Breeding Management in Swine Flashcards
They ovulate _______________ each estrus
15-30 oocytes producing 12-13 piglets
When do gilts reach puberty?
150-220 days
Factors influencing onset of puberty
Nutrition
Season/ lighting
Confinement
Boar exposure
Which hormones does boar exposure ↑?
GnRH leading to ↑ LH and E2
When should gilts be exposed to boars?
@ 150-170 days *
Early: 70 days of age
Boar Exposure duration
5- 30 minutes a day via physical contact
continuous exposure, gilt won’t come in heat
>70% gilts in heat in the next 28 days
How can greater response to boar exposure be obtained?
When combined with transportation (>1km) stress @160 days
Boar exposure + PG600 (or HCG)
↑ LH and FSH
More animals coming in heat in 5-10 dys after treatment
Pregnancy period
113-115 days (3m, 3w, 3d)
When is AI administered?
During 2nd or 3rd cycle (90%)
first cycle is silent, not fertile
Lactation anestrus period
Between 16-40 days in lactation
What happens during lactation anestrus?
LH suppressed due to suckling-induced inhibition of the GnRH-pulse generator
Due to suckling intensity, negative energy balance of sow and stress
Weaning to estrus interval
4-6 days
How long is the estrous cycle?
18-24 days
Luteal phase
15 days
Estrus phase
In standing heat, reflex immobility
Has 6-12 mm follicles
Pink, swollen vulva → 12 hr later breed gilt
Duration of estrus
40-60 hr
OV 44+/- 3 hr after onset of LH surge
Factors affecting estrus
Intensity of boar contact
Stress
Parity (shorter in gilts)
Weaning to estrous interval
Diestrus
CL reach final diameter 1 week after OV
Why don’t gilts use PGF2a?
PGF2a causes luteolysis @ 15 days but the CL is responsive already @ 12 days
Litter size
10-13
Fertility improvement post-weaning
Post-weaning follicle regression by:
1. Feed progesterone analogue at least 4 days post weaning
2. Inseminating sows @ 2nd estrus after weaning
Induction and control of the estrous cycle
eCG- estrus and ovulation induction
hCG- stimulate OV
PG600
PG600
Induction of puberty in gilts of 185 lbs and 5 months
Induction of gilts in estrus within 7 days from injection
What drug is used for synchronization?
Altrenogest (matrix)- most common
Tritptoreline gen (GnRH agonist)- AI 22 hrs post treatments
Altrenogest (matrix)
Only in pubertal cycle females (sows)
Fed for @ least 14 days individually
Estrous synchronization in pubertal and cyclic gilts
Progesterone
PG600
GnRH or hCG
Triptorelin
Stimulating the onset of estrous in prepubertal gilts
PG600
Boar exposure
Travel
Combination
Estrous synchronization in weaned sows
Synchronization estrus based on weaning time
Check for heat 4-6 days post weaning
Triptorelin
Where will AI be administered?
Cervix**
Tip of uterine horn (if little semen)
How much semen is used for AI?
50 mL in gilts
80 mL in sows
