A3559 Using AI Young Sires in Your Herd - LearningStore

A3559

Using AI Young
Sires in Your Herd:

Some Genetic and
Economic Considerations

By Denny Funk

Many dairy farmers are reluctant to use AI Figure 1 examines 158 bulls with parent averages
progeny-test young sires in their herds. After between 950 and 1050 pounds. The average of the
all, why use a young sire when so many good proven parent average for milk was 1000 pounds. Although
bulls are available? Why gamble on a young sire all bulls had similar pedigree expectations, actual
before you know what his progeny-test proof will be? PTAs for milk ranged between -371 pounds and
These are good questions; therefore, let’s take a closer +1713 pounds, a difference of 2084 pounds. However,
look at some of the genetic and economic implications the average PTA milk for these 158 bulls is +1002
of using young sires. pounds, only two pounds higher than the average of
the parent average. As Figure 1 shows, PTA milk
Can we predict what a young sire’s values are evenly distributed above and below parent
proof will be before he has milking average. Using a group of young sires minimizes the
daughters? risk of having daughters from only those bulls with
PTA milk values below parent average.
Afrequent argument made against using a young
sire is that we don’t know what his production Figure 1. Parent Average and PTA Milk distribution
proof will be until after he has milking daughters. from July 1991 for 158 bulls born in 1985 with Parent
This is not entirely true. Averages between 950 and 1050 lbs. milk.

AI organizations select young sires for progeny PTA Milk Parent Average Milk
sampling based on pedigree merit. One common
measure of pedigree merit is parent average. A bull’s PTA or Parent Average Milk (rounded to the nearest 100#) -550
parent average is calculated as one-half of his sire’s -450
Predicted Transmitting Ability (PTA) plus one-half of -350
his dam’s PTA for a particular trait. Although parent -250
average is a good predictor of the bull’s eventual -150
proof, we know that some young sires will come
through with proofs below their parent average, -50
while others will come through with higher proofs. 50
The net result is that the average proofs for a group of 150
bulls is usually quite close to the overall average of 250
the bulls’ parents. 350
450
How good a predictor is parent average? In 550
Figure 1, the July 1991 USDA sire summary for 650
Holsteins is used to compare the bulls’ PTAs for milk 750
with their parent averages. The bulls in the 850
comparison were born in 1985, but due to recent 950
major changes in genetic evaluation procedures, 1050
(particularly the incorporation of the animal model in 1150
1989) using parent averages from 1985 is not valid. 1250
Although there is some overlap between a bull’s 1350
current parent average and production proof which 1450
reduces the size of the difference, the general 1550
relationship still exists. 1650
1750
1850

0 20 40 60 80
Number of bulls

How do proofs on young sires How heavily can young sires be
compare with proofs on proven used in a herd?
bulls that were available at the
same time the young sires were What are the risks associated with breeding a
sampled? large portion of the herd to young sires? A
research herd in North Carolina has been breeding a
As a group, little difference exists between the part of the herd to 100 percent young sires since 1971.3
genetic merit of young sires and the genetic The bulls were the highest genetic merit young sires
merit of the Active AI bulls that were available at the available based upon pedigree. Simultaneously,
same time the progeny-tested bulls were sampled. another portion of the herd was bred to the highest
Figure 2 lists the PTA Milk average for AI progeny- proven bulls for milk yield. Average Estimated Real
test young sires and Active AI proven bulls used in Producing Abilities of cows sired by young bulls and
the years 1971-1984.1 The averages were calculated proven bulls are depicted in Figure 3. As reported
using the bulls’ January 1988 PTA milk proofs. The previously in the USDA study,2 little difference exists
results indicate that dairy farmers not using proven bulls in the genetic merit of cows sired by the young sires
from at least the 50th percentile or higher could possibly and the proven bulls. Average production for the two
make faster genetic progress by using young sires in their groups has been essentially equal. A preliminary
herds. study on the proportion of daughters surviving to
later lactations again showed little difference between
Dairy farmers should also consider that the the two groups.3 Overall, the performance of the cows
average genetic merit of AI progeny-test bulls is sired by young bulls was very comparable to the
substantially higher than the average genetic merit of performance of the cows sired by proven bulls.
natural service bulls. First-time proofs on AI progeny-
sampled bulls were $106 higher for PTA$ Protein than Although dairy farmers may be reluctant to breed
first-time proofs on non-AI bulls in July 1991.2 This 100 percent of their herds to young sires, almost any
means that daughters of AI young sires are expected dairy farmer can confidently breed 25 percent or more
to generate an additional $106 of income (305-2x-ME to them. The key is to use a few units of semen on
basis) per lactation compared to daughters of young, many different bulls rather than many units of
non-AI bulls. Over the course of three lactations, semen on a few bulls. Do not use more than ten
average daughters of AI young sires would generate units of semen from any one young sire. Since about
approximately $300 additional income per daughter six units of semen are needed to get a milking
from milk sales compared to average daughters of daughter, using ten units of semen or less on a bull
natural service bulls. should normally result in only one or two milking
daughters of the bull. Milking ten daughters from ten
Figure 2. PTA Milk average (January 1988) for different young sires is a far safer bet than milking ten
Active AI sires and AI progeny test bulls used in daughters from just one young sire, as demonstrated
years 1971-1984.* in Figure 1. Consequently, if a young sire comes
through with a poor proof, you have only one milking
300 daughter from this bull, rather than ten.

