This document summarizes a presentation on defining optimal wean age in the swine industry. It discusses several factors to consider in determining optimal wean age, including mortality, production costs, space requirements, and pig performance. Research suggests benefits from increasing wean age such as improved sow reproductive performance and pig growth. Data from trials show increased average daily gain and decreased mortality with older wean ages. The costs of increasing wean age on sow farms is also examined, with examples showing the increased investment needed per additional wean day. There is a need for more large-scale trials examining impacts beyond 22 days and under reduced antibiotic conditions.

1. HOW DO WE DEFINE OPTIMUM
WEAN AGE?
DR. KYLE COBLE
LEMAN SWINE CONFERENCE, TUESDAY, SEPTEMBER 19TH, 20117

2. “EARLY WEAN AGE IS AMONGST THE
MOST DEVASTATING DISEASES THAT
THE U.S. SWINE INDUSTRY HAS EVER
FACED”
DR. DEAN BOYD

3. OPTIMAL WEAN AGE SPEAKERS
 Dr. Kyle Coble – New Fashion Pork, Minnesota
 Introduction to past data and current trends
 Dr. Adam Moeser – Michigan State University, Michigan
 Biological and production basis of optimal wean age
 Dr. Cameron Schmitt – Pipestone Veterinary Services, Minnesota
 Our thought process and a field trial

4. OPTIMAL WEAN AGE?
 Many factors to consider when determining “optimal”
wean age….
1. Mortality
2. Cost of production
3. Crate space at the sow farm
4. Finishing space in your flow
5. Growth performance of off-spring
6. Subsequent reproductive performance of the sow
7. Nutrition changes (diet complexity)
8. Health (vaccination efficacy and immunity)

5. INDUSTRY TREND FOR WEAN AGE
22.10
20.54
y = 0.3329x - 648.58
R² = 0.9551
y = 0.165x - 311.75
R² = 0.8006
17.0
18.0
19.0
20.0
21.0
22.0
23.0
NPB PigChamp Linear (NPB) Linear (PigChamp)

6. NEW FASHION PORK WEAN AGE
16.0
17.0
18.0
19.0
20.0
21.0
22.0
19.1 19.1
19.4
20 20
19.4
*Forward target is 21-22 days

7. SUGGESTED BENEFITS FROM PAST
RESEARCH
 Improvement in subsequent breed back, total born, and
live born pigs per sow (Mabry et al., 1996; Correa et
al., 2013)
 Improved nursery, and weaned-to finish performance,
both in terms of growth and mortality (Main et al., 2004;
Smith et al., 2007).

8. EFFECT OF WEAN AGE ON PERFORMANCE,
MAIN ET AL., 2004 (WEAN-TO-FINISH)
0
1
2
3
4
5
6
7
8
9
10
12 15 18 21
9.39
7.88
6.80
3.68
Wean age, d
Mortality, %
Linear, P < 0.001
SEM = 0.95
600
620
640
660
680
700
720
12 15 18 21
643
671
686
714
Wean age, d
ADG, g
Linear, P < 0.001
SEM = 8.0

9. Item
Linear
Change/day SE
Allotment wt, kg 0.257 0.003
D 42 post weaning, kg 0.93 0.017
Off-test wt., kg 1.35 0.08
Wean-to-finish ADG, g 9.9 0.74
Wean-to-finish mort., % -0.47 0.09
Wt. sold per pig weaned, kg 1.80 0.12
EFFECT OF WEAN AGE ON PERFORMANCE,
MAIN ET AL., 2004 (WEAN-TO-FINISH)

10. Variable
Linear
Change/day SE
Cost/100 kg ($) -0.41 0.05
Income over cost/pig weaned ($) 0.58 0.006
Post-weaning days to mrkt -1.73 0.11
Cost/100 kg at common mrkt wt ($) -0.31 0.04
Income over costs/pig weaned ($) 0.39 0.06
Cost per head sold at common mrkt wt ($) -0.37 0.05
EFFECT OF WEAN AGE ON ECONOMICS,
MAIN ET AL., 2005 (WEAN-TO-FINISH)

11. WEAN AGE BECOMES MORE IMPORTANT IF
HEALTH IS WORSE
0
1
2
3
4
5
6
7
8
9
10
18 19 20 21 22 23 24
Mortality,%
Weaning Age, d
18 19 20 21 22 23 24
Weaning Age, d
HIGH HEALTHPOOR HEALTH
P = 0.003 P = 0.04
Hanor Memo

12. WEAN AGE BECOMES MORE IMPORTANT IF
HEALTH IS WORSE
18 19 20 21 22 23 24
Weaning Age, d
620
640
660
680
700
720
740
760
18 19 20 21 22 23 24
ADG,g
Weaning Age, d
HIGH HEALTHPOOR HEALTH
P = 0.003 P = 0.04
Hanor Memo

