Objective—To identify foal-related risk factors associated
with development of Rhodococcus equi pneumonia
among foals on farms with endemic R equi
Design—Prospective case-control study.
Animals—220 foals at 2 equine breeding farms in
Texas during a 2-year period.
Procedure—Information collected for each dam
included age, time housed on the farm prior to parturition,
whether there were any peripartum illnesses,
parity, and health of previous foals. Information collected
for each foal included breed, sex, gestational
age, month and year of birth, location of birth, type of
flooring and bedding in stall, postpartum management
and preventive health care, passive immunity
status, supplementation of immunoglobulins, exposure
to other farms or foals affected with R equi pneumonia,
stall and pasture exposure, commingling with
other mare-foal pairs, age at weaning, and whether
the foal developed R equi pneumonia.
Results—32 of the 220 (15%) foals developed R equi pneumonia, of which 4 (13%) died. Foals at 1 of the 2
farms and foals born during the second year of the
study were more likely to develop R equi pneumonia.
Foal-related factors that were examined were not significantly
associated with risk of R equi pneumonia in
Conclusions and Clinical Relevance—Results suggest
that there are farm- and year-related effects on
the risk that foals will develop R equi pneumonia.
Other foal-related factors significantly associated with
R equi pneumonia were not identified. (J Am Vet Med