PROSTAGLANDIN F2 ALPHA

1
PROSTAGLANDIN F2 ALPHA

• A pseudohormone manufactured by the non-pregnant
  uterus.
• Chemically is a fatty acid derived from
  arachadonic acid.
• Major function is to cause luteolysis which will
  then decrease progesterone production and
  release.

2
ROLE IN THE ESTROUS CYCLE

• Day 14 of the estrous cycle is decision day. 1.
  Live and viable embryo-nothing alters 2. No
  embryo or a non-viable embryo will remove any
  suppression of prostaglandin F2 Alpha production
  and release.
• PGF2 Alpha is carried via the mid-uterine artery
  to the corpus luteum where it causes luteolysis
  (destruction) of the corpus luteum.

3
ROLE CONTINUED

• Once the corpus luteum is destroyed, progesterone
  levels in the blood go down and the inhibition
  of GnRH is removed.
• On day 18 GnRH levels rise due to a lack of
  estradiol 17 beta and the cycle begins anew.

4
ROLE IN PARTURITION

• In order for parturition to take place the levels
  of progesterone must decline, thus the corpus
  luteum must be destroyed.
• The fetus controls its own destiny. As the fetus
  matures and approaches term for the species, its
  adrenal gland begins the secretion of adrenal
  corticosteroids. These hormones rise and pass
  into the maternal blood.

5
PARTURITION CONT.

• Estradiol 17 beta has been rising in the blood of
  the dam since the beginning of the third
  trimester.
• With this estrogen priming, the fetal adrenal
  corticosteroids stimulate the uterus to begin
  production and release of PGF2 alpha. The corpus
  luteum of pregnancy is destroyed and parturition
  begins.

6
PARTURITION

• The estrogens produced by the placenta can now
  begin mild uterine contractions.
• As these contractions continue they cause the
  fetus and membranes to stimulate the cervix.
  This stimulation will cause the release of
  oxytocin by the posterior pituitary. A cascade
  effect results in stronger and stronger
  contractions.

7
PARTURITION CONT.

• Due to previous priming by relaxin, the pelvic
  area ligaments and muscles have elongated and
  relaxed allowing free passage of the fetus.
• Continuing contractions of the uterus force the
  fetus out of the uterus into the vagina and out
  the vulva.

8
PARTURITION CONT.

• After the fetus is expelled, the placenta must be
  expelled.
• Continuing contractions by the uterus loosens the
  connections and the placenta should pass within
  24 hours of birth.
• In the case of a difficult birth, oxytocin may be
  depleted resulting in a retained placenta.
  Treat, do not remove manually.

9
MANAGEMENT USING PROSTAGLANDINS

• Estrus synchronization IF there is an active
  corpus luteum at least 4 days old, then
  exogenously administered PGF2 alpha will cause
  this c.l. to regress and the animal will return
  to estrus within 72 hours.
• In a group of cycling females, check estrus and
  administer PGF2 alpha at same time thus
  synchronizing all their estrus.

10
APPLICATION CONT.

• IF the exact breeding date is known, then 15 days
  before expected parturition, PGF2 alpha may be
  administered. This will destroy the c.l. of
  pregnancy and initiate parturition. In 50 of
  the treated females we will expect retained
  placentas. Treat with antibiotics.
• Can accomplish this with corticosteroids also.
  Aimax and dex and flumethazone.

11
PROSTAGLANDINS

• Lutylase
• Bovalene
• Estrumate
• REMEMBER The animal must be cycling and have a
  4 day old c.l. for any of these to cause
  destruction of the c.l. and synchrony.