Lecture 11: Porcine Repro Flashcards
semen characteristics of the sow
large volume: 150 - 300ml /ejaculate
30 - 60 billion sperm/ejaculate
spermatogenesis = 35 days with 9 - 12 for epididymal transport
** mammary gland characteristics of the sow **
** minimum of 6 teats on each side with 3 in front of umbilicus **
** 10 functional teats minimum**
what is the ideal semen in the boar?
> 65% motile
100,000 sperm/ml
< 20% morphologic abnormoalities
what effect does heat stress have on semen quality?
decreased motility, head and tail abnormalities, cytoplasmic droplets
how long does it take to resolve symptoms caused by heat stress?
6 - 8 week lag
what are boar phermones?
5alpha-androstenone
- bound to proteins in boar saliva
when is puberty in the boar?
9 months
puberty in the sow?
6 - 7 months
the estrous cycle in the sow: general characteristics
non-seasonal, polyestrus
estrous cycle length = 21 days
single follicular wave
follicular estradiol causes standing heat: 2- 3 days
when does ovulation occur in reference to the onset of estrus?
36 - 44 hours from onset of estrus (2/3 into estrus)
what is “flush feeding”?
a way to increase the number of oocytes by increasing feed intake a few days to 2 weeks before estrus
when will the sow NOT respond to PGF2alpha?
before day 12 - 13
what happens if the sow does not get pregnant
the uterus will release PGF2alpha which naturally lyses CL and the sow can return to estrus
how long is estrus in the sow?
2 - 3 days
when do embryos enter the uterus?
2 - 4 days after conception
when does implantation occur?
day 14 - 18
when do embryos secrete estradiol? what is its significance?
day 10 and 11
its the maternal recognition of pregnancy
when does a sow stop bing CL dependent?
never - she is CL dependent throughout entire pregnancy
what is the minimum number of embryos and fetuses needed to maintain a pregnancy?
2 embryos per horn before 30 days
2 fetuses total required to maintain pregnancy after 30 days
pregnancy parameters - gestation length variable litter size average placentation farrowing
gestation length = 114 days (3 months, 3 weeks, 3 days)
variable litter size average = 11
placentation = diffuse, epitheliochorial
farrowing = parturition
pregnancy diagnosis:
failure to return to estrus at 17 - 25 days after breeding
rectal palpation = 90% accurate after 30 days
ultrasound
ultrasound preg dianosis:
doppler
a-mode
b-mode
doppler: after 30 days of gestation, detects increased blood flow to uterine artery, fetal heart, umbilical arteries
Amplitude-depth (a-mode): detects fluid in uterus
Real-time (B-mode): typically >21 days gestation transabdominally
pregnancy CL dependent with what hormone?
PGF2alpha - give sows 1 - 2 days before due date
most will farrow in 36 hours
- if no response within 24 hours give oxytocin
when does sow return to estrus post farrowing?
28 days to allow time for lactation and uterine involution
porcine respiratory and reproductive syndrome virus (PRRSV): transmission, dx and control
transmission: direct pig-pig contact and semen, crosses placenta in late term preg
dx: serologic testing and screening of semen via PCR
control: introduce PRRS negative or naiive animals, strict biosecurity, modified-live virus vaccine
porcine respiratory and reproductive syndrome virus (PRRSV): clinically affected herds
decreased conception rates
decreased farrowing rates = long-term abortion storms
increased neonatal mortality
Parvovirus effects
the placenta
SMEDI - stillbirths, mummified fetus, embryonic death and infertility
abortion is typically NOT seen
is abortion seen with Parvo?
no!
pseudorabies (Aujezky’s disease): transmission, dx, control
transmission: contact, aerosol, transplacentally, via milk or semen
dx: serology
control: screen boars and strict biosecurity - test and cull. reportable!
what is the effect of pseudorabies in boars?
herpesvirus reproduces in the genital tract
acute phase –> semen quality decreases if febrile, latent infection and recrudescence with stress
what is affect of pseudorabies in the sow?
herd is asymptomatic
- high reproductive failure: increase return to estrus and abortion
- high neonatal mortality
