Swine Swine Reproduction Reproduction

Breeding herdsBreeding herds

Replacement giltsReplacement gilts Sows Sows BoarsBoars

The boar’s function inThe boar’s function inreproduction:reproduction:

1. Produce spermatozoa1. Produce spermatozoa

2. Introduce sperm into the female2. Introduce sperm into the female

reproductive tract at the properreproductive tract at the proper

timetime

Reproductive Organs ofReproductive Organs ofthe Boarthe Boar

• • TestesTestes

• • EpididymusEpididymus

• • Vas deferensVas deferens

most fluid in most fluid in ejaculateejaculate

• • Vesicular glandsVesicular glands

• • Bulbourethral Bulbourethral glandgland

gel portion of gel portion of ejaculateejaculate

• • UrethraUrethra

• • PenisPenis

Boar’sBoar’sReproductive TractReproductive Tract

BoarsBoars Boars influence conception rate and litter size, and contribute Boars influence conception rate and litter size, and contribute

one-half of the genetic makeup of their daughters. one-half of the genetic makeup of their daughters. Boars lacking fertility or sex drive should be culled as soon as Boars lacking fertility or sex drive should be culled as soon as

possible. possible. For optimal breeding performance, mature boars should not be For optimal breeding performance, mature boars should not be

used for natural service more than twice daily; young boars used for natural service more than twice daily; young boars should be used less often (2-3/week)should be used less often (2-3/week)

The breeding system used should produce the best results in The breeding system used should produce the best results in reproductive performance for the particular physical facilities reproductive performance for the particular physical facilities and management program. and management program.

BoarsBoars Boars should be provided the Boars should be provided the

best environment possible to best environment possible to enhance their breeding enhance their breeding performance. performance.

Thermal stress should be Thermal stress should be prevented. prevented.

Boars should be exposed to Boars should be exposed to females as much as possible to females as much as possible to stimulate male mating stimulate male mating behavior. (20:1)behavior. (20:1)

Slippery floors should be Slippery floors should be avoided in the breeding area. avoided in the breeding area.

Breeding records should be Breeding records should be maintained to determine the maintained to determine the reproductive performance of reproductive performance of boars. boars.

An ejaculate consists of the followingAn ejaculate consists of the followingthree phases:three phases:

1. The first, or pre-sperm phase, which lasts 1 to 51. The first, or pre-sperm phase, which lasts 1 to 5minutes, consists of a watery fluid in which there areminutes, consists of a watery fluid in which there aretapioca-like pellets but no sperm, and comprises 5 totapioca-like pellets but no sperm, and comprises 5 to20% of the ejaculate.20% of the ejaculate.2. The sperm containing phase, which lasts 2 to 52. The sperm containing phase, which lasts 2 to 5minutes, consists of a whitish, uniform fluid whichminutes, consists of a whitish, uniform fluid whichcontains the sperm, and comprises 30 to 50% of thecontains the sperm, and comprises 30 to 50% of theejaculate.ejaculate.3. The last phase, which lasts 3 to 8 minutes contains3. The last phase, which lasts 3 to 8 minutes containsvery few sperm, helps form a gelatinous plug in thevery few sperm, helps form a gelatinous plug in thecervix of the sow, and comprises 40 to 60% of thecervix of the sow, and comprises 40 to 60% of thetotal volume.total volume.

The spermatogenic cycle in the boar is 35 days, with 10 days for epididymal transport. Thus 45 days are required from the start of production to ejaculation of sperm

fertility as measured by farrowing rates and litter size, fertility as measured by farrowing rates and litter size, gradually decreases as the prevalence of proximal (near gradually decreases as the prevalence of proximal (near

the head) droplets increasethe head) droplets increase

Semen Evaluation:Semen Evaluation:

• • MotilityMotility• • ConcentrationConcentration• • VolumeVolume

TargetTarget::• • Motility:Motility:

60% or better60% or better• • Concentration & Volume:Concentration & Volume:

Determine number ofDetermine number ofinseminations (3-5 billion)inseminations (3-5 billion)

The Sow’s Function inThe Sow’s Function inReproduction:Reproduction:

1. To produce ova1. To produce ova

2. To nourish the developing ova2. To nourish the developing ova

3. To produce piglets3. To produce piglets

4. To produce milk4. To produce milk

Reproductive Organs ofReproductive Organs ofthe Sowthe Sow

1. Ovaries1. Ovaries

2. Oviducts2. Oviducts

3. Uterus3. Uterus

4. Cervix4. Cervix

5. Vagina5. Vagina

6. Vulva6. Vulva

Sow’sSow’sReproductive TractReproductive Tract

www.ansc.purdue.edu/swine/porkpage/repro/sow2.htm

Puberty and breeding Puberty and breeding maturitymaturity

Puberty: 5-7 months (hybrids perform Puberty: 5-7 months (hybrids perform better)better)

Breeding: approx. 7 monthsBreeding: approx. 7 months Polyoestrous (temperature stress!)Polyoestrous (temperature stress!) Length of oestrous cycle 21 daysLength of oestrous cycle 21 days Duration of oestrus 2-3 daysDuration of oestrus 2-3 days Ovulation during the last day of oestrus Ovulation during the last day of oestrus

(back(backpressure test)pressure test)

PGF2A-sensitivity only after day 12PGF2A-sensitivity only after day 12

Breeding factsBreeding facts

Estrus 1-5 days

Heat Period 18-22 days

Gestation 114 days

Breeding age-gilts 7-8 mos.

