Lecture 11: Breeding Management and Infertility in Swine (Risco) Flashcards
accessory sex glands in boar
prostate
vesicular
bulboruethral
biggest health problems in boars
lameness (laminitis)
type of penis in boar
fibroelastic
orientation of testes in boar
caudal (upside down)
Describe sow’s repro tract
- bicornuate uterus
- paired ovaries
- red corpora lutea
- long, twisted cervix
- more resistant to uterine infections than other species
when do boars hit puberty?
~9 mo.
testosterone influence on puberty
–> penile growth (sigmoid flexure) + mounting behavior
penile frenulum
breaks down during first breeding/puberty
day light effect on puberty
inc. day light (15h/d) stimulatory in both boar and sow
“gloved hand method”
method of boar semen collection in which boar trained to mount dummy and semen collected by hand
most common method of breeding in swine
natural service
volume of boar ejaculate
150-300ml/ejaculate (LARGE) w/ 30-60 million sperm/ejaculate
ideal boar semen (motility/morph)
> 65% motile
>80% morphologically normal
boar pheromones
5alpha-androstenone
- bound to proteins in boar saliva
- helps stimulate estrus in sows (via HPA axis), puberty in gilts, and mounting behavior in young boars
- sprays not recommended
when do gilts hit puberty?
6-7mo.
“Boar Effect”
helps stimulate puberty via pheromones
-continuous fence line exposure or full physical contact 10 mins/day
puberty in gilts is defined as
the beginning of cyclicity (follicular growth, ovulation, estrus, CL, CH, etc.)
estrous cycle in sow/gilt
- non-seasonal, polyestrus
- slight decrease in fertility during late summer
- 21 d
- SINGLE long follicular wave*
how many follicular waves in lactating cows?
2
how many follic. waves in mares, heifers?
3
what causes standing heat (2-3d) in sows?
follicular estradiol
how long after onset of estrus does ovulation occur?
35-44hrs (2/3 into estrus)
flush feeding
increase feed intake few days-2 weeks before estrus to increase # of oocytes. Helps with HPA axis
polytaucus (sp?) animals
bitch, sow, queen, SR. (often bare more than 1 fetus)
at what point in estrous cycle is CL functional?
by day 5-6
when will sow respond to exogenous PGF2a?
after day 12-13
T/F: non-pregnant uterus naturally releases PGF2a which lyses CL and returns sow to estrus
T
standing heat
when sow allows mounting by the boar
back pressure test
firm pressure on back or sacrum causes sow to show standing heat
how long does estrus last in sow? cow?
2-3 days; cow: 14-16hrs
2ary signs of estrus
restlessness during feeding not settling down after feeding frequent small-volume urination ear cocking red, swollen vulva with mucoid discharge
swine breeding methods
pen mating (most common, natural service)
hand breeding
AI
major reproductive diseases in swine
PRRSV** Brucellosis Parvo Virus** Lepto Postpartum Dysgalactia Syndrome Pseudorabies Swine Influenza
PRRSV =
Porcine Respiratory and Reproductive Syndrome Virus
PRRSV chars.
- -A Lelystad virus
- respiratory signs wean-finish
- repro losses in all stages of production (abortions, stillbirths, etc.)
- Epi: aerosol, pig to pig, semen trans.
- acute (epizootic) or chronic (endemic)
Parvovirus immunity
- delayed loss of maternal AB
- 6-8 mo. of age decline and susceptible to infection
- vaccination, acclimatization possible
Parvo chars.
- causes SMEDI: stillbirth, mummies, embryonic death, infertility
- common, ubiquitous, endemic
- viremia, fetal vasculitis, death
- prolonged gestations, small litters, etc.
- primarily gilt disease
what percent of oocytes are fertilized?
~100%
what percent of oocytes die within first 30 days? Until term?
20-30% by first 30 days, another 10% by term (~40% loss overall)
uterine capacity
uterus limits # of embryos that survive
embryos enter uterus how many days after conception?
2-4 days
how long do embryos migrate?
2 wks
implantation occurs when?**
14-18d
maternal recognition of pregnancy is determined by:
interferon tao/estradiol
which species are CL dependent?***
sow
cow
small ruminants (mainly goats)
(bitch, queen to lesser extent)
when do embryos secrete estradiol? what is the significance of this?***
day 10-11; maternal recognition of pregnancy (2nd peak occurs after day 14)
hormone progression of non-pregnant cycling sow
- oxytocin released from posterior pituitary AND CL
2. oxytocin releases prostaglandin, which then becomes ENDOCRINE in nature –> regression of CL
hormone progression of pregnant non-cycling sow
- blastocyst releases estrogen
2. prostaglandin is EXOCRINE in nature and is released but is NOT absorbed and doesn’t get back to CL
oxytocin receptors in endometrium are upregulated by:
estrogen (from follicles)
how many embryos needed to maintain pregnancy up to 30 days?
2 per horn
how many fetuses total required to maintain pregnancy after 30 days?**
2 total
sow gestation length
114 days (3 mo, 3 wks, 3 d)
average litter size
11
swine placenta type
diffuse epitheliochorial (see slide 31)
what is parturition called in swine?
farrowing
methods of pregnancy dx in swine
- failure to return to estrus at 17-25 days after breeding
- rectal palpation (>90% accurate after 30 days)
- ultrasound
3 types of US used in swine for preg. dx
1) Doppler - Rectal/Transabdominal
2) Amplitude-Depth (A-mode)
3) Real-Time (B-mode) <– most common
When can Doppler-Rectal/Transabdominal US detect pregnancy?*** What does it also detect?
after 30 days of gestation-term. Detects inc. blood flow to uterine a., fetal heart, or umbilical aa. (150-250bpm)
When can Amplitude-Depth (A-mode) US detect pregnancy? What does it also detect?
28-80 days after breeding. Detects fluid in uterus
When can Real-Time (B-mode) US detect pregnancy?
16-20 days rectally, >21 days transabdominally
avg. farrowing takes how long?
2-5 hrs
placenta delivered how long after delivery?
4 hrs
induction of parturition advantage
- ensures attendance of farrowing –> inc. survival rate of pigs
- chance to cross-foster pigs to sows w/ small litters
how to induce parturition
prostaglandin (PGF2a):
- tx 1-2 days before due date
- most will farrow w/n 36 hrs
- can give oxytocin if no response
lactational anestrus
inability of sows to cycle while nursing (normal)
- wean pigs and sows will return to estrus by 28 days post farrowing
- boar exposure can help synchronize sows
losing weight –> neg. energy balance –> ketotic –> betahydroxybutarate increases, glucose decreases, etc. –> HPA axis disrupted
(prevented by proper diet)
sows weaned during which season may take longer to return to estrus?
summer (due to dec. feed intake)
boars can get what if diet too rich in calcium/minerals?
spondylosis deformans
larger testes size in boars correlates to what in daughters?
more teets
