Reproduction

Question 1

When is the first ovulation and first ejaculation in GPs? At which weight does breeding onset occur?

Answer 1

Female: First ovulate at 4-5 weeks, breeding onset at 350-450g (2-3 months)
Male: First ejaculation at 8-10 weeks, breeding onset at 600-700g (3-4 months)

Question 2

What is the length of the estrous cycle?

Answer 2

15-17 days

Question 3

What is the gestation length? When does implantation occur?

Answer 3

59-72 days. Implantation 6-7 days postovulation

Question 4

How fertile is postpartum estrus?

Answer 4

60-80%

Question 5

What is the average litter size and litter interval?

Answer 5

2-5 piglets/litter. 96 day interval

Question 6

When are piglets weaned?

Answer 6

At 180g (14-28 days)

Question 7

What is the breeding life of a GP?

Answer 7

18 months to 4 years (4-5 litters)

Question 8

What accessory sex glands do male GP possess?

Answer 8

Large, smooth seminal vesicles, prostate, coagulating glands, bulbourethral glands, and rudimentary preputial glands.

Question 9

Describe teste placement.

Answer 9

Remain in inguinal pouches, inguinal canals are open for life.

Question 10

Do GP have an os penis?

Answer 10

Yes

Question 11

Describe the GP uterus.

Answer 11

Bicornuate with single os cervix.

Question 12

Describe the vaginal closure membrane.

Answer 12

An epithelial structure that seals the vagina. Ruptures just before the onset of estrus and reforms after ovulation.

Question 13

When should sows be bred? Why?

Answer 13

Large enough to bear a litter, but before calcification of the fibrocartilaginous pubic symphysis (between 6 and 9 months of age). GP that give birth for the first time after fusion are prone to dystocia.

Question 14

Describe ovulation in GPs.

Answer 14

Spontaneous and polyestrous. Fertile post-partum estrus.

Question 15

How many litters per year can a sow produce, on average?

Answer 15

5

Question 16

What is an indicator of heavy breeding in sows?

Answer 16

Cessation of hair growth with patchy alopecia.

Question 17

How long does estrus last?

Answer 17

16 days

Question 18

What is the length of proestrus? What is it characterized by?

Answer 18

1-1.5 days. Vaginal swelling, rupture of vaginal closure membrane, increased activity, and vaginal smear of nucleated and cornified epithelial cells.

Question 19

How long does estrus last? What is it characterized by?

Answer 19

8-11hr. Swollen, congested vulva, perforate vaginal membrane, and lordosis posture.

Question 20

What is the length of metestrus and diestrus?

Answer 20

Metestrus: 3 days
Diestrus: 11-12 days

Question 21

When does postpartum estrus occur?

Answer 21

2-10hr after parturition

Question 22

How can estrus in sows be synchronized?

Answer 22

No evidence of cycle synchronization among group-housed sows. Synchronized with progesterone orally or as SQ implant

Question 23

What behaviors indicate coital completion? Why item can be used as evidence of mating?

Answer 23

Grooming, scooting, and perianal marking by boar. Copulatory plug

Question 24

What percentage of matings are fertile?

Answer 24

60-85%

Question 25

What placentation type do GPs have? What model can GPs serve as related to placenta type?

Answer 25

Labyrinthine heomonochorionic, similar to humans. Model for repro toxicology studies.

Question 26

How can pregnancy be detected?

Answer 26

Gentle palpation at day 15.
Radiographs and ultrasound by day 16
Abdominal distension with pubic symphysis separation of 3cm during the last week.

Question 27

How are litter and gestation length connected?

Answer 27

Gestation length inversely related to litter size.

Question 28

What hormone is responsible for the loosening of thfibrocartilaginous pelvic symphysis? What organ produces it? When?

Answer 28

Relaxin. Produced by placenta starting at day 30 and continuing to day 63.

Question 29

Do sows build nests?

Answer 29

No

Question 30

How quickly does parturition occur?

Answer 30

Pups delivered every 3-7min, with completion of parturition in 30 minutes.

Question 31

What are large litters associated with?

Answer 31

Higher incidence of stillborn pups. Sows rarely eat stillborn pups.

Question 32

What predisposes a sow to dystocia?

Answer 32

Obese sows, sows bred for the first time after fusion of the pubic symphysis, and sows with large fetuses.

Question 33

Describe newborn GP pups.

Answer 33

Born precocious, with hair, teeth, and open eyes and ears. Begin to eat and drink within hours of birth.

Question 34

Pups below what birth rate generally do not survive?

Answer 34

50 grams

Question 35

When do young begin nursing?

Answer 35

Not in the first 24h.

Question 36

What can cause pup mortality of up to 50%?

Answer 36

If pups are undersized or do not receive milk from a sow in the first 3-4 days.

Question 37

What process are pups unable to carry out on their own?

Answer 37

Voluntary micturition from 7-14 days of age.

Question 38

Does AI work in GP?

Answer 38

Yes. Sperm collected via electroejaculation or collection from vasa deferentia and epididymides. Place in vagina, intraperitoneal, directly into uterine horns, and endoscope-guided transcervical insemination. Up to 16h postestrus.

Question 39

What hormones are used for superovulation in GP?

Answer 39

Human menopausal gonadotropin and active immunization against the inhibin a-subunit.

Question 40

How successful in embryo transfer in GP?

Answer 40

Rarely reported. One cause saw 2 live births/59 embryos in 10 females.