Management of Dairy
Heifer From Weaning to
Calving
Today’s heifer replacements should
be tomorrow’s top producers.
Attention to young stock will mean a
good line of heifers entering the herd
as two-year- olds capable of
producing to their genetic potential.
Feeding and management should
meet this objective by ensuring that
heifers reach:
 A satisfactory weight at mating
 An adequate size and condition
at first calving
The two broad post-weaning periods
are:
1. Weaning to mating (3 – 15
months of age)
The onset of puberty, and hence the
commencement of cycling, is related
to weight rather than age. A delay in
the onset of puberty could mean a
later conception, resulting in delayed
production
or,
at
worst,
no
production. Calving patterns could
easily be disrupted if the onset of
puberty is delayed.
All heifers must reach a minimum
weight before joining. Post-weaning
management must provide sufficient
feed to reach certain target weights.
Practical experience shows that
there is some flexibility in the rate at
which heifers need to grow at
different
stages
to
reach
a
satisfactory bodyweight. For a calf
weaned at a live weight of 70 kg at
70 days, the average growth rate
needs to be 0.4 kg/day to reach
desired target weights at mating.
Heifers can gain weight at up to 1.1
kg per day. There may be periods of
quite low growth rates, provided
these are compensated for by
periods when feed is unrestricted
and of good quality.
As a guide, weight gain with
unrestricted feeding on dry pasture is
around 0.2 to 0.4 kg per day, on hay
or silage it is 0.5 to 0.7 kg per day
and on green leafy pasture 0.7 to 1
kg per day.
2. Mating to calving (15 – 24
months)
All heifers should calve as two-yearolds. Calving at three years of age
does not return enough extra milk to
cover the increased cost of feeding
the heifer an extra year to calving.
Herd and nutritional management
may b complicated if heifers are
joined to calve later than two years
of age.
Undersized two-year-olds are poor
competitors for feed after calving and
because they are still growing, feed
is used for growth rather than milk
production. Hence production is
likely to be poor and difficulties may
arise in getting the heifers back into
calf. Therefore, heifer management
should aim for:
 Well grown heifers at calving
 Butterfat production of first
calvers to be within 30 – 35 kg of
mature cows
 Good body condition at calving –
condition score at 3
Another useful measurement is
height at withers (shoulders). A
relationship exists between the
height of the animal and its weight. A
minimum
recommended
wither
height can be equated to minimum
recommended
heifer
weight.
Measuring wither height on the farm
can be done in a number of ways. A
couple of ideas are:
Target weights for dairy heifers
Because dairy heifers must attain
satisfactory growth rates and reach
sufficient size to be good producing
members of the milking herd, regular
checks should be made on them to
ensure they are achieving these
standards.
Minimum recommended weights are
available for different classes of
livestock at certain ages. Heifers
under target weight should be
treated preferentially by:
 Walk stock through a race with a
stick or similar object set at the
recommended
height.
Stock
needing to stoop under the stick
are above weight, those that do
not touch it need special
treatment.
 Feeding more, and better quality
pasture
 A better method is to mark a line
on a convenient fence or race at
the recommended height and run
stock between the markers and
yourself. By eyeing the stock with
the line under weight animals can
be identified.
 Supplementing
pasture
with
pellets, grains and or hay, silage.
Often stock weight is difficult to
record on farms, since scales are not
available. Alternative methods of
measurement are available which
give a reasonable approximation of
body weight.
One such measurement is chest
girth. Using a dressmaker’s or similar
tape, and measuring just behind the
forelegs of the animal can make an
estimate of the heifer’s weight.
Beware of using plastic tapes, as
they have a habit of stretching.
The table gives the minimum target
weights, chest girths and wither
heights for Jersey and Friesian
animals. For crossbred animals and
other breeds, estimates can be
made from the table for the
approximate
minimum
recommended
weight
and
corresponding measurements.
Minimum target weights for dairy heifers
Liveweight (kg)
Age
(months)
Weaning
Jersey Friesian
Chest girth (cm)
Jersey Friesian
2
60
70
87
12
480
230
127
Mating
15
220
290
Calving
24
320
410
92
Wither height (cm)
Jersey
Friesian.
-
-
139
100
104
137
151
109
114
157
170
116
125
Grazing management for heifers
Grazing management should allow
for continuous growth throughout the
rearing period. Uniform growth is not
necessary and may be impracticable
with fluctuating pasture availability.
However, it is most important to
avoid periods of very low growth or
weight loss.
Grazing systems
suitable are:
that
may
be
 Rotationally graze young stock
ahead of milkers
 Graze young stock behind
milkers, grazing out a paddock
for 3 – 4 days before moving onto
the next paddock.
 Graze two replacements per
pasture paddock. This provides
ample feed, without affecting
available milker feed. At such a
low stocking rate, parasite buildup will be minimised.
 Rotationally graze young stock
around the farm, independent of
milkers. This is a good system if
care is taken to ensure adequate
feed is available.
