Chad Dechow

Penn State University

SIRE SELECTION

CONSIDERATIONS FOR DAIRY PRODUCERS

Adoption of genomicsProgress versus lagSelection indexes Breeding for healthier cows

OUTLINE

NUMBER GENOTYPED

1-200

99-2

0109-2

0119-2

0129-2

0139-2

0149-2

015

05,000

10,00015,00020,00025,00030,000

Females

1-200

9

11-20

101-2

0123-2

0135-2

0147-2

015

02,0004,0006,0008,000

10,00012,00014,000

Males

HolsteinJersey

CDCB; 2016

GENERATION INTERVAL

2005 2006 2007 2008 2009 2010 2011 2012 2013012345678

Sire Dam

Age

whe

n so

n bo

rn

Norman et al., 2014.

GENOMIC EFFECT

Number of bulls entering AI has not shifted dramaticallyUsed differently

Generation interval halved for siresDams also lower

Accelerated rate of genetic progress Degree is uncertain

GENETIC PROGRESS ASSUMPTION

Interval Generation Dev.St. Genetic*Intensity Selection*yreliabilit

ΔG/Year

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

2011

-800-600-400-200

0200400

Net Merit

Sire BVCow BVLong lagShort lag

Birth Year

$

UNFAVORABLE TREND AND LAG

PROGRESS & LAG EXPECTATIONS

Genetic progress Same for elite breeders and commercial population

Lag depends onGeneration interval, Reliability, Selection after

daughter proof, Rate of progress in the elite population

Good bulls are good bulls! It is not essential that commercial herds use young

siresMature bulls make more semen than young bulls

Young siresBorn 2008 to 2009 0 daughters in

2012 ≥100 daughters in

2015DPR

Top 25%Protein lbs

Top 10%

Proven BullsBorn 2000 to 2007 ≥100 daughters in

2012 ≥100 added by

2015DPR

Top 10%Protein lbs

Top 5%

2012 V. 2015

Young Proven0

0.5

1

1.5

2

2.5

3

3.5

20122015

DPR

Young Proven05

1015202530354045

20122015

PROTEIN LBS

We evaluate bulls for more than 40 traits!Time consumingEasy to lose focus on most important traits

Start with a selection index

HOW MANY TRAITS?

Protein yield exampleProtein price projection = $2.48/pound Increased feed required = $0.90/poundHealth costs = $0.09/pound

[$2.48/pound - $0.90 additional feed - $0.09 additional health] * 2.78 lactations = $4.14/pound

HOW IS AN INDEX VALUE DERIVED?

"Parmigiano reggiano factory". CC BY-SA 3.0 via Wikimedia Commons

Protein20%

Fat22%

Milk1%PL

19%

SCS7%

Udder8%

Feet/legs3%

Body size5%

Fertility10%

Calving ability5%

EMPHASIS IN $NM

Holstein TPI Jersey JPI Brown Swiss PPR

Lifetime Net Merit

0%20%40%60%80%

100%

Protein Fat Fertility Productive lifeMastitis resistance Other

Emph

asis

INDEX COMPARISON

REALISTIC WITH HIGH HERD TURNOVERS?

Died, High Mortality

Herds

Died, Low Mortality

Herds

60-d, High Mortality

Herds

60-d, Low Mortality

Herds

0123456789

10

Low PL High PL

% d

ied

/ cul

led

HERD ENVIRONMENT & PRODUCTIVE LIFE

*

*

*P<0.05 Dechow et al., 2012

*

*

MASTITIS EXAMPLE

-2.5 -1.5 -0.5 0.5 1.5 2.5 3.5-2

-1.5-1

-0.50

0.51

1.52

2.5

Udder Depth

STA

Mas

titis

2.4 2.8 3.2 3.6SCS

KETOSIS EXAMPLE

-2.5 -1.5 -0.5 0.5 1.5 2.5 3.5-2

-1.5-1

-0.50

0.51

1.52

2.5

Dairy Form

STA

Ket

osis

-5 -3 -1 1 3 5PL

OPPORTUNITIES:GENOMIC EVALUATION OF HEALTH?

Producer records from 1996 to 2012132,066 (ketosis) to 274,890 (mastitis)

Mastitis DA Ketosis Lameness Metritis0

1020304050

Mean Reliability

Cole et al., 2013

Breed for extremes, or optimal?Be realistic about your

management systemPSU trial herds

Split into high/low for dry matter refusals How much was left in front of the cow

MATCH GENOTYPE TO ENVIRONMENT

SIRE REGRESSION COEFFICIENTS

Milk Fat Protein0

0.2

0.4

0.6

0.8

1

1.2

1.4

High DMRLow DMR

(Dekleva, 2012)

GENETIC CORRELATIONS WITH YIELD

BW BCS

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

High DMRLow DMR

Dekleva et al., 2012

Use good siresMarketing?

Use young siresCommercial producers?

Young and daughter proven are both good options Head-to-head proof comparisons not recommended

TAKE HOME MESSAGE

Start with a selection indexMatch the genotype of your cows to your

management levelHerds that struggle with cow health

Avoid HIGH dairy form Use high PL sires Look for new health evaluations $Net Merit places more emphasis on productive life

Herds maximizing production Less emphasis on PL if cow health is not a concern

TAKE HOME MESSAGE

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QUESTIONS?