Improving the Impact of AI Boars in the Production System...(Foxcroft et al., 2008). •Improving the impact of AI boars through the accurate assessment of male fertility will result

Improving the Impact of AI Boars in the Production System

Jennifer Patterson

Natalie Diether, Michael Dyck & George Foxcroft

RED DEER SWINE TECHNOLOGY WORKSHOPOctober 24th, 2018

• The fertility of breeding males in a pork production system greatly contributes to the reproductive efficiency of the herd.

• Sub-fertility of a single boar used in AI can negatively affect reproductive outcomes for many sows (Foxcroft et al., 2008).

• Improving the impact of AI boars through the accurate assessment of male fertility will result in:

• Increased efficiency at the boar stud,

• Increased reproductive efficiency,

• Rate of genetic gain (DeJarnette et al., 2004).

(Diether et al., 2018)

Introduction

What was AI supposed to deliver?

1. Reduced labor inputs at breeding

2. Improved occupational health

3. Reduced disease risk

4. Easier working environment

5. More consistent production

6. Greater genetic gain7. Rapid integration of new genes

(From Campbell, 2008 Billy Day Symposium)

• Decreasing the number of sperm cells per insemination.

• Use fewer superior boars siring slaughter pigs.

Maximizing genetic progress made in the breeding nucleus is achieved by:

• Maintaining (improving) fertility performance in production units.

• The efficient use of AI boars with high genetic merit in the boar studs.

(Broekhuijse et al., 2015)

(Pork Storks, Australia)

1) Fertility is generally unknown

• Using sub-fertile boars and low quality ejaculates reduces production efficiency

2) Excessive number of sperm used per litter produced (9B)

• Increases the numbers of boars needed for semen production

• Reduces the genetic impact of our best boars

3) Pooled semen (from poorly defined males) is largely used in NA studs

• Breaks the link between known genetic value of individual boars and the paternity of progeny produced

Opportunities for improvement are based on 3 assumptions:

Not all boars are created equal……

Assessing Reproductive Performance

– Despite “rigorous” semen evaluation, certain boars do not have the same reproductive performance

– Routine semen evaluation standards (> 70% motility & < 30% abnormal sperm) detect male reproductive disorders…..

…… but do not predict relative fertility among “acceptable”, healthy sires

(Flowers et al. 1997; Alm et al. 2006; Ruiz-Sanchez et al. 2006)

Relative Fertility of Boars with “Acceptable” Semen

(USA boar stud ~ 450 boars) Based on ~50 SS matings

0%10%20%30%40%50%60%70%80%90%

100%

12

24

36

48

51

06

12

71

48

16

91

90

21

12

32

25

32

74

29

53

16

33

73

58

37

94

00

42

14

42

Rat

e (

%)

Boar (sorted by pregnancy rate (%)

6

8

10

12

14

16

18

0

250

500

750

1000

1250

1500

Pig p

rod

uced

Total b

orn

PR - 57 - 100%FR - 50- 100%

TB 7.6 – 15.2

PP - 500 - 1500

USA data suggests up to 20% of boars are sub-fertile

Relative Fertility of Boars with “Acceptable” Semen (CAN boar stud ~ 120 boars)

PR: 55 - 100%

FR: 54 - 96%

TB: 9 - 16

BA: 8 - 15

PP: 465-1380

In your opinion what is the greatest opportunity to improve the use of AI boars?

Type Slido.com into your smart phone’s internet browser address bar, then enter event code #C204.

Click the “Polls” tab to respond. RDSTW guests’ responses will display in real-time.

In order to safeguard against unknown “relative” fertility, the industry:

• Uses excessive amounts of sperm in each AI dose.

Why are excessive amounts of sperm used in each AI dose?

• Compensable traits are those that can be overcome by introducing large numbers of sperm during insemination (Braundmeier and Miller, 2001

and Flowers, 2013)

– i.e. motility, normal morphology (Flowers, 2013)

• Non-compensable traits are those that male fertility is unresponsive to increases in sperm number

– i.e. those associated with plasma membrane binding and DNA integrity (Flowers, 2013)

Why are excessive amounts of sperm used?

