at high levels to low genetic merit cows would
not transform them into high producing cows.
Such cows tend to become fat which is an
indirect and expensive way of showing their
genetic merit.
During mid-lactation (100 to 200 days in milk)
or after peak milk yield, feed intake is usually
sufficient for the energy requirements for
milk production. Production is maintained
although declines in weekly milk yields may
occur because of differences in genetic merit
for persistency.
In late lactation (200 to 300 days in milk) cows
are once again in a positive energy balance
because more feed energy is consumed
than is required for maintenance and milk
production. The recovery of body reserves
during this period is more effective than
during the dry period. This means that cows
should already be prepared for the following
lactation period in the late lactation period.
A dry (non-lactating) period of 50 to 60 days is
essential for the recovery of the milk secreting
cells in the udder to ensure a high lifetime
performance. When the dry period is less
than 40 days or more than 80 days, a 5 to 10%
decrease in milk production could be expected
during the following lactation period. When
cows become pregnant soon after calving, the
lactation period should preferably be shorter
to provide sufficient time for the udder to
recover after milking.
Dry cows should be kept separately
from other cows and must be fed a diet
specifically formulated for them. Their lower
nutritional requirements should be taken into
consideration and care must be taken that
they do not become too fat. Cows that become
fat often develop problems after calving, such
as ketosis, displaced abomasum, and even
milk fever. However, the diet during the dry
period should also prevent them from losing
body condition, as this will adversely affect
their milk yield during the following lactation
period.
In closing
Dairy farming requires a large initial capital
outlay. For this reason, planning a new dairy
is very important. Breed selection depends on
the owner’s preference, possible production
system and farm natural resources. Lactating
cows should be bought at first as this provides
an immediate cash flow. Facilities should be
in place before cows are bought as feeding
and milking start on the first day after arriving
on the farm. The correct feeding programme
should be followed to ensure a profitable
operation. Feeding poor quality feed to high
genetic merit cows would reduce their milk
yield and farm income. During the dry period
the udder recovers after the milk production
phase. The dry period should not be too long
or short as this affects the cow’s milk yield in
the following lactation period.
Photo: Madeline Kriel
AgriKultuur |AgriCulture
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