DAIRY HERD MANAGEMENT EVALUATION
DAIRY HERD MANAGEMENT EVALUATION
James W. Smith
Extension Dairy Scientist
The current economic situation requires the producer to
carefully examine every phase of the dairy operation to uncover
weaknesses. Today's dairy producer must be able to pinpoint areas
that reduce profitability and make corrections as soon as possible.
Dairy Herd Improvement (DHI) records are indispensable when
evaluating and analyzing production management practices. The Herd
Summary Report (DHI-202) is mailed to participating dairymen by the
Dairy Records Processing Center at Raleigh, North Carolina
following each test day. This report summarizes herd production
data on a monthly and yearly basis.
This bulletin will aid the user in the analysis and evaluation
of the herd summary report. The next step is to decide which
management practices need improvement.
Some changes in management practices may be relatively easy to
implement with limited added expense. Changing other management
practices may require further analysis. Partial or complete farm
budgeting may be required to ascertain the cost-benefit of adopting
or changing practices where increased investment, expense or labor
is necessary.
Once decisions are made, goals for improvement should be
established and progress monitored. Keeping records can make a
difference in improving net farm income through improved
efficiency.
HERD PRODUCTION EVALUATION
Milk production is the single most important factor
influencing profit on the dairy farm. Generally, as production per
cow increases, so does the return to management income.
The average DHI production for various dairy breeds in the
region served by the Dairy Records Processing Center at Raleigh,
North Carolina is shown in Table 1.
TABLE 1. Average DHI production per cow
Breed Number of herds Cows per herd Milk Fat Protein
------in lbs.--------
___________________________________________________________________
Ayrshire 38 63 13,702 529 461
Brown Swiss 47 72 14,012 555 500
Guernsey 79 72 11,997 550 431
Holstein 4491 118 15,111 567 512
Jersey 432 98 11,411 537 430
_________________________________________________________________
You can obtain an overview of your herd's production by filling in
the following information.
Last Test Day 12 Months Ago
Total Number of Cows _______ _______
R.H.A. * for Milk (lbs.) _______ _______
R.H.A.* for Fat (lbs.) _______ _______
R.H.A.* for Protein (lbs.) _______ _______
Test Day Average Milk:
All Cows ________ _______
Milk Cows ________ _______
Percent Days in Milk ________ _______
* Rolling Herd Average
How does your herd's production compare with average DHI
production? How does herd size compare with a year ago? If
production has increased or decreased during the last year, can you
identify any cause? Has the percent cows in milk changed
significantly? Answers to these questions may require a more
detailed analysis of your herd's performance.
PEAK MILK PERFORMANCE
Peak milk production is the highest level of production
achieved during lactation and usually occurs six to eight weeks
after calving. With each additional pound of peak milk, you can
expect about 200 to 230 more pounds of total milk yield for the
lactation.
Average peak test day production is calculated for cows in
milk 50 days or longer. The pounds of milk produced on the first
test day after 50 days in milk is the peak production value. Milk
production on succeeding tests is compared to the stored peak
production value and, if higher, replaces the stored value.
The average peak milk production of first lactation, second
lactation and of older cows at various production levels is shown
in Table 2. Peak production of first lactation cows is about 80
percent of the peak production of second lactation cows and about
75 percent of the peak production of older cows.
Are the cows in your herd peaking at an adequate level?______.
Is the peak production of first lactation cows high, normal or low
in relation to older cows? ____. A larger than expected deviation
in peak yield between cows of different ages may indicate that
management conditions vary between these groups.
