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Caitríona believes that the main priority for dairy heifer calf
nutritionists is to convince farmers to feed these valuable
milking herd replacements appropriately.
"It is also important to recognise that although water and
energy are the first limiting nutrients for the young calf,
feeding high-quality protein is also crucial. After water
and energy, protein is the next most important nutritional
component of the diet," she says.
"The nutritional requirement for protein in the young
ruminant animal ­ whose digestive system in the first few
weeks of life is very similar to a mono-gastric ­ is better
referenced by looking at the availability and digestibility of
the amino acids supplied. Breaking this down further, there
are essential amino acids that cannot be synthesised by the
pre-ruminant calf and these must be supplied in the diet
in sufficient quantity to ensure the maintenance of normal
bodily functions and growth," Caitríona points out.
She adds that the absolute
amount of each amino acid
(in g/day) required by the
pre-ruminant calf will depend
on a number of factors
including liveweight, health
status, energy supply and the
target daily liveweight gain.
"When formulating diets the
term most commonly used
to describe protein is `crude
protein' ­ but this is simply
a measure of the nitrogen
(N) content of animal feed
multiplied by a conversion
factor of 6.25. Sadly, there
is no correlation between
the amino acid content of a
feed and the crude protein
declaration on the label," she
Caitríona says Volac is always
examining how best to ensure
its milk replacers meet the
crucial balance between
energy level, ideal amino acid
balance and cost efficiency.
"With the current volatility
in dairy markets (dairy
protein supply and cost),
there is increasing industry-
wide interest in replacing
a proportion of the dairy
protein in milk replacers with
vegetable protein. However,
when precision formulating
diets using non-dairy
proteins, both the physical
and nutritional attributes
of the alternative protein
sources must be taken into
account," Caitríona says.
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