The Impact of Wean Age and Feeding Program on Nursery Performance - Dr. Christina Phillips, Director of Production Research, Smithfield, from the 2016 Allen D. Leman Swine Conference, September 17-20, 2016, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2016-leman-swine-conference-material

1. Impact of Wean Age and Feeding
Program on Nursery Performance
Christina Phillips, Ph.D.
Director of Production Research
Smithfield Hog Production Division
September 19, 2016

2. Outline
 Background
 Brief Literature Review
 Wean age and nursery feeding program: Exp 1
 Wean age and nursery feeding program: Exp 2
 Overall Implications
 Acknowledgements
 Questions

3. Background
 The swine industry adopted the practice of earlier
weaning to:
 Improve farrowing crate utilization
 Increase numbers of pigs born per sow per year
 Improve piglet health
 Many producers and scientists are re-evaluating
weaning age decisions, by comparing growth
performance of pigs of different wean ages.
3

4. Literature Review
 Increasing wean age (15.5, 18.5, and 21.5 d) linearly
improved nursery (0-42 d) ADG and decreased nursery
mortality (Main et al., 2004).
 Magnitude of growth rate improvement is predictable within a
system, but magnitude of mortality improvement is dependent
upon baseline mortality, pig flow, and specific health
challenges.
 Nursery diet complexity (defined as more or less complex)
determined by amount of lactose and spray-dried animal
plasma in the diet, did not influence performance.
4

5. Literature Review
 Increasing wean age (from 20 d to 15 d) increased
nursery (0-42 d) ADG, decreased the coefficient of
variation for weaning weight, and decreased morbidity
(Smith et al., 2006).
 Increasing wean age (from 21.8 to 18.9 d) improved
nursery (0-42 d) ADG (Bass et al., 2007).
5

6. Experiment 1
 Experiment Title: Impact of wean age and feed program
on nursery performance
 Experiment Objective: To determine the impact of wean
age and nursery feeding program on nursery performance

7. Experimental Design
 2420 mixed sex pigs (Sow farm, NC) were allocated to 1
of 12 treatments (Research Nursery Farm, NC) in a 3 x 4
design.
 3 wean age groups and 4 dietary feeding programs
 Pigs were weaned weekly and allotted to the appropriate
wean age group. All wean age groups were represented in
each week. Six weeks of weaned pigs were used in the
trial.
 A PRRS break was confirmed 7 d after the 1st group was
placed.

8. Experimental Design
Groups were created to avoid confounding wean age
with week of weaning.
Litters Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 8
Week 42 1 24 13 9
Week 43 15 3 28 2
Week 44 15 6 14 12
Week 45 10 3 15 14
Week 46 17 4 17 13
Week 47 7 9 9 21 5

9. Experimental Design
 Sow farm
 All pigs were ear tagged at processing and location recorded
 No piglets were cross fostered after processing
 Day before weaning litters were painted with respective color to
correspond to wean age group
 Research Nursery farm
 Pig sorted by color (wean age group)
 Pigs assigned to pens within each color grouping
 Pigs were placed at 2.5 sq.ft./pig
 Pens were then assigned to dietary treatments within each wean age
group

10. Experimental Design
 Standard nursery management
 Comfort boards placed in all pens for 21 days
 Gruel fed pens with avg wt less than 12 lbs for 3 days
 Treatments administered daily, pigs pulled if non responsive in 3 days
 PRRS Outbreak Protocol (Implemented in week 2)
 Water meds: Electrolytes, Oral aspirin; Denagard/Neomycin/Tetracyline
if needed
 Individual treatments : Draxxin (d 0 – 14), Baytril (d 15-28), Excede (d
29 – sale), Predef 2X (anytime)

11. Experimental Design
 3 wean ages:
 ≤ 25 d (18-25 d)
 26-29 d
 ≥30 d (30-38 d)
 4 dietary treatments, combined total = 23 lbs of early
wean (EW) and pre-starter (PS), remainder fed for 49 d
nursery period was starter:
 0 lbs EW, 23 lbs PS
 2.5 lbs EW, 20.5 lbs PS
 5 lbs EW, 18 lbs PS
 7.5 lbs EW, 15.5 lbs PS

12. Data Collection and Analysis
 Data Collection
 Pens were weighed at days 0, 7, 14, 28, and 49 post placement
 Amount of feed delivered to each pen
 Fall behinds and mortality were recorded
 Feed samples for every diet phase and treatment were collected
 Data Analysis
 General Linear Model
 Main Effect
 Age
 Diet
 Age X Diet