TABLE 2. Average peak milk at various production levels
Herd First Second Third or Later All Cows
Average Lactation Lactation Lactation Average
_________________________________________________________________
(lbs.) lbs. of milk
_________________________________________________________________
Holstein
11000 46 55 61 56
12000 48 60 64 59
13000 51 63 69 63
14000 54 67 73 66
15000 57 71 77 70
16000 60 75 81 73
17000 63 79 85 76
18000 65 83 89 80
19000 68 86 93 83
20000 71 90 96 86
21000 74 94 101 89
All Herds 60 75 81 73
Jersey
9000 35 45 49 45
10000 39 47 52 48
11000 41 52 56 51
12000 45 54 59 54
13000 46 57 63 58
14000 51 63 69 62
All Herds 43 52 57 52
Although many factors influence peak milk production, nutrition
and feeding are usually the most important. Check those factors in
the following lists that may be limiting peak milk production in
your herd.
Factors limiting peak Factors limiting peak
performance-1st lactation cows: performance-older cows:
___ 1. Poor calf- and heifer- raising 1. Inadequate dietary
prgms resulting in small heifers. protein.
___ 2. Use of genetically inferior sires. 2. Inadequate dietary
energy.
___ 3. Inadequate feeding programs for 3. Lack of proper body
young cows. condition at
calving.
___ 4. Mastitis or other health problems. 4. Genetic ability.
___ 5. Limited bunk space resulting in too 5. Mastitis
much competition among younger
cows 6. Metabolic disorders
-Milk fever,
ketosis.
7. Short dry period
length.
PERSISTENCY EVALUATION
Total milk production for the lactation depends not only on
peak milk yield but also on persistency or how well milk production
is maintained during the lactation.
Table 3 shows the average production for first lactation and
older cows at various stages of the lactation. Compare the
persistency of your herd to the values in Table 3 by listing the
average milk production at different stages of the lactation.
Lactation Number 1-40 41-100 101-199 200-305 306+
First ___ ___ ___ ___ ___
Second and over ___ ___ ___ ___ ___
TABLE 3. Persistency at various production levels
Herd Average Stage of lactation (days)
(lbs.) lact. No. 1-40 41-100 101-199 200-305 306+
lbs. of milk
Holstein
12000 1 41 42 39 34 30
2+ 56 56 46 36 28
14000 1 44 48 45 39 33
2+ 62 64 53 40 31
16000 1 50 54 50 44 38
2+ 68 70 59 44 35
18000 1 55 60 56 48 42
2+ 75 78 66 50 38
20000 1 58 66 62 54 46
2+ 81 86 73 54 42
All Herds 1 47 52 48 42 36
2+ 63 65 56 43 33
Jersey
10000 1 34 35 30 26 24
2+ 46 46 37 29 23
12000 1 38 40 38 32 29
2+ 52 53 44 34 28
14000 1 42 46 44 38 36
2+ 60 62 52 42 34
All Herds 1 35 36 34 31 26
2+ 47 48 31 33 25
Another method of evaluating persistency is to use the Test
Period Persistency Index. (See the Yearly Production and Mastitis
Summary section on DHI-202.) The expected production of each cow in
the herd is determined each month using a standard lactation curve.
Actual production is compared to expected production and an average
index for the herd is calculated. A normal index should be close to
100. Indexes less than 100 indicate more than a normal drop in
production and indexes over 100 indicate that production is above
expected levels compared to the previous month. List the
persistency index for the last test day. _____. List the average
persistency index for the past year _____.
The persistency of individual cows can be evaluated using the
persistency of lactation curve index on the Monthly Report
(DHI-200). The index is calculated by comparing the individual
cow's current projected 305-day mature equivalent production to a
base projection calculated after 80 days in milk. An index close
to 100 is considered normal.
Evaluation of individual cow persistency and a review of the
average persistency for the herd can indicate management
weaknesses.
The following factors can lower persistency. Check those that
are suspected problems. Proper feeding and mastitis control are
major factors in maintaining persistency throughout the lactation.
___ 1. Inadequate dietary energy.
___ 2. Metabolic disorders.
___ 3. Mastitis.
___ 4. Improper milking practices or equipment.
___ 5. Genetic ability.
___ 6. Stray voltage.
MILK QUALITY EVALUATION
Mastitis is the most costly disease on the dairy farm. The DHI
Somatic Cell Count (SCC) program is available for use in monitoring
the level of subclinical mastitis in the herd.
