Received: 23 October 2017
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Revised: 27 March 2018
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Accepted: 1 May 2018
DOI: 10.1111/jvim.15223
Journal of Veterinary Internal Medicine
STANDARD ARTICLE
Use of a national identification database to determine the lifetime prognosis in cattle with necrotic laryngitis and the predictive value of venous pCO2 Bart Pardon1
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Stefaan Ribbens2 | Lien Van Damme1 | Lieven Vlaminck3 |
Ann Martens3 | Piet Deprez1 1 Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium 2 Animal Health Service Flanders, Industrielaan 29, Torhout, Belgium 3
Department of Surgery and Anaesthesiology of Domestic Animals, Ghent University, Salisburylaan 133, Merelbeke, Belgium
Background: Necrotic laryngitis, caused by Fusobacterium necrophorum, frequently requires surgical intervention (laryngostomy) in the chronic stage. Hypothesis/Objectives: To determine survival until slaughter of cattle surgically treated for necrotic laryngitis and to identify predictors of mortality. Animals: A total of 221 cattle diagnosed with necrotic laryngitis by laryngoscopy and surgically treated Methods: Retrospective cohort study. Clinical records were matched with the national cattle iden-
Correspondence Bart Pardon, Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium. Email:
[email protected]
tification, registration, and movement database. Information on possible predictors including clinical examination, biochemistry, and surgery was collected. A multivariable Cox proportional hazard model was used to identify predictors of mortality. Results: The overall survival rate was 65.2% and 58.6% of the animals with a completed life cycle could be slaughtered. Animals 0.60, only the most significant predictor was added to the mul-
(R, 20–172) and 93.627/min (R, 40–150), respectively. Rectal tempera-
tivariable model. The final multivariable model was built in a stepwise
ture averaged 39.6 6 0.88C (R, 37.3–42.4). Laryngoscopy showed par-
backwards manner, gradually excluding nonsignificant variables. Next,
tial and total absence of arytenoid movement in 85.1% (40/47) and
all biologically relevant 2-way interactions of significant fixed effects
14.9% (7/47) of the cases, respectively. The arytenoids were severely
were tested. Significance was set at P < .05. Wald’s test was used to
swollen in 90.8% (109/120) of the cases and moderately swollen in
assess parameter estimate significance. Visual inspection of the log-
9.2% (11/120). Necrotic tissue could be visualized in 84.1% (37/44) of
cumulative hazard plots and construction of time-varying covariates
the cases. Of the calves, 58.1% (93/160) were hypercapnic on venous
were used to evaluate the proportional hazard assumption. Diagnostic
blood (pCO2 > 51 mm Hg) and 11.9% (19/160) had too low pCO2
accuracy (sensitivity and specificity) was determined by means of logis-
( 7.45), and the majority
ear regression (PROC MIXED) was used to explore the relationship
(53.2% [82/154]) had normal venous pH. Further details on clinical
between partial pressure of carbon dioxide (pCO2) and other predic-
examination, blood gas analysis, and electrolytes are presented in Table
tors. All values are presented as mean 6 standard deviation (SD).
1. Laryngostomy was performed in 95% (210/221) of cases and tracheotomy in only 5% of cases (11/221).
3 | RESULTS 3.2 | Survival analysis 3.1 | Descriptive results
Of the 221 cases, 49.3% (109/221) were slaughtered, 34.8% (77/221)
Of the initial 239 records meeting the inclusion criteria in the 8-year
died, 1.4% (3/221) were exported and 14.5% (32/221) were still alive
study period, 221 could be matched with the national database. The
at the time of analysis. The overall survival rate was 65.2% (Figure 2).
annual number of admitted cases in the period 2008–2011 ranged
Of all animals that had completed their life cycle, 58.6% (77/186) could
between 33 and 37 cases, whereas this number was much lower from
be slaughtered. The majority (approximately 20%) died in the first 60
2012 to 2016 (range, 16–24 cases per year). The study population con-
postoperative days (Figure 2) and 6.3% (14/221) died at the clinic in
sisted mainly of Belgian Blue beef cattle (96.8% [214/221]) and other
the first year post-operative period, 30.3% (67/221) died, but detailed
breeds were Maine Anjou (n 5 1), Holstein Friesian (n 5 2) or cross-
information on the cause of death was not available. The median sur-
breds (Maine Anjou crossed with Belgian Blue [n 5 1]). There were
vival time was 340.7 6 298.3 days (R, 16–2201) for slaughtered
4
| Journal of Veterinary Internal Medicine
PARDON
ET AL.
Results of the univariable survival analysisa for potential categorical predictors of mortality after surgical treatment of laryngeal necrobacillosis in cattle (221 cases)
T AB LE 1
Parameter
Category
Observed mortality (%) (number/total)
Breed
Belgian Blue Other
35.5 (76/214) 0 (0/4)
.31
Sex
Female Male
32.7 (32/98) 36.1 (44/120)
.09
Age
6 months
50.0% (47/94) 23.6% (30/127)
