Identification of measures predictive of age at first puberty - Dr. Jason Ross, 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. Identification of measures
predictive of age at first puberty
Kody L. Graves, Bethany
Mordhorst, Nicole Oldfather, Elane C.
Wright, Benjamin Hale, Aileen F.
Keating, Ken Stalder, Jason W. Ross

2. What is the importance of age of first
puberty?
• Impacts the profitability of a swine enterprise.
• Gilts that demonstrate puberty early have less non-productive days
than those that demonstrate first estrus late. (Patterson et
al., 2010)
• Heavier gilts at first breeding remain heavier compared to lighter
counterparts at first breeding. (Rozeboom et al., 1996)
• Age at first puberty is an indicators of lifetime productivity.
• Lifetime productivity lacks heritability and can be influenced by
environment.

3. Age of Puberty Impacts Fallout
Patterson et al., 2010 J. Anim Science

4. The Hypothalamic Pituitary Gonadal Axis
Hypothalamus Hypothalamus
5
GnRH 4 Positive
feedback exerted 8
Travels via
portal blood by large in
estrogen
1 output.
Anterior pituitary
1 5
Progesterone
LH surge Estrogen
FSH LH 6
Inhibin
Ruptured
2 2 8
follicle
3 Slightly
elevated 7
estrogen Thecal
and rising cells
inhibin
levels. Granulosa Androgens Corpus luteum
cells Mature follicle Ovulated
Convert secondary
androgens to 2
Inhibin oocyte
estrogens Late follicular and
Early and midfollicular phases luteal phases
Figure 27.19

5. Kiss1 is the Ligand for GPR54
A proposed
model linking
energy balance
and the initial
GnRH pulsatile
secretions
responsible for
puberty onset.
Roa and Tena-Sempere, 2010

6. Figure 1 Serum concentrations of LH and FSH (means±s.e.m.) for prepubertal gilts receiving
i.c.v. infusion of saline or either 10 or 100 μg kisspeptin (Kiss).
Lents C A et al. Reproduction 2008;135:879-887
© 2008 Society for Reproduction and Fertility

7. Variation in Prepubertal Follicular
Development
Day 98 ± 4 days
N = 21 N = 27
Ross, Keating and Baumgard, unpublished.

8. Hypothesis
• Gilts that demonstrate follicular activity earliest
will achieve puberty earliest. Additionally, these
gilts will be phenotypically distinct in at least one
physiological parameter.

9. Objectives
• To identify a specific time when a cohort of gilts
demonstrate variability with regard to follicular
development.
• To determine the feasibility measuring parameters related
to follicular development during prepubertal development.
– Trans-abdominal ultrasound
– Vulva development
– Serum estradiol
– Body weight
• To determine if those factors have any relationship with age
of puberty.

10. Experimental Design
• 155 Gilts ± 2 days of age
• On Days 75, 85, 95, 105, 115 of age:
– Body weight
– Ultrasound (trans-abdominal)
– Measure vulva width, vulva length
– Blood draw
– Sacrificed 10 gilts
• Recorded follicular development
• Uterine weight

11. Experimental Design
• Remaining 105 Gilts
– Heat checked daily
– Beginning at 129 days of age
– Ending at 200 days of age
• Determine association between phenotypes
on days 75, 85, 95, 105, and 115 and age of
first estrus.

12. Body weight gain during prepubertal
gilt development
90
80
70
Body Weight (Kg)
60
50
40
30
20
10
0
75 85 95 105 115
Day of Age

13. Change in vulva length during
prepubertal development
45
40
35
30
Millimeters
25
20
15
10
5
0
75 85 95 105 115
Day of Age

14. Change in vulva width during
prepubertal development
40
35
30
Millimeters
25
20
15
10
5
0
75 85 95 105 115
Day of Age

15. Change in vulva area during
prepubertal development
1400
1200
1000
Millimeters2
800
600
400
200
0
75 85 95 105 115
Day of Age

16. Prepubertal Follicle Development
12
No Follicle develoment
10
< 10 small follicles
Frequency
8
10->100 small follicles
6
4
2
0
75 85 95 105 115
Day of Age

17. Uterine Weight of Gilts Sacrificed
during Prepubertal Development
80
Uterine Weight (grams)
d
70 Day Effect P < 0.001
60 d
50
40 c
30 bc
20 ab
10
0
75 85 95 105 115
Day of Age

18. Distribution of Age of First Estrus
30
25
20
Frequency
15
10
5
0
Day of Age

19. Body weight association with puberty by
200 days
χ2 = .75 .57 .61 .78 .65
90
80
70 Estrus
60 No Estrus
Kilograms
50
40
30
20
10
0
75 85 95 105 115
Day of Age

20. Body weight at Day 75 is correlated to
age at first estrus
55
r = -0.217
50
Day 75 body weight (Kg)
P =0.055
45
40
35
30
25
135 155 175 195
Age of First Estrus

21. Body weight at Day 85 lacks
correlation to age at first estrus
r = -0.136
60 P = 0.23
Day 85 body weight (Kg)
55
50
45
40
35
30
135 155 175 195
Age of First Estrus