The cells found in milk are about 75 percent white blood cells
or leucocytes and about 25 percent epithelial cells. Leucocyte
numbers increase in response to bacterial infection and tissue
injury or stress. The epithelial cells originate from the udder
secretory tissue and increase in number as a result of injury
or infection. Both types of cells come from within the cow's body,
so they are called somatic or body cells.
An increase in the number of somatic cells is largely a result
of an increase in the number of leucocytes. The relationship
between the level of somatic cell production and udder infection is
shown in Table 4.
Unfortunately, there is no single number of somatic cells
below which a cow is absolutely free from infection or above which
she has a serious mastitis problem. In general, higher levels of
somatic cells are associated with an increased likelihood of
subclinical or clinical mastitis.
Although milk production declines as the level of somatic
cells increases, the relationship is not linear. Consequently, a
somatic cell count score (SCCS) has been developed. The SCCS is
based on a logarithmic conversion of the actual SCC as shown in
Table 5.
TABLE 4. Relationship of somatic cell counts (SCC) to percentage
of infected cows
SCC Percentage of Infected Cows
(1000/ml) Pennsylvania New York
_________________________________________________________________
0-99 6 5
100-199 17 12
200-299 34 33
300-399 45 38
400-499 51 58
500-599 67 53
Over 600 79 61
TABLE 5. Somatic cell count scores related to actual somatic cell
counts (1000/ml) and the California Mastitis Test (CMT)
Range
Linear Score Mid-point Low--- ---High CMT
0 12.5 0 18 Negative
1 25 19 35 Negative
2 50 36 71 Negative
3 100 72 141 Negative
4 200 142 283 Negative
5 400 284 565 Trace
6 800 566 1130 1
7 1600 1131 2262 2
8 3200 2263 4522 2
9 6400 Over 452 3
Each increase in SCCS is associated with a doubling of the
actual SCC. For example, the loss in production between scores two
and three is estimated at 1.5 pounds per cow per day for second
lactation and older cows, based on an actual SCC difference of
about 50,000 cells. However, the same loss in production between
scores six and seven is associated with an actual SCC difference of
about 800,000 cells. The SCC system indicates that significant
improvements in milk production are possible even when actual
somatic cell counts are relatively low. Table 6 shows the
relationship between milk production loss, somatic cell counts and
somatic cell count scores.
TABLE 6. Estimated milk production loss versus somatic cell count
(SCC) and somatic cell count score
Milk Production Loss(pounds)
SCC Cell Count Score Per Day Per Lactation
50,000 2 0 0
100,000 3 1.5 400
200,000 4 3.0 800
400,000 5 4.5 1,200
800,000 6 6.0 1,600
1,600,000 7 7.5 2,000
3,200,000 8 9.0 2,400
6,400,000 9 10.5 2,800
The relationship between somatic cell count score and level of
herd milk production is shown in Table 7. High producing herds have
lower average SCCS's with a high percentage of cows in the low cell
count score categories.
TABLE 7. Relationship between somatic cell count score and level
of milk production
SCC Scores Average
Herd Average 0-3 4 5 6 7-9 Score
(pounds)
Percentage of Cows in Herd
Holstein
11,000 44 19 16 10 11 3.8
12,000 46 18 15 10 11 3.7
13,000 46 18 15 10 11 3.7
14,000 52 17 13 9 9 3.5
15,000 54 17 13 8 8 3.4
16,000 55 17 12 8 8 3.3
17,000 58 17 11 7 7 3.2
18,000 61 16 10 7 6 3.0
19,000 63 16 10 6 5 2.9
20,000 63 16 10 6 5 2.9
21,000 66 15 9 5 5 2.8
All Herds 55 17 12 8 8 3.3
Jersey
10,000 53 19 13 8 7 3.4
11,000 55 19 13 7 6 3.3
12,000 58 17 12 7 6 3.2
13,000 61 15 11 7 6 3.0
14,000 63 16 10 6 5 2.9
All Herds 56 18 12 7 7 3.2
Compare the SCC Scores for your herd with the values in Table 7.
