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What are the 3 categories of causes of embryonic loss?
- maternal
- external
- embryonic
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What endocrine issue can cause a problem in mares?
low progesterone levels
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Why can low progesterone levels cause problems?
- failure to recognize pregnancy
- insufficient primary CL
- uterine-induced leutolysis caused by endometrial irritation
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What are some issues with oviductal environment?
- reduced levels of embryographic factors
- increased levels of embryotoxic factors
- poor timing of oviduct transport
- salpingitis
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What is salpingitis?
inflammation of fallopian tubes due to bacterial infection
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What are some issues with the uterine environment?
- endometritis
- periglandular fibrosis
- intraluminal fluid accumulation
- endometrial cysts
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Why is age a problem in mares?
- reproductive efficiency declines with age (increased embryonic death rates in older mares)
- degeneration of uterus
- oocyte quality decreases since eggs are older
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Why can bad nutrition cause a problem in mares?
- cause decline in body condition score
- causes delayed uterine involution and persistent endometriosis
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What is pneumovagina?
air is sucked into the vulva
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What is urovagina?
pooling of urine in the vagina
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What is pendant uterus?
allows for poor drainage and fluid accumulation
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Why do age-related anatomic changes cause issues?
- genital tract changes over time with age and the number of pregnancies
- this can cause certain problems that can contribute to infections that can compromise fetal-placental unit
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What are some external factors that can result in embryonic loss?
- stress
- inadequate nutrition
- ingestion of toxins or infectious agents
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Why is stress bad?
can cause a decrease in progesterone
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What are some embryonic factors that can cause embryonic loss?
- small size (get lost in folds)
- morphological defects
- embryos from sub fertile mares transferred to healthy recipient mares
- chromosomal abnormalities
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How can you diagnose embryonic death?
- small for age embryonic vesicles
- retarded development of the embryo
- abnormalities of embryo location and orientation
- development adjacent to endometrial cysts
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How can you treat increased uterine edema during early pregnancy?
progesterone and progestrogen supplements
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If a viable embryo is not located by day 30, what can you do?
give PGF2a
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pregnancy loss beyond the embryonic period:
- occurs after day 40 of gestation
- usually no signs or warnings
- expelled fetus and membranes are often found in stall bedding or pasture but can go unnoticed
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What can cause placental dysfunction?
- acute or chronic placentitis
- hypoxia
- defective placenta
- inadequate attachment
- edema of placenta
- maternal disease
- malnutrition
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What can result from placental dysfunction?
- malformed fetus
- mummification
- abortion
- lack of fetal growth
- prematurity
- stillborn foals
- weak foals
- death
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What is an acute abortion?
occurs with no premonitory signs, such as EHV-1
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What is a chronic abortion?
premonitory signs such as twins and bacteria
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How is an abortion diagnosed?
laboratory analysis of tissues and fluids
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What is twinning?
- embryo can split and make twins
- either abort pregnancy or choose one and pinch it to get rid of one
- usually relates in late term abortion of both are kept
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What is a body pregnancy?
- conceptus fixates to uterine body during early pregnancy
- abortion occurs later, most often due to placental insufficiency
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What is premature placental separation?
- most often occurs during birth
- aka red bag
- if caught early enough you can save them
- flush mare for retained placenta
- placenta separates without rupturing, causing hypoxia/anoxia
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What is uterine torsion?
- occurs mid to late term
- twisting of uterus
- flip the mare to try to untwist if it is less than 180 degrees
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What is hydrallantosis or hydraminosis?
- results of a malfunction of the uterus or placenta, causing an increased production and accumulation of fluid in the amnionic sac or allantoic sac
- can cause the fetus to drown
- can be caused by an infection, sometimes you can catch it
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What is a ruptured prepubic tendon?
- occurs in older mares with hydrallantois or carrying a large fetus or twins
- results in loss of ventral abdominal support to pelvis
- either induce labor to save the mare or use support wraps and nursing care to save the foal
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What are some gestational abnormalities?
- twinning
- body pregnancy
- PPS
- uterine torsion
- hydrallantois/hydraminosis
- ruptured prepubic tendon
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