1994, Number 2
Use of survival curves to evaluate the expectancy comparing disease and non-disease history in dairy cattle
PDF size: 339.54 Kb.
Text ExtractionThe purpose of this study was to evaluate the effect of diseases such as mastitis, metritis, pneumonia and tuberculosis over life expectancy in dairy cattle by means of survival curve procedures. Statistical differences were found for survival experience in cows with mastitis (P ‹ 0.00001), pneumonia (P ‹ 0.01) and tuberculosis (P ‹ 0.00001), compared to healthy cows. However, no statistical difference was found between survival curves for cows affected by metritis and those not affected (P= 0.30). The usefulness of survival curves for epidemiological studies in veterinary medicine is discussed.
Anderson, S., Auquier, A., Hauck, W.W., Oakes, D., Vandaele, W. and Weisberg, H.I.: Statistical Methods for Comparative Studies. John Wiley and Sons, New York, 1985.
Brown, B.B. and Hollander, M.: Statistics: A Biomedical Introduction. John Wiley and Sons, New York, 1977.
Campos, F.N. and Franco, E.L.: KMSURV: Univariate Survival Data Analysis in MS-DOS-Based Microcomputers. Manual del Usuario. Ludwing, Institute for Cancer Research: Epidemiology and Biostatistics Unit, Sao Paulo, Brasil, 1985.
Cox, D.R.: Regression models and life-tables. J.R. Stat. Soc. Ser. B, 34: 187-202 (1972).
Cricket Software: Cricket Graph. Version 1.2. Cricket Software, Malvern, Philadelphia, 1987.
Cuttler, S. and Ederer, F.: Maximum utilization of the life-table method in analysing survival. J. Chronic Dis., 8: 699-712 (1958).
Kalbfleisch, J.D. and Prentice, R.L.: The Statistical Analysis of Failure Data. John Wiley and Sons, New York, 1979.
Kaplan, E. and Meier, P.: Non-parametric estimation from incomplete observations. J. Am. Stat. Ass., 53: 457-481 (1958).
Lawrence, M.F., Furberg, D.C. and DeMets., L.D.: Fundamentals of Clinical Trials. 2nd ed. PSG, Littleton, Massachussets, 1985.
Miller Jr., R.G.: Survival Analysis. John Wiley and Sons. New York, 1981.
Peto, R., Pike, M.C., Armitage, P., Breslow, N.E., Cox, D.R., Howard, S.V., Mantel, N., McPherson, K., Peto, J. and Smith, P.G.: Design and analysis of randomized clinical trials requiring prolonged observations of each patient I. Introduction and design. Br. J. Cancer., 34: 585-612 (1976).
Peto, R., Pike, M.C., Armitage, P., Breslow, N.E., Cox, D.R., Howard, S.V., Mantel, N., McPherson, K., Peto, J. and Smith, P.G.: Design and analysis of randomized clinical trials requiring prolonged observations of each patient. II. Analysis and examples. Br. J. Cancer, 35: 1-39 (1977).