THE USE OF DHIA RECORDS BY VETERINARIANS IN DAIRY PRACTICE
DAIRY HERD IMPROVEMENT
1987
SHEARER, J.K., WEBB, D.W., & BRAUN, R.K.
VOLUME: NCDHIP HANDBOOK
Introduction
Interest in the use and interpretation of Dairy Herd Improvement
Association (DHIA) records continues to increase in the veterinary
profession. Possibly the best evidence of the growing popularity of
this topic is found in the number of educational programs and
seminars that address this subject. Because each processing center
has its own version of a report format, it is difficult, if not
impossible, to prepare a paper that will adequately cover the topic
of record interpretation and satisfy everyone's needs. However,
this paper attempts to help the practicing veterinarian understand
the importance of using DHIA records when consulting with dairy
producers.
The Changing Role of the Dairy Practitioner
The nature of veterinary practice is determined by the needs or
demands of the commodity group the practice serves. Over the past
few decades, an emphasis on the health care of individual animals
has been replaced by a broader and more holistic approach. This new
emphasis focuses on the dynamics of health and disease on a herd
level. During the 1960's and 1970's, services to dairy producers
that focused on herd health were called herd health programs. The
majority of these programs concentrated on reproduction and on the
control of infectious diseases.
During the late 1970's and into the 1980's, producers' demands for
expanded services involving udder health and milk quality,
replacement rearing, nutrition, and personnel training increased.
As a result of these demands, veterinarians have assumed a more
active role in the overall health and management program on dairy
farms. This active role has helped to affirm the importance of
their contribution to the improvement of the productivity and the
profitability of the dairy operation. Therefore, a transition is
taking place from a "herd health" program to "production medicine"
programs.
This production-oriented approach to the provision of veterinary
services includes an emphasis on the following areas: health care,
management, nutrition, production and expenditure control. The
approach requires developing skills to evaluate and analyze
production data, management skills, and economic information.
Properly implemented, the production medicine scheme maximizes the
usefulness of veterinarians to producers because it makes them an
integral part of the total management and production team.
The physical examination, diagnosis, and treatment and advice on a
therapeutic regimen, plus guidelines for prevention or control of
disease prob- lems will continue to be the veterinarian's area of
expertise. Encouragement of the veterinarian to assist in an
advisory or consultatory capacity to the total health management
program provides the opportunity for the veterinarian-dairy
relationship to become mutually beneficial and profitable. Using a
veterinarian primarily as a consultant differs from the traditional
view held by some producers. Therefore changes in understanding,
attitude, and orientation may be necessary before a production
oriented health program can be implemented on a majority of dairy
farms. However as the dairy industry continues its development
toward large-scale, highly mechanized, and technologically advanced
operations, the consultation role of the veterinarian will
undoubtedly increase.
The Importance and Use of Records
The veterinarian, of all persons, should know the importance of
records. In the process of arriving at a diagnosis on a poorly
performing animal, the veterinarian must rely on information
provided from records contained in the patient's health history.
Records also are necessary to define herd prob- lems. If the herd
problem is characterized by low production, a database capable of
accumulating, processing and summarizing a vast amount of data on
all of the cows in the herd is necessary. Fortunately, such a
system exists through the Dairy Herd Improvement Association
(DHIA). This system has become an indispensable tool for the
producer and the veterinarian.
DHIA records can be used to evaluate individual cows as well as
herd performance. These records can provide valuable information
concerning income and comparing product value with feed costs. They
are effective in detecting management deficiency areas, motivating
labor, and as a guide to sire selection in the herd's breeding
program. DHIA records provide the basis for objective
decisionmaking, program planning, and goal-setting for the dairy
producers and the veterinarian.
The value of records becomes apparent in herd situations when
little or no reliable data is available for review. In these cases,
herd problems are difficult for 2 primary reasons: (1) there is no
information available to help accurately identify the problem, and
(2) even if a potential problem is identified, there is no way to
demonstrate proof of the diagnosis or establish a base of
supporting evidence. In such cases the diagnosis is made through
subjective evaluation and clinical impression. An inaccurate
diagnosis may result from this. In addition, without a good record
system it is very difficult to monitor progress after changes are
instituted.
