Non-Infectious Abortion
Twinning
Multiple pregnancy is not desireable because:
- Second leading cause of abortion
- 60-75% are aborted or stillbirths
- 31% loose both pregnancies (often so late that they cannot be rebred that season)
- 9% deliver twins
- both foal dead: 65%
- one foal alive: 21%
- both foals alive: 14%
- live foals are often weak and require extensive care to survive
Detection and management of twins is reviewed in pregnancy detection.
Abortion of twins can occur at any time during the pregnancy and the twins can die at different times. Fetal death is attributed to placental insufficiency. When only one twin is found after abortion, diagnosis of twin pregnancy can be made by observing the placenta. Large, smooth areas where the chorions of the twins do not allow contact with the uterus are prominent.
Abnormalities of the Placenta
- Umbilical cord length: abnormal long cord length may be associated with torsion of the umbilical cord, short cord length leads to premature intrapartum rupture of the cord and fetal asphyxia
- Premature Placental Separation: causes death of full term fetus as a result of anoxia as a result of detachment of the placenta before birth
- Body Pregnancy: the fetus largely occupies the the uterine body and the growth retarded (rare)
Developmental Abnormalities
Most chromosomal abnormalities cause early embryonic death. Other developmental abnormalities may be incompatible with life outside the womb.
Maternal Stress
Effects on glucocorticoids, can trigger parturition (moving mare, handling, trauma)
Chemical Poisoning
Plant poisoning: Fescue toxicosis, sorhum and sudan grass
Parasite control: cambendazole, organophosphates, carbon disulfide and other medicines.Check the label carefully for use in pregnant mares!
Accidents, Injuries
Accidents and injuries to the uterus or fetus.