 Agist young stick off the farm. Dry
standing pasture will achieve
satisfactory
growth
rates,
providing it is in ample supply
and of good quality. Quality green
pasture is preference.
These methods do not allocate
paddocks solely for use by young
stock, so more paddocks are
available for grazing by the milkers.
Set-stocking
can
result
in
underfeeding and a heavy worm
burden on young stock unless care
is taken.
Feeding with hay or concentrates will
be necessary as a supplement when
pasture is in short supply. However,
remember that pasture is the
cheapest feed source on your farm,
and that excessive supplementary
feeding and excessive growth rates
(particularly if growth rates are above
1 kg per day during the age 7 – 12
months) appear to lead to excessive
fat deposition in the udder and poor
milking
performance.
So
concentrates should only be used as
a supplement, not as a substitute for
pasture.
Stock Health
With any grazing system for heifers
the need to care for animal health is
paramount, but too often neglected.
Worm and liver fluke infestations are
the most common disease problems,
and a drenching programme should
be adopted to minimise any build-up
of parasites.
A basic drenching programme would
begin with both a worm and liver
fluke treatment (if liver fluke is a
district problem) at weaning followed
by further worm treatments every
three months and liver fluke
treatments every six months.
All replacement heifers should be
vaccinated twice with “five-in-one”
vaccine by four months of age. On
properties where black disease is a
problem annual booster vaccinations
with “five-in-one” will be necessary.
Vaccination for leptospirosis should
be carried out before calving with
two vaccinations four weeks apart.
Regular observation of heifers is
necessary to check for problems.
The common symptoms of disease
are ill-thrift, roughness of the coat,
scouring or coughing.
Prevention is better than cure.
Disease can make a good lime of
heifers lose up to a month’s
condition in a few days.
Mating Heifers
If heifers have achieved satisfactory
growth rates, they will be at a
suitable liveweight for mating and be
showing clear signs of cycling by 14
– 15 months of age.
Many farmers use a bull over their
heifers. Select a bull that is young or
light-framed to avoid physical
damage and preferably one known
to throw a small-sized calf.
When using a bull, a practical way to
check whether he is performing
satisfactorily is to use recognised tail
paint on the heifers and observe
them at least twice weekly after the
start of mating. After three weeks,
repaint the heifers with paint of a
different
colour.
Continuing
observation helps determine those
heifers that appear to be in calf; the
tail paint is not rubbed off. It also
gives some guide to the fertility of
the bull running with the heifers.
Watch the bull at work to make sure
he is actually serving the heifers. An
injured or ill bull may only mount,
rubbing off the tail paint, but not
inseminate them.
If the paint stripes on many of the
heifers are being rubbed off regularly
after three-week periods (that is after
they should have been mated) then it
can be assumed that either the bull
is a at fault, or , if the heifers are thin,
that they could be temporarily
infertile.
If the heifers are well grown and in
good condition then the bull should
be changed. If the heifers are thin, a
better level of feeding is necessary.
60% to 70% of heifers should be
mated within the first three weeks,
and not return to heat in the next
three weeks. A lesser percentage
would suggest that the remaining
heifers and the bull be examined by
a veterinarian.
For good conception rates, one bull
for 25 – 30 heifers is the best ratio.
This avoids both temporary infertility
and physical incapability on the part
of the bull.
There is growing trend toward using
artificial insemination on heifers to
increase the speed of genetic
improvement in the herd. By holding
heifers in a handy paddock, using tail
paint and regular observations,
heifers in heat can be detected for
insemination.
This interest has led to the increased
use of prostaglandins to synchronise
heats in heifers for artificial
insemination. Systems used include
single or double injections of
prostaglandins followed by visual
heat detection and insemination, or
blanket
insemination
over
all
synchronised heifers.
Whether using a bull or AI, you
should aim to mate 10 – 15% more
heifers that required to allow for
losses such as heifers not in calf,
abortions and deaths. Also, mating
heifers to calve 10 days ahead of the
cows allows time to patiently break
them into shed routine.
Pregnancy testing after six weeks of
mating permits a check on the
fertility of the bull, and fecundity of
the heifers. Any heifer that is not
going to be able to get into calf can
be culled.
Stockmanship
Young stock are inquisitive. Avoid
putting them where there are cliffs,
steep-sided drains and other death
traps. They may also try to eat
pieces of wire and hay bale strings,
which can injure them.
Handle young stock as much as
possible. Regular walks through the
mob and hand feeding make them
quiet. This can save time when
shifting stock or where fencing is
inadequate. Running heifers through
the milking shed routine before they
calve, if done quietly, will make
breaking them in after calving much
easier.
Summing up
The penalties for
management are:
poor
heifer
 Higher costs for getting animals
to a satisfactory size and weight
 A loss of returns through low
production in first lactation
 A high culling rate in two-yearolds because they are hard to get
back in calf
 More money spent on stock
medicines
 More time and money spent per
animal
 An upset mating programme
caused by a spread out calving
pattern in young stock
Better management of young stock
through adequate care and nutrition
encourages full expression of their
potential.