Interpretation of DHIA Records
DHIA data is little more than a cluster of numbers on a computer
sheet until it is analyzed and interpreted. Whether looking at the
parameters from an individual cow or reviewing the herd summary,
the veterinarian can provide valuable input to the meaning of
record data. By assisting in the interpretation process, the
veterinarian can help the producer turn raw data into usable facts
concerning herd production, management, health and profitability.
Thorough review of the dairy records will suggest areas of the
dairy operation needing minor adjustment, major overhauling, or
further scrutiny. The opportunity to fine-tune dairy operations
through an information update helps prevent minor crises from
becoming major catastrophes.
To be useful to dairy producers, DHIA records contain personal
information concerning the producers' business. As a result, some
dairy producers often are reluctant to allow access to their
records. On the other hand, most dairy producers recognize the
importance of the veterinarian's role in record interpretation and
allow them access to the DHIA records.
Today, copies of the dairy producer's monthly DHIA report can be
mailed directly to his or her veterinarian. In this way, the
veterinarian does not need to review records during a herd visit,
and instead comes prepared to address specific areas of concern as
identified in the monthly report. This results in a more efficient
and effective use of veterinary service.
Parameters To Help Monitor Herd Progress
Examples of the data available on the herd summary sheet from most
Dairy Record Processing Centers (DRPC) follow. Interested readers
are encouraged to contact the Cooperative Extension Service or DHIA
staff in their state for specific details on the format of reports
processed in their area.
Production, Income and Feed Cost
The monthly herd summary report includes information pertinent to
the performance of the herd. The report contains: the total number
of cows in the herd; the percentage of cows in milk; the average
number of days in milk; and the average milk, fat and protein
production for all cows in the herd (average pounds on test day and
a 12-month rolling herd average).
Some dairy producers think of an individual cow's milk production
or the herd's production in terms of daily averages, whereas other
producers use rolling herd averages. Either of these averages
describes the herd as a low, high or average producing herd.
However, what is probably more important is whether the trend is up
or down when compared with production from previous months. In
herds where production continues to improve, progress is in the
right direction. On the other hand, if production remains stable or
takes a downward turn, an investigation is warranted.
Profit is an important parameter to monitor any business. DHIA
monthly herd summaries may contain product value and feed cost data
particularly useful to the dairy producers. As feed costs rise
relative to product value, the importance of feeding efficiency
increases. A veterinarian may be helpful by counseling with
management concerning the culling of marginal cows.
A final production parameter worthy of mention is the average peak
test day milk production. While this figure is affected by a
variety of factors includ- ing disease and climatic conditions, it
can indicate the nutritional status of cows in early lactation.
When the average peak test day milk production is low (young cows
less than 50 pounds or cows less than 65 pounds), the feeding may
not be meeting production demands. Supplementing this information
with body condition scores on cows taken at drying off, calving,
and at or near peak milk production can be used to document feeding
deficiencies.
Several other parameters indicate estrus detection efficiency,
conception rate and possible reproductive disease problems. These
parameters include data for a test interval relating to the total
number of breedings, the number of cows experiencing estrous cycles
abnormal in length, the number and percentage of successful
breedings, the percentage of reproductive problem cows in the herd,
and the number of cows sold from the herd for reproductive reasons.
Statistics from dry cow profiles include the average number of days
dry, and the number of cows with short or excessively long dry
periods. Dry periods less than 40 days in length have been shown to
have a detrimental impact on milk production in the subsequent
lactation. If the average number of days dry exceeds 70 days,
reproductive problems may be a contributing factor.
Mastitis
Mastitis, the most costly disease in dairy cattle, robs the dairy
industry of more than $2 billion annually. The majority of this
economic loss (65 percent) results from decreased milk yield in
infected cows. In most cases, the infection is undetected. The
advent of electronic cell counting technology has provided a
convenient way to accurately identify subclinically infected cows
and monitor mastitis in herds. Today somatic cell count (SCC)
information is available from milk cooperatives, state regulatory
programs, and the DHIA program. While milk co-ops and regulatory
departments provide bulk milk SCC, the most comprehensive cell
count information (including an SCC on individual cows) is provided
through DHIA.