If the average SCCS rises by 0.5 or more from one month to the next
the causes for the increase should be investigated. A herd goal
should be a SCCS of 3.5 or an actual count of less than 200,000.
Less than three percent of the cows in the herd should have a score
above seven.
Last Test Day Months Previous
Average Herd 1 2 3 12
SCC Score ____ ____ ____ ____ ____
Percent of Cows
Scoring 7 or Above ____ ____ ____ ____ ____
Percent of Cows
Scoring 3 or Below ____ ____ ____ ____ ____
The Stage of Lactation Profile helps determine when infections
occur during the lactation. The average SCCS for first lactation
cows should be less than 2.0 during the first 40 days in milk. The
average SCCS for older cows during the same period should be less
than 2.5.
TABLE 8. Relationship between the level of milk production and
average somatic cell count score of cows fresh less than
40 days
Herd Average 1st Lactation Cows 2nd or Later Lactation Cows
(lbs) (SCC Scores)
Holstein
12,000 2.3 3.8
14,000 2.2 3.5
16,000 2.5 3.4
18,000 2.7 3.1
20,000 2.6 3.1
All Herds 2.4 3.4
Jersey
10,000 2.7 3.5
12,000 2.6 3.3
14,000 2.1 3.0
All Herds 2.5 3.4
Compare the average SCCS of older cows fresh less than 40 days
with the values in Table 8. If scores are high, evaluate dry cow
management. Compare the average SCCS of first lactation cows fresh
less than 40 days with the values in Table 8. Evaluate conditions
at calving if scores are much greater than two. Low SCCS during
early lactation followed by increased counts as the lactation
progresses indicates a lapse in mastitis management.
The DHI Herd Summary also shows the percentage of first
lactation, second lactation and third and later lactation cows in
each of five SCCS ranges. Fill in the following information for
your herd.
SOMATIC CELL COUNT
Percentage of Cows SCC Score
0-3 4 5 6 7-9
Lactation Below 142,000- 284,000- 566,000- Over
42,000 283,000 565,000 1,130,000 1,130,000
1 ______ ______ ______ ______ ______
2 ______ ______ ______ ______ ______
3+ ______ ______ ______ ______ ______
Most cows in the first category will not be infected. Cows with
scores of four to six probably have subclinical mastitis. Scores
above seven indicate a high probability of clinical mastitis. These
tend to be chronically infected cows.
Set some goals for your herd according to the following
information.
GOALS FOR IMPROVING MILK QUALITY
Present Herd Average Target Goal Your Goal
3.0 or
Herd SCC Score ______ less ______
3.0 or
% of scores above 7 ______ less ______
2.0 or
Avg. Score of 1st Lact. ______ less ______
Cows Fresh < 40 days
2.5 or
Avg. Score of 2nd Lact. ______ less ______
and Over Cows Fresh < 40 days
The following are possible causes of high somatic cell counts in
your herd.
____ 1. Poor milking practices. ____ 7. High proportion of
older cows.
____ 2. Improperly operating milking ____ 8. Poor dry cow
equipment management
____ 3. Poor sanitation practices. ____ 9. Failure to treat
all dry cows.
___ 4. Unclean environment. ____ 10. Failure to dip
teats.
____ 5. Infection by specific ____ 11. Improper treatment
organisms procedures.
____ 6. Long lactations. ____ 12. Stray voltage.
REPRODUCTIVE EVALUATION
The net profit of many herds can be increased by improved
reproductive efficiency. Improved reproductive efficiency pays off
in several ways. Reduced calving intervals help eliminate long dry
periods. If cows are bred back sooner, they are less likely to
have long periods of low production at the end of the lactation.
Table 9 shows the relationship between reproductive efficiency
and level of milk production.
