Home' NZ Dairy Farmer : April 2011 Contents 68 The Dairyman APRIL 2011
UNTIL recently there has not been a
significant push to supplement B vita-
mins in dairy cow diets, since they are
known to be synthesized in large amounts in
a cow's rumen.
It has been recognized for many years that
B vitamins are essential for various aspects
of a cow's metabolism, her overall health and
As milk production per cow has increased
over the years, it may very well be that a
cow's ability to synthesize enough B vita-
mins may be a limiting factor in milk pro-
With the increased demand for greater lev-
els of milk production from modern dairy
herds, ruminant scientists and researchers are
taking a closer look at some of the B vita-
mins as possibly being limiting for milk pro-
duction and milk components, as well as
being a factor in preventing some metabolic
B vitamins are a group of vitamins that are
water-soluble and necessary for mainte-
nance, growth, milk production and repro-
duction. A partial list includes:
• Thiamine, which is involved in energy
metabolism as well as the synthesis of nucle-
ic acids and neurotransmitters.
• Riboflavin is found in the enzymes
involved with energy transfer from carbohy-
drates, proteins and fats.
• Niacin is needed for the synthesis of
glycerol, the oxidation of fatty acids and the
synthesis of certain steroids and amino acids.
• Pantothenic acid is a required element of
an important enzyme necessary for the con-
version of all organic substances to energy.
• Biotin is a key element in the formation
of keratin and epidermal cells necessary for
the formation of hooves. In the rumen it is
needed for the formation of propionate, one
of the key VFAs.
• Folic acid is a key component for cell
division, protein metabolism and the synthe-
sis of red blood cells.
• Pyridoxine is converted into a compound
that is a co-factor in the metabolism of pro-
teins as well as the metabolism of carbohy-
• B12 is another necessary component of
energy metabolism as well as the synthesis
of the all-important and often-limiting amino
Rumen microbes have the ability to both
destroy and synthesize B vitamins.
Research has shown that many B vitamins
found coming from feedstuffs are largely
destroyed in the rumen, but, ironically, the
rumen microbes make those same B vitamins
that are then metabolized in the small intes-
Many of the B vitamins are instrumental
for both energy and protein metabolism. It is
believed that vitamins work together syner-
gistically with minerals.
Several metabolic diseases in dairy cows
such as milk fever, metritis, ketosis and fatty
liver syndrome are associated with a margin-
al energy balance. Even though they are
required only in very small amounts, vita-
mins are necessary for nutrient metabolism
in all animals.
The National Research Council (NRC
2001) has determined that two specific B
vitamins, folic acid and pantothenic acid, are
likely to be nutritionally limiting. Even
though deficiencies are rare, studies have
shown that cows respond to judicious appli-
cations of B vitamins.
According to Dr Essi Evans, it is difficult
to design studies that limit B vitamin intakes
since the rumen microbes go ahead and syn-
thesize them. Her work focuses on providing
B vitamins in a form that protects them from
rumen destruction as a means of getting
added levels into the small intestine.
A research trial supplementing dairy cows
with ruminally protected B vitamins was
conducted to see if a selection of vitamins
would increase production of milk and milk
components, in particular those B vitamins
involved with milk protein synthesis.
The trials done on two different California
herds used a rumen-protected B vitamin
complex containing folic acid, pantothenic
acid, biotin and pyridoxine.
That study concluded that both milk pro-
duction and milk protein were improved,
particularly in those cows milking in early
The study also concluded that "the results
can be interpreted to suggest that the mecha-
nism leading to the positive overall produc-
tion response with B vitamin supplementa-
tion was due to improvements in metabolic
efficiency of intermediary metabolism,
rather than increased metabolic activity per
se ... the general increase in lactational per-
formance was probably due to increases in
metabolic efficiencies in energy and protein
metabolism, particularly in the early lacta-
The principle use of biotin for dairy cows
has been to improve hoof health. However,
hoof improvements will not be noticeable
until the new growth is at the wear surface,
which can be a considerable amount of time
-- 12 to 18 months later.
• Continued page 70
Consider rumen protected B vitamins for dairy cows
By JOHN HIBMA
Links Archive March 2011 June 2011 Navigation Previous Page Next Page