Porcine Patterns- Lecture 17

Question 1

Boar anatomy

Answer 1

Fibroelastic penis.
Corkscrew shaped glans.
Pepucial diverticulum.
Caudally oriented testes.
No ampullae.

Question 2

Sow anatomy

Answer 2

Bicornuate uterus.
Paired ovaries.
Red corpora lutea.
Long, twisted cervix.

Question 3

Male repro stats

Answer 3

Puberty: 9 mon.
Spermatogenesis: 35 days.
Epididymal transport: 9-12 days.
Ejaculate volume: 150-300ml.

Question 4

Boar puberty

Answer 4

Average 9 months. Crossbred boards reach puberty quicker than purebred boars.
Testosterone leads to penile growth and mounting behavior.
Penile frenulum breaks down.

Question 5

Boar semen

Answer 5

Large volume: 150-300ml/ejaculate.
30-60 billion sperm/ejaculate.
Spermatogenesis: 35 days with 9-12 days for epididymal transport.
Ideal semen: >65% motile, >100k sperm/ml, <20% abnormal.

Question 6

Heat stress in boars

Answer 6

Affects semen quality. Ideal temperature in under 80% and 60% humidity. 7-14 days after heat stress: decreased motility, head and tail abnormalities, cytoplasmic droplets.

Question 7

Boar pheromones

Answer 7

5a-androstenone.
Bound to proteins in boar saliva.
Helps to stimulate estrus in sows, puberty in gilts, and mounting behavior in young boars.

Question 8

Female repro stats

Answer 8

Age of puberty: 6-7 mins.
Estrous cycle length: 21 days.
Ovulation from time of estrus onset: 36-44 hrs.
CL life span: 13-15 days.
Source of progesterone: CL only.

Question 9

Gilt puberty

Answer 9

6-7 months of age.
240-300 lbs.
“Boar effect”- helps stimulate puberty via pheromones.

Question 10

Sow estrous cycle

Answer 10

Non-seasonal polyestrus.
Slight decrease in fertility during late summer.
Cycle length- 21 days.
Single follicular wave.
Follicular estrogen causes standing heat (1-3 days).
Number of oocytes: 15-20.

Question 11

Flush feeding

Answer 11

Increase feed intake for two weeks before estrus in order to increase the number of oocytes.

Question 12

Sow if not pregnant…

Answer 12

the uterus releases PGF2a which naturally lyses CL and the sow can return to estrus.

Question 13

Estrus

Answer 13

“Standing heat”- sow allows mounting by the boar.
Back pressure test- firm pressure on back causes sow to show standing heat.
Average is 2-3 days.
Secondary signs- restlessness, frequent urination, ear cocking, red and swollen vulva, mucoid discharge.

Question 14

Gestational length

Answer 14

3 months, 3 weeks and 3 days,.

114 days total.

Question 15

Pregnancy

Answer 15

100% of oocytes are fertilized but up to 30% die within the first 30 days.
Embryos enter uterus 2-4 days after conception.
Migrate throughout for 2 weeks.
Implantation: day 14-18.
Embryos secrete estradiol day 10. Second E2 peak occurs after day 14.

Question 16

Uterine capacity

Answer 16

Uterus limits number of embryos that survives.

Question 17

Pregnancy maintenance

Answer 17

2 embryos per horn to maintain pregnancy up to 30 days.

Question 18

Farrowing

Answer 18

Parturition

Question 19

Litter size

Answer 19

11 pigs average

Question 20

Placenta type

Answer 20

Diffuse, epitheliochorial

Question 21

Epitheliochorial placenta (6 layers)

Answer 21

Fetal endothelial cells.
Fetal CT.
Chorionic epithelial cells.
Enodmetrial epithelial cells.
Maternal CT.
Maternal endothelial cells.

Question 22

Parturition

Answer 22

Occurs later afternoon or night.
On average takes 2-5 hours.
Deliveries in 15 minute intervals.
Placenta delivered within 4 hours.

Question 23

Pregnancy CL dependant

Answer 23

Treat sows 2 days before due date with PGF2a. Most will farrow within 36 hours. If no response within 24 hours, give oxytocin.

Question 24

Lactational anestrus

Answer 24

Most sows can’t cycle while nursing. Allow pigs to nurse for 21 days. When pigs are weaned the sow will return to estrus by 28 days post farrowing.

Question 25

Weaning

Answer 25

Sows weaned during summer take longer to return to estrus (decreased feed intake).
Ensure sow has adequate nutrition during weaning- subsequent litters may be smaller.