Among the economic longevity of dairy cattle breeding goals for each trap., In recent decades, genetic evaluation of dairy cattle in addition traits, characteristics, shelf-life is also takes into consideration. Increase lifetime productivity by reducing replacement costs animals Prtvlyd an important role in increasing profits. The aim of this study assessed the genetic and genetic parameters of the productive life of dairy cattle in Isfahan Province Using survival analysis models respectively. The Database contains over 35,137 records that are productive life at calving between 1991 and 2012 AD did. Data animals were removed uncensored and animals were not removed until the present (February 2013) considered censorship. Number of observations per herd of at least 20 and at least 10 girls were considered for each parent. Estimate genetic parameters using the Weibull model and the software Survival Kit. The average life span of animals removed with 937.8 and Animals censored average 1002.8 days. Observed by an increase in somatic cells, increases the relative risk of removal. The milk was divided into five kashida; TEXT-ALIGN: justify; LINE-HEIGHT: normal; TEXT-KASHIDA: 0%; TEXT-INDENT: 0in; MARGIN: 0in 0in 0pt 17.85pt; unicode-bidi: embed; DIRECTION: ltr; mso-add-space: auto" Keyword : Survival analysis, Length of productive life, Censoring, Somatic cell count, Age at first calving
