Possible physiological benchmarks for sow longevity prior to puberty - Dr. Billy Flowers, from the 2012 Allen D. Leman Swine Conference, September 15-18, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2012-leman-swine-conference-material

1. Possible Physiological Benchmarks
for Sow Longevity prior to Puberty
W.L. Flowers
North Carolina State University
Raleigh, N.C.

2. Developmental Period

3. It would be useful if there were things
we could measure during the
developmental period that provide
us with some idea of the longevity
potential of prospective
replacement females.

4. The period just prior to birth is an active period of
fetal growth and ovarian development.
Birth weight is positively correlated with organ
development.

5. Relationships between Piglet Birth Weights and Organ Weights
Small
0.24 Intestines
Liver
0.20
Organ Weight (lbs)
0.16
Brain
0.12
0.08
0.00
0 1.0 2.0 3.0 4.0
Birth Weight (lbs)
(Adapted from Foxcroft et al., 2009)

6. Some aspects of fetal development
probably respond the same way to competition
as pig growth in “crowded pens”.
12 developing fetuses 6 developing fetuses

7. Birth weight probably is also positively related to
the development of reproductive organs.

8. Birth Weight and Reproductive Performance of Gilts
Piglet Birth Weight (lbs)
Reproductive
Performance 2.0 – 2.8 > 3.5
Age at puberty (days) 188 + 8 170 + 6
Ovulation rate 12.9 + 0.6 15.3 + 0.7
Embryonic survival (%) 69 + 7 83 + 6
(Flowers, unpublished)

9. Birth Weight and Longevity from Neonatal Study
• Study was conducted with 1820 gilts in an
80,000 sow commercial production system.
• Only used litters that had between 10 and 14
pigs born alive.
• Litter size was adjusted after birth to either
< 7 pigs (n=899) or > 10 pigs (n=921).
• Examined birth weight categories in only the
sows that nursed > 10 pigs (n=921)

10. Effect of Replacement Gilt Birth Weight on Sow Longevity
100
Females remaining in production (%)
90
80
70
60
50
40
30 > 3.6 lbs
E = Entry
20 B = Breeding - gilts 2.6 - 3.5 lbs
10 F = Farrowing
< 2.5 lbs
R = Rebreeding
0
E B F1 R1 F2 R2 F3 R3 F4 R4 F5 R5 F6
Production phase (Flowers, unpublished)

11. There probably is a minimum birth weight below
which gilts simply don’t have the reproductive
machinery to function adequately as adults no
matter how well they are managed subsequently.

12. While most of the follicles on the ovaries are present
at birth they begin to acquire their functional
competence during the next 30 days – most of which
occurs during their nursing period.

13. Birth Weaning
(Morbeck et al. 1993)

14. Producers have very little control
prospectively over birth weight, but
can affect pre-weaning growth.

15. Effect of Neonatal Litter Size on Sow Longevity
• Study was conducted with 1820 gilts in an
80,000 sow commercial production system.
• Only used litters that had between 10 and 14
pigs born alive.
• Litter size was adjusted after birth to either
< 7 pigs (n=899) or > 10 pigs (n=921).
• Commercial farm used pen gestation and had
average birth weights less than 3 lbs.

16. > 10 pigs nursing < 7 pigs nursing

17. Cross section
of ovaries from a
17-day old gilt from
litter of > 10 pigs
Cross section
of ovaries from a
17-day old gilt from
litter of < 7 pigs

18. Effect of Neonatal Lactation Litter Size on Sow Longevity
100
* p < 0.05
Females remaining in production (%)
90
80
*
70 *
60 * < 7 piglets
* *
50
* * *
40
**
30
E = Entry
20 B = Breeding - gilts
10 F = Farrowing
R = Rebreeding > 10 piglets
0
E B F1 R1 F2 R2 F3 R3 F4 R4 F5 R5 F6
Production phase (Flowers et al., in press)

19. Reproductive Performance and Neonatal Litter Size
100 12
90
11
80
10
70
%
m
w
N
A
B
F
e
g
n
o
a
n
o
e
b
u
v
)
(
r
r
t
i
i
l
60 9
0 0
1 2 3 4 5 6 1 2 3 4 5 6
Sow Parity Sow Parity
< 7 piglets (88.7%) < 7 piglets (11.0 + 0.1)
> 10 piglets (83.3%) > 10 piglets (10.5 + 0.2)
p < 0.05 p < 0.07

20. Reducing competition during the neonatal period
enhances early ovarian development which improved
longevity.
What can we measure during this period to accurately
assess growth and development of gilts?