TABLE 9. Reproductive efficiency of Holsteins(H) and Jerseys(J)
at various levels of milk production
Herd Avg 10,000 12,000 14,000 16,000 18,000 20,000
(lbs)
Minimum (J) 13.2 12.9 12.9
Calving (H) 14.1 13.9 13.7 13.6 13.6
Interval
Services
per Con- (J) 2.3 2.1 2.1
ception (H) 1.9 2.1 2.3 2.4 2.4
Days to (J) 78.0 79.0 76.0
First (H) 89.0 90.0 89.0 88.0 91.0
Breeding
TABLE 9. Continued
Herd Avg 10,000 12,000 14,000 16,000 18,000 20,000
(lbs)
Average (J) 123.0 112.0 112.0
Days (H) 149.0 142.0 137.0 132.0 132.0
Open
Average (J) 64.0 64.0 59.0
Days Dry (H) 74.0 69.0 66.0 64.0 62.0
Average
Age of (J) 26.0 26.0 25.0
1st Calf (H) 28.0 28.0 28.0 28.0 27.0
Heifers
Percent (J) 86.0 86.0 87.0
Cows in (H) 84.0 86.0 87.0 88.0 88.0
Milk
Percent (J) 44.0 47.0 47.0
Success. (H) 53.0 47.0 43.0 42.0 41.0
Breedings
GOALS TO IMPROVE REPRODUCTION
Present Herd Target Goal Your Goal
Average
1. Calving Interval (mos) ______ 12.5 ______
2. Services per Conception ______ 1.5 ______
3. Days to First Breeding ______ 70.0 ______
4. Average Days Open ______ 110.0 ______
5. Average Days Dry ______ 60.0 ______
6. Percentage of Cows in Milk ______ 88.0 ______
7. Average Age 1st Calf Heifer ______ 24 - 26 ______
The following are possible reasons for poor reproductive
performance. Check those areas that may apply to your herd.
1. Heat periods not observed. 7. Poor semen quality.
2. Unfamiliarity with all 8. Poor reproductive
signs of heat. records.
3. All heats not recorded. 9. Fat dry cows.
4. Waiting too long to breed 10. Unsanitary calving
cows after calving. conditions.
5. Health problem (retained placenta, 11. Low fertility or
metritis, etc.). diseased herd bulls.
6. Poor A. I. breeding techniques. 12. Slippery concrete
lots.
GENETIC EVALUATION
The use of high predicted transmitting ability (PTA) sires has
the greatest impact upon genetic improvement in the dairy herd.
Cows from high PTA sires produce more milk, fat and protein on the
average than do cows from non-A.I. sires or low PTA sires. Table 10
shows that service sires with high PTAs are used in herds with high
averages as an investment in future genetic improvement.
TABLE 10. Genetic information related to herd production level
Average PTA $$ of Cow's Sire
Herd Percent of 1st 2nd 3rd/Later All PTA $$
Average Cows with Lacta- Lacta- Lacta- Lacta- of Svc
(pounds) Sire I.D. tion tion tion tions Sires
Holstein
12,000 27 +58 +44 +8 +28 +122
14,000 46 +61 +4 +14 +36 +131
16,000 61 +68 +54 +20 +44 +131
18,000 73 +79 +66 +31 +56 +138
20,000 78 +91 +76 +41 +67 +144
All Herds 60 +73 +59 +24 +48 +133
Jersey
10,000 86 +58 +43 +11 +30 +112
12,000 93 +78 +58 +24 +48 +123
14,000 99 +95 +66 +34 +57 +129
All Herds 89 +71 +51 +19 +40 +117
Record the following information for your herd:
Percentage of cows with sire identified ______
Average PTA $$ of First Lactation Cows ______
Average PTA $$ of Second Lactation Cows ______
Average PTA $$ of Third Lactation and Older Cows ______
Average PTA $$ of All Cows _____
Average PTA $$ of Service Sires ______
What system is used to permanently identify newborn calves?
