EQUINE | Equine Disease Quarterly
Equine Disease Quarterly
April 2020
COMMENTARY
One benefit of being older is the ability to reflect on
many equine medical crises. Contagious equine metritis
was the first notable crisis of my career, but I have
unfortunately witnessed numerous others including:
equine viral arteritis, leptospirosis, mare reproductive
loss syndrome, track breakdowns, and more recently
nocardioform placentitis. With each of these crises,
scientists have stepped up to search for solutions, and I
have seen first-hand the positive results that take place
when practitioners work with scientists on the medical
issues facing our horses.
This year central Kentucky has again been confronted
with a substantial increase in the number of nocardioform
placentitis cases. As with any case of placentitis, and
certainly with nocardioform placentitis, the first clinical
sign that the mare’s pregnancy may be compromised
is evident with “bagging up” early, which is horseman’s
lingo for premature lactation or increased udder size.
Unlike ascending placentitis, there is usually no vulvar
discharge in mares with nocardioform placentitis.
For the most part, it is relatively easy to diagnose
nocardioform placentitis after the mare has either
aborted or foaled, as the placenta is usually covered by
a very characteristic brown mucoid discharge—many
people think it looks like peanut butter. A diagnosis of
nocardioform placentitis is more challenging before
the mare delivers her foal (or fetus) and is made based
on clinical signs and abdominal ultrasound scans.
Nocardioform placentitis frequently forms lesions on
the ventral aspect of the placenta. This unique location
negates the usefulness of the standard placentitis
ultrasound measurement of the combined thickness of
the uterus and placenta (CTUP), which is taken by rectal
ultrasound of the uterus and placenta near the cervix.
With suspect nocardioform placentitis cases, one
may see a range of abnormalities on transabdominal
ultrasound scans. These include pockets of separation
with apparent exudate between the uterus and placenta
and signs of placental inflammation. It is important to
note that not all lesions will be apparent by this method,
and placental examination for lesions should still be
done after abortion or parturition.
The greatest incidence of nocardioform placentitis
occurs in December, January, and February. As we enter
March, the number of cases should soon decrease. While
we have unfortunately seen an increased incidence of
nocardioform placentitis this year, one positive is that
more cases have been examined and increased samples
have been collected to better understand this unique
condition.
CONTACT
Tom Riddle, DVM, [email protected], (859) 233-0371,
Rood and Riddle Equine Hospital, Lexington, Kentucky
16 • Equine Health Update •