The graph below is the production of the 11 cows that calved before we changed to the prefresh
program These cows averaged 74# milk at 37 DIM and calved after 7-1-99 It is apparent that
fewer cows hit above an 80# average (73%) compared to the current fresh cows. We also see that
the largest group here is at 80# where the previous graph shows most at 100#,
00% of 11 00% of 11 00% of 11
The last picture is a bit of insurance By this, I mean that we want to compare apples to apples
We will go to the same time frame as last year just in case the difference was due more to July-
August freshening versus September-October Here we see cows that calved last September at
the same days in milk (35 DIM) aveiaged 76# with a large majouty over 80#. This 91 % above
eighty pounds milk is bettei then the current 84% as seen in the first graph. The big difference is
shown above this level. We see that 36% of the cows are 100# or higher. Looking back to the
first giaph, that number is 56%
1 11
1 10
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I 5
I
3
I
OQ%O/22 00%Qt 22 00% Of 22
A total evaluation needs to be done when we see more cows calve over the next few months. It is
promising that cows currently average 80# in the start of the lactation compared to the 74 - 76#
that we previously saw. Sometimes we make management decisions and do not take the time to
see if we are getting the predicted results. This is an example of using production information to
evaluate those decisions. The trends in this herd say that the prefresh management change was
needed and I would expect the results to continue to be better.
Bam Owl 2000 is the tool that I used to look at the herd production changes to determine if
progress is being made
(Continued from Page 04)
MILK PRODUCTION FREQUENCY BEFORE PREFRESH
2+ LACTATIONS CALVED AFTER 7-1-99 AND 37 DIM
AVERAGE MILK 0
MILK PRODUCTION FREQUENCY BEFORE PREFRESH
2+ LACTATIONS CALVED AFTER 9-1-98 AND 35 DIM
AVERAGE MILK 0
Dairyman To Dairyman
4 363 S %Of 11
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Lancaster Farming, Saturday, December 18, 1999-DS
Question: Is it necessary to
use a transitional period for
heifers that are put with the
dry cows for their last three
months of gestation?
I always recommend a
transitional or prefresh diet for
all animals before their next
calving. I believe this to be es
pecially needed by heifers that
calve for the first time due to
all the changes that happen to
them during this period. What
are some statistical indicators
that help us reach these conclu
sions?
One place that I look to
evaluate heifer performance
and how well prepared they are
to become cows is found on the
third section down on the Herd
Summary 11. Here we see “Pro
file of Cows by Lactation
Number.” Near the center of
the page is a column that states
the average days to peak and
the average milk at peak. In
this particular herd, we see a
large contrast between older
cows and first lactation heifers
as we compare days to peak.
The second lactation reaches
its peak at 80 days and older
cows at 60 days. In contrast,
we see that the first lactation
heifers take 130 days to reach
their peak. It is normal for heif
ers to reach their peak slower
than their older counterparts
but certainly not this slow. Past
first lactation, cows should
reach peak milk production
two to three weeks ahead of
reaching peak dry matter in
take. We recognize the need
for proper body reserves with
this bit of knowledge and pre
fresh diets help reduce the
weight loss that is seen as cows
reach peak around 60 days in
milk. Heifers that are going
through more changes at this
lime usually peak milk a bit lat
er at 75 to 85 days in milk. The
heifers that are peaking much
later arc telling us we have not
prepared them to be milk cows.
Another evaluation that
serves to tell us if we are meet
ing the needs of these changing
animals is to look at some
reproductive performance
parameters and how they differ
from one age group to another.
Again, we look at the PA
DHIA Herd Summary II Re
port for this information. The
second section down is the
“Reproductive Profile of
Breeding Herd.” Going tight to
left we come across the column
labeled “Average Days to Ist
Service.” This herd again
shows great disparity between
first lactation and older cows.
Performance differs little be
tween second lactation and
older cows with the average
days to first service at 110
days. When we look at the first
lactation animals, we see a sub
stantial difference. Noting that
the performance of the older
cows could be improved repro
ductively, the first lactation
animals show a more severe
problem. Here we see these
cows being bred for the first
time at over 160 days. When
we see that the first lactation
cows make up 45 percent of the
herd it is no wonder that over-
all herd reproductive perform
ance is not what we would like.
These two evaluations do
not exclusively point to prob
lems caused by lack of a transi
tional period. When first lacta
tion performance lags behind
the rest of the herd, bunk man
gement and grouping needs
should be addressed. The num
bers seen for this herd suggest
that the lack of a prefresh per
iod might initiate problems as
these new animals come into
the herd. Getting off to a good
start by proper preparation
should be your first step.
Question: Our cows are
not milking as we think they
should. Can you tell by our
records if they are really
down or are our expectations
too high?
Evaluating production
trends by looking at all avail
able information is vital to an
swering this question. Looking
at statistics like RHA or daily
milk averages by themselves
will not allow us to get a feel
ing about production potential
during a given time.
Two items found on the
Herd Summary II report that I
find useful when assessing if
your cows are giving all they
can are the “% Days in Milk”
and the “Average Days in
Milk.” On their October test,
the herd increased percent days
in milk from 86 percent to 91
percent with the average days
in milk for the whole herd stay
ing the same at 197 days. This
tells me that there are fresh
cows entering the herd faster
than we are drying cows off
and the herd has potential to
improve production from last
month. The cows are down five
pounds on the daily average
when they probably should
have stayed at least the same.
Another way that we can de
termine what the cows are cap
able of milking is to look at the
current test period average.
Typically, when percentage of
days in milk increases so does
the 30-day milk average. Dur
ing the previous four months
the percent days in milk has
been stable at about 87 percent
while the milk average for each
one-month period has dropped
from 84 to 75. This month it
has dropped further to 72.8
pounds. We are seeing milk de
creases when we should be see
ing increases. The cows are
actually producing at the year’s
low in October although aver
age days in milk and percent
days in milk show favorable
trends.
Another figure that is useful
when we compare performance
to potential is to look at the
150-day adjusted milk average.
This number attempts to look
at cows equally throughout the
differences seen during the
year. Up until July, the 150-day
average was 85 pounds for the
previous 11 months. The range
over those 11 months was 83 to
88 pounds. Since then, the
range was 79 to 82 pounds and
averaged 81 pounds for a four
month period.