13. EXAMPLE SOW FARM COST TO INCREASE
WEAN AGE
 Example Input Variables:
1. 6,000 hd filtered sow farm
2. Current wean age of 18 days
3. 829 crates
4. Cost per new crate = $6,200

14. EXAMPLE SOW FARM COST TO INCREASING
WEAN AGE
Breakeven Cost/weaned pig (@ 10.5)
Target
Farrowings
Wean
Age Crates Need SumCost
1 yr
return
2 yr
return
3yr
return
Crate
Turns/yr
290 16 746 . . . . .
290 17 787 $256,857 $1.62 $0.81 $0.54 19.2
290 18 829 $513,714 $3.24 $1.62 $1.08 18.2
290 19 870 $770,571 $4.87 $2.43 $1.62 17.3
290 20 911 $1,027,429 $6.49 $3.24 $2.16 16.5
290 21 953 $1,284,286 $8.11 $4.06 $2.70 15.8
290 22 994 $1,541,143 $9.73 $4.87 $3.24 15.2
290 23 1036 $1,798,000 $11.36 $5.68 $3.79 14.6
290 24 1077 $2,054,857 $12.98 $6.49 $4.33 14.0
290 25 1119 $2,311,714 $14.60 $7.30 $4.87 13.5
290 26 1160 $2,568,571 $16.22 $8.11 $5.41 13.0
290 27 1201 $2,825,429 $17.84 $8.92 $5.95 12.6
290 28 1243 $3,082,286 $19.47 $9.73 $6.49 12.1

15. EXAMPLE SOW FARM COST TO INCREASING
WEAN AGE
Breakeven Cost/weaned pig (@ 10.5)
Target
Farrowings
Wean
Age Crates Need SumCost
1 yr
return
2 yr
return
3yr
return
Crate
Turns/yr
290 16 746 . . . . .
290 17 787 $256,857 $1.62 $0.81 $0.54 19.2
290 18 829 $513,714 $3.24 $1.62 $1.08 18.2
290 19 870 $770,571 $4.87 $2.43 $1.62 17.3
290 20 911 $1,027,429 $6.49 $3.24 $2.16 16.5
290 21 953 $1,284,286 $8.11 $4.06 $2.70 15.8
290 22 994 $1,541,143 $9.73 $4.87 $3.24 15.2
290 23 1036 $1,798,000 $11.36 $5.68 $3.79 14.6
290 24 1077 $2,054,857 $12.98 $6.49 $4.33 14.0
290 25 1119 $2,311,714 $14.60 $7.30 $4.87 13.5
290 26 1160 $2,568,571 $16.22 $8.11 $5.41 13.0
290 27 1201 $2,825,429 $17.84 $8.92 $5.95 12.6
290 28 1243 $3,082,286 $19.47 $9.73 $6.49 12.1
$257,000 or $0.54 per weaned pig
over 3 yr to increase wean age 1 day

16. EXAMPLE SOW FARM COST TO INCREASING
WEAN AGE
Breakeven Cost/weaned pig (@ 10.5)
Target
Farrowings
Wean
Age Crates Need SumCost
1 yr
return
2 yr
return
3yr
return
Crate
Turns/yr
290 16 746 . . . . .
290 17 787 $256,857 $1.62 $0.81 $0.54 19.2
290 18 829 $513,714 $3.24 $1.62 $1.08 18.2
290 19 870 $770,571 $4.87 $2.43 $1.62 17.3
290 20 911 $1,027,429 $6.49 $3.24 $2.16 16.5
290 21 953 $1,284,286 $8.11 $4.06 $2.70 15.8
290 22 994 $1,541,143 $9.73 $4.87 $3.24 15.2
290 23 1036 $1,798,000 $11.36 $5.68 $3.79 14.6
290 24 1077 $2,054,857 $12.98 $6.49 $4.33 14.0
290 25 1119 $2,311,714 $14.60 $7.30 $4.87 13.5
290 26 1160 $2,568,571 $16.22 $8.11 $5.41 13.0
290 27 1201 $2,825,429 $17.84 $8.92 $5.95 12.6
290 28 1243 $3,082,286 $19.47 $9.73 $6.49 12.1
$1,027,429 or $2.16 per weaned pig
over 3 yr to increase wean age 4 day

17. WHAT DO WE NEED TO KNOW?
 More large scale trials that have data past 22 days of
wean age that:
1. Look at subsequent sow performance.
2. Determine overall producer cost and returns.
 How does this impact growth in the face of reduced
antibiotic usage?
 More information on vaccine efficacy.

18. “EARLY WEAN AGE IS AMONGST THE
MOST DEVASTATING DISEASES THAT
THE U.S. SWINE INDUSTRY HAS EVER
FACED”
DR. DEAN BOYD
“WE RESERVE THE RIGHT TO GET
SMARTER”
DR. GARY LOUIS

19. NEXT SPEAKERS
 How does wean age effect the gut and what challenges
does that lead to?
 How does one production system define their optimal
wean age?