Pregnancy and parturition

This presentation outlines the vocabulary associated with livestock reproduction, specifically during pregnancy. It also outlines a human's developmental milestones in the womb.

1. Pregnancy and Parturition

2. Pregnancy begins with
•Fertilization – the union of sperm and
ovum
•Creates a zygote

3. 24 hours
•Zona locks out all other sperm
•Sperm DNA and egg DNA combine
•Cell divides

4. 8 celled pig zygotes

5. Day 5
•Arrive in the uterus
•About 100 cells
•Called a blastisist

6. Day 6
•Break out of Zona
•Suppresses Mother’s immune system in
the uterus
•Attaches to uterine wall
•Begin to form placenta
•Placenta is the membrane that surrounds
and supports the embryo inside the uterus

7. Week 2
•Blastisist is the size of a poppy seed
•Gasterlation begins – forms 3 layers of
cells
–lungs, liver, digestion
–heart, muscles, bones, blood
–central nervous system, skin, hair
•Embryo

8. Week 3
•Form a neural tube
•Brain begins to form
•Blood vessels connect
•Heart begins to beat
•Backbone begins to form

9. Week 4
•Arm buds develop
•Backbone curls into a tail
•1/5 inch long

10. Week 5
•Retina and lens form
•Ear begins to form
•1/4 inch long

11. Growth of Embryo
•Week 6 - 5/8 inch long
•Week 7 - 3/4 inch long
•Week 8 - 1 inch long
•Week 9 - 1 1/2 inch long
•Week 12 - 3 inches long
•Week 16 - 5 inches long

12. Milestones of the embryo
•Month 4 - Hard bone begins to form
•Month 5 - Fetus can hear sound
•Month 7 - Fetus begins to lay down fat
deposits under skin and in brain

13. Gestation
•period of pregnancy
•Lengths of Gestation in livestock
Cow 285 days
Sow 114 days
Mare 336 days
Ewe 147 day

14. Parturition
•birth of the fetus
•Begins with the release of cortisol
•Cervix relaxes and dilates
•Oxytocin and estrogen are released to
begin labor and milk production

15. Parturition (cont)
•Contractions of the uterus push the
fetus through the cervix and down the
birth canal out in to the world
•Fetus must fine the path of least
resistance through the pelvic bones
•The normal presentation for lambs,
calves, and foals is front feet first with
the head tucked between

16. Problems
•Wrong presentation of fetus
•Too small pelvic area
•Too large fetus
•Placenta does not break
•Mother does not come to milk

18. After Parturition
•Afterbirth – the uterus releases the
placenta, and it passes out shortly after
the fetus is born. ** Retained placenta
•Lactation – mother making milk for baby
•Colostrum – mother’s first milk that
contains antibodies for the baby; foals die
without it, so horse breeders milk mares
and freeze it.

19. 28 day pig embryo