Page 472 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 447

VetBooks.ir 2.54 2.55

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Fig. 2.55 Ultrasound image allowing measurement
of the combined thickness of the uterus and placenta
(CTUP). The distance between the uterine vessel and
Fig. 2.54 Vulval discharge in a pregnant mare with allantoic fluid is measured three times (x-x on screen)
placentitis. and averaged. This is the CTUP measurement.

Vaginal/vulval discharge is an inconsistent sign in fluid assessment. Specifically, the CTUP should be
bacterial and fungal placentitis as the volume pro- measured. The probe should be positioned just cra-
duced may be quite low and go unnoticed (Fig. 2.54). nial to the cervix, then moved laterally until a uter-
Careful examination of the tail may reveal evidence ine blood vessel is identified on the ventral uterine
of a buildup of dry discharge over time. Abortion body. The distance between the uterine vessel and
or premature delivery may occur immediately or allantoic fluid is measured three times and aver-
be delayed, but is usually sporadic. EHV-induced aged. This is the CTUP measurement. Assessment
placentitis can result in abortion outbreaks. Post- of the placental fluids as described previously can
partum purulent or fetid vaginal discharge should also be made and monitored over the treatment
be investigated as a potential sign of pre-existing period. Transabdominal ultrasonographic examina-
placentitis and the foal monitored as high risk. tion allows more in-depth assessment of the fetus.
Following abortion or parturition, the placenta and
Differential diagnosis aborted foal should be examined carefully for any
Other causes of abortion. Other causes of vaginal gross diagnostic lesions (Fig. 2.56). Culture and
discharge: vulval trauma; premature placental sepa- histopathological examination of stained tissue sam-
ration; urine staining from urogenital disorder; vag- ples and smears from affected areas of the placenta/
inal varicose veins (old, multiparous mares). foal and/or swabs taken from the uterus post abor-
tion may help identify the pathogen (some bacteria
Diagnosis are difficult to isolate [e.g. Leptospira spp.]). ELISA
Any vaginal discharge should be sampled for cul- or agglutination tests are available for identification
ture and/or histopathology. Transrectal ultraso- of some pathogens. Blood samples for inflammatory
nographic examination allows assessment of the markers and haematology, together with plasma hor-
caudal placental thickness and cervical pole appear- mone measurement (progesterone and oestradiol),
ance (Fig. 2.55), together with fetal and placental may be helpful in diagnosing placental pathology.