programme (and diets) should be
adjusted according to their age.
Grouping heifers within specific age
groups makes feeding management
easier as a specific diet can be formulated according to the nutrient
requirements of the heifers within
the age group. The amount of feed
being fed per day can also be adjusted according to the age group.
Feeding tables that are generally
being used to formulate diets provide information on the expected
daily dry matter intake, protein,
energy and mineral requirements
for heifers according to their live
weight and expected growth rate.
Provision is also being made for
large and small breeds, usually being Holsteins and Jerseys. Because
the availability of feeds varies
among farms, specific diets for heifer rearing are not provided here. At
best general guidelines are provided. Feeding of heifers is generally
being done according to the following age groups:
3 to 6 months of age;
6 to 12 months of age;
12 months to late gestation; and
The last 3 months before calving.
Three to six months of age
Heifers in this age group may be
put in small groups inside suitable
sized pens within a shed or outside
in open camps. Preferably groups
should consist of heifers of similar
age. The age difference between
heifers within a group should not
be more than two months. At this
stage, the rumen is not yet fully
developed and therefore during this
stage, the heifers should receive a
high quality growth meal (or pellets) and good quality roughage in
the form of pasture or legume hay.
Feeding young heifers in this age
group low quality feeds such as
straw or chaff or keeping them on
stubble fields or fallow lands containing little plant material without
giving them extra feed will be ex-
tremely detrimental to their skeletal
development and growth rate.
When pasture is not available the
best option would be to formulate
and mix a suitable total mixed ration which is then fed ad libitum on
a daily basis. Alternatively, high
quality roughage, such as Lucerne
hay, grass-legume hay or grassclover pasture, can be fed together
with calf growth meal at a rate of
approximately 1.5 to 2.0 kg per
heifer per day.
Six to twelve months of age
At this stage, the rumen is fully developed and heifers are able to utilise roughage effectively. High quality roughage such as cultivated pasture, silage and/or hay should be
the most important feed source.
Also at this stage, poor quality
roughages and inadequate or a low
feed intake are the most important
reasons for poor growth and malnutrition. If no high quality roughage is available, the best option
would be to provide a total mixed
ration formulated to satisfy the nutritional requirement of heifers.
From twelve months of age to first
calving
Depending on the type, quantity
and quality of roughage available,
any of the following feeding programmes can be followed at this
stage:
Programme 1: using excellent
quality hay
Provide good quality legume hay
(Lucerne) or cultivated pasture plus
one kg of maize meal (or small
grains) per day until first service.
Concentrate feeding is then
stopped until three months before
expected calving dates after which
heifers should again get one kg of
dairy meal per day.
Programme 2: using medium
quality hay
Provide hay of a medium quality
(containing about 6% of crude protein on a DM basis) plus two kg per
day of concentrate containing 16%
crude protein until first service. After conception heifers could be fed
one kg of growth meal per day in
addition to the medium quality hay.
From about three months before
their expected calving dates, heifers
can be fed two kg of a growth meal
per day in addition to the medium
quality hay.
The additional concentrates being
fed during the last three months
before calving, are extremely important as the nutritional requirement of the heifer increases drastically because foetal and placental
growth takes place during this time.
When heifers at this stage tend to
increase their body condition, the
amount o f concentrates should be
limited.
An early age at first calving
Heifers should start their productive
lives as early as possible, as this is
the only way to save on their rearing cost. However, many dairy
farmers believe that feeding replacement heifers should be at a
low level to prevent fat accumulation in the udder. There is a general
perception that heifers being fed
supplementary feeding in the form
of concentrates do not grow in size,
but rather gain weight because of
fat accumulation. Although this is
indeed the case for older heifers
that have already reached target
live weights and which are fed diets
containing high levels of concentrates, this does not apply to
younger heifers which are in a
growing phase. Comparing heifers
which are at the same age, faster
growing heifers tend to have more
body fat, although comparing heifers at the same live weight, there is
little difference between them with
regard to body fat. One should,
however, guard against an excessively high growth rate, as this
could cause fatty deposits in the
udder. If this occurs before puberty,