13. Results
Treatments SE Age Diet
Age X
Diet
18 - 25d 26 - 29d 30 - 38d
Item
0 EW 23
PS
2.5 EW
20.5 PS
5 EW 18
PS
7.5 EW
15.5 PS
0 EW 23
PS
2.5 EW
20.5 PS
5 EW 18
PS
7.5 EW
15.5 PS
0 EW 23
PS
2.5 EW
20.5 PS
5 EW
18 PS
7.5 EW
15.5 PS (P<) (P<) (P<)
Number of pens 11 11 11 11 6 7 6 7 10 10 10 10
Start Weight, 0d, lb 10.00 9.91 9.68 9.99 13.88 13.21 13.92 13.04 15.05 15.10 15.57 14.87 0.58 <0.01 0.68 0.84
Trial Duration (0-49d)
ADG, lb 0.66 0.63 0.65 0.68 0.93 0.89 0.93 0.89 0.99 0.99 1.02 0.94 0.05 <0.01 0.64 0.71
Mortality, % 22.7% 26.1% 23.5% 18.2% 4.5% 3.9% 3.0% 4.5% 5.0% 3.6% 7.3% 7.3% 4.5% <0.01 0.97 0.77
Fall behinds, % 2.8% 2.5% 2.6% 4.1% 2.9% 2.3% 0.7% 5.5% 3.8% 3.3% 3.2% 5.0% 1.3% 0.35 0.02 0.86
F:G 1.47 1.54 1.53 1.49 1.47 1.43 1.38 1.36 1.48 1.46 1.47 1.44 0.04 <0.01 0.44 0.52
Sale weight, lb 46.9 46.97 47.04 48.46 60.8 58.19 59.74 58.67 64.9 65.02 68.02 63.94 2.15 <0.01 0.74 0.71
Period Results
ADG, lb (0-7 d) -0.03 -0.03 -0.03 -0.03 0.18 0.19 0.21 0.15 0.33 0.32 0.36 0.30 0.05 <0.01 0.75 0.99
ADG, lb (7-14 d) 0.32 0.25 0.26 0.26 0.60 0.48 0.52 0.51 0.73 0.70 0.72 0.55 0.06 <0.01 0.04 0.30
ADG, lb (14-28 d) 0.67 0.62 0.65 0.68 0.90 0.88 0.89 0.85 0.97 0.99 1.00 0.94 0.04 <0.01 0.80 0.78
ADG, lb (28-49 d) 1.13 1.16 1.17 1.21 1.34 1.30 1.34 1.33 1.32 1.34 1.40 1.33 0.05 <0.01 0.58 0.76

14. Main Effect of Agea
AGE
Item 18 - 25d 26 - 29d 30 - 38d SE (P<)
Number of pens 44 26 40
Start Weight, 0d, lb 9.90 13.51 15.15 0.28 <0.01
Trial Duration (0-49d)
ADG, lb 0.66a 0.91b 0.98c 0.02 <0.01
Mortality, % 22.6%a 4.0%b 5.8%b 2.2% <0.01
Fall behinds, % 3.0% 2.8% 3.8% 0.6% 0.35
F:G 1.51a 1.41b 1.46c 0.02 <0.01
Sale weight, lb 47.4a 59.35b 65.48c 1.04 <0.01
Period Results
ADG, lb (0-7 d) -0.03a 0.18b 0.33c 0.03 <0.01
ADG, lb (7-14 d) 0.27a 0.53b 0.68c 0.03 <0.01
ADG, lb (14-28 d) 0.66a 0.88b 0.97c 0.02 <0.01
ADG, lb (28-49 d) 1.17a 1.33b 1.35b 0.02 <0.01
aMeans that do not share superscripts differ by p <0.05.

15. Main Effect of Dieta
DIET
Item
0 EW
23 PS
2.5 EW
20.5 PS
5 EW
18 PS
7.5 EW
15.5 PS SE (P<)
Number of pens 27 28 27 28
Start Weight, 0d, lb 12.98 12.74 13.06 12.64 0.28 0.68
Trial Duration (0-49d)
ADG, lb 0.86 0.83 0.87 0.84 0.02 0.64
Mortality, % 10.8% 11.2% 11.3% 10.0% 2.1% 0.97
Fall behinds, % 3.2%a 2.7%a 2.2%a 4.9%b 0.6% 0.02
F:G 1.47 1.48 1.46 1.43 0.02 0.44
Sale weight, lb 57.6 56.73 58.26 57.02 1.05 0.74
Period Results
ADG, lb (0-7 d) 0.16 0.16 0.18 0.14 0.03 0.75
ADG, lb (7-14 d) 0.55a 0.48b 0.50ab 0.44b 0.03 0.04
ADG, lb (14-28 d) 0.85 0.83 0.85 0.82 0.02 0.80
ADG, lb (28-49 d) 1.26 1.27 1.30 1.29 0.02 0.58
aMeans that do not share superscripts differ by p <0.05.

