Swine Repro Flashcards
Describe the basic anatomy of the swine repro tract
-the uterine body is relatively short
-uterine horn: non gravid horn is 1 meter in length, may double in length during pregnancy
-cervix is up to 25 cm in length
-long vaginal vault
T/F: it is common for the prolific females to have a ton of follicles
True
- can have 14-16 on each ovary on occasion
-good for production, but sows don’t have enough teats
Describe the basic physiology of the female pig estrous cycle
-HPG axis is similar to other domestic species
-females still develop surge center and males a tonic center
-one follicular wave per cycle
-18-24 days average length
-follicles produce estrogen leading to estrous behavior
-gilt estrus is 36-48 h, sows 48-72 h
-ovulation occurs 2/3 of the way through estrus (36 h average)
-ovulation occurs 24 hours after LH peak
-multiple follicles rupture over a 1-4 hr period
T/F: you can short cycle pigs with prostaglandin
False- not effective until after day 12-13
- by this time they are already close to ovulation
-can be used for abortions
What are some of the main signs of estrus in sows?
-vulva swelling and redness, vaginal discharge (white and chalky), restlessness and vocalization, increased motor activity (seeking out boar)
-actively seeking boar, pricking of ears, lordosis response
Will sows that come into heat early stay in shorter or longer?
Longer
What are the main factors that influence ovulation rate?
-Age: sows usually have 18-20 ova vs gilts usually have 12-14
-nutrition: higher in full fed gilts, flushing may increase ovulation rate
-breed: white or maternal breeds have higher ovulation rates
Describe ovulation in pigs
-occurs about 42 hours? after LH surge
-all of the follicles from both ovaries will ovulate over a short period of time
-timing of the ovulation can vary between females
-the life span of the egg is 8-12 h
Are pigs CL or placental dependent?
CL
-cant short cycle them as CLs not responsive until 2 weeks
Describe maternal recognition of pregnancy in pigs
-an estrogen compound causes it
-if no MRP, prostaglandin is release
-if MRP occurs, estradiol causes intraluminal PGF2 alpha release (so it doesnt get to ovaries) and prevents luteolysis
-MRP requires 4 embryos to be present, 2 in each horn
How can you select females sows for breeding?
- good number of teats and conformation
-good immunity
-good feet and legs
-good maternal qualities
What are some things to consider when helping a producer decide on purchasing?
Depends on individual operation goals
-are you raising your own gilts or purchasing? are you buying piglets? will you start with gilt purchase? are you buying a bred female or prebreeding?
What are some main considerations when selecting gitls
-selection based on various characteristics: feet and leg soundness, breed/genetics (litter size, etc), underline and vulva size, growth parameters- fast or slow growing, age at puberty and breeding
-todays gilts grow faster, reach puberty at heavier weights, and are mated leaner and at younger ages
-selection based on performance testing methods can help determine the most productive females
-selecting for leaner animals can at many times adversely affect repro
What lean growth traits should you select for?
- must look at boar
-look at backfat thickness, feed intake, feed efficiency, days to market
-Hampshire’s and durocs, some patrons are known to be very muscled -aim for heterozygotes
What maternal traits should you consider when selecting?
-number born alive, number weaned, 21 day litter weight
Why do we want white pigs?
We like uniformity
-often breed to F1 females to select for this
T/F: you should use purebred grandparent stock to make F1 females
True
Describe the selection criteria for the musculoskeletal system and repro system
-for the musculoskeletal system, assess conformation and structure, feet and legs. pay attention to all of the joint angles as it is important that animals can do well on concrete
-for repro system: assess when they meet puberty, external genitalia and underlines. look for well developed normal sized vulva, smaller better for avoiding injuries
What specific things should you look for when looking at toes?
-examine size
-unevenness of toes can cause problems as well as injuries
-small toes, especially if close together can create soundness problems
-look for cracks, abrasions and/or swellings
What should you look for in terms of teat assessment?
-good spacing, 6-8 functional teats per side, no inverted or underdeveloped teats
When should gilts come into estrus?
