Induction and Synchronization of Estrus in Prepubertal gilts Dr. Rob Knox University of Illinois 1 Induction and Synchronization of Estrus in Prepubertal gilts Rob Knox Department of Animal Sciences University of Illinois, Champaign-Urbana, IL USA 61801 Feb. 28 th 2011 Puberty the real story • Pubertal estrus – Can be hit or miss – may be spread over >60 days – Some never express puberty – Variable symptoms of heat • (standing is strong or weak, vulval swelling) Percent of 120 farms reporting problems with infertility in a 2007 sow survey (220,000 sows) 0 10 20 30 40 50 60 Sows bred within 7 days Irregular returns Regular returns Gilt estrus NIP Irregular estrus intervals Low born alive No decline Multiple matings Abort Stillborns Mummies % of farms Reasons
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Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 1
Induction and Synchronization of Estrus in Prepubertal gilts
Rob Knox
Department of Animal Sciences
University of Illinois,
Champaign-Urbana, IL USA 61801
Feb. 28th 2011
Puberty the real story
• Pubertal estrus – Can be hit or miss
– may be spread over >60 days
– Some never express puberty
– Variable symptoms of heat • (standing is strong or weak, vulval swelling)
Percent of 120 farms reporting problems with infertility in a 2007 sow survey (220,000 sows)
0 10 20 30 40 50 60
Sows bred within 7 days
Irregular returns
Regular returns
Gilt estrus
NIP
Irregular estrus intervals
Low born alive
No decline
Multiple matings
Abort
Stillborns
Mummies
% of farms
Rea
son
s
Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 2
Maturation occurs over time but can be influenced by factors in proportions of gilts
0102030405060708090
100
50 75 100 125 150 175 200 225 250
Per
cen
t
Days of Age
Med Foll
LH Pulses
There are limited methods to induce estrus in swine within a week but techniques can be additive
ITEM INDUCTION RESPONSE
• Boar exposure 20-40%
• Relocation stress 5-10%
• Regroup stress 5-10%
• Hormones 50-90%
Age at Puberty in BreedsRange may be more appropriate
Breed (1951-2000)C. White 201-259P. China 198-216Yorkshire 199- 210-249Landrace 173Large White 211Hampshire 207Duroc 224PietranSynthetics/cross 200-225Meishan 90
Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 3
Genetic Influence on ReproductionNPPC Maternal Line Project
Genetic % Age at 1st %
Line bf 1st estrus estrus farrowing
American diamond .79 91 225 77
Danbred USA .56 87 222 77
Dekalb Monsanto DK44 .70 87 222 75
Dekalb Monsanto MXP200 .71 97 209 92*
Natl. Swine Reg (Y x L) .66 90 222 77
Newsham Hybrids USA .58 88 223 78
Estrus detection: Moved from pens of 25 into crated 1600 sows facility at 180 d and exposed to a V boar 2/x /d
Moeller et al., JAS 2004 82: 41-53
-GROWTH RATE
Growth rate and pubertal estrus + BE at 140 d
Foxcroft, 2005 from Beltranena 1991
Select for >600 g/d
Gilt estrus is unique
• Females very sensitive and aware of humans– Perform routine to get them accustomed
– Allow more time and patience
– Be consistent in daily process
• May go off feed
Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 4
To improve consistency
– Use record sheet to aid the process• Females can be tracked across cycles
• Patterns can be revealed
A record sheet example
i.d. day day day day day day
am pm am pm am pm am pm am pm am pm
Gilt 1 - - -R -R +R +R ++R ++R E E E -
Gilt 2 + + + - - -R - + + - -
Gilt 3 - - - - - - - - - + + +R
Gilt 4 + + + + +E + + + + + + +
Gilt 5 - - + + + +R +R +R E E - -
Vulval swelling scoresSwelling (none (-), some (+), evident (++)Red color (-R), (+R)
Boar Exposure Factors
• Choices– Pens or Stalls
• Move – Boar to gilts– Gilts to boar
• Physical vs. Fenceline• Frequency• Duration • Age to start
Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 5
Number of gilts per day showing estrus after stimulation with direct boar contact from 160 d
From: Foxcroft, 2004
0102030405060708090
100
140 160 180 200 220 240 260
cum
mul
ativ
e es
tru
s (%
)
Days of age
140
160
190
210
What age to start boar exposure ?
How often to apply boar contact for puberty
0
10
20
30
40
50
60
Jan May Oct
day
s
Month at start of boar exposure
0 d / week
2 d/week
5 d / week
7 d/ week
Paterson et al., 1989; Anim. Reprod. Sci. 21:115-124
Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 6
Dept. of Animal Sciences, University of Illinois
Watch for unintended boar exposure -Estrus Detection Test-
(3 min test)
3 ft Alley
Boar
Gilts
Opposite
BoarGilts
Adjacent
Boar
Gilts
Isolated
Tilbrook & Hemsworth, 1990
Duration of daily boar exposure on puberty
0
10
20
30
40
50
60
70
0 2 10 30
day
s
Minutes of exposure/day
Paterson et al., 1989; Anim. Reprod. Sci. 21:115-124
Effect of once or twice daily Boar exposure on Puberty
0
20
40
60
80
100
120
0 10 20 30 40
% e
stru
s
Days to estrus
1X
2X
Induction and Synchronization of Estrus in Prepubertal gilts
Dr. Rob Knox University of Illinois 7
Effect of Type of Boar Exposure On Accumulative Estrous Expression
Zimmerman et al., 1998
0
20
40
60
80
100
120
10 20 30 40 50 60 70 80
Cu
mm
ula
tive
Est
rus
(%)
Day of age
FBE-2x
FBE-1x
PBE-2x
PBE-1x
160 d exposure, 10 min/day
Effect of Transportation and Boar Exposure on Gilt Puberty
Control Transport 1X BE 1X BE + T
Pubertal 29% 0 25% 56%
AAP 186 - 179 187
Hughes et al, 2007 ARS 46:159-65
Percent of gilts pubertal and days to puberty in response to LIBIDO