Culling of dairy cows is probably one of the most complex decisions in dairy operations. It involves several factors and farmers consider e.g. stage of lactation, age, health status, level of milk production and current reproductive status of cows while making decisions about which cows to keep and which ones to call. The aim of this study was to determine the proles of culled cows in order to access the possible contribution to economic losses due to health disorders in the dairy herds of Khorasan province (Northeast of Iran). Data regarding all exits of cows from the herd were collected during a 5-year prospective survey in 15 large dairy commercial Holstein herds with over 4000 milking cows totally (From March 1999 to March 2004). All herds were recorded by an ofcial milk-recording scheme. The management and feeding systems were almost similar in all herds. Rolling herd’s averages were also similar in all herds; over 24000 lb. A polytomous stepwise logistic regression method was used because it allows the use of a non-ordinal categorical variable. The model was run (Procedure PR of BMDP). Table 1 shows the results of this study. The most frequent primary culling reasons were infertility and health disorders, 25.13, 28.57 of total cull respectively. Percentages of six groups of culling reasons for level of parity showed that the rst parity level had more frequent reproductive problems and health problems too. Therefore, in this study, more than one half of the cows were declared culled for health or reproductive related problems

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