FOP 2 Equine notes + presentation Flashcards

1
Q

overall pregnancy rate in mares

A

50%

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2
Q

in mares, when investigating failure of pregnancy, is it more important to investigate the placenta or the fetus?

A

arguably, the placenta

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3
Q

why is the birth of live twins so rare in horses?

A

lack of functional reserve in the equine placenta

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4
Q

when will we see a lack of villi in regions of the equine placenta?

A
  • Twinning, where the connecting surfaces of adjoining
    placentas meet.
  • Ascending infection, which is one of the common ways
    that agents gain access to the fetus and membranes in
    horses.
  • Premature separation of the placenta, that occurs, in
    part, with cervical laxity or with body pregnancies.
    >body pregnancy is where umbilical cord and fetus attach in body of placenta rather than horn: pushes out cervix, so we get avillus area where placenta sticks out of the ervix
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5
Q

length of the normal umbilical cord in the mare. What happens if it is too long, or too short?

A

-normal is between 36 and 83 cm long
-Longer may strangle the fetus, develop torsion, and necrosis of the cervical pole of the placenta.
- shorter may rupture prematurely in labour or prematurely separate at the site of attachment.

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6
Q

how many twists should the equine umbilical cord have?

A

The cord should have no more than 4 twists.

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7
Q

how often can we determine the cause of failure of pregnancy in the mare by examining the placenta and umbilical cord?

A

1/2 of cases

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8
Q

what region of the placenta is it important to examine to determine the cause of FOP in the mare? why?

A

cervical star
-most infectious cases (aside from EHV) are related to ascending vaginal infection

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9
Q

Infection and inflammation of the placenta releases what?

A

-proinflammatory cytokines that cause fetal ‘distress’ and abortion

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10
Q

what fetal changes can Equid alphaherpesvirus 1 cause?

A

An important cause of abortion and there are prominent changes in the fetus. One or more of the following may be found
* fibrin cast in the trachea
* interstitial pneumonia
* focal necrosis in the liver

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11
Q

common way to begin an outbreak of EHV-1 in a group of mares:

A

Introduction of an infected mare to a group of naïve mares

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12
Q

what type of vaccine do we have for Equid alphaherpesvirus 1?

A

killed vaccine that requires multiple injections

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13
Q

normal fetus to placenta weight ratio is what? why should we weight these?

A

normal ratio is 10:1
-can examine to identify placental edema – an indication of fescue toxicosis

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14
Q

What part of the chorioallantois would you routinely sample when investigating an abortion?

A

cervical star - this is where infectious disease occurs most often in equine placentas

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15
Q

Mummification of a fetus in mares is associated with what situations?

A

twins

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16
Q

How would you determine if there were torsion of the umbilical cord and what would you expect to find in the fetus to confirm this?

A
  • More than 3 twists in umbilical cord; look for evidence of fetal stress (meconium staining) or autolysis (indicating death prior to abortion)
    -see effects of venous, arterial, urachal obstruction
    -swelling of urachus
17
Q

What is the difference between an allantoic pouch and a chorioallantoic pouch?

A

chorioallantoic pouches - structures opposite the endometrial cups
allantoic pouches - 1 or 2 is normal, more is abnormal, accumulation of material in allantoic membrane. Basically, outpouchings of the allantois that may have a long stalk.

18
Q

Why does Streptococcus equi zooepidemicus cause abortion in mares when it only affects a small part of the placenta?

A

-occurs at cervical star: exudate and necrosis
Infection and inflammation of the placenta (placentitis) causes the release of inflammatory cytokines which result in fetal distress which can lead to abortion + equine placenta has a lack of functional reserve, so even a small loss of surface area can lead to FOP

19
Q

What is a hippomane?

A

found in the allantoic cavity in every mare placenta - allantoic precipitate, of the allantoic fluid: carbohydrate, protein…

20
Q

When is placental mineralization abnormal?

A

placental infarct can lead to abnormal mineralization due to necrosis
- Abnormal is there’s necrosis, inflammation, or not in ruminant/pig

normal:
- When in the chorioallantois in early pregnancy in ruminants, in yolk sac remnants, where adjoining placentae touch (pigs)

21
Q

what is unique about the cervix of the mare compared with other species?

A

it is “loose”, ie. a worse barrier to the outside world than in other species

22
Q

where do we find the fetus in the mare placenta? how is it positioned?

A

-arrangement is very consistent
-fetus always develops at the bifurcation of the uterus
-umbilical cord is always dorsal, with the foal lying on its back
-when the fetus gets big enough, the legs stretch into the non-pregnant horn, with head near the cervix

23
Q

how does the length of the umbilical cord compare with the lengths of the uterine horns?

A

-about the same length as the pregnant horn and a little but longer than the non-pregnant horn

24
Q

where does the mare placenta rupture during birth?

A

cervical star

25
Q

the horse is the only species that has what structure related to the yolk sac? where do we find this?

A

yolk sac remnant, in the allantoic portion of the umbilical cord
-attached to the umbilical cord and is quite often mineralized

26
Q

breakdown of common FOP diseases in the mare, broadly:

A

no diagnosis: 16%
non-infectious: 47% (mostly dystocia)
infectious: 37% (mostly bacteria)

27
Q

main sign of dystocia

A

meconium staining, indicates fetal distress

28
Q

congenital abnormalities we might see in the horse:

A

schistosomus reflexus: body division/reflection

29
Q

what is musculoskeletal disease and thyroid hyperplasia?

A

subtle disease, variety of skeletal abnormalities
-limb deformities, arthrogryposis, osteopetrosis

-microscopic hyperplasia of the thyroid
>found with poor feed in winter, with nitrite/nitrate, but probably more related to micronutrients

30
Q

what lesions will we see if fetus is aborted due to Equid alphaherpesvirus 1?

A

-fibrin cast in trachea: horse is the only species where this happens, due to bronchiolar necrosis
-interstitial pneumonia: solid, rubbery lungs
-focal necrosis on liver
-prominent lymphoid follicles in spleen (but this is seen in other cases too: every foal has this)

31
Q

umbilical cord too short - what happens?

A

<36cm, pulls chorion off endometrium, see large avillus region at the insertion of the cord

32
Q

umbilical cord too long - what happens?

A

> 83cm
-placental infarct: see mineral on placenta due to necrosis
-torsion (>3 turns): 3 or less is the norm. Hemorrhagic appearance, urine wont flow, venous and arterial obstruction.
-strangulation of foal

> cord too long causes problems because tiny fetal heart has to pump blood all through fetus and placenta, and it can’t generate that much pressure (large volume, low pressure system) - if you alter the pressure even slightly, you can cause fetal distress

33
Q

Fescue endophyte mycotoxicosis: what is it? where is it found? symptoms?

A

◼ Neotyphodium coenophialum: toxic disease that you get from this fungus
◼ Kentucky and southern Ontario!
◼ Ergot alkaloids (vasoactive and prolactin)
◼ Hyperthermia
◼ Placental edema and thickening
◼ Dysmaturity
◼ Prolonged gestation

34
Q

‘Mare Reproductive Loss Syndrome’ and ‘Equine
Amnionitis and fetal loss’ in 2002 were related to what?

A

Processionary caterpillars: eastern tent caterpillar, had tiny hairs which are consumed with food
>hairs penetrate intestine, uterus, and placenta, carrying with them bacteria that infect placenta, causing endotoxemia/bacteremia