Skip to main content

Research Repository

Advanced Search

Using simulation to interpret a discrete time survival model in a complex biological system: fertility and lameness in dairy cows

Hudson, Christopher D.; Huxley, Jonathan N.; Green, Martin J.

Authors

Jonathan N. Huxley jon.huxley@nottingham.ac.uk

MARTIN GREEN martin.green@nottingham.ac.uk
Professor of Cattle Health & Epidemiology



Abstract

The ever-growing volume of data routinely collected and stored in everyday life presents researchers with a number of opportunities to gain insight and make predictions. This study aimed to demonstrate the usefulness in a specific clinical context of a simulation-based technique called probabilistic sensitivity analysis (PSA) in interpreting the results of a discrete time survival model based on a large dataset of routinely collected dairy herd management data. Data from 12,515 dairy cows (from 39 herds) were used to construct a multilevel discrete time survival model in which the outcome was the probability of a cow becoming pregnant during a given two day period of risk, and presence or absence of a recorded lameness event during various time frames relative to the risk period amongst the potential explanatory variables. A separate simulation model was then constructed to evaluate the wider clinical implications of the model results (i.e. the potential for a herd’s incidence rate of lameness to influence its overall reproductive performance) using PSA. Although the discrete time survival analysis revealed some relatively large associations between lameness events and risk of pregnancy (for example, occurrence of a lameness case within 14 days of a risk period was associated with a 25% reduction in the risk of the cow becoming pregnant during that risk period), PSA revealed that, when viewed in the context of a realistic clinical situation, a herd’s lameness incidence rate is highly unlikely to influence its overall reproductive performance to a meaningful extent in the vast majority of situations. Construction of a simulation model within a PSA framework proved to be a very useful additional step to aid contextualisation of the results from a discrete time survival model, especially where the research is designed to guide on-farm management decisions at population (i.e. herd) rather than individual level.

Citation

Hudson, C. D., Huxley, J. N., & Green, M. J. (2014). Using simulation to interpret a discrete time survival model in a complex biological system: fertility and lameness in dairy cows. PLoS ONE, 9(8), doi:10.1371/journal.pone.0103426

Journal Article Type Article
Publication Date Aug 7, 2014
Deposit Date Aug 6, 2015
Publicly Available Date Aug 6, 2015
Journal PLoS ONE
Electronic ISSN 1932-6203
Publisher Public Library of Science
Peer Reviewed Peer Reviewed
Volume 9
Issue 8
DOI https://doi.org/10.1371/journal.pone.0103426
Public URL http://eprints.nottingham.ac.uk/id/eprint/29525
Publisher URL http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0103426
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0

Files

Hudson PLOSone 14.pdf (718 Kb)
PDF

Copyright Statement
Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0





You might also like



Downloadable Citations