Section 5: Swine Flashcards
what are the functions of the swine uterus?
sperm transport
environment for pre-attachment embryo
maternal contribution for the placenta
expulsion of the fetus and fetal placenta
luteolysis and control of the estrous cycle
what promotes prostaglandin (PGF2alpha) synthesis by the uterine endometrium?
oxytocin from endometrium, posterior pituitary, and corpus luteum
how large is the swine cervix?
up to 20cm in length
what does the swine cervix contain?
interdigitating prominences
do swine ovaries have multiple ovulations?
yes
multi-ovulatory ovaries
how large does the ovarian follicle grow before ovulation in swine?
8-12mm in diameter
where does ovulation occur in the swine ovary?
random locations
what is produced from the ovary that contributes to estrus behavior and morphologic changes in the reproductive tract?
estradiol
what type of breeders are sows?
nonseasonal polyestrous breeders
what percentage of USA swine farms use artificial insemination?
90%
when does the first AI tend to be performed on gilts?
second or third cycle
how long does pregnancy last in the sow?
113-115 days
what is the weaning to estrus interval in sows? how is this useful?
4-6 days
weaning can be used to synchronize estrus
how many oocytes do sows ovulate each estrus?
15-30 oocytes
there are lower farrowing rates for sows mated during ___________________________
late summer through fall
why are there lower farrowing rates for sows mated during late summer to fall?
increased postweaning anestrus
decreased conception rate
decreased boar fertility
how long does the corpus luteum last in the sow?
about 14 days
what is luteolysis caused by?
PGF2alpha from the uterus
when does the corpus luteum respond to exogenous prostaglandin?
only after day 11-12
do not use prostaglandin to synchronize estrus
how long is the sow proestrus?
long
4 days: luteolysis to estrus
how long is the sow estrus?
1-4 days
2 days: owner detected
3-4 days in presence of boar
when are sows bred?
first and second day of estrus
when do most sows ovulate?
second day of estrus
36-44 hours after onset of estrus
sows may ovulate ______________ follicles
10 to 25+
when does puberty occur in gilts?
6 months
200 days
when are gilts bred?
7 months
second or third estrus: first estrus fertility low
when does a gilt farrow?
11 months old
what factors influence the onset of puberty in gilts?
age
nutrition
body weight
season/lighting
confinement
boar exposure
how does confinement affect the age of puberty?
confinement/crowding increases stress a little, which leads to earlier onset of puberty
how can the first estrus be induced in gilts?
hormonal manipulation: stimulate follicle growth or modulate luteal function
what things may delay puberty?
long days
high ambient temperature
restricted diet
small group size
fewer than 4 gilts in a pen
________ generally have a higher ovulation rate than ________
sows
gilts
when does the ovulation rate of gilts increase?
over first four estrus periods
what is the cardinal sign of heat detection?
“standing” to back pressure
best if boar is present
“boar-mate”
what are the non-cardinal signs of heat detection in the sow?
restlessness
boar seeking
swollen, red vulva
mucous discharge
what accessory sex glands do boars have?
vesicular gland
prostate gland
bulbourethral gland
what accessory sex gland do boars not have?
ampulla
what accessory sex gland contributes the bulk of the seminal volume?
vesicular gland
what type of penis does the boar have?
fibroelastic with sigmoid flexure
corkscrew-shaped glans penis
where are the boar testes located?
immediately ventral to the anus
what is the volume of the boar ejaculate?
100-300ml
greatest volume of all domestic species
how many sperm are in a boar’s ejaculate?
30-55 billion sperm/ejaculate
what day do the embryos enter the uterus?
day 3
what day do the embryos migrate to evenly space out in the uterus?
after day 7
when does maternal recognition of the fetuses occur in the sow?
day 11-12
how many embryos must be present for maternal recognition of pregnancy in the sow?
at least 2 embryos in each horn
when do crowded embryos die in the sow?
after day 30
how does maternal recognition of pregnancy occur in the sow?
estradiol causes prostaglandin to be rerouted into uterine lumen
PGF2alpha destroyed in uterine lumen, preventing it from entering circulation and luteinizing the corpus luteum
when do swine embryos start to attach?
day 14
what type of placenta is the swine placenta?
diffuse epitheliochorial placenta
how long does stage two of parturition last in the sow?
1-6 hours
how long does the average lactation last in the sow?
4 weeks
can you breed a sow while she is nursing?
no- anestrus
when are sows bred?
5 days after piglets removed
at first postweaning estrus
what is the goal of breeding sows soon after the piglets are removed?
2 litters/sow/year
what does the swine cervix require for insemination?
specialized penis
AI catheter
what is something that can externally be monitored for heat detection in swine?
vulva: significant changes seen in estrus and diestrus
how long is the estrous cycle of sows?
21 days
what is used to stimulate follicle growth?
gonadotropin use
what is used to modulate luteal function?
PGF2alpha
what is associated with a negative effect on ovulation rate and conception?
high temperature
what is the smallest accessory sex gland in the boar?
prostate gland
what does the bulbourethral gland produce?
large gel fraction of boar’s semen
what does the preputial cavity of the boar collect?
urine
semen
other fluids
harbors large bacterial population
what is the medial raphe in the boar testes and scrotum like?
prominent
what is the motility and morphology of boar semen like?
excellent
is the swine pregnancy dependent upon the corpus luteum for the whole time?
yes
when do swine embryos start to attach?
day 14
how common are stillbirths and mummies in swine parturition?
stillbirths common
mummies may be seen in normal litters
