FOP 3 Bovine notes + presentation Flashcards
when does abortion occur after infection with Pestivirus A/B (BVDV)? what lesions can will we see?
Abortion occurs 10 to 27 days after infection, but there may be no macroscopic or histological lesions, and virus isolation is not always successful.
how can we identify the cause of abortion as caused by organisms vs contaminants? what should we observe?
Examination of the placenta is focused on identifying lesions caused by infectious agents.
Basic observations should include
* freshness
* placental and fetal weight
* distribution of lesions, both within each membrane
and between membranes
how much should the placenta weigh compared to the bovine fetus?
Placental weight is usually about 14% of fetal weight.
Placental insufficiency would cause this ratio to be lower.
what does the distribution of lesions in the bovine placenta tell us?
The distribution of lesions assist in determining the route of entry of the agent. The usual possibilities include ascending infection through the cervix, descending through the uterine tube, and random multifocal if hematogenous.
Ureaplasma diversum typically causes what type of lesions?
amniotic lesions
why do infecting agents have more access to the bovine amniotic fluid vs in other species?
because the amnion and chorion are fused over a part of their surface area, infecting agents have a more direct access to amniotic fluid than is the case in the horse, cat and dog.
why do infecting agents have more access to the bovine amniotic fluid vs in other species?
because the amnion and chorion are fused over a part of their surface area, infecting agents have a more direct access to amniotic fluid than is the case in the horse, cat and dog.
Abnormalities of the placenta seen in disease include:
- necrosis and infarction
- fibrin exudation
- edema
- cupping of the cotyledon
- fibrosis and thickening
- exudation onto the surface
- mineralization
- vasculitis
Fetal heart failure as a cause of abortion occurs with:
Heart failure as a cause of abortion occurs with
-BVD myocarditis (Pestivirus A/B)
-Neospora myocarditis,
-nutritional myopathy (Vitamin E / Selenium deficiency).
> note messed up liver
Fetal dermatitis is associated with
mycotic abortion
>note thickened skin, exudate, esp in neck and shoulder regions
(aspergillis fumigatus)
amnionitis is associated with
Ureaplasma abortion.
rarely: mycotic or bacterial
Focal necrosis in the liver or other fetal tissues suggests
-herpesviral infection (IBP/IPV).
-listeria
Samples collected for investigation of infectious causes of abortion should include the tissues most often affected:
bovine brain and heart especially. In addition, tissues that sample amniotic fluids are a must to collect.
proportion of cases that are infectious vs non-infectious vs unknown in bovine (by examining placenta):
No diagnosis (58%) –most likely not going to get diagnosis from sporadic cases
Non-infectious (1%)
Infectious (42%) – more important in bovine than equine!!!!
are we usually able to diagnose the reason for a sporadic failure of pregnancy in cows?
no
