Rate of transmission: a major determinant of the cost of clinical mastitis

Down, P.M.; Green, Martin J.; Hudson, C.D.

Abstract

The aim of this research was to use probabilistic sensitivity
analysis to evaluate the relative importance of
different components of a model designed to estimate
the cost of clinical mastitis (CM). A particular focus
was placed on the importance of pathogen transmission
relative to other factors, such as milk price or
treatment costs. A stochastic Monte Carlo model was
developed to simulate a case of CM at the cow level and
to calculate the associated costs for 5 defined treatment
protocols. The 5 treatment protocols modeled were 3 d
of antibiotic intramammary treatment, 5 d of antibiotic
intramammary treatment, 3 d of intramammary and
systemic antibiotic treatment, 3 d of intramammary
and systemic antibiotic treatment plus 1 d of nonsteroidal
antiinflammatory drug treatment, and 5 d of
intramammary and systemic antibiotic treatment. Uniform
distributions were used throughout the model to
enable investigation of the cost of CM over a spectrum
of clinically realistic scenarios without specifying which
scenario was more or less likely. A risk of transmission
parameter distribution, based on literature values, was
included to model the effect of pathogen transmission
to uninfected cows, from cows that remained subclinically
infected after treatment for CM. Spearman rank
correlation coefficients were used to evaluate the relationships
between model input values and the estimated
cost of CM. Linear regression models were used to
explore the effect that changes to specific independent
variables had on the cost of CM. Risk of transmission
was found to have the strongest association with the
cost of CM, followed by bacteriological cure rate, cost of
culling, and yield loss. Other factors such as milk price,
cost of labor, and cost of medicines were of minimal
influence in comparison. The cost of CM was similar for
all 5 treatment protocols. The results from this study
suggest that, when seeking to minimize the economic
impact of CM in dairy herds, great emphasis should be
placed on the reduction of pathogen transmission from
cows with CM to uninfected cows.

Citation

Down, P., Green, M. J., & Hudson, C. (2013). Rate of transmission: a major determinant of the cost of clinical mastitis. Journal of Dairy Science, 96(10), https://doi.org/10.3168/jds.2012-6470

• Journal Article Type: Article
• Publication Date: Oct 1, 2013
• Deposit Date: Apr 22, 2014
• Publicly Available Date: Apr 22, 2014
• Journal: Journal of Dairy Science
• Print ISSN: 0022-0302
• Electronic ISSN: 1525-3198
• Publisher: American Dairy Science Association
• Peer Reviewed: Peer Reviewed
• Volume: 96
• Issue: 10
• DOI: https://doi.org/10.3168/jds.2012-6470
• Public URL: https://nottingham-repository.worktribe.com/output/1000999
• Publisher URL: http://www.journalofdairyscience.org/article/S0022-0302(13)00555-9/abstract