Lecture 11: Porcine Repro

Question 0

semen characteristics of the sow

Answer 0

large volume: 150 - 300ml /ejaculate

30 - 60 billion sperm/ejaculate
spermatogenesis = 35 days with 9 - 12 for epididymal transport

Question 1

** mammary gland characteristics of the sow **

Answer 1

** minimum of 6 teats on each side with 3 in front of umbilicus **

** 10 functional teats minimum**

Question 2

what is the ideal semen in the boar?

Answer 2

> 65% motile
100,000 sperm/ml
< 20% morphologic abnormoalities

Question 3

what effect does heat stress have on semen quality?

Answer 3

decreased motility, head and tail abnormalities, cytoplasmic droplets

Question 4

how long does it take to resolve symptoms caused by heat stress?

Answer 4

6 - 8 week lag

Question 5

what are boar phermones?

Answer 5

5alpha-androstenone

• bound to proteins in boar saliva

Question 6

when is puberty in the boar?

Answer 6

9 months

Question 7

puberty in the sow?

Answer 7

6 - 7 months

Question 8

the estrous cycle in the sow: general characteristics

Answer 8

non-seasonal, polyestrus
estrous cycle length = 21 days
single follicular wave
follicular estradiol causes standing heat: 2- 3 days

Question 9

when does ovulation occur in reference to the onset of estrus?

Answer 9

36 - 44 hours from onset of estrus (2/3 into estrus)

Question 10

what is “flush feeding”?

Answer 10

a way to increase the number of oocytes by increasing feed intake a few days to 2 weeks before estrus

Question 11

when will the sow NOT respond to PGF2alpha?

Answer 11

before day 12 - 13

Question 12

what happens if the sow does not get pregnant

Answer 12

the uterus will release PGF2alpha which naturally lyses CL and the sow can return to estrus

Question 13

how long is estrus in the sow?

Answer 13

2 - 3 days

Question 14

when do embryos enter the uterus?

Answer 14

2 - 4 days after conception

Question 15

when does implantation occur?

Answer 15

day 14 - 18

Question 16

when do embryos secrete estradiol? what is its significance?

Answer 16

day 10 and 11

its the maternal recognition of pregnancy

Question 17

when does a sow stop bing CL dependent?

Answer 17

never - she is CL dependent throughout entire pregnancy

Question 18

what is the minimum number of embryos and fetuses needed to maintain a pregnancy?

Answer 18

2 embryos per horn before 30 days

2 fetuses total required to maintain pregnancy after 30 days

Question 19

pregnancy parameters - 
gestation length
variable litter size average
placentation
farrowing

Answer 19

gestation length = 114 days (3 months, 3 weeks, 3 days)
variable litter size average = 11
placentation = diffuse, epitheliochorial
farrowing = parturition

Question 20

pregnancy diagnosis:

Answer 20

failure to return to estrus at 17 - 25 days after breeding
rectal palpation = 90% accurate after 30 days
ultrasound

Question 21

ultrasound preg dianosis:
doppler
a-mode
b-mode

Answer 21

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

Question 22

pregnancy CL dependent with what hormone?

Answer 22

PGF2alpha - give sows 1 - 2 days before due date
most will farrow in 36 hours
- if no response within 24 hours give oxytocin

Question 23

when does sow return to estrus post farrowing?

Answer 23

28 days to allow time for lactation and uterine involution

Question 24

porcine respiratory and reproductive syndrome virus (PRRSV): transmission, dx and control

Answer 24

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

Question 25

porcine respiratory and reproductive syndrome virus (PRRSV): clinically affected herds

Answer 25

decreased conception rates
decreased farrowing rates = long-term abortion storms
increased neonatal mortality

Question 26

Parvovirus effects

Answer 26

the placenta
SMEDI - stillbirths, mummified fetus, embryonic death and infertility
abortion is typically NOT seen

Question 27

is abortion seen with Parvo?

Answer 27

no!

Question 28

pseudorabies (Aujezky’s disease): transmission, dx, control

Answer 28

transmission: contact, aerosol, transplacentally, via milk or semen
dx: serology
control: screen boars and strict biosecurity - test and cull. reportable!

Question 29

what is the effect of pseudorabies in boars?

Answer 29

herpesvirus reproduces in the genital tract

acute phase –> semen quality decreases if febrile, latent infection and recrudescence with stress

Question 30

what is affect of pseudorabies in the sow?

Answer 30

herd is asymptomatic

• high reproductive failure: increase return to estrus and abortion
• high neonatal mortality