Objective—To compare use of 4 disease severity scoring systems to predict bacteremia (yes vs no) and outcome (survived vs died or culled) in dairy cows with acute coliform mastitis (ACM).
Design—Retrospective cohort study.
Animals—99 dairy cows with ACM.
Procedures—Cows were classified as having mild, moderate, or severe disease with a scoring system based on systemic disease signs alone (systemic severity score [SSS] system), a system based on local disease signs alone (local severity score [LSS] system), and 2 previously described systems based on a combination of local and systemic signs (local-systemic score 1 [LS1] and local-systemic score 2 [LS2] systems). Test performance was calculated to determine whether a severe disease classification could be used to predict bacteremia or outcome.
Results—21%, 53%, 63%, and 38% of cows were classified as having severe disease with the SSS, LSS, LS1, and LS2 systems, respectively. For both bacteremia and outcome, sensitivity was highest for the LS1 system, but specificity and accuracy were highest for the SSS system. Examination of a scatterplot of true-positive rate versus false-positive rate for each of the scoring systems indicated that the SSS and LS2 systems were similar in their ability to correctly identify cows with bacteremia or an adverse outcome.
Conclusions and Clinical Relevance—Results suggest that the SSS scoring system was better for identifying cows with bacteremia or an adverse outcome than was the LSS system and that the LS1 and LS2 systems were intermediate in their discriminatory abilities.
Objective—To evaluate the use of systemic disease
signs for classifying severity of acute coliform mastitis
in dairy cows.
Design—Prospective cohort study.
Animals—144 dairy cows.
Procedure—Cows were examined at the time of initial
identification of disease (time 0) and classified as having
mild, moderate, or severe disease on the basis of
rectal temperature, hydration status, rumen contraction
rate, and attitude. A CBC and serum biochemical
analyses were performed, and milk samples were submitted
for bacterial culture at time 0 and 48 hours later.
Results—69 cows were classified as having mild disease,
44 as having moderate disease, and 31 as having
severe disease. Median WBC and neutrophil
counts were significantly lower in cows with moderate
or severe disease at time 0 than in cows with mild
disease. Band neutrophil count was significantly higher
at 48 hours and serum calcium concentration was
significantly lower at time 0 and at 48 hours in cows
with severe or moderate disease, compared with
cows with mild disease. Twenty-eight, 51, and 77% of
cows with mild, moderate, and severe disease,
respectively, had > 100,000 colony-forming units/ml
of milk at time 0. The odds that a cow with severe disease
would die or be culled were 3.6 times the odds
for a cow with moderate disease and 11.2 times the
odds for a cow with mild disease.
Conclusions and Clinical Relevance—Results suggest
that a classification scheme based on readily
observable systemic disease signs can be used to
classify disease severity in cows with acute coliform
mastitis. (J Am Vet Med Assoc 2001;218:567–572)
ANIMALS 1,081 dogs training or competing in agility events.
PROCEDURES Data were collected for eligible animals via retrospective surveys distributed electronically to handlers of dogs participating in agility-related activities. Variables evaluated included demographic (handlers) and signalment (dogs) information, physical characteristics of dogs, and injury characteristics. A separate survey of dogs competing in similar agility-related activities but without digit injuries was also administered. Multivariable logistic regression was used to develop a model for assessment of risk factors.
RESULTS Data were collected from 207 agility dogs with digit injuries and 874 agility dogs without digit injuries. Factors associated with significantly increased odds of injury included Border Collie breed (OR, 2.3; 95% confidence interval [CI], 1.5 to 3.3), long nails (OR, 2.4; 95% CI, 1.3 to 4.5), absence of front dewclaws (OR, 1.9; 95% CI, 1.3 to 2.6), and greater weight-to-height ratio (OR, 1.5; 95% CI, 1.1 to 2.0). Odds of injury decreased with increasing age of the dog (OR, 0.8; 95% CI, 0.76 to 0.86).
CONCLUSIONS AND CLINICAL RELEVANCE Results should be cautiously interpreted because of potential respondent and recall bias and lack of review of medical records. Nevertheless, results suggested that retaining healthy dewclaws, maintaining lean body mass, and trimming nails short for training and competition may decrease the likelihood of digit injuries. Research to investigate training practices, obstacle construction specifcations, and surface considerations for dogs competing in agility activities is indicated.
Case Description—Severe disease and death were identified in cattle exhibited at a state fair that were naturally infected with ovine herpesvirus type 2 (OvHV-2).
Clinical Findings—Most affected cattle had anorexia, signs of depression, diarrhea, fever, and respiratory distress ultimately leading to death. Mean duration of clinical signs prior to death was 6 days (range, 1 to 26 days). Mean number of days between apparent exposure and death was 71 days (range, 46 to 139 days).
Treatment and Outcomes—19 of 132 cattle cohoused in 1 barn died of malignant catarrhal fever (MCF). The diagnosis of sheep-associated MCF was confirmed on the basis of results of an OvHV-2–specific PCR assay performed on tissue samples obtained from affected cattle. The disease was associated but not significantly with distance from the center of the barn and was not associated with distance from the center of the sheep pens.
Clinical Relevance—Outbreaks of MCF in cattle are unusual, particularly in association with livestock exhibitions. Because the clinical signs may be similar to those of some transboundary diseases, cases of MCF should be reported and investigated. Findings for this outbreak provided evidence to suggest that fair boards and veterinarians should reexamine biosecurity recommendations for livestock exhibitions.
Objective—To determine the incidence of bacteremia
in dairy cows with naturally occurring acute coliform
mastitis (ACM) with a wide range of disease severity.
Animals—144 dairy cows with ACM from 6 herds.
Procedure—Cows were examined at time of identification
of ACM (time 0) and classified as having mild,
moderate, or severe mastitis on the basis of rectal temperature,
hydration status, rumen contraction rate, and
attitude. Cows were reexamined at 24 or 48 hours.
Bacteriologic culturing of milk and blood (30 ml), CBC,
and serum biochemical analysis were performed at
each time point. Appropriate samples were obtained at
a single point from herdmates without mastitis (controls)
that were closely matched for lactation number
and days since parturition. Blood culture results were
compared among severity groups and controls by use
of χ2 tests, as was outcome of an ACM episode for
cows grouped by blood bacterial isolates.
Results—Bacteria were isolated from 52 blood samples
from 46 of 144 (32%) cows with ACM, which was significantly
more than control cows (11/156; 7.1%). Group-1
isolates (Escherichia coli, Pasteurella multocida,
Mannheimia haemolytica, Klebsiella pneumoniae,
Enterobacter agglomerans, and Salmonella enterica
serotype Typhimurium) were identified in 20 of 144 (14%)
cows with ACM and 0 of 156 control cows. Group-1 isolates
were identified in 4.3, 9.1, and 42% of cows classified
as having mild, moderate, and severe ACM, respectively.
Escherichia coli and K pneumoniae milk and blood
isolates obtained from the same cow were of the same
genotype. Bacillus spp were identified in 21 of 144 (15%)
cows with ACM, which was significantly more than control
cows (3/156; 1.9%). Thirty-five percent of cows with a
group-1 isolate died during the mastitis episode.
Conclusions and Clinical Relevance—Results suggest
that bacteremia develops in a substantial proportion
of cows with ACM. Classification of severity
of disease is important for establishment of effective
treatment protocols; parenteral antimicrobial treatment
may be indicated in cows with ACM. (J Am Vet
Med Assoc 2001;219:976–981)