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Thank you for participating in SowBridge 2014-2015.
To start this presentation, advance one slide by pressing enter or the
down or right arrow key.
Gilt Development
W.L. (Billy) Flowers
Alumni Distinguished Professor
Department of Animal Science
North Carolina State University
Raleigh, N.C. 27695-7621
919-515-4003
Developmental Period
2 2
It would be useful to know to what
degree management during the
Developmental and Functional Periods
influence longevity;
3 3
Gestation management – birth weight
Lactation management – pre-weaning growth
Comprehensive management – early puberty
4 4
Some aspects of fetal development
probably respond the same way to competition
as pig growth in “crowded pens”.
6 developing fetuses 12 developing fetuses
5 5
0.24
0.20
0.16
0.12
0.08
Org
an
We
igh
t (lb
s)
0 1.0 2.0 3.0 4.0
Birth Weight (lbs)
Relationships between Piglet Birth Weights and Organ Weights
0.00
(Adapted from Foxcroft et al., 2009)
Small
Intestines
Liver
Brain
6 6
Piglet Birth Weight (lbs)
Reproductive
Performance 2.0 – 2.5 > 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
Birth Weight and Reproductive Performance of Gilts
(Flowers, unpublished)
7 7
< 7 pigs nursing > 10 pigs nursing 8
8
Fem
ale
s r
em
ain
ing in p
roduction (
%)
E = Entry
B = Breeding - gilts
F = Farrowing
R = Rebreeding
Effect of Neonatal Lactation Litter Size on Sow Longevity
90
(Flowers et al., in press)
80
70
60
50
40
30
20
10
F1
100
0
R1 F2 R2 F3 R3 F4 R4 F5 R5 F6 E B
Production phase
p < 0.05 *
* * * * * * * *
* *
< 7 piglets
> 10 piglets
9 9
Farr
ow
ing rate
(%
)
90
80
70
60
2
100
0
3 4 5 61
Sow ParityN
um
ber B
orn
Aliv
e
11
10
9
2
12
0
3 4 5 61
Sow Parity
> 10 piglets (10.5 + 0.2)
< 7 piglets (11.0 + 0.1)
p < 0.07
> 10 piglets (83.3%)
< 7 piglets (88.7%)
p < 0.05
Reproductive Performance and Neonatal Litter Size
10 10
Sow
s t
hat
pro
duced
6 litte
rs (
%)
Interactions between Birth Weight and Neonatal Litter Size
(Flowers, unpublished)
40
30
20
10
50
0
2.6 – 3.5 lbs > 3.6 lbs < 2.5 lbs
Birth Weight Categories
> 10 piglets
< 7 piglets
p < 0.05
*
*
*
11 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 12
Pre-weaning growth and pre-weaning growth relative
to birth weight appear to have positive associations
with sow longevity and lifetime productivity
13 13
14 14
LH, FSH
Estrogens
+
15 15
Effect of Early Puberty on Herd Retention through 3 Parities
Patterson et al., 2010
EP < 153 days
IP 154 – 167 days
LP 168 – 180 days
NS > 180 days
16 16
0 5 10 15 20 25 30 35 40 45 50 55 60
Nu
mber
of
Gilt
s in
Estr
us 50
40
30
20
10
0
Days from Onset of Boar Exposure
140 160 180 200
Gilt Response to Boar Exposure at 140 days of age
17 17
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
(Flowers et al., in press)
*
*
†
†
p < 0.08 p < 0.05
18 18
Early puberty is an excellent cumulative measure of manage-
ment during the developmental period.
Gilts that respond early to boar exposure typically are have
enhanced productivity and longevity in herds.
19 19
WeaningRebreeding
Interval
Farrowing
Gestation
Lactation
Breeding
FunctionalPeriod
20 20
Low Longevity Farm
8% sows farrow 6 litters
High Longevity Farm
28% sows farrow 6 litters
Significant differences exist among farms in sow longevity in
the same system and multiplication flow.
Farms have same genetics, feed, standard operating
procedures and often are located in the same or
adjacent counties.
21 21
Low Longevity Farm
8% sows farrow 6 litters
High Longevity Farm
28% sows farrow 6 litters
Standardized developmental period
management and sent cohorts of
litter mates to commercial farms
with different sow longevities.
Multiplication Farm
22 22
Gilts arrived at farms at 200 days of age and 250 lbs.
Standard operating procedures for both farms are as follows:
• housed in pens;
• daily direct contact with boars;
• heat/no serve (bred at least second detected estrus);
• separate gilts with recorded estrus from non-estrus pool;
• bred once each day of estrus; and
• 2 weeks after last insemination moved to gestation crate.
Average breeding age and weight were 240 days and 290 lbs.
Entry of Gilts on Farms and First Breeding
23 23
High Low
Longevity Longevity
Gilts delivered to farm that are not bred 7% 18%
Gilts per pen (12 ft x 12 ft) 8 10
High/Low temperatures in barn (oF) 84/68 83/64
Designated person – gilt estrus/breeding Yes No
Gilt estrus/breeding separate from sows Yes Yes
Daily boar exposure per pen (min) 15 15
Heat, check boars – age (months) 14 > 24
Heat, check boars – libido good moderate
Periodically collect heat check boars Yes No
Entry of Gilts on Farms until First Breeding – Farm Comparisons
24 24
Fem
ale
s r
em
ain
ing in p
roduction (
%)
E = Entry
B = Breeding - gilts
F = Farrowing
R = Rebreeding
Female Inventory Changes through Rebreeding after First Parity
90
80
70
60
50
40
30
20
10
F1
100
0
R1 F2 R2 F3 R3 F4 R4 F5 R5 F6 E B
Production phase
p < 0.05 *
*
Low Longevity
*
High Longevity * *
25 25
Normal estrous cycles – missed estrus
Corpora Lutea / Corpora Albicantia
26 26
Previous ovulations, but stopped exhibiting normal cycles
Corpora Albicantia / No Corpora Lutea
27 27
Never Ovulated / Infertile
No Corpora Albicantia / No Corpora Lutea / Avascular
28 28
15
10
0
20
5
Perc
enta
ge
Missed Estrus /
Stopped Cycling
Total difference
in Longevity
Infertile
Gilts
Gilts
not bred
Relative Contributions of Factors to Sow Longevity
Differences between High ( ) and Low ( ) Farms
29 29
15
10
0
20
5
Perc
enta
ge
Missed Estrus /
Stopped Cycling
Total difference
in Longevity
Developmental 20%
Relative Contributions of Factors to Sow Longevity
Differences between High ( ) and Low ( ) Farms
Gilts
not bred
6.8%
11% 1.3% 2.5%
Infertile
Gilts
Developmental Functional
30 30
Need to be recording birth weights of potential replacement
gilts and develop strategies to identify early puberty
attainment.
Routine evaluation of reproductive organs of culled gilts/sows
is an extremely important tool that is grossly underutilized.
Summary and Suggestions
31 31
Animal-to-animal contact is the best way to provide boar
exposure to stimulate gilts (and sows).
Management of boars used for estrus detection and stimulation
deserves more attention that it has currently received.
There may be some advantages in developing breeding barn
employees to manage replacement gilts.
Summary and Suggestions
32 32
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
33
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