Fertility of some boars is compromised when their

semen is inseminated at less than 3 billion sperm/AI dose.

(Flowers 2013)

Fertility of some boars is maintained with AI doses of 1 billion sperm

Compensable traits

In order to safeguard against unknown “relative” fertility, the industry:

• Uses excessive amounts of sperm in each AI dose.

• Uses pooled semen.

– Pooled semen guards against detrimental production results if the semen from one boar has very poor fertility.

– However, it also appears to “average” AI results below what is achievable.

Boar “Competitiveness” – UofA SRTC • Two “fertile” boars use in homospermic or heterospermic

(pooled) AI doses, with 2 billion sperm/dose

Variable Pooled

AI Doses

# Sows bred 32

Ovulation rate

20.3

Live embryos – d30

15.2

Embryo survival

75%

(SRTC – unpublished data, 2009)

Blue Boar Single Sire AI

Red Boar Single Sire AI

11 14

20.7 20.3

17.7 15.0

85% 75%

Using pooled semen from poorly defined males also breaks the link between known genetic value of individual boars and the

paternity of progeny produced.

Boar “Competitiveness” – Field Study

• Assessed five working stud boars with similar

(“normal”) semen parameters

• Fertility initially evaluated using field data

from single boar inseminations (over 3

ejaculates)

• Boar “Competitive” analysis carried out using

pooled semen (all 5 boars) – followed by

paternity testing on resulting litters

(SRTC – unpublished data, 2008)

Homospermic AI

Boar A Boar B

# Breedings 31 27

Farrowing rate 45% 100%

Av. Total born 9.22 12.04

Heterospermic AI

(Pool of 5 boars, including A and B,

at equal sperm nos.)

# Breedings 10

Farrowing rate 90% (9 litters)

Av. Total Born 10.4

% Pigs sired – (N=104) <1% 30%

Boar “Competitiveness” – Field Study

Steps for Improved AI programs?

1. Select boars with acceptable fertility

• Characterize boar fertility using Single-Sire AI

(50 matings per boar)

2. Eliminate boars with limited reproductive

capacity at lower sperm doses

3. Use boars with proven fertility at lower

sperm doses (<1.5 billion) for PC-AI &/or

sFT-AI use

1. Characterize boar fertility at

lower sperm dose, using single-

sire AI.

3 ➔ 2 Billion

Multiple breedings, standard AI

Pooled ➔ SS

Steps for Improved AI programs

Fertility Testing

Methods - Characterizing boar fertility

• Boars

– Semen quality included >75% motile and >70% normal

– Ejaculates processed at:• 2 billion sperm cells/dose ~ conventional AI

• 1.5 billion sperm cells /dose ~ PCAI

– Fifty SS matings evaluated

– Semen used within 4 days of age

• Sows

– Multiparous (no gilts)

– WEI 3 to 6 days• No returns, aborts or rebreds

• Data

– Pregnancy rate, farrowing rate and litter size

Concentration is adjusted based on

AI method used

Minimize variation due to the sow by selecting sows with

improved fertility

1. Characterize boar fertility at

lower sperm dose, using single-

sire AI.

3 ➔ 2 Billion

2. Remove boars with lower fertility,

use boars with proven fertility at

lower doses.

3. Use boars with proven fertility at

lower sperm doses for PC-AI &/or sFT-

AI use.

1.5 Billion

Multiple breedings, standard AI

Multiple breedings, standard AI

IUI and/or Fixed Time Insemination

Proven fertile boars

Pooled ➔ SS Single sire Single sire

2 Billion

Steps for Improved AI programs

Fertility Testing

Relative Fertility of Boars with “Acceptable” Semen (USA boar stud ~ 450 boars)

0%10%20%30%40%50%60%70%80%90%

100%

12

24

36

48

51

06

12

71

48

16

91

90

21

12

32

25

32

74

29

53

16

33

73

58

37

94

00

42

14

42

Rat

e (

%)

Boar (sorted by pregnancy rate (%)