16. Conclusions
 There were no Age x Diet interactions. Regardless of wean
age, pigs responded similarly to the different feeding
programs.
 As wean age increased there was significant improvement in
livability and growth rate.
 No differences in performance due to feeding program.

17. Experiment 2
 Experiment Title: Impact of wean age and feed program
on nursery performance
 Experiment Objective: To determine the impact of
wean age and nursery feeding program on nursery
performance

18. Experimental Design
 3454 mixed sex wean pigs were allocated to 1 of 12
treatments in a 3 x 4 design.
 Pigs were weaned weekly and allotted to the appropriate
wean age group. Eight weeks of weaned pigs were used
in the trial.
 All wean age groups were not represented in each week.
 Pigs were considered PRRS stable.

19. Experimental Design
Groups were unable to be created to avoid
confounding wean age with week of weaning.
Nursery Room 1 Room 2 Room 3 Room 4 Room 5 Room 6 Room 7 Room 1
Week 14 15 16 17 18 19 20 22
No. Pens
18-25 d 14 19 14 10 4 7 3
26-29 d 2 4 10 12 7 15
30-38 d 2 2 4 7 3 18

20. Experimental Design
 Sow farm
 All pigs were ear tagged at processing and location recorded
 No piglets were cross fostered after processing
 Day before weaning litters were painted with respective color to
correspond to wean age group
 Research Nursery farm
 Pig sorted by color (wean age group)
 Pigs assigned to pens within each color grouping
 Pigs were placed at 2.5 sq.ft./pig
 Pens were then assigned to dietary treatments within each wean age
group

21. Experimental Design
 3 wean ages:
 ≤ 25 d (18-25 d)
 26-29 d
 ≥30 d (30-38 d)
 4 dietary treatments, combined total = 23 lbs of early
wean (EW) and pre-starter (PS), remainder fed for 49 d
nursery period was starter:
 0 lbs EW, 23 lbs PS
 2.5 lbs EW, 20.5 lbs PS
 5 lbs EW, 18 lbs PS
 7.5 lbs EW, 15.5 lbs PS

22. Data Collection and Analysis
 Data Collection
 Pens were weighed at days 0, 7, 14, 28, and 49 post placement
 Amount of feed delivered to each pen
 Fall behinds and mortality were recorded
 Feed samples for every diet phase and treatment were collected
 Data Analysis
 General Linear Model
 Main Effect
 Age
 Diet
 Age X Diet

23. Results
SE Age Diet
Age X
Diet
Growth Performance
0 EW
23 PS
2.5 EW
21.5 PS
5 EW
18 PS
7.5 EW
14.5 PS
0 EW
23 PS
2.5 EW
21.5 PS
5 EW
18 PS
7.5 EW
14.5 PS
0 EW
23 PS
2.5 EW
21.5 PS
5 EW
18 PS
7.5 EW
14.5 PS (P<) (P<) (P<)
Number of pens 18 18 17 18 13 13 12 12 9 9 9 9
Start Weight, 0d, lb 12.64 12.85 12.75 12.72 15.40 15.44 15.28 15.32 18.32 18.34 18.03 18.14 0.24 <0.01 0.70 0.98
Trial Duration (0-49d)
ADG, lb 0.89 0.92 0.91 0.91 0.94 1.00 0.97 0.96 1.01 1.06 1.00 0.99 0.02 <0.01 0.01 0.65
Mortality, % 3.0% 3.0% 3.2% 5.3% 5.2% 3.5% 6.8% 7.2% 5.1% 6.1% 10.6% 6.6% 1.5% <0.01 0.02 0.26
Fall behinds, % 4.5% 4.5% 5.3% 6.6% 5.9% 4.2% 3.8% 3.8% 3.5% 4.0% 5.1% 4.0% 1.5% 0.41 0.96 0.62
F:G 1.38 1.38 1.31 1.30 1.45 1.39 1.42 1.33 1.53 1.52 1.51 1.44 0.10 0.03 0.53 1.00
Sale weight, lb 57.5 59.34 58.91 58.77 63.4 65.95 64.73 64.26 69.7 71.71 70.32 68.96 0.99 <0.01 0.02 0.89
Interim Results
ADG, lb (0-7 d) 0.10 0.13 0.10 0.12 0.11 0.15 0.17 0.15 0.20 0.22 0.10 0.20 0.03 <0.01 0.21 0.28
ADG, lb (7-14 d) 0.53 0.51 0.49 0.50 0.60 0.61 0.55 0.55 0.79 0.83 0.78 0.72 0.03 <0.01 0.03 0.73
ADG, lb (14-28 d) 0.88 0.92 0.91 0.88 0.93 1.01 0.97 0.93 0.93 1.04 0.98 0.99 0.03 <0.01 <0.01 0.77
ADG, lb (28-49 d) 1.30 1.35 1.36 1.38 1.37 1.43 1.41 1.43 1.45 1.46 1.43 1.39 0.04 <0.01 0.57 0.73
18 - 25d 26 - 29d 30 - 38d
Treatments