______________________________
Does identification of animals by sire, dam and date of birth
need improvement? ______
Are all cows bred to A.I. Sires? ______
Is the PTA $$ level of service sires adequate? _______
The following factors may limit genetic improvement. Check
those factors that apply to your herd.
____ 1. Not using A.l. Sires.
____ 2. Not breeding heifers to A.l. Sires.
____ 3. Not using high PTA $$ Sires
____ 4. Poor identification
____ 5. Sire selection based on non-productive traits.
FEEDING EVALUATIONS
Feed costs usually represent about one-half of the cost of
producing milk. Consequently, improvements in feeding efficiency
can have a significant effect upon profitability. Although DHI
records are useful in evaluating a feeding program, additional
information on inventories, feed prices and forage test results are
usually required for a complete evaluation.
As shown in Table 11, feed efficiency increases as production
rises.
Fill in the following information for your herd:
1. Calculate pounds of milk produced per pound of grain fed by
using R.H.A. milk (in pounds) divided by R.H.A. concentrate
(in pounds) _______
2. Income over feed cost per cow per year _______
3. Feed cost per cwt. of milk _______
TABLE 11. Feed efficiency of Holsteins(H) and Jerseys(J) related to
milk production level
Herd Average (lbs) 10,000 12,000 14,000 16,000 18,000 20,000
Pounds milk/ (J) 2.5 2.4 2.4
pounds grain (H) 2.3 2.2 2.3 2.6 2.7
IOFC* per cow (J) 828 1143 1377
per year ($) (H) 903 1104 1321 1492 1658
Feed cost per (J) 7.11 6.05 5.81
cwt milk ($) (H) 6.34 6.14 5.60 5.43 5.03
*IOFC = Income Over Feed Cost
Check the following list for factors that may lower feed efficiency
in your herd.
____ 1. Poor quality forage. ____ 5. Mineral imbalances.
____ 2. Failure to analyze forages ____ 6. Lack of fiber in
and balance rations. the ration.
____ 3. Overfeeding grain during ____ 7. Crowded feeding
late lactation. facilities.
____ 4. Underfeeding grain in ____ 8. Inadequate water.
early lactation.
____ 9. Lack of shade.
SUMMARY
List those areas of herd management that offer the greatest
opportunity to improve net income.
1.
2.
3.
4.
5.
6.
In which management area(s) will the potential for improvement be
the easiest to achieve?
1.
2.
3.
In which area will the results of improvement be noticed most
quickly?
How can the necessary changes be made and what is required to
make the changes?
List the improvement goals you would like to achieve during
the next 12 months.
1. Herd Production __________________________________________
2. Milk Quality _____________________________________________
3. Reproduction _____________________________________________
4. Genetics _________________________________________________
5. Feeding __________________________________________________
When you have a question...Call or visit your local office of The
University of Georgia's Cooperative Extension Service.
You'll find a friendly, well-trained staff ready to help you with
information, advice and free publications covering agriculture and
natural resources, home economics, 4-H and youth development and
resource development.
Prepared by
James W. Smith
Extension Dairy Scientist
The Cooperative Extension Service, The University of Georgia
College of Agriculture offers educational programs, assistance and
materials to all people without regard to race, color, national
origin, age, sex or handicap status.
AN EQUAL OPPORTUNITY EMPLOYER
DS 1-3
Bulletin 1033 May 1990
Issued in furtherance of cooperative Extension work, Acts of May 8
and June 30, 1914, The University of Georgia College of Agriculture
and the U.S. Department of Agriculture cooperating.
C. Wayne Jordan, Director
UPD 8571/4-90
90-136
%f TITLE;DAIRY HERD MANAGEMENT EVALUATION
%f COLLECTION;DAIRY HERD IMPROVEMENT
%f ORIGIN;UNIVERSITY OF GEORGIA-ATHENS
%f DATE_INCLUDED;OCTOBER, 1993