-boars 7-8 mos.

Breeding weight-gilts 220 lbs.

Temperature effects on Temperature effects on femalefemale

Heat important when affects body temperature - Sources, bothHeat important when affects body temperature - Sources, bothbody and environmentbody and environment

Effect oocyte cause polyploidyEffect oocyte cause polyploidy Prior to breeding is Prior to breeding is greatestgreatest

loss of fertilityloss of fertility

Cause early embryonic mortalityCause early embryonic mortality Especially within the Especially within the firstfirst

7 days past breeding7 days past breeding

Late pregnant sow: Heat stress last week of gestation will greatly Late pregnant sow: Heat stress last week of gestation will greatly increase number of stillborn pigletsincrease number of stillborn piglets

Intensity of estrus may be reducedIntensity of estrus may be reduced

One mechanism, stress causes high glucocorticoids which inhibit One mechanism, stress causes high glucocorticoids which inhibit LH release. Direct effects of heat on gametes is greatest effect!LH release. Direct effects of heat on gametes is greatest effect!

Low temperatures - Reduce intensity of estrusLow temperatures - Reduce intensity of estrus

Species variation in estrous Species variation in estrous cyclecycle

characteristicscharacteristics

Gilt exposure to a mature Gilt exposure to a mature boar boar

Aspects off the vulva,, Aspects off the vulva,, sexualsexual

behavior and fertilitybehavior and fertility

Physical signs to consider for Physical signs to consider for matingmating

Too earlyToo early Vulva heavily red and swollenVulva heavily red and swollenHardly any mucus on vaginal mucosaHardly any mucus on vaginal mucosaNegative back pressure test, only standing Negative back pressure test, only standing reflex in presence of a boarreflex in presence of a boar

In timeIn time Vulva moderately red and swollenVulva moderately red and swollen Vaginal mucosa with mucusVaginal mucosa with mucus Positive back pressure testPositive back pressure test

Too lateToo late No redness or swelling of vulvaNo redness or swelling of vulva Sticky vaginal mucosaSticky vaginal mucosa Negative back pressure test, only Negative back pressure test, only standing reflex in presence of a boarstanding reflex in presence of a boar

2nd mating or AI ‘s are necessary in animals with positive back pressure test 24 h after mating

Gilt standing for "back Gilt standing for "back pressure" testpressure" test

Gilt "in heat", Gilt "in heat",

immobileimmobile Gilt with swollen Gilt with swollen

vulva, secondary vulva, secondary sign of estrus sign of estrus Gilt with swollen vulva,Gilt with swollen vulva,

secondary sign of estrussecondary sign of estrus

Breeding Breeding The The hypothalamushypothalamus located located

at the base of the brain at the base of the brain secretes gonadotropin secretes gonadotropin releasing hormone (GnRH) releasing hormone (GnRH) >>>>> regulates the >>>>> regulates the anterior anterior pituitary glandpituitary gland >>>>> FSH (Follicle >>>>> FSH (Follicle Stimulating Hormone) & LH Stimulating Hormone) & LH (Luteinizing Hormone) into (Luteinizing Hormone) into the blood which stimulates the blood which stimulates >>>>>>> ovarian >>>>>>> ovarian hormones: estrogen and hormones: estrogen and progesterone >>>>> which progesterone >>>>> which in turn regulate the in turn regulate the reproductive process. reproductive process.

Oxytocin is released from the Oxytocin is released from the posterior pituitary gland.posterior pituitary gland.

A.I.A.I.

ReferencesReferences

Sow gestation period???Sow gestation period??? http://www.thepigsite.com/video/single/41/http://www.thepigsite.com/video/single/41/ http://edis.ifas.ufl.edu/an051http://edis.ifas.ufl.edu/an051 http://www.aces.uiuc.edu/vista/html_pubs/http://www.aces.uiuc.edu/vista/html_pubs/

pigs/pigs.htmpigs/pigs.htm http://www.ncsu.edu/project/http://www.ncsu.edu/project/

swine_extension/publications/factsheets/swine_extension/publications/factsheets/812s.htm812s.htm

http://www.ansc.purdue.edu/swine/http://www.ansc.purdue.edu/swine/porkpage/repro/physiol/reppaper.htmporkpage/repro/physiol/reppaper.htm