Wk 10 maintenance of pregnancy Flashcards
Cow - gestation length and time of placental takeover
9month gestation
6-8month placental takeover
ewe gestation length and time of placental takeover
5month gestation
50 day placental takeover
mare gestation length and time of placental takeover
11 month gestation
70 day time of placenta takeover
sow gestation length and time of placental takeover
3.8month gestation, no placental takeover
bitch gestation length and placental takeover
2 month gestation
no placental takeover
queen gestation length and placental takeover
2 month gestation
no placental takeover
Risk of foetal loss decreases over gestation. Touch on what is high, moderate and low risk
- 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
What are some physiological processes that might cause foetal loss if interrupted, incomplete or absent?
- 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
Outcomes of foetal loss and signs of embryonic and early foetal loss
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
Outcome and signs of abortion in foetal loss
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
Expected rates of foetal loss depending on species:
- What species is probably the worst?
When most commonly does foetal loss occur during pregnancy?
- 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
Common infectious causes of foetal loss
Caused by everything: bacterial, viral, fungal and protozoan infections can all cause foetal loss
Common non-infectious causes of foetal loss: list some of these
- 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)
What would you investigate in case of abortion
- 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
Strategies for preventing foetal loss - infectious circumstances
- Biosecurity/controlling movement in and out of facilities
- Vaccinations
Herd/individual health
Strategies for preventing foetal loss- non infectious circumstances
- Genetic selection
- Adequate nutrition
- Low stress handling
- Heat management - provide shade/sprinklers
- Foetal reduction
Progesterone supplementation throughout pregnancy
Pregnancy termination- what are some typical indicators for termination
- Maternal risk (very young maternal age
- Abnormal pregnancy (congenital abnormality)
- Multiple gestation (twins, triplets)
- Production efficiency (feedlot heifers)
Convenience (accidental mating)
Manual techniques of abortion
- rupture of foetal membrane (chorioallantois or amniotic vesicle)
- fetal crushing, decapitation or cardiac puncture
- surgical spay
Pharmacological techniques of abortion
- luteolysis (PGF2a)
- placental P4 shutdown
- parturition induction/cervical dilation
Some things we can do to maternally monitor for pregnancy
- Circulating P4 concentration
- Body condition
- Feed intake/weight gain
Mammary development
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?
- 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
Time of placental takeover in relation to abortion times
Placental takeover –> Timing of placental P4 takeover
