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CALF REARING FOCUS
JANUARY
30
Recent research is helping dairy farmers re-think
calf milk feeding strategies for optimum health and
lifetime performance. Volac nutritionist
Caitríona
Mullin talks about what the future holds
The dairy industry is starting to wake up to the fact that it
may have been underfeeding calves for quite some time, but
the next step change will be driven by improvements in the
quality of pre-weaning diets fed to the nation's calves. That's
the view of Volac nutritionist Caitríona Mullin, who says the
specialist young animal nutrition company is ready to meet
the technical challenge.
"We know that feeding a good heifer calf up to 900g of milk
replacer daily may be needed to meet optimum rearing
targets ­ and absolutely crucial if you want to calve heifers
down at 24 months. But more importantly, we also know
feeding modern dairy calves to this level makes sound
economic sense," she says.
Caitríona points to studies showing that calves gaining 800g
a day have the potential to produce 450 litres more milk
during their first lactation, compared with calves reared
on a traditional system gaining only about 500g per day.
"Research also shows that feeding higher milk replacer levels
leads to fewer calves failing to reach a second lactation. So
providing the necessary nutrition to sustain rapid growth
rates (>750g per day) during the first two months of life
should not only result in more efficient and economical
heifer rearing, but also deliver greater lifetime milk
output when these replacement animals join the milking
herd," she says. She adds that if milk replacer intakes are
restricted, calves simply look for nutrition from the other
feeds available and invariably this means eating more
concentrates.
"But this can limit early growth because the rumen is not
developed to efficiently digest solid starter feeds until
around four weeks of age," Caitríona points out.
"Calves on a high-quality, precision-formulated milk
replacer are receiving a highly concentrated energy source
­ so much so that to achieve the same energy intake from a
solid starter feed requires a dry matter intake 1.5 times that
of the milk. What's more, further research has shown that
there is a large amount of important early life development
in the pre-weaned phase. The development of both
mammary cells and the gut ­ and metabolic programming ­
all take place during this crucial early life period, so feeding
high levels of milk enables us to take full advantage. It's also
the time when feed conversion efficiency is at its highest."
The importance of feeding calves more milk has also been
supported by recent research at Harper Adams University,
albeit with male calves. In this study with British Blue x
Holstein and Holstein bull calves, starting at 15.4 days old
until weaning six weeks later, calves fed 150g/day more milk
replacer were 5.6kg heavier, on average, at 12 weeks of age.
"The team at Harper noted that the calves fed higher levels
of milk were healthier and had better faecal and coat bloom
OPTIMISING CALF NUTRITION TO
DRIVE HEALTHY PERFORMANCE
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