Reproduction Flashcards
When is the first ovulation and first ejaculation in GPs? At which weight does breeding onset occur?
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)
What is the length of the estrous cycle?
15-17 days
What is the gestation length? When does implantation occur?
59-72 days. Implantation 6-7 days postovulation
How fertile is postpartum estrus?
60-80%
What is the average litter size and litter interval?
2-5 piglets/litter. 96 day interval
When are piglets weaned?
At 180g (14-28 days)
What is the breeding life of a GP?
18 months to 4 years (4-5 litters)
What accessory sex glands do male GP possess?
Large, smooth seminal vesicles, prostate, coagulating glands, bulbourethral glands, and rudimentary preputial glands.
Describe teste placement.
Remain in inguinal pouches, inguinal canals are open for life.
Do GP have an os penis?
Yes
Describe the GP uterus.
Bicornuate with single os cervix.
Describe the vaginal closure membrane.
An epithelial structure that seals the vagina. Ruptures just before the onset of estrus and reforms after ovulation.
When should sows be bred? Why?
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.
Describe ovulation in GPs.
Spontaneous and polyestrous. Fertile post-partum estrus.
How many litters per year can a sow produce, on average?
5
What is an indicator of heavy breeding in sows?
Cessation of hair growth with patchy alopecia.
How long does estrus last?
16 days
What is the length of proestrus? What is it characterized by?
1-1.5 days. Vaginal swelling, rupture of vaginal closure membrane, increased activity, and vaginal smear of nucleated and cornified epithelial cells.
How long does estrus last? What is it characterized by?
8-11hr. Swollen, congested vulva, perforate vaginal membrane, and lordosis posture.
What is the length of metestrus and diestrus?
Metestrus: 3 days
Diestrus: 11-12 days
When does postpartum estrus occur?
2-10hr after parturition
How can estrus in sows be synchronized?
No evidence of cycle synchronization among group-housed sows. Synchronized with progesterone orally or as SQ implant
What behaviors indicate coital completion? Why item can be used as evidence of mating?
Grooming, scooting, and perianal marking by boar. Copulatory plug
What percentage of matings are fertile?
60-85%
What placentation type do GPs have? What model can GPs serve as related to placenta type?
Labyrinthine heomonochorionic, similar to humans. Model for repro toxicology studies.
How can pregnancy be detected?
Gentle palpation at day 15.
Radiographs and ultrasound by day 16
Abdominal distension with pubic symphysis separation of 3cm during the last week.
How are litter and gestation length connected?
Gestation length inversely related to litter size.
What hormone is responsible for the loosening of thfibrocartilaginous pelvic symphysis? What organ produces it? When?
Relaxin. Produced by placenta starting at day 30 and continuing to day 63.
Do sows build nests?
No
How quickly does parturition occur?
Pups delivered every 3-7min, with completion of parturition in 30 minutes.
What are large litters associated with?
Higher incidence of stillborn pups. Sows rarely eat stillborn pups.
What predisposes a sow to dystocia?
Obese sows, sows bred for the first time after fusion of the pubic symphysis, and sows with large fetuses.
Describe newborn GP pups.
Born precocious, with hair, teeth, and open eyes and ears. Begin to eat and drink within hours of birth.
Pups below what birth rate generally do not survive?
50 grams
When do young begin nursing?
Not in the first 24h.
What can cause pup mortality of up to 50%?
If pups are undersized or do not receive milk from a sow in the first 3-4 days.
What process are pups unable to carry out on their own?
Voluntary micturition from 7-14 days of age.
Does AI work in GP?
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.
What hormones are used for superovulation in GP?
Human menopausal gonadotropin and active immunization against the inhibin a-subunit.
How successful in embryo transfer in GP?
Rarely reported. One cause saw 2 live births/59 embryos in 10 females.
