Swine Theriogenology Flashcards
What are 3 unique aspects to the reproductive anatomy of sows?
- UTERUS - long horns, which are the ultimate limiting factor to the high number of offspring sow are able to have (avg. 10)
- CERVIX - interdigitating bands, boar has a corkscrew-shaped penis to move pass
- OVARIES - bursa surrounds ovary where 15-30 oocytes are ovulated in each estrus
When do pigs go through puberty? What 6 factors affect this?
5-8 months (mini pet pigs = 12-16 weeks)
- genetics/cross-breeding - express first estrus earlier and produce more piglets/litter
- nutrition - reaching 2/3 of mature BW
- season/lighting - long days (summer) delays puberty
- confinement
- boar exposure - 5-30 mins (with physical contact) can make gilts go into heat in the next 28 days
- controlled stressors - transportation and relocation
How does parity cause changes in litter sizes of sows?
P2 has the lowest performance (sophomore slump)
- litters increase beyond P2 and are typically highest P5-P6
What are 2 pig breed differences that affect litter size?
- heterosis (crossbreeding) - more piglets/litter
- Meishan pigs - reach puberty earlier and have larger litter sizes (may have longer uterine horns)
What kind of estrous cycle do pigs have? How long is it? How do follicles develop in this time?
nonseasonal polyestrous
average 21 days (17-25 day range)
those destined to ovulate frow from 5 mm on day 15 to 8-12 mm at ovulation
What does the onset of estrus coincide with in pigs? How long are females sexually receptive?
LH surge
1-3 days depending on weaning to estrus interval (WEI) –> shorter in gilts (hard to monitor!)
When do sows ovulate? When is it preferred to inseminate?
36-44 hours after the onset of estrus –> 2/3 to 3/4 of the way through estrus
within 24 hours (preferred 12 hours) prior to ovulation
When is the sow corpus luteum responsive to PGF2a? How does this compare to natural luteolysis?
only after day 12
natural luteolysis occurs within days 14-16
What are some behavioral signs of estrus in pigs?
- receptive to mounting - can be sat on by farmer and remains still
- fence walking
- vocalization
- tilted ears
- kyphosis
What are the 2 anatomical changes associated with estrus in pigs?
- vulvar swelling
- mucinous vaginal discharge
What semen is most commonly used for pigs? What concentration is used?
chilled > frozen
1.5-5 billion sperm diluted in a total volume of 80-100 mL - long uterine horns = more distance to travel, be patient
What are the 3 most common sites of semen deposition in sows?
- intra-cervical
- post-cervical
- deep uterine (endoscope)
gently rotate catheter counterclockwise to go through cervix
When are sows in pig farms artificially inseminated? What is batch production?
during 2nd or 3rd cycle
the farm turns in an all-in all-out manner at the time of weaning
How long do sows go through lactational anesterus? What is the optimum weaning to estrus interval (WEI)?
18-21 days
4-7 days
What happens if the weaning to estrus interval is too early? Delayed?
<3 days = longer estrus duration (ovulation occurs later, wastes sperm)
> 8 days = shorter estrus duration (ovulates before expectation and won’t be detected)
How are prepubertal gilts, postpubertal and cyclic gilts, and weaned sows managed in pig farms?
stimulate onset of first estrus - PG600, boar exposure, transportation, relocation
synchronize estrus - progestins, PG600, GnRH analog (Triptorelin)
synchronize estrus - post-weaning heat detection, GnRH analog (Triptorelin)
What are the 4 most common options for hormonal manipulation of sows?
- PG600 - 400 IU eCG (FSH-like) / 200 IU hCG (LH-like) per 5 mL induces etrus in non-cycling animals (>5.5 months, >85 kg)
- Triptorelin - given intravaginally to sows 4 days post-weaning to induce ovulation within 36-48 hr –> AI 22 +/- 2 hr after
- progestins (Altrenogest) - given orally at 14 days to synchronize cyclicity with estrus within 4-9 days
- PGF2a - only useful after 12 days, natural luteolysis occurs in 14-16 days
How long is gestation in pigs?
average 114 days
“3/3/3” = 3 months, 3 weeks, 3 days
What induces maternal recognition of pregnancy in pigs? What does this require? What other molecule may be responsible?
- blastocysts produce estradiol between day 11 and 12 after ovulation
- this afters the secretion of PGF2a by endocrine (uterine vasculature) to exocrine (uterine lumen)
- estrogen does NOT inhibit the production of PGF2a
2 embryos per horn
fibroblast growth factor (FGF-7)
What are the 2 major ways of diagnosing pregnancy in pigs?
- behavior - failure to return to estrus in 18-25 days
- U/S
What are 3 options for U/S diagnosis of pregnancy in pigs?
- A-mode - amplitude-depth –> detects fluid-filled uterus with conversion to an audible signal
- doppler - detect fetal heat, pulsating umbilical vessels, and uterine arteries
- B-mode - real-time, done within 24-35 days
What is the main option for parturition induction in sows? What can be added?
PGF2a - induce parturition 24 +/- 5 hours after a dose of Dinoprost on day 112 of gestation –> IM, intravulval injection no more than 1 mL from a 0.5”. 20 g needle
10 IU oxytocin 20 hours after PG2a
When do udders develop in pregnant sows? What are other signs of farrowing?
weeks before farrowing
- restless for 24 hours
- decreased appetite* and water intake
- relaxed, swollen, red vulva
Why is it important to promote water intake in pregnant sows? What is the normal piglet interval? How do they most commonly present?
avoids constipation that can also block piglets from being pushed out
10-15 min –> ~2 hours is abnormal
cranially (60%) > causally (40%)
What is the epidermal membrane?
4th fetal membrane, epithelion
normal structure of neonatal pigs and camelids with NO pathological consequence
What are the 3 most common causes of abortion in pigs?
- environment, genetics - fall abortion syndrome
- infectious - maternal infection, Parvovirus (SMEDI), swine influenza, PRRS, Leptospirosis, Brucellosis (reportable!!)
- non-infectious - mycotoxins (Zearalenone), carbon monoxide
only 40-60% of cases have a definitive diagnosis
Infectious and toxic diseases causing abortion, stillbirth, and mummification in swine:
Infectious and toxic diseases causing abortion, stillbirth, and mummification in swine:
How can porcine parvovirus be transmitted? What reproductive signs are associated?
oronasal or intrauterine (SMEDI)
viral reproductive disease - stillbirths, mummies, embryonic death, infertility
What pigs are most commonly affected by porcine parvovirus? How is it prevented? Treated?
replacement gilts
vaccination
acclimatization
What produces zearalenone? What is the characteristic signs in piglets? What else is seen?
Fusarium fungus –> grows on corn, wheat, milo, barley, cottonseed, and sorghum
female piglets born with enlarged vulvas
- vulvovaginitis
- vulvar edema
- mammary development
- cyclingq sows - anestrus if consumed in diestrus
- reduced fetal size
- young boars - reduced libido and testicular size
What are the 3 minimum pig breeding herd vaccinations required? When are pre-farrowing vaccines given?
- Parvovirus
- Leptospirosis (5/6 way available)
- Erysipelas
- others considered risk-based
2-6 weeks prior to farrowing