21. Association of Growth Characteristics with Longevity
Growth Measures R2 P value
Weaning weight (lbs) 0.06 ( 6%) 0.14
(Flowers, unpublished)

22. Association of Growth Characteristics with Longevity
Growth Measures R2 P value
Weaning weight (lbs) 0.06 ( 6%) 0.14
Pre-weaning gain (lbs) 0.14 (14%) 0.04
(Flowers, unpublished)

23. Association of Growth Characteristics with Longevity
Growth Measures R2 P value
Weaning weight (lbs) 0.06 ( 6%) 0.14
Pre-weaning gain (lbs) 0.14 (14%) 0.04
Pre-weaning gain /
birth weight
(Flowers, unpublished)

24. Pre-weaning gain / birth weight
Pig A Pig B Pig C Pig D
Birth weight (lbs) 2.5 2.5 3.5 3.5
Weaning weight (lbs) 16.5 22.5 16.5 17.5
Pre-weaning growth (lbs) 14.0 20.0 13.5 14.0
Pre-weaning growth / 5.6 8.0 3.8 4.0
birth weight

25. Association of Growth Characteristics with Longevity
Growth Measures R2 P value
Weaning weight (lbs) 0.06 ( 6%) 0.14
Pre-weaning gain (lbs) 0.14 (14%) 0.04
Pre-weaning gain / 0.22 (22%) 0.001
birth weight (%)
(Flowers, unpublished)

26. Interactions between Birth Weight and Neonatal Litter Size
50
Sows that produced 6 litters (%)
40
*
< 7 piglets
30 > 10 piglets
*
20
10
* p < 0.05
0
< 2.5 lbs 2.6 – 3.5 lbs > 3.6 lbs
Birth Weight Categories (Flowers, unpublished)

27. Association of Growth Characteristics with Longevity
Growth Measures R2 P value
Weaning weight (lbs) 0.06 ( 6%) 0.14
Pre-weaning gain (lbs) 0.14 (14%) 0.04
Pre-weaning gain / 0.22 (22%) 0.001
birth weight (%)
Total Growth 0.42 (42%)
Other factors 0.58 (58%)
(Flowers, unpublished)

28. Pre-weaning growth and pre-weaning growth relative
to birth weight appear to have positive associations
with sow longevity and lifetime productivity

29. The best physiological test for longevity would be
something that mimics what the mature sow asked
required to do effectively each parity.

30. +
LH, FSH
Estrogens

31. 50
40 Boar
Exposure
30
170 days
20
10
50 m
G
N
E
n
o
e
b
u
s
r
t
f
l
i 0
0 5 10 15 20 25 30 35 40 45 50 55 60
40
Days from Onset of Boar Exposure
30
20
Boar
10 Exposure
m
G
140 days
N
E
n
o
e
b
u
s
r
t
f
l
i
0
0 5 10 15 20 25 30 35 40 45 50 55 60
Days from Onset of Boar Exposure
140 160 180 200 220

32. Effect of Neonatal Environment on Female
Response to Early Boar Exposure
Neonatal Environment
Variables < 7 pigs > 10 pigs
Proportion of gilts in estrus 77.0* 53.0
28 days after exposure (%)
†
Average number born 11.3 10.8
alive – early responders
Average number born 10.3 10.2
alive – late responders
* p < 0.05 † p < 0.08
(Flowers et al., in press)

33. Effect of Neonatal Lactation Litter Size on Sow Longevity
100
* p < 0.05
Females remaining in production (%)
90
80
*
70 *
60 * < 7 piglets
* *
50
* * *
40
**
30
E = Entry 22%
20 B = Breeding - gilts
10 F = Farrowing
R = Rebreeding > 10 piglets
0
E B F1 R1 F2 R2 F3 R3 F4 R4 F5 R5 F6
Production phase (Flowers et al., in press)

34. 50
40 Boar
Exposure
30
170 days
20
10
50 m
G
N
E
n
o
e
b
u
s
r
t
f
l
i 0
0 5 10 15 20 25 30 35 40 45 50 55 60
40
Days from Onset of Boar Exposure
30
20
Boar
10 Exposure
m
G
140 days
N
E
n
o
e
b
u
s
r
t
f
l
i
0
0 5 10 15 20 25 30 35 40 45 50 55 60
Days from Onset of Boar Exposure
140 160 180 200 220

35. LH, FSH
Estrogens

36. Effect of Neonatal Litter Size on Response to PG600
Gilts exhibiting vulvar swelling (%) 100 *
80
* < 7 piglets
> 10 piglets
60
* *p < 0.05
40
20
0
80 100 120 140 160
Age of gilts (days)

37. No response
at 140 days of age
Positive response
at 140 days of age

38. Strategic use of commercially available gonado-
tropins might be a way to screen for gilts capable
of early puberty without using a boar.

39. Developmental Period

40. Graduate Students Undergraduate Students
Dr. Jean Popwell Dr. Chad Smith
Dr. Lauren Job
Dr. Brad Belstra Dr. Patrick O’Quinn
Jennifer Griffin Dr. Catherine Hefley
Dr. Kara Stewart
Dr. Kyle Lovercamp Dr. Lisa Thompson
Frances Turner Kristey Kenney
Sara Shute Nikhol Garbacik
Shelley Swing Stefani Garbacik

41. Relationship between Number Born Alive
and Litter Birth Weights
15
Number Born Alive
14
13
12
11
10
9
8
0
10 20 30 40 50
Litter Birth Weight (lbs)

42. Number Born Alive and Litter Birth Weights
2.5 lb birth
weight
Market animals ?
15 Potential
Number Born Alive
Replace-
14 ment gilts
13
12
11
10
9
8
0
10 20 30 40 50
Litter Birth Weight (lbs)

43. Number Born Alive and Litter Birth Weights
2.5 lb birth 3.6 lb birth
weight weight
15
Number Born Alive
Strategic
14 Crossfostering Replace-
13 ment gilts
12
11
10
9
8
0
10 20 30 40 50
Litter Birth Weight (lbs)

44. Developmental Period
Periodic assessment
of management
during development.