24. Main Effect of Agea
aMeans that do not share superscripts differ by p <0.05.
Item 18 - 25d 26 - 29d 30 - 38d SE (P<)
Number of pens 71 50 36
Start Weight, 0d, lb 12.74a
15.36b
18.21c
0.12 <0.01
Trial Duration (0-49d)
ADG, lb 0.91a
0.96b
1.02c
0.01 <0.01
Mortality, % 3.6%
a
5.7%
b
7.1%
b
0.8% <0.01
Fall behinds, % 5.2% 4.2% 4.5% 0.7% 0.41
F:G 1.34
a
1.40
ab
1.50
b
0.05 0.03
Sale weight, lb 58.6
a
64.6
b
70.2
c
0.50 <0.01
Interim Results
ADG, lb (0-7 d) 0.11
a
0.15
ab
0.18
b
0.02 <0.01
ADG, lb (7-14 d) 0.51a
0.58b
0.78c
0.02 <0.01
ADG, lb (14-28 d) 0.90
a
0.96
b
0.99
b
0.01 <0.01
ADG, lb (28-49 d) 1.35
a
1.41
b
1.43
b
0.02 <0.01
AGE

25. Main Effect of Dieta
aMeans that do not share superscripts differ by p <0.05.
Item
0 EW
23 PS
2.5 EW
21.5 PS
5 EW
18 PS
7.5 EW
14.5 PS SE (P<)
Number of pens 40 40 38 39
Start Weight, 0d, lb 15.45 15.54 15.35 15.39 0.12 0.70
Trial Duration (0-49d)
ADG, lb 0.95a
0.99b
0.96ab
0.95ab
0.01 0.01
Mortality, % 4.4% 4.2% 6.9% 6.4% 0.8% 0.02
Fall behinds, % 4.7% 4.3% 4.7% 4.8% 0.7% 0.96
F:G 1.45 1.43 1.41 1.36 0.05 0.53
Sale weight, lb 63.5
a
65.7
b
64.7
ab
64.0
ab
0.50 0.02
Interim Results
ADG, lb (0-7 d) 0.14 0.17 0.12 0.16 0.02 0.21
ADG, lb (7-14 d) 0.64
a
0.65
ab
0.61
a
0.59
ac
0.02 0.03
ADG, lb (14-28 d) 0.92
a
0.99
b
0.95
ab
0.93
a
0.01 <0.01
ADG, lb (28-49 d) 1.37 1.41 1.40 1.40 0.02 0.57
DIET

26. Conclusions
 There were no Age x Diet interactions. Regardless of wean
age pigs responded similarly to the different feeding
programs.
 As wean age increased there was significant improvement
growth rate.
 Mortality rates appeared higher in older wean pigs, but the
higher rate is believed to be due to more litters of older
wean age occurring during a period of elevated nursery
mortality.
 No differences in performance due to feeding program.

27. Overall Implications
 Increasing wean age increases growth rate.
 Increasing wean age improves nursery mortality in
an acute PRRS break.
 Feeding a 2 phase nursery diet program provides
similar growth for older wean pigs, in comparison
to a 3 phase nursery diet program.

28. Acknowledgements
 Alma Terpening, Intern
 Tim Autry, Sow Farm Manager
 Piotr Zubrowicz, Production Specialist
 Daniel Sykes, Research Specialist

29. Contact Information
Christina Phillips, Ph.D.
Director of Production Research
Smithfield Hog Production Division
Email: cephillips@smithfield.com
Phone: 910-282-4025