C4: Reproduction features and traits of swine (prolificacy)

Question 1

when does puberty take place in pigs?

Answer 1

5 - 7motnhs

Question 2

when does the first breeding take palce in pigs?

Answer 2

8 - 9 months or at 90 - 100kg body mass

Varies greatly depending on breed, sex & nutrition

Question 3

at what age does the first farrowing occur

Answer 3

◦ Age @ 1st farrowing ~12-14 months

Question 4

which is more important in terms of breeding; genital development or weight?

Answer 4

Genital development & maturity is more important than weight!

Question 5

are the main reproduction features of swine?

Answer 5

• Early puberty
• Pluripary — wide range in litter size
• Continuous breeding
• 1st heat often silent (~ 5-6 months)
• Pheromonal effects & biostimulation are important

Question 6

what is there a negative correlation btw in terms of reproduction features?

Answer 6

Negative correlation between intensive feeding & rapid weight gain (STH) & sexual development (FSH, LH)

Question 7

how long is the ovarian cycle?

Answer 7

18 - 23 days

Question 8

how many phases are in teh ovarian cycle?

Answer 8

biphasic: 2 phases
follicular and luteal phase

Question 9

how many eggs are released?

Answer 9

polyovulation
15 - 20 eggs –> (embryonic & perinatal losses may be up to 10-30 %)
spontaneous release of eggs

Question 10

what are frequent disorders of the ovulatory cycle?

Answer 10

◦ Anovulatory cycles,
delayed ovulation,
persistence of follicles,
ovarian cysts.

Question 11

how long does heat last in sows?

Answer 11

2 - 3 days

Question 12

what are the symptoms of heat?

Answer 12

◦ Restlessness
◦ Swollen genitals
◦ Mucous discharge
◦ Frequent urination
◦ Mounting other sows

Question 13

how can farmers detect heat?

Answer 13

• Immobilization/ back pressure test → heat detection

Question 14

when does mating or AI occur and how often?

Answer 14

• Mating / insemination is performed prior to or around ovulation (2x in 24 hours).
• Usually occurs 36 - 40 hours after the first sign of heat.

Question 15

how long is the gestation period of sows?

Answer 15

114 ays

Question 16

how is gestation maintained in sows?

Answer 16

• Maintained by PPL (porcine placental lactogen)

Question 17

what are common disadvantages during gestation?

Answer 17

• Frequent fetal atrophy (natural embryonic selection)
• Sensitivity to stressors

Question 18

what is peritoneal dialysis and when can it occur?

Answer 18

removal of content form the abdomen.

abdominal pregnancy = rare, life-threatening condition defined as pregnancy in the peritoneal cavity exclusive of tubal, ovarian or intraligamentary locations) –> when embryo escapes fallopian tube.

Question 19

how can pregnancy be confirmed?

Answer 19

◦ Rectal palpitation
◦ Sonography
◦ Hormonal methods (oestrogen – sulphate in blood)

Question 20

how long does lactation last?

Answer 20

28 days

Question 21

when does weaning occur?

Answer 21

→ Weaning can be early or late (commonly ~ 25-42 days)

Question 22

when does heat occur after weaning?

Answer 22

→ Heat occurs ~ 7 days after weaning
allows rebreeding of sow

Question 23

what are the hereditary & Environmental Factors Influencing Production & Litter Size?

Answer 23

• Hereditary: Genetic basis for prolificacy (Meishan), Estrogen & prolactin receptor.
• Environmental: Feeding –> Flushing may increase fertility (weaning + flushing = heat within 10-day period).
• Hormonal factors can be used to regulate or stimulate sexual functions.

Question 24

what are the causes of fetal atrophy?

Answer 24

• Hereditary
• Chromosomal abnormalities
• Lethal factors
• Overcrowding
• Limited uterine surface for fetal nutrition
• Incomplete nutrition during gestation
• Overweight animals