Fetal Abortion

Question 1

What is an embryo

Answer 1

product o conception (correct term in zygote)
used to define the embryonic mass that has not yet reached the stage of differentiation (i.e. the species cannot be discerned)

Question 2

What is a fetus

Answer 2

From the completion of differentiation (largely similar to the time that mineralisation occurs) onwards

Question 3

What is the terminology for embryo is lost compared to when a fetus is lost

Answer 3

Resorption – loss of the embryo
Abortion – loss and expulsion of the fetus

Question 4

What is the luteal-placental shift in pregnancy
when does it occur in cows

Answer 4

When progesterone moves from being produced by the corpus luteum to the placenta
In the cow happens on around day 210-250/285 day pregancy

Question 5

What happens if there is fetal death after the luteal-placental shift

Answer 5

No corpus luteum-> no more progesterone produced -> expulsion of fetus

Question 6

what happens if there is fetal death between fetal mineralisation (moves from embryo->fetus) and the luteal-placenta shift

Answer 6

CL present-> progesterone still produced, either:

Mummification or

If bacteria/inflammation present PG is released which causes expulsion of fetus

Question 7

What happens if there is embryonic death before fetal mineralisation

Answer 7

Resorption, or possible pyo

Question 8

What is resorption

Answer 8

death and resorption of embryo

Question 9

3 outcomes of fetal death and conditions of each

Answer 9

Expulsion- requires a decline in progesterone and onset of uterine contractions = Abortion

Mummification- here there is maintenance of progesterone with rapid absorption of fluid and no bacteria so the contents dehydrate and mummify

Maceration- here there is autolysis [aseptic] / putrification [bacteria] of the dead fetus that has not been expulsed [progesterone is high or there is obstruction to expulsion] bacteria invade

Question 10

What is a stillbirth

Answer 10

fetus reaches term but dies during the process of delivery

Question 11

5 examples of non infectious causes of pregnancy loss

Answer 11

Genetic abnormalities
Uterine disease (not able to form effective placenta)
Stress (nutritional, heat, other)
Maternal illness
Nutritional phytotoxins

Question 12

4 examples of infectious causes of pregnancy loss

Answer 12

Exposure of the pregnant female to reproductive pathogens (often viruses or bacterial [but also neospora, trichomonas, fungal etc]
- Many of these are not venereal transmission i.e. animal exposed when already pregnant

Recrudescence of latent viral infections

Ascending infection (eg placentitis)

Few bacterial venereal pathogens cause pregnancy loss. They do cause endometritis (e.g. CEM in mares = endometritis only; Campylobacteriosis in cattle = endometritis but if persists and cow can get pregnant some abort)

Question 13

What is the significance of pregnancy loss

Answer 13

Many infectious / environmental causes may affect other animals in the group / herd
Infectious causes are often associated with systemic illness
Overall there can be significant financial loss = cost treatment / lost production / mortality / prevention
Many infectious causes of abortion are also potential zoonotic diseases

Question 14

Which species have no placental shift and what is the consequence of this

Answer 14

Species with no placental shift
Sow
Doe
Bitch
Queen
Rabbit

Always have a CL (CLs)
Fetal death = mummification more likely

Exogenous PG = Abortion at any stage of pregnancy/
Exogenous PG could be used for induction of parturition