Breeding Management in Swine

Question 1

They ovulate _______________ each estrus

Answer 1

15-30 oocytes producing 12-13 piglets

Question 2

When do gilts reach puberty?

Answer 2

150-220 days

Question 3

Factors influencing onset of puberty

Answer 3

Nutrition
Season/ lighting
Confinement
Boar exposure

Question 4

Which hormones does boar exposure ↑?

Answer 4

GnRH leading to ↑ LH and E2

Question 5

When should gilts be exposed to boars?

Answer 5

@ 150-170 days *
Early: 70 days of age

Question 6

Boar Exposure duration

Answer 6

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

Question 7

How can greater response to boar exposure be obtained?

Answer 7

When combined with transportation (>1km) stress @160 days

Question 8

Boar exposure + PG600 (or HCG)

Answer 8

↑ LH and FSH
More animals coming in heat in 5-10 dys after treatment

Question 9

Pregnancy period

Answer 9

113-115 days (3m, 3w, 3d)

Question 10

When is AI administered?

Answer 10

During 2nd or 3rd cycle (90%)
first cycle is silent, not fertile

Question 11

Lactation anestrus period

Answer 11

Between 16-40 days in lactation

Question 12

What happens during lactation anestrus?

Answer 12

LH suppressed due to suckling-induced inhibition of the GnRH-pulse generator
Due to suckling intensity, negative energy balance of sow and stress

Question 13

Weaning to estrus interval

Answer 13

4-6 days

Question 14

How long is the estrous cycle?

Answer 14

18-24 days

Question 15

Luteal phase

Answer 15

15 days

Question 16

Estrus phase

Answer 16

In standing heat, reflex immobility
Has 6-12 mm follicles
Pink, swollen vulva → 12 hr later breed gilt

Question 17

Duration of estrus

Answer 17

40-60 hr
OV 44+/- 3 hr after onset of LH surge

Question 18

Factors affecting estrus

Answer 18

Intensity of boar contact
Stress
Parity (shorter in gilts)
Weaning to estrous interval

Question 19

Diestrus

Answer 19

CL reach final diameter 1 week after OV

Question 20

Why don’t gilts use PGF2a?

Answer 20

PGF2a causes luteolysis @ 15 days but the CL is responsive already @ 12 days

Question 21

Litter size

Answer 21

10-13

Question 22

Fertility improvement post-weaning

Answer 22

Post-weaning follicle regression by:
1. Feed progesterone analogue at least 4 days post weaning
2. Inseminating sows @ 2nd estrus after weaning

Question 23

Induction and control of the estrous cycle

Answer 23

eCG- estrus and ovulation induction
hCG- stimulate OV
PG600

Question 24

PG600

Answer 24

Induction of puberty in gilts of 185 lbs and 5 months
Induction of gilts in estrus within 7 days from injection

Question 25

What drug is used for synchronization?

Answer 25

Altrenogest (matrix)- most common
Tritptoreline gen (GnRH agonist)- AI 22 hrs post treatments

Question 26

Altrenogest (matrix)

Answer 26

Only in pubertal cycle females (sows)
Fed for @ least 14 days individually

Question 27

Estrous synchronization in pubertal and cyclic gilts

Answer 27

Progesterone
PG600
GnRH or hCG
Triptorelin

Question 28

Stimulating the onset of estrous in prepubertal gilts

Answer 28

PG600
Boar exposure
Travel
Combination

Question 29

Estrous synchronization in weaned sows

Answer 29

Synchronization estrus based on weaning time
Check for heat 4-6 days post weaning
Triptorelin

Question 30

Where will AI be administered?

Answer 30

Cervix**
Tip of uterine horn (if little semen)

Question 31

How much semen is used for AI?

Answer 31

50 mL in gilts
80 mL in sows