Parturition and Postpartum Period

Birth and it Importance to the Producer

• Parturition is the conclusion of this growth is the process.

• Parturition- the birthing process

• Parturition is the true separation of the new animal as an independent functional life form, no longer dependent on its mother’s physiology.

• If an animal is born prior to completion of all these tasks it  has little hope of surviving on its own and will most likely die just after birth. 

• How does this affect the Producer? What can producer do to minimize this loss?

  • know the signs of parturition and watch carefully

• Losses to Producer Include: 

  • lost production days of its mother

  • the feed  

  • death may lead to issues with the mother

  • Cull mother from the herd 

    • may be too risky to try again

Length of Gestation

• Gestational lengths will vary from species to species

  • Gestation- Pregnancy 

  • Gestational Length Influences:

• Maternal age - Young dams deliver sooner than older animals. 

  • Two potential reasons: 

    • the animal is not fully grown, does not have the body frame or the nutrients to allow the fetus to grow to full size.

    • The Uterus cannot expand sufficiently to accommodate the developing fetus

• Women may be induced earlier because placentas have a “shelf-life”

  • horses cannot be induced

• Male fetuses-  on average will remain in utero an additional 1–2 days longer than females of the same species,

• Twins - which on average remain 3–6 days less than singleton pregnancies (in non-litter bearers). 

• The genotype – when embryos from shorter-length gestation cattle breeds are transferred into animals with longer gestational period, the fetuses still deliver according to their genetics, not those of the carrier.  (rate of cellular divisions, which leads to larger fetuses)

  • the fetus chooses the day, the mother chooses the time

Parturition

• “ We do not fully understand the exact mechanisms leading to the onset of parturition.”

  Parturition can be divided into three separate phases:

  (1) labor

  (2) delivery of the fetus

  (3) delivery of the placenta.

  Signs of approaching parturition: 

  • Date- how close the animal is getting to her normal gestation length

  • Enlargement of the mammary glands - may culminate in milk or colostrum dripping from the teats

  • Colostrum-  the first secretions from the mammary glands after parturition which are high in antibodies

  • Exhibiting nest- building behavior (SWINE)

  • Mucous-  becoming liquidly and seen stringing from the vulva.

• The first phase of parturition:

  1.) Labor –

  • Dilation of the cervix

  • First contractions-  started by estrogen > trigger prostaglandin 2α (PGF_2α) > placenta pulls away from the uterine wall. 

  • Combination of estrogen and PGF_2α -> rhythmic contractions (In general, longest phase of labor)

  • Labor progresses…

    • Uterus contracts around the fetus. 

    • Membranes of the placenta separate

    • Cervix should be fully dilated 

    • Collapsing of the membranes and the uterus around the fetus will cause it to struggle.

    • Struggling Fetus leads to  > arc-reflex reaction

    Arc Reflex= fetal movement > oxytocin to be released from PP > stronger contractions

    • Contractions move fetus from the uterus, through the open birth canal, to the outside worlD

  • Fetus must be both the right size and in the right orientation in order to have a smooth delivery

• Delay in delivery could have dire consequences for the fetus and is termed Dystocia. 

• Dystocia- Difficulty during delivery 

•  Severe dystocia will lead to fetus becoming starved for oxygen as once the membrane separates.

•  Delivery of Fetus can last between 30 minutes and 3 hours

• Fetus passes through the birth canal,:

  1.) Ductus arteriosus, (a blood vessel that has shunted blood away from the lungs and through the umbilical cord), must close. 

  2.) Foramen ovale, (an opening that has allowed blood to move directly from the right to left atria (which until now has been moving oxygenated blood from the placenta, through the umbilical cord, to the fetus), must close,- = Lung Function= Oxygen to body 

  Neo Nate on ground > contractions decrease > oxytocin secretions stop. 

  What still needs to happen???? Placenta must be expelled!

• Placenta Expulsion

  Generally in litter bearing animals the fetus and the placenta deliver together. 

  Singleton species, placenta expulsion between 6 and 12 hours.

  Essential this phase of labor …  birth canal will remain open, until placenta expelled.

  Retained placenta. So what? 

  Blood, warm and moist and full of nutrients = Infection “ideal bacteria growth”

   Metritis- Uterine infection associated with delivery

• Deficiencies can increase likelihood of retained placenta. vitamins A, E, selenium

   Treatment of retained placentas: 

  1. Hormones: oxytocin and PGF_2α administration of either hormone 

     • oxytocin is less aggressive

     • PGF2a is more aggressive and make contractions more painful

  2. Antibiotics:  place antibiotics directly into the uterus=  fight the infection, acidity of antibiotic >irritate the endometrium> release  PGF_2α,> contractions

  3. Combination of Hormones and Antibiotics

The Postpartum Period

•  Uterine Repair

  Need to repair Uterus. 

  • First step is: Involution- shrinking of the uterus after parturition, back to pre-pregnancy size

  Shrinking will cause a flow of blood and membranes termed Lochia. 7-10 days. Gradually darkening brown color

  Lochia- Uterine discharge of fetal membranes, maternal membranes and blood after parturition.

  • Second step:  Regrowth of the endometrium. Amount of damage  to endometrium mainly dependent on how a species’ placenta attaches and detaches from endometrium

• What can delay the animal returning to cycle after parturition?

  • Dystocia- difficult births will lead to more damage to the endometrium, which will require longer periods for repair. 

  • Metritis

  • Retained placentas

  • Suckling (species-specific)

  • Poor nutrient of the dam

  • Age of the dam

  • Season of the year (especially in seasonal breeders)

  • Breeds (larger breeds tend to spend slightly longer for uterine involution and endometrial repair. 

  Delay in return to estrus = increased production cost and a delay to future income.

  • Lets talk about …The horse

    • Horse does not go through a postpartum anestrus. 

    • Exhibits a postpartum estrus or what is also called foal heat. 

    • Horse will return to estrus in 5–15 days post delivery, not always fertile cycles.

    • Lactation

      • Lactation- the secretion of milk from mammary glands. 

        • Series of physiological events in the mammary tissue, which allow for the synthesis and release of milk providing the essential nutrients necessary for the neonate’s survival.

      • Mammary tissue during pregnancy: 

      • progesterone and estrogen from the placenta cause the mammary tissue to organize the glands that will synthesize the milk and the ducts that will then deliver the milk to the cistern.

      • Prolactin, early in pregnancy, stimulation of synthesis of milk in the glands: placental lactogen, cortisol, growth hormone, and thyroid hormone (all of which are synergistic with prolactin). 

      Milk synthesis will start early in pregnancy, no milk will be expressed                                                                 from the mammary until just before parturition. 

      Waxing of teats, composed of proteins and lipids.

    • Species have significant differences in the anatomy of the mammary glands of each species. 

    • Expression of milk works the same in all species. 

    Arc Reflex of young animal suckling

  • The Milk Itself: 

    • The first milk will be what is termed colostrum.

     Colostrum- the first secretions from mammary tissue after parturition

    • Colostrum is higher in protein, sugar, and vitamin A than milk later produced. Higher levels of antibodies.

    “Neonates have the ability to move intact immunoglobins across the gut to provide passive immunity until the young animal’s own immune system kicks into gear.” 

    • the milk will thin; having few if any immunoglobulins, and fewer nutrients  than colostrum

    • Mother’s milk production will slow as the glands stay full of milk for longer and longer periods until it finally stops (dries up). 

      • if there is no or poor quality colostrum, plasma can be administered to the neonate

        • can be $$$ (around $1500)