-between 5-8 months when they weigh 100-125 kg
-landrace at 173 days of age, crossbreds reach puberty earlier than purebreds, durocs are latest to reach puberty (224 days)
Describe the lactational anestrus that sows exhibit
-suckling stimulus suppresses FSH and LH secretion leading to no follicular development
-removing all piglets removes suppression and sows enter estrus 4-7 days postweaning (can be influenced by genetics, nutrition, parity, litter size, BCS, and lactation length)
-allows for estrus detection and planning
What is the problem with delayed estrus postweaning?
-increases non productive sow days and maintenance costs
What is the target weight for breeding gilts?
-200 lb with at least 1 recorded estrus
-try not to have overweight at breeding or gestation as this can increase culling rate
What are sows generally fed?
-5 lbs corn-soybean meal diet per day for maintenance
-lactating sows may eat >14-15 lb/day
-be sure they dont get too fat!
Describe the normal prebreeding vaccination program?
Parvo, lepto, and erysipelas vaccine
-should be administered 3-5 weeks apart with the last one being 2 weeks prior to breeding
-if not vaccinated previously, only 2 weeks prior for sows
Describe some breeding targets in the swine industry
2.2-2.5 litters/sow/year, >19 pigs weaned/mated female/year, 21 day litter weight >120 lb, farrowing rate >85%, >10 piglets born alive, NPS days <60 and WEI <7 days
What are some methods of estrus detection that do not require humans to watch?
-boar bot, breeding saddles
Describe synchronization protocols in cycling females
-gilts and some sows: altrenogest 15 mg orally for 14 days
-weaned sows: triptorelin 200 mg intravaginal 4 days post weaning, breed on day 5
Describe the AM/PM rule for breeding
-If a gilt is in estrus in the AM, breed, then again in PM and then again 12 hours later
-sows: when you find in estrus, breed then breed again 24 hours later
Describe how you perform AI in pigs
-introduce rod at 45 degree angle
-on gilts they have ones that spiral, in sows they have spongey ones
How long is the boar orgasm?
3-5 minutes
Are BSEs routinely performed in boars?
NO
-there is a manual for it however
Why do people like hereford breed of pigs?
Novelty, do well on pasture
How are boars selected?
-for growth traits primarily
-can pass on maternal traits too
-if show pigs, they want big butts
-depends on breeding system: boar breeding, AI
-select for carcass yield, quality, feed efficiency, rate of gain, overall productivity of the herd
Why are boars castrated?
Boar taint is real
What is reproductive capacity best measured by for boars?
-testicular weight
-cant do scrotal circumference as they are non-pendulous
-can use calipers or ultrasound
Describe some features of boar anatomy
Fibroelastic penis, sigmoid flexure
-preputial diverticulum- unknown purpose, might lubricate penis (collects grossness and some boars can masturbate into them)
-biggest glands are vesicular glands- huge volume of ejaculate
-bulbourethral glands are very muscular to support gel fraction
-small prostate
-orientation of testes like the cat (tail to tail)
How can semen be collected in boars?
-AV- rare-have to be under GA
-electroejaculator- also rare- have to be under GA
-most commonly via the gloved hand technique
What is the value of the AI boar?
-can collect 1-2 times per week
-3 billion sperm per dose
-20-50 doses per week
-1000-2000 litters sired per year
-offspring marketed 10000-20000
-gross income 1.7-3.4 million per boar
What does semen evaluation involve?
Measuring volume, assessing progressively motile sperm, evaluating sperm morphology (including acrosomes), calculation of total sperm numbers
What do you want sperm progressive motility to be?
70% at the minimum
Which sperm abnormality is more common in boars than other species?
Acrosomal abnormalities
What is responsible for the most contamination of sperm samples?
Improper water treatment when making extender
What should the collection pen look like?
-clean, large, allows for good footing, safety for handlers, place for boars to put feet
-never vaccinate where you collect- only good things happen there
How can you train boars to collect?
-get them familiar with the handlers (provide them food-they will like you for this)
-must be patient with them
-should work with each boar for 20-30 min per session
-can use prostaglandins to jumpstart them-will contract accessory sex glands
What is the best way to analyze semen?
-stained slides with phase contrast microscope, can see bacteria
-still a manual process
What are some developmental problems that can occur in boars?
-cryptorchidism (failure of one or both testes to descend)
-hypoplasia of penis (smaller than normal for age and size- more common in show pigs)
-persistent frenulum (tissue between end of penis and prepuce fails to regress)
What can cause problems with extending the penis?
