency.
Synthesis of vitamin B12 by rumen or
other bacteria is amazing, as it is
one of the most complex non-polymeric
natural products produced in
nature. The general formula for vitamin
B is CHNOPCo with
1263881414
molecular weight of 1355. Ruminal
synthesis of B12 is dramatically increased
within hours of cobalt
supplementation of a deficient diet.
Suttle et al. (1989) reported that ruminal
B12 synthesis increased quadratically,
being proportional to the
square root of the dose between 1
and 32 mg of cobalt per head in
sheep. A 10 mg dose resulted in approximately
three times greater B12
synthesis than a 1 mg dose. In general,
high forage diets and high levels
of intake favor B12 synthesis in
ruminants.
Signs of Cobalt
Deficiency:
When ruminants are on a cobalt deficient
diet, there is a gradual loss of
appetite, weight loss, muscle wasting,
depraved appetite, anemia, and
eventually death (Underwood and
Suttle, 1999). The animals appear as
if they have been starved, except
that the visible mucus membranes
are blanched and the skin is pale
and fragile. Secondary signs of a cobalt
deficiency include fatty liver, increased
mortality of offspring
shortly after birth, increased susceptibility
to infectious agents and infertility.
The rapid loss of appetite in cobalt
deficient ruminants is not nearly as
Cobalt Deficiency
obvious in vitamin B12 deficient monogastric
animals. Monogastric energy
metabolism is based on glucose
absorbed from the small intestine,
while ruminants get approximately
70% of their metabolizable energy
from volatile fatty acids produced in
the rumen. Acetate, propionate and
butyrate are the main volatile fatty
acids utilized for energy. Normal
propionate metabolism requires vitamin
B12. Accumulation of propionate
in the blood rapidly depresses
appetite (Farningham and Whyte,
1993), and there is an inverse relationship
between feed intake and
propionate clearance in cobalt-deficient
sheep (Marston et al., 1972).
Cobalt and Rumen
Bacteria:
Recent Irish research suggests that
cobalt deficiency may directly affect
the metabolism of rumen bacteria
which in turn may affect the digestion
process. Kennedy et al. (1991)
reported large increases in succinate
concentration in rumen fluid within
two weeks after sheep were fed a cobalt-
deficient barley-based diet.
They suggested that propionateproducing
bacteria like Selenomonas
ruminantium may be especially susceptible
to a cobalt deficiency. In
1996 Kennedy et al. reported that
succinate concentrations increased
within two days after being fed a
diet containing 0.02 ppm cobalt, but
not when 0.04 ppm cobalt was
present. Florida researchers also reported
rapid changes in the rumen
microbial population of animals
grazing cobalt-deficient forages (Gall
et al., 1949).
Lopez-Guisa and Satter (1992) reported
that cobalt supplementation
above that required for B12 synthesis
may improve the utilization of poor
quality forages. The rate of fiber digestion
in the rumen is a major factor
affecting voluntary intake on
high forage diets. Supplementation
of cobalt above animal requirements
may increase the ability of bacteria
to digest fiber. Divalent cations such
as cobalt may allow bacteria to connect
to plant cell walls. The cellulase
enzymes produced by bacteria
are retained on the cell membrane
and are not released into the environment.
Consequently, the bacteria
must physically attach to the fiber
particle for the enzymes to digest
the cellulose. It appears that when a
negatively charged bacteria has difficulty
attaching to a negatively
charged fiber particle, cobalt with
two positive charges can serve as a
continued on page 3
SALT & Trace Minerals / Summer 2005
Cobalt in Ruminant Nutrition (continued from page 2) Cobalt in Ruminant
Nutrition (continued from page 2)
means of linking the two surfaces
(Lopez-Guisa and Satter, 1992). In
one experiment, cobalt increased
the rate of in situ corn fiber digestion
from 3.4 to 6.2% per hour. In
other experiments cobalt supplementation
above that required by
the animal increased volatile fatty
acid concentrations in the rumen
fluid (Gridin, 1986), suggesting that
the rate of fiber digestion was improved.
Cobalt
Supplementation:
Forages containing less than 0.07
ppm cobalt require supplementation
(Underwood and Suttle, 1999). Inorganic
sources of cobalt must be
soluble in the rumen to allow bacteria
to incorporate cobalt into vitamin
B12. Cobalt oxide has lower
nutritive value than equal amounts
of cobalt from more soluble sources
such as cobalt carbonate or cobalt
sulfate (Ammerman et al., 1982).
Cobalt Deficient
Areas:
As shown in the map, cobalt deficiency
has been reported in over 15
states throughout the United States.
Florida and the eastern seaboard
SALT & Trace Minerals / Summer 2005
states all the way to Maine have reported
cobalt deficiencies. In the
upper Midwest, parts of Michigan,
Wisconsin, Minnesota, Iowa, Missouri
and Nebraska produce feeds
low in cobalt. Feedstuffs produced
in these areas are often shipped to
other states that are considered cobalt
adequate. Consequently, cobalt
supplementation of all ruminant diets
throughout the US is recommended.
Summary:
Cobalt is essential in ruminant diets
for the synthesis of vitamin B12. Cobalt
may also be beneficial in ruminant
diets as a means of improving
the efficiency of fiber digestion by
bacteria. Although cobalt requirements
are less than 1 ppm in the
diet, cobalt deficiency has devastating
effects on animal health. Feeding
a well fortified trace mineralized
salt containing cobalt is the best
means of insuring that animals get
adequate cobalt nutrition.
Literature Cited
Ammerman, C.B., P.R. Henry, and P.R.
Loggins. 1992. Cobalt bioavailablity in
sheep. J. Anim. Sci. 55(1):403
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