Several sections of the DHIA reports include SCC data for dairy
producers enrolled in the DHIA program. Based on research from
Wisconsin and Vir- ginia, DHIA reports SCC as a linear score SCC to
the log base 2. Reporting data as a linear score rather than as a
whole number improves the interpretive value of SCC data. As shown
in Table 1, daily milk loss (pounds) increases by 1.5 pounds each
time the cell count doubles. Also, milk loss is greatest at the
lower cell count levels.
Optional services are available to assist producers in interpreting
SCC information. For example, a Somatic Cell Count Profile lists
cows in groups according to their SCC. In large herds, this list
permits the rapid identification of high cell count cows. In
addition, these cow lists provide historical data. These data make
it easier to find information that may be needed when evaluating
individual cows and the herd.
Some general uses for SCC data include:
- identification of subclinically infected cows;
- identification of cows for culture and susceptibility testing;
- identification of cows to use in a selective dry cow therapy
program;
- segregation of cows with a high probability for infection and
alteration of the milking procedure;
- identification of potential culls; and
- monitoring of mastitis and milk quality.
TABLE 1. Daily and 305-day lactation milk
losses associated with increased linear cell
count scores.(a)
305-Day
Daily lactation
SCC milk loss* milk loss*
Score (thousands) (pounds) (pounds)
1 25 0 0
2 50 0 0
3 100 1.5 400
4 200 3 800
5 400 4.5 1200
6 800 6 1600
7 1600 7.5 2000
8 3200 9 2400
9 6400 10.5 2800
a Adapted from Shook, G., Soeman, A: The new DHI Lin-
ear score for somatic cell count. Presented at Technology
Transfer Session, National Mastitis Council 22nd Annual
Meeting, Louisville, Kentucky, February 22, 1983.
* This loss applies to second or later lactations. First lac-
tation losses are one-half these amounts.
Culling
Culling is one of the most important decisions made on the dairy
farm. In fact, DHIA records indicate that management culls
approximately 33 percent of the cows from their herds annually.
Proper culling decisions require accurate information on milk
production, reproductive status, and udder and general health.
While herd summaries provide an account of cows entering and
leaving the herd, specific information for assistance in the
development of cull cow lists can be obtained as an optional
service from most DRPC's. Monitoring the number of cows culled as
a result of low milk production, reproductive problems, mastitis,
or for feet and leg problems provides important clues to management
about the areas that may need more attention.
Health Management
The DHIA program is designed to be flexible. The development of
remote access systems that allow communication between onfarm
computers and DRPC mainframes permits record availability to update
files and to create action lists and management reports. Several
dairy producers and their veterinarians routinely take advantage of
this option in conducting their health programs. Lists of cows in
estrus, cows to check for pregnancy, or cows that need a
post-partum examination can be generated in a fraction of the time
needed for making up such lists by hand.
These online systems provide extensive data on herd health. At
least one DRPC offers a program that accumulates the number of days
that cows are in the sick herd. This program provides an objective
measurement of the productive days lost because of disease or
treatment.
Information concerning a variety of disease disorders and treatment
procedures can be collected and stored for future review. Having a
complete history of health disorders is helpful in the diagnosis of
potential feeding and nutritional deficiencies. For example,
knowing the rate of milk fever cases from month to month helps a
producer evaluate the dry cow feeding program. Monitoring the
number of clinical mastitis cases is valuable diag- nostically.
Through careful monitoring, dairy producers and employees can be
alerted to the potential problems associated with milking hygiene
practices, environmental sanitation and faulty machine function.
Summary
The role of the veterinarian as a consultant to the dairy
enterprise continues to grow. Today's veterinarian must be
knowledgeable in management skills on the dairy farm as well as in
medical and surgical skills. A veterinarian must be able to detect
not only the health disorders but also the management deficiencies
that reduce production efficiency and profitability. One of the
best resources available to assist in the accomplishment of this
task is the DHIA records.
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תתתתתתתתתתתתתתתתתתתתThe National Dairy Database (1992)תתתתתתתתתתתתתתתתתתתת
תתתתתתתתתתתתתתתתתתתתתתת\NDB\DAIRY\TEXT\DA108100.TXTתתתתתתתתתתתתתתתתתתתתתתת
%f TITLE;THE USE OF DHIA RECORDS BY VETERINARIANS IN DAIRY PRACTICE
%f COLLECTION;DAIRY HERD IMPROVEMENT
%f ORIGIN;Florida
%f DATE_INCLUDED;June 1992