6

8

10

12

14

16

18

0

250

500

750

1000

1250

1500

Pig p

rod

uced

Total b

orn

Relative Fertility of Boars With “Acceptable” Semen

0%10%20%30%40%50%60%70%80%90%

100%

12

24

36

48

51

06

12

71

48

16

91

90

21

12

32

25

32

74

29

53

16

33

73

58

37

94

00

42

14

42

Rat

e (

%)

Boar (sorted by pregnancy rate (%)

6

8

10

12

14

16

18

0

250

500

750

1000

1250

1500

Low Medium High

Pig p

rod

uced

Total b

orn

Performance of low, medium and highest performing boars with “acceptable” semen

Category Low Medium High

Pregnancy rate 85.5%a 93.9%b 97.7%c

Farrow Rate 80.6%a 90.5%b 94.2%c

Total born 13.2a 13.8b 13.8b

Born alive 11.8a 12.5b 12.5b

Pigs produced* 1065.0a 1245.5b 1294.9c

*Estimated on 100 sows bred+200 pigs produced

for 100 sows bredAre the progeny equally valued? NO....

Results: Pigs produced vs genetic index

0%10%20%30%40%50%60%70%80%90%

100%

12

24

36

48

51

06

12

71

48

16

91

90

21

12

32

25

32

74

29

53

16

33

73

58

37

94

00

42

14

42

Rat

e (

%)

Boar (sorted by pregnancy rate (%)

6

8

10

12

14

16

18

0

250

500

750

1000

1250

1500

Pig p

rod

uced

Total b

orn

6085

110135160

Ind

ex

No relationship between index and fertility

Factors contributing to the value of boar

NPD

Pigs

Produced

Farrowing

Rate

Litter

Size

EBV

Others? survivability

Doses

produced

Why is genetic index important?

A high indexing commercial boar passes these traits on to his progeny.

3. Decreased mortality

1. Improved feed conversion

2. Fewer days to market

Increase $$ per pig marketed

*The optimum environment must be provided for a pig to reach it’s genetic potential.

Production “Value” of a boar = Pigs produced x index

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175001 9

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Boar

3 – 2 bIdentify boars

with low performance

Remove boars with lower fertility & use boars with proven fertility at lower doses for PC-AI &/or sFT-AI

use.

• Faster than traditional AI.

• Fewer technicians required.

• Improved job satisfaction (less breeder fatigue).

• Fewer sperm cells required and lower volume per dose

• Higher indexing boars can be used that will result in higher-performing finishing pigs.

Proposed Benefits of Post-Cervical AI (PCAI)

Ketchum, Rix & Duttlinger, 2017

Proposed Benefits of Fixed-time AI

• Reduces labor needed for multiple inseminations.

• Reduces semen requirements by reducing the number of inseminations needed to produce a litter.

• Allows the same genetic royalty costs to be invested in higher index boars.

• Most of the production benefits provide economic benefits to the primary producer.

The benefit of improved AI programs

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Boar

Phase 2 Phase 3

Boar value

Phase 1

Boar inventory

Doses per boar

Boar fertility

Improved AI practices are beneficial to the pig industry

Breeding companies

Production systems/sow

farms

Boar studs

• Improved transfer of genetics to customers

(modified from Broekhuijse et al., 2015)

Improved AI practices are beneficial to the pig industry

Breeding companies

Production systems/sow

farms

Boar studs

• Improved efficiency in AI dose production.

• Must deliver high quality product to producer:

– Optimal genetics

– Known high fertility boars

(modified from Broekhuijse et al., 2015)

Improved AI practices are beneficial to the pig industry

Breeding companies

Production systems/sow

farms

Boar studs

• Improvements in overall efficiency and fertility at the sow farm.

• Maximizes gain from the use of proven high fertility and high genetic index boars.

• Requires continual monitoring of field results and transfer of information with boar studs.

(modified from Broekhuijse et al., 2015)

Conclusions

• Use of single-sire matings at reduced spermnumbers to identify sub-fertile boarsimproves overall performance of aproduction system

• Fewer boars are required and theopportunity exists to remove boars withlower fertility & lower genetic merit

• Optimizes the use of proven high fertility andhigh genetic index boars to maximize gains.

Acknowledgments:

Thank-you! Questions?