22. Body weight at Day 95 lacks
correlation to age at first estrus
70
r = -0.141
65
Day 95 body weight (Kg)
P = 0.22
60
55
50
45
40
135 155 175 195
Age of First Estrus

23. Body weight at Day 105 lacks
correlation to age at first estrus
80 r = -0.068
P = 0.55
Day 105 body weight (Kg)
75
70
65
60
55
50
135 155 175 195
Age of First Estrus

24. Body weight at Day 115 lacks
correlation to age at first estrus
90 r = -0.102
Day 115 body weight (Kg)
P = 0.37
85
80
75
70
65
60
135 155 175 195
Age of First Estrus

25. Relationship between body weight on
days 75 and 115 and puberty onset
90% 85%
80% 77% 77% 77%
72% 73% 180 69% 69%
70%
Percentage
60% 200 60%
60% 54%
50% 46%
40%
30%
20%
10%
0%
Top Quartile Two Quartiles
Middle Bottom Quartile Top Quartile Two Quartiles
Middle Bottom Quartile
r = -0.217 r = -0.102
P = 0.055 Day 75 Day 115 P = 0.37

26. Vulva Length association with puberty
by 200 days
χ2 = .97 .93 .10 .69 .47
50
40 Estrus
Millimeters
30 No Estrus
20
10
0
75 85 95 105 115
Day of Age

27. Vulva Width association with puberty
by 200 days
χ2 = .56 .74 .07 .24 .84
40
35 Estrus
30 No Estrus
Millimeters
25
20
15
10
5
0
75 85 95 105 115
Day of Age

28. Correlation between Vulva Width at
Day 75 to age at first estrus
35 r = -0.083
Day 75 Vulva Width (mm)
P = 0.46
30
25
20
15
10
140 150 160 170 180 190 200
Age of First Estrus

29. Correlation between Vulva Width at
Day 85 to age at first estrus
35 r = -0.118
Day 85 Vulva Width (mm)
P = 0.30
30
25
20
15
10
140 150 160 170 180 190 200
Age of First Estrus

30. Correlation between Vulva Width at
Day 95 to age at first estrus
40
r = -0.117
Day 95 Vulva Width (mm)
35
P = 0.31
30
25
20
15
140 150 160 170 180 190 200
Age of First Estrus

31. Correlation between Vulva Width at
Day 105 to age at first estrus
45 r = -0.20
Day 105 Vulva Width (mm)
P = 0.07
40
35
30
25
20
140 150 160 170 180 190 200
Age of First Estrus

32. Correlation between Vulva Width at
Day 115 to age at first estrus
45 r = -0.28
Day 115 Vulva Width (mm)
P = 0.01
40
35
30
25
20
140 150 160 170 180 190 200
Age of First Estrus

33. Vulva Area association with puberty by
200 days
χ2 = .56 .90 .10 .39 .64
1400
1200
Estrus
Millimeters2
1000
No Estrus
800
600
400
200
0
75 85 95 105 115
Day of Age

34. Correlation between Vulva Area at Day
75 to age at first estrus
1400
r = -0.075
Day 75 Vulva Area (mm2)
1200
P =0.51
1000
800
600
400
200
140 150 160 170 180 190 200
Age of First Estrus

35. Correlation between Vulva Area at Day
85 to age at first estrus
1200 r = -0.065
1100
P =0.56
Day 85 Vulva Area (mm2)
1000
900
800
700
600
500
400
300
200
140 150 160 170 180 190 200
Age of First Estrus

36. Correlation between Vulva Area at Day
95 to age at first estrus
1800 r = -0.119
Day 95 Vulva Area (mm2)
1600 P = 0.30
1400
1200
1000
800
600
400
200
140 150 160 170 180 190 200
Age of First Estrus

37. Correlation between Vulva Area at Day
105 to age at first estrus
2000
1800 r = -0.135
Day 105 Vulva Area (mm2)
1600
P = 0.24
1400
1200
1000
800
600
400
200
0
140 150 160 170 180 190 200
Age of First Estrus

38. Correlation between Vulva Area at Day
115 to age at first estrus
2000 r = -0.167
1800
P = 0.14
Day 115 Vulva Area (mm2)
1600
1400
1200
1000
800
600
400
200
0
140 150 160 170 180 190 200
Age of First Estrus

39. Vulva Area association with puberty by
180 days of age
< 1 St. Dev. Of Mean
Within or > 1 St. Dev of Mean
70%
Total
60%
50%
40%
30%
20%
10%
0%
75 85 95 105 115

40. Vulva Area association with puberty by
200 days of age
< 1 St. Dev. Of Mean
90% Within or > 1 St. Dev of Mean
80%
Total
70%
60%
50%
40%
30%
20%
10%
0%
75 85 95 105 115

41. Summary and Implications
• These data demonstrate an association between vulva
development on day 95 and ability to achieve puberty
by 200 days.
• Of those animals that achieved puberty by 200 days:
– body weight at day 75 and vulva width at days 105 and 115
were significantly correlated to age at first estrus.
• These developmental time-points represent specific
days in age that observations can be made to
distinguish gilts with high and low probability of
achieving puberty by 200 days of age.

42. Questions?