- hypoplastic penis
-persistent frenulum
-behavioral - masturbation into preputial diverticulum
How can you examine an untrained boar?
-TKX- due to cost
-reconstitute telazol bottle with 250 mg xylazine and 250 mg ketamine
-makes a 100 mg/mL solution of telazol
-dose at 4.4 mg/kg IM, can do half IV if quick procedure
** not reversible
What are bozeman uterine forceps used for in boars?
to grab the end of the penis
- long enough to go through opening of prepuce, past diverticulum to penis
What is the indication for preputial diverticulectomy?
Bad diverticulitis due to crap accumulating in there
-can lead to enlarged prepuce
-in boars where they ejaculate into it
How do you perform a preputial diverticulectomy?
Perform lateral incision, dissect around the whole diverticulum, clamp and ligate large vessels
When should you deposit semen into a gilt/sow?
Within 12 hours of ovulation
-optimal time of breeding is 18-24 hours apart on days 1 and 2 of estrus
-breed gilts on second or third estrous cycles to increase fertility rates
Describe the events associated with fertilization in the sow
- pregnancy is CL dependent
-after fertilization, embryos will undergo cleavage and enter the uterus at the 4 cell stage
-there is a 20-30% loss up to day 13
-maternal recognition of pregnancy occurs on day 11-12 by estrogenic compounds
-need a minimum of 4 embryos
What is the type of placentation in the sow?
Diffuse microcotyledonary
- same as the horse
Describe the fetal development in sows
-mineralization occurs between 35-42 days
-immunocompetence begins around day 70-75
-can measure crown to rump length to determine gestational age of fetus
*total gestation is 114 days (3 months, 3 weeks, 3 days)
When during pregnancy is resorption possible?
Between day 0-35
- up until the fetus starts mineralizing
When can you see mummification of fetuses/abortions?
35-114 days
Why is it that some piglets in a litter can be mummified, while others are stillbirths and some are completely normal?
They all have a separate placenta and sac
On average, what is the number of embryos that suffer from early embryonic death prior to implantation?
2-2.5
If fetal death is within 14 days of pregnancy, will there be a regular or irregular return to estrus? What about if >35 days? In between?
14: Regular!
>35: irregular
14-35: might be regular, might be irregular
What is an acceptable pregnancy loss rate on farms?
<5%
With mummification of a whole litter, when will pregnancy progress to pseudopregnancy?
-at >114 days
-main causes are PRRS and parvo
T/F: you should induce after day 116
True
Define a stillbirth
Full term piglets born dead, but grossly normal
-lungs never inflated
-may die shortly before, during or immediately after birth
What are some common noninfectious causes of infertility in female pigs?
Hydrosalpinx: most common cause of infertility, occurs secondarily to bursitis or peritonitis that results in adhesions
Cystic ovarian disease: second most common cause of infertility
How can you diagnose cystic ovarian disease?
Via ultrasound
-will see multiple cysts or irregular cycles or anestrus
-does not respond to hormonal therapy
-can be caused by estrus induction agents
-generally bilateral
-no treatment really works
How do you treat cystic ovarian disease in cattle?
ovsynch + CIDR
What is PG600?
A combo of HcG and PMSG
- HcG has LH like activity, PMSG has FSH like activity
What are the top 3 infections that cause abortions in swine?
PRRS, Lepto, secondary to viruses (flu causes the most)
Describe some features of porcine parvovirus
-results in SMEDI=stillbirths, mummification, embryonic death and infertility (also caused by PRRS)
-results in no maternal signs
-females may nest and get mammary development but fail to farrow due to fetal mummification
Describe the pathogenesis of parvovirus in pigs
-can be spread orally or venereally
-viremia leads to transplacental infections leading to fetal vasculitis and death
-depending on the day of infection, can see a variety of forms of fetal death
-litters may be carried greater than 114 days
-usually occurs in naiive replacement gilts
-sows infected do not normally show signs until farrowing
How can you diagnose parvovirus?
-lesions of aborted fetuses
-look into vaccination program
-clinical signs of increased irregular returns to estrus and increased mummies
-serology
How can you prevent parvovirus infection?