qs Even if a young bull has an outstanding pedigree,
don’t get caught up in his credentials and breed a
200 s AI progeny test bulls q Active AI sires sq large portion of your herd to him. Research shows
100 that elite sampler bulls have no better track records
q q than other progeny-test bulls in the stud. The safest
q s and simplest approach is to use a few units of semen
qs from a randomly selected group of young sires.
Average PTA Milk 0 ss
sq
qs
-100 q

-200 qs

q q q s
s

-300 q s
s s

-400

71 72 73 74 75 76 77 78 79 80 81 82 83 84
Year of Service

*Powell and Norman, 1989. J Dairy Science. 72:1842

Figure 3. Estimated Real Producing Abilities of cows sired by AI progeny test
bulls and AI proven bulls for milk yield, North Carolina research herd.*

s AI progeny test bulls q AI proven bulls

4000

Estimated Real Producing Abilities sq q
3.7% Fat-Corrected Milk s

3000

q

2000 qs q s
q q
qs
s s s
q
s
q
1000 qs s
s qs q
s
q

0

71 72 73 74 75 76 77 78 79 80 81 82 83 84
Birth Year

*North Carolina Ag Research Service, 1988. S-49 Technical Committee Report, NC State University (Mimeo)

Additional economic

considerations

Young sire semen usually costs $3 or less per
unit—almost always less than semen from

proven bulls. Additionally, most AI organizations Table 1. Sample costs when breeding 25% of
provide various incentive payments to dairy farmers herd to AI progeny test bulls rather than
participating in their stud’s progeny test programs. average AI proven bulls.
For example, payment for

identifying daughters might Assumptions:

be $5 per daughter, and

payment for first milking Herd size 80 cows

daughters could be $20 or % herd bred to young sires 0% or 25%
more per daughter. You Conception rate 2 services/conception
might also get preferred Semen cost, young sires $2/unit
access to bulls with limited

semen supply or discounts Semen cost, proven bulls $10/unit

on semen of proven bulls. Incentive payments $5/daughter for identifying daughter;
$20/daughter for first milking daughters.
The information in Table

1 compares sample costs of Percent of heifers born that 90%
breeding a portion of the enter milking string
herd to young sires rather
than proven bulls. In this Young Sires Proven Sires
example herd of 80 cows, -$400
semen costs and incentive Semen cost for 25% of herd -$80
payments resulted in a (20 cows, 2 services per conception; $0
savings of $550 per year 40 breedings @ either $2 or $10) $0
when 25 percent of the herd -$400
was bred to young sires Heifer identification incentive payment +$50
rather than proven bulls. (50% heifer crop, 10 heifers @ $5/heifer)

First milking daughter incentive payment +$180
(9 heifers @ $20 per heifer)

TOTAL +$150

Cost advantage of using young sires per year: $550

Semen costs should always be taken into References
consideration when selecting sires to use in the herd.
Because of the low semen price and high genetic 1. Powell, R.L., and H.D. Norman. 1989. Genetic
merit, all dairy farmers should consider using young differences among categories of service sires. Journal
sires. Dairy farmers who want to improve cash flow of Dairy Science. 72:1842.
can take particular advantage of the low-cost semen
and incentive payments. Under no circumstances should 2. USDA-DHIA Active AI Bull Evaluations, July, 1991.
a natural service sire be used as a method of saving money Animal Improvement Programs Laboratory, United
on the semen bill. States Department of Agriculture, Beltsville, MD.
Mimeo.
Summary
3. North Carolina Agricultural Research Service -
After looking at the facts, dairy farmers may Report to the Technical Committee, S-49. December,
safely conclude that the the genetic and economic 1988. North Carolina State University, Raleigh, NC.
advantages of incorporating AI young sires into a Mimeo.
breeding program compare very favorably to using
AI proven bulls. The main points to remember are
summarized below:

(1) The average genetic merit of AI progeny-test
bulls is comparable to the average genetic merit of
Active AI bulls available at the same time.

(2) When using young sires, use a few units of
semen from many different bulls rather than many
units of semen from any one bull.

(3) Consider breeding 25 percent or more of the
herd to AI progeny-test young bulls.

(4) Take advantage of the low semen cost and
incentive payments offered by most AI progeny
sampling programs.

Produced by Cooperative Extension Publications

University of Wisconsin-Extension, Cooperative Extension, in cooperation with the U.S. Department of
Agriculture and Wisconsin counties, publishes this information to further the purpose of the May 8 and June 30,
1914 Acts of Congress; and provides equal opportunities in employment and programming including Title IX
requirements.

Author: Denny Funk is an assistant professor in the Department of Dairy Science, College of Agricultural and
Life Sciences, University of Wisconsin - Madison, and Extension dairy specialist, University of Wisconsin -
Extension, Cooperative Extension.

This publication is available from your Wisconsin county Extension office or from: Extension Publications, Rm.
245, 30 N. Murray St., Madison, Wisconsin 53715; phone 608-262-3346.

A3559 Using AI Young Sires in Your Herd: Some Genetic and Economic Considerations

I-05-92-2M-30-E