Wk 10 maintenance of pregnancy

Question 1

Cow - gestation length and time of placental takeover

Answer 1

9month gestation
6-8month placental takeover

Question 2

ewe gestation length and time of placental takeover

Answer 2

5month gestation
50 day placental takeover

Question 3

mare gestation length and time of placental takeover

Answer 3

11 month gestation
70 day time of placenta takeover

Question 4

sow gestation length and time of placental takeover

Answer 4

3.8month gestation, no placental takeover

Question 5

bitch gestation length and placental takeover

Answer 5

2 month gestation
no placental takeover

Question 6

queen gestation length and placental takeover

Answer 6

2 month gestation
no placental takeover

Question 7

Risk of foetal loss decreases over gestation. Touch on what is high, moderate and low risk

Answer 7

• Early embryonic loss = loss prior to or around implantation
  
  • High risk
• Abortion = post implantation, foetus unlikely to survive birth
  
  • Moderate risk
• Still birth = very late in pregnancy - foetal death at an age likely to survive birth
  Low risk

Question 8

What are some physiological processes that might cause foetal loss if interrupted, incomplete or absent?

Answer 8

• Progesterone
• PGF2a injections
• Failed maternal recognition - so luteolysis will occur as usual
• Disease and illness/stress or trauma/pathogens
  Placental disruption - anything that goes wrong with the placenta will cause concern

Question 9

Outcomes of foetal loss and signs of embryonic and early foetal loss

Answer 9

Outcome: conceptus typically resorbed by uterus, leaving little or no indication
Signs: may have limited signs, may occur before pregnancy diagnosis, long cycle or loss of previous foetal signs

Question 10

Outcome and signs of abortion in foetal loss

Answer 10

Outcome: conceptus typically resorbed by uterus, leaving little or no indication
Signs: may have limited signs, may occur before pregnancy diagnosis, long cycle or loss of previous foetal signs

Question 11

Expected rates of foetal loss depending on species:
- What species is probably the worst?
When most commonly does foetal loss occur during pregnancy?

Answer 11

• Cows - 50% of early pregnancy lost in cattle
• Majority of foetal loss occurs early in pregnancy* with moderate loss in first half of gestation and few losses late in gestation

Question 12

Common infectious causes of foetal loss

Answer 12

Caused by everything: bacterial, viral, fungal and protozoan infections can all cause foetal loss

Question 13

Common non-infectious causes of foetal loss: list some of these

Answer 13

• Genetic abnormalities - can be lethal or non lethal
• Toxins: plants, mycotoxins, drugs
• Endocrine disruption: inadequate progesterone (poor luteal function), endocrine disruption chemicals (e.g. Clover, pesticides)
• Nutritional deficiency: vitamins, minerals (selenium, iodine, copper)
• Uterine crowding: twinning in mares
• Anatomical: ectopic/mis located pregnancy, umbilical torsion
  Trauma/stress: heat-stress, overcrowding, uterine trauma (torsion of uterus)

Question 14

What would you investigate in case of abortion

Answer 14

• Hormonal profile of the mother - and mother health
• Infection/disease
• Environment - pasture and weather
• Herd health and nutrition
  Want to assess placenta and foetus itself

Question 15

Strategies for preventing foetal loss - infectious circumstances

Answer 15

• Biosecurity/controlling movement in and out of facilities
• Vaccinations
  Herd/individual health

Question 16

Strategies for preventing foetal loss- non infectious circumstances

Answer 16

• Genetic selection
• Adequate nutrition
• Low stress handling
• Heat management - provide shade/sprinklers
• Foetal reduction
  Progesterone supplementation throughout pregnancy

Question 17

Pregnancy termination- what are some typical indicators for termination

Answer 17

• Maternal risk (very young maternal age
• Abnormal pregnancy (congenital abnormality)
• Multiple gestation (twins, triplets)
• Production efficiency (feedlot heifers)
  Convenience (accidental mating)

Question 18

Manual techniques of abortion

Answer 18

• rupture of foetal membrane (chorioallantois or amniotic vesicle)
• fetal crushing, decapitation or cardiac puncture
• surgical spay

Question 19

Pharmacological techniques of abortion

Answer 19

• luteolysis (PGF2a)
• placental P4 shutdown
• parturition induction/cervical dilation

Question 20

Some things we can do to maternally monitor for pregnancy

Answer 20

• Circulating P4 concentration
• Body condition
• Feed intake/weight gain
  Mammary development

Question 21

In late summer flock of merino ewes, on ryegrass, have an abortion rate of 10% during late gestation. The ewes have no other clinical signs, they were recently shorn on farm.
Is this cause for concern, and if so, what would be a likely issue?

Answer 21

• E - Yes, pathogen
• This is a high abortion rate in sheep - should be about 2%

Recently shorn - biosecurity random person on the property who could bring a pathogen

Question 22

Time of placental takeover in relation to abortion times

Answer 22

Placental takeover –> Timing of placental P4 takeover