Interpretation of Specialty Exams 
Hematology: Blood cultures are often negative in cases of 
osteomyelitis due to intermittent bacteremia. 
Urinalysis: Urine specific gravity is normal, assuming the 
calf is well-hydrated.  A one-time evaluation of urine 
specific gravity above 1.025 for a ruminant assumes the 
ability to concentrate the urine.  Since the calf is able to 
nurse normally, and there is no mention of dehydration, the 
specific gravity may be accepted as normal.  If the calf had 
been dehydrated, we would like to see a higher specific 
gravity to show he is able to concentrate the urine.  
Otherwise the urinalysis is normal. 
Culture and Sensitivity of Fracture site: mixed infection of 
Staphylococcus aureus (probably from the animal's or the 
handler's skin) and E. coli (from dirt contamination of 
the wound).    These two bacteria are the most common causes 
of osteomyelitis.  The sensitivity results will help direct 
effective therapy.  Gentamicin is not approved for cattle and 
has a tremendous withdrawal time, so the amoxicillin-
gentamicin combination would be inappropriate, and the third 
generation cephalosporin, Ceftiofur, which is approved in 
cattle, should be selected to manage the bacterial 
osteomyelitis. 
Radiographs: The open, distal diaphyseal fracture of the 
metacarpals is too infected and remodeled to determine 
whether the several small radioopacities between the large 
fragment ends are osteophytes and enthesophytes beside an 
originally simple fracture or bone fragments from an 
originally comminuted fracture.  The radiographs show 
evidence that the ends of the original fracture did not 
unite.  This suggests delayed union of the fracture.  This is 
a viable delayed union, categorized as either slight 
hypertrophic or oligotrophic based on callus formation.  
There is also active periosteal reaction to the steomyelitis, 
seen as periosteal new bone formation, lysis of medullary and 
cortical bone with indistinct margins (this is possible, but 
hard to evaluate due to the combination of insults to the 
bone).