-proper acclimatization of replacement gilts
-regular vaccination of breeding herd
-no treatment except for supportive care for the aborting sows or gilts
Describe the clinical features of pseudorabies in pigs
-herpes virus (always affect CNS, repro, resp)
-can cause encephalitis, repro failure, and reduced litter size
-recrudescence of virus from boars and/or sows under stress
-can be transmitted in semen
Describe the pathgenesis of pseudorabies
-can be spread by nose to nose contact, feco oral, aerosol, or through semen
-clinical signs depend on age at time of infection: if young will see CNS signs
-weaned pigs and older see respiratory signs
-fever, anorexia, weight loss can occur at all ages
-resorption, abortion, and increased mummies and stillbirths can occur
How do you diagnose pseudorabies?
-gross lesions +/- histological lesions (pulmonary edema, meningoencephalitis)
-virus isolation
-serology
How do you control speudorabies?
-eradication programs: whole herd depopulation, test and remove all breeding swine, segregate offspring to an off site production unit
-vaccination with a G1 gene deleted product
Describe the clinical features of swine influenza
-two types: H1N1 and H3N2
-usually causes more respiratory signs
-there is interspecies transmission
-spread by oronasal secretions and aerosols
-seasonal in october-march
-not considered a primary reproductive pathogen
How do you diagnose and treat swine influenza?
Diagnosis through clinical signs and serology
Prevention and treatment: injectable antibiotics for secondary infections, could vaccinate in the face of an outbreak
Describe some clinical features of PRRS
-Porcine Respiratory and Repro Syndrome
-caused by arterivirus
-sow mortality can be 5-10%
-can be transmitted in semen
-signs include agalactia, anorexic sow
How is PRRS spread?
-direct pig to pig contact or aerosols
-two distinct forms: repro failure or post weaning repro disease
Describe some diagnostics you can do for PRRS
-history and herd records
-herd serology
-virus isolation from aborted fetus, lungs, tonsils and lymph nodes
-sequencing the virus
What is the prevention and treatment of PRRS?
-symptomatic therapy
-isolation and acclimatization of new entries
-herd stabilization
-vaccination with MLV (have ability to mutate) or killed product
-management techniques- no more cross fostering of litters
What is hog cholera?
-classical swine fever
-reportable
-pig is the only natural host
-occurs when you feed raw garbage to hogs
-clinical signs include anorexia, cyanosis, fever, diarrhea, vomiting, and abortions
-can be transmitted in semen
Describe the pathogenesis of lepto in pigs
-ZOONOTIC
-many different serovars
-L pomona most common
-penetrates mucous membranes, can be brought in by carrier animals
-clinical signs depend on stage in which females become infected but it usually results in mummified and macerated fetuses
-mild signs except for abortion
-immunity lasts for one year following abortion
How can you prevent lepto?
-vaccination of herds every 6 months (generally in combo with parvo)
-antibiotics (tetracycline) to help to reduce shedding, does not eliminate carrier state
Why is brucella such a concern in pig operations?
It is reportable
-causes pig abortion, stillbirths and infertility in sows, piglet mortality, orchitis in boars
-primarily introduced and transmitted by boar, can carry for >4 years
-infections can occur at coitus or by ingestion of infected material
-report positives to federal government, mostly eradicated from US
-test and slaughter is the method of choice for control
-buy replacement animals from certified brucellosis free herds
Describe the pathogenesis of erysipelothrix
-many pigs carry the organism on tonsils without clinical signs
-organism can gain access via contaminated feed and water
-in acute cases the organism enters circulation via pharynx and infects blood vessels
-clinical course depends on stress levels and depends if acute or chronic
-can see arthritis in little pigs, fever and skin lesions in gilts
-abortion secondary to fever and septicemia
What protozoa can cause problems in pigs?
-toxoplasma (causes individual abortion and stillbirth)
-eperuthrozoonosis (causes silent estrus or anestrus, abortion, weak and anemic pigs)- treat with tetracyclines, but does not remove carriers, can treat whole herd with arsenics
What does zearalenone cause?
- implantation failure
-enlarged vulva with delayed maturity
-increased vaginal and/or rectal prolapses
-found in moldy corn
-prepubertal males have reduced testicular development
