Exiting is a complex issue, and many factors are involved in the decision to exit a cow. Farmer consider many cow factors, such as age, stage of lactation, milk production, health status, disposition, and reproductive performance, when determining whether or not a cow should be exited (Beaudeau et al., 2000). The exiting decision may also be affected by economic factors, such as milk price, the price of exited cows, and the price and availability of replacement heifers. In addition, the attitudes of farmers have an effect on which cows are removed from a herd (Bascom and Young, 1998). Iranian dairy production has undergone significant and considerable structural changes during the last two decades with creation of larger herds. Replacement of dairy cows is a major expense for producers. To keep a cow until a higher parity allows the farmer to spread over a longer period the difference between the production cost of the replacement heifer and the carcass value of the exited cow (Seegers et al., 1998). In Iran, the increased price for replacement heifer in the last several years has increased the interest in increasing productive life and there by lowering exiting rates. Analyses of the reason of exiting are needed to predict herd performance and maximizing herd profit. The objective of this study was to study the reasons for exiting in Iranian Holstein cows.

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