Lecture 17: Porcine Reproduction (McNaughten) Flashcards
barrow =
castrated male
boar =
intact male
sow =
female pig
gilt =
young female that has not had a litter
farrowing =
parturition
piglet =
offspring
describe the cervix of the sow:
long and twisted. it has a corkscrew configuration and a left-handed turn. this adaptation is for the glans penis to interlock and place itself directly into the cervix.
what color are CLs in the sow? this is a unique trait in sows!
RED!
CLs are usually yellow
describe uterine horns in sow
they are long, torturous, and convulted.
“ribbon-like” was a description on last year’s exam!
what is the normal shape of the vulva?
dorsally tilted
“skytipped” or “fishooked” may be male psuedohermaphrodite
how many mammary glands should a sow have?
minimum of 12 teats, with at least 10 being functional
nipple abnormalities - we spoke about 2:
- inverted nipples = hereditary
2. blind nipples = acquired (when the sow is a little too fat and there is a fat pad around the teats)
where is the sigmoid flexure located in the pig?
pre-scrotal sigmoid flexure
bull is post
describe penis in the boar
its fibroelastic, has a corkscrew shaped glans
function of preputial diverticulum
it is a bi-lobed sac located dorsally to prepuce; meant to lubricate the penis prior to intermission.
describe the position of the testis in the boar
non-pedulous
- caudally oriented
what is the orientation of the epididymis?
head, body, tail - dorsally oriented
accessory sex glands in the boar
boar has: prostate, vesicular glands, bulbourethral glands
ampullae are not present
when do piglets reach puberty? how can they reach puberty faster?
9 months
crossbred boars mature sooner than purebred boars
they mature faster with increased daylight
what is the frenulum in the boar?
it is piece of tissue or mucous membrane that physically prevents the male from using the penis
what physical and behavioral changes does testosterone have on the boar?
growth of penis - development of sigmoid flexure, breakdown of frenulum
mounting behavior
Name the pheromone that elicits the “boar effect.” Describe the “boar effect.”
boars emit a pheromone bound to protein in saliva called 5a-Androsterone
“boar effect” = stimulates puberty in gilts, elicits estrus in sows, encourages mounting behavior in young boars
spermatogenesis in pigs takes how many days? how many days for epididymal transport?
spermatogenesis = 35 days
epididymal transport = 9 - 12 days.
when do female piglet to hit puberty?
6- 7 months
what type of estrous cycle do sows have?
non-seasonally polyestrous
how many days is the estrous cycle in the sow?
21 days
how many follicular waves does the sow have?
just ONE!
this is unique to the pig!
how can you tell when a sow is in heat? how long will they be in heat for?
they will stand to be mounted due to estrogen influence. will be in heat for an average of 2 - 3 days
what are the secondary signs to tell if they are in heat?
restlessness during feeding, not settling down after feeding, frequent small urination, red swollen vulva with mucoid discharge
breeding methods (there are 3)
pen mating - allow boar to mate female
hand breeding
AI (insert 80 ml into cervix, lock into place and she sucks semen into uterus)
at what point does ovulation occur in the estrous cycle?
2/3 of way through estrus
how many mature ova are released? how can this be enhanced?
15 - 20!!
can enhance by “flush feeding” - increasing sow’s diet 2 weeks prior to ovulation
when is the CL functional?
5 - 6 days after estus.
how many oocytes are fertilized?
100%
what determines how many embryos survive?
“uterine capacity” - the size of the uterus
when do embryos enter the uterus? what is the significance of this?
at day 4.
this is vital in maternal recognition of pregnancy
when does implantation occur?
day 14 - 18
what hormone is essential for pregnancy recognition in the sow?
when is it secreted?
estradiol.
1st secreted: 10 - 11 days
2nd increase in estradiol occurs: 14 days
when is PGF2-alpha released if sow fails to get pregnant?
day 13 - 15
how is luteolysis inhibited in the sow?
high estrogen levels alter the PGF2alpha pathway.
- increases PGE2 and maintains lutenizing hormone receptors in CL which is important because CL maintains pregnancy through its release of progesterone.
how many embryos are needed in each horn to maintain pregnancy?
a minimum of two embryos per horn up to day 30
after day 30, how many embryos are required to maintain pregnancy?
2 live embryos
what type of placenta does the sow have?
epitheliochorial - has all 6 layers
what is the placentation of the sow?
epitheliochorial, non-deciduate, diffuse
what is unique about the placentation of the sow?
it has necrotic tips - degeneration of placentation where fetuses met and becomes a fibrotic area.
how is pregnancy diagnosed in sows? two different ways
- ultrasound
2. traditionally - just waited for sow to return to estrus
what is the gestation length of the sow?
114 days
just remember: 3 months - 3 weeks - 3 days
333
what is the average litter size?
11
what is the source of progesterone in sows?
the CL!
how is parturition handled in sow?
we induce it with PGF2alpha 2 days before due date (most will farrow in 36 hours)
we do this to be sure we are present for farrowing to increase the survival rate of pigs.
when do most sows farrow? how long does it take?
in the late afternoon and night
-> 2 - 5 hours
when are placentas passed?
all placentas are passed within 4 hours after the last pig. may also occur once each horn is emptied.
how long are the intervals per piglet?
about 15 minutes
when do mammary glands begin developing?
not until day 75 of gestation
do sows cycle while nursing?
most sows do not - they experience lactational anestrus
how long do piglets nurse for? what does it allow for?
21 days - allows for uterine involution
when are pigs weaned?
28 days post farrowing
how is weaning different during the summer?
sows may take longer to return to estrus because of the reduced food intake during the summer. so it is important to ensure adequate nutrition during the summer to help sow return to estrus.
