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FOLIC ACID
An ingredient to consider in feeding dairy cattle
Christiane L. Girard, Dairy and Swine Research and Development Centre, Agriculture and Agri-Food
Canada, Lennoxville
Traditionally, it was believed that
the minimum amount of Vitamin B
Complex produced by microorganisms in the rumen was
enough to avoid a cow
developing deficiency symptoms.
But recent studies on folic acid, a
B Complex vitamin, have cast a
doubt on this belief.
amount of vitamin needed in an animal’s diet to prevent
it from developing deficiency symptoms. In the case of
dairy cattle however, it is known that even if their
rations contain none of the B complex vitamins, these
are synthesized by micro-organisms in the rumen in
sufficient quantity to avoid the development of
deficiency symptoms. It has therefore been considered
unnecessary to add vitamins of the B complex to dairy
cattle rations.
Folic acid is one of the vitamins in
the B Complex. Others are thiamine,
riboflavin, niacin, panthotenic acid,
biotin, pyridoxin and vitamin B12.
Choline is sometimes included in
this group although it is not a
vitamin in the strict sense of the
term. Vitamins are essential to the
body’s proper function and cannot be
synthesized in animal tissue. They
must therefore come from food or, as
in the case of B complex vitamins in
ruminants, be synthesized by microorganisms in the rumen.
Yet, three factors have led us to question the validity of
this traditional definition where the dairy cow’s folic
acid requirement is concerned. The first of these factors
is the very definition of requirement, as described above.
We can easily imagine our cattle’s level of milk
production if protein requirements had been defined as
the smallest amount of protein that needs to be added to
cattle rations to prevent the development of deficiency
symptoms… Accordingly, we felt it was necessary to
redefine folic acid requirements on the basis of a cow’s
optimum health, its herd status and the product’s quality
rather than on the basis of deficiency.
THE DAIRY COW’S
VITAMIN
REQUIREMENTS
Vitamin requirements have always
been defined in terms of the smallest
The second factor of influence has been the extent of
changes in dairy farming since the last studies on
vitamins were done between 1940 and 1950. Cows are
now producing three times as much milk as they did
then. It is very unlikely that micro-organisms in the
rumen have increased their production of B complex
vitamins sufficiently to keep up with the cow’s
increased milk production.
At a Glance
COVERAGE: Animal feeding
RESEARCH OBJECTIVE: Reassessing folic acid requirements in cattle rations
POTENTIAL IMPACT: Improving feed efficiency: increased production, especially of protein.
The third factor is that folic
acid is essential to cell
division and protein synthesis.
The dairy cow’s folic acid
requirements must therefore
be substantial since it
synthesizes extensive
amounts of proteins and new
tissues, with the foetus and
mammary gland development.
We need only consider that a
cow producing 30 kg of milk
per day at 3.2% protein
content must synthesize 1 kg
of protein in its milk daily.
Having come to this
conclusion, we undertook to
study the dairy cow’s folic
acid requirements at the
Lennoxville Research Centre.
Two farming experiments
have shown that, first, the
dairy cow’s folic acid
requirements are not entirely
met during lactation and, two,
the cow’s milk production
improves with increased folic
acid intake.
EXPERIMENT
ABSTRACTS
In the first experiment, folic
acid supplements were
administered through
intramuscular injections in
order to determine the precise
effect of folic acid on
metabolism, ignoring the
effects the vitamin might have
on the rumen’s microflora.
However, intramuscular
vitamin injections are a great
research tool but they are not
easy to use on the farm. A
second experiment was
therefore conducted to study
the effects of adding folic acid
to cattle feed.
In both experiments, folic
acid supplements had little
effect on a cow’s first
lactation. The major effects of
folic acid supplements on
cows were noted in the
second or subsequent
lactations. Basically, whether
administered by injection or
through feed, folic acid
supplements increased the
cow’s milk production, the
concentration of folic acid in
the milk and the amount of
milk protein produced daily.
In the first experiment, milk
production was increased by
1.5 kg/day between the
45th day of gestation and
depletion. In the second
experiment, milk production
increased by 2.2 kg/day for a
lactation period of 305 days
in cows that got the maximum
dose of folic acid (see table).
The effect of intramuscular folic acid injections on the percentage of milk protein when
administered between 45th day of gestation and six weeks after calving. The higher
graph shows variations in milk protein (%) between the 45th day of gestation and
depletion while the lower graph shows variations observed over the first six weeks of
subsequent lactation.
Given the beneficial effects
of folic acid on preventing
congenital neurological
disorders as well as
cardiovascular disease and
cancer in adults, the fact that
folic acid supplements result
in a greater folic acid
concentration in milk is
significant for human
nutrition. The intensity of
folic acid impact on milk
protein synthesis varies
according to the composition
of rations used in the two
experiments. In the first
experiment, there was an
increase in the percentage
and quantity of protein
produced. In the six weeks
following calving, the
average percentage of milk
protein increased to 3.5% in
cows injected with folic acid
compared with the usual
3.2% found in untreated
cows.
MILK PRODUCTION, OVER 305 DAYS, OF
MULTIPAROUS COWS (TWO LACTATIONS OR MORE)
RECEIVING FOLIC ACID FOOD SUPPLEMENTS
Folic acid supplements (mg/kg body weight/day)
0
2
4
Milk production (kg)
8,300
8,600
9,000
In the second experiment
this balance, we must adjust
IN CONCLUSION
however only casein (protein
the animal’s food intake to its
used in making cheese) was
needs as precisely as possible,
Our
work
shows
it
is
time
to
produced in greater quantity,
thereby reducing losses. No
not affecting the 3.3% level of conduct an in-depth review of nutrient can be neglected if
folic acid recommendations
milk protein.
we are to reach this objective.
for dairy cattle. Still, folic
acid must not be seen as a
Both experiments saw an
Folic acid supplements
“miracle ingredient” in
increase in the quantities of
increase the efficiency with
feeding
dairy
cattle;
it
is,
milk and protein produced
which cows transform food
however, a significant
even though the cows did not
protein into milk protein.
component
of
a
balanced
diet.
eat any more than usual. This
However, the amount of folic
We must aim at providing our acid that needs to be added to
increase in milk and protein
cattle with a diet suited to
production in the absence of
dairy cattle feed varies
any change in feed, combined their needs, a diet that
depending on the amount of
maintains
a
balance
between
with other metabolic
other nutrients. Current
variations observed during the maximum production, good
research is aimed at arriving
health
and
reproduction
experiments, indicate that
at specific recommendations
capacity. This diet must also
folic acid supplements
on the amount of folic acid
reduce
feeding
costs
by
improved the cows’ efficiency
that should be included in
in transforming their feed into increasing the efficiency with
dairy cattle feed, based on the
which
ingested
nutrients
are
milk and, especially, milk
type of diet used, such as to
used in order to reduce losses
protein.
maximize folic acid impact
and the discharge of waste in
and reduce waste.
the environment. To reach
This is a translation of an article published in Le producteur de lait québécois January 1998.