Exiting is the departure of cows from the herd for several reasons. Cows are exited for a variety of reasons. The predominant reasons for exiting are reproduction (i.e., failure to conceive), health, and low production (Bascom and Young, 1998). Half of the herd removals occur involuntarily and prematurely because of health disorders (Beaudeau et al., 2000). On the other hand, the risk of exiting is not consistent across all stages of lactation. Cows experience the highest risk shortly after calving (Fetrow et al., 2006). Cow longevity is highly related to dairy farm profit. Only a few previous studies have characterized exited cows based on the associations between exiting reasons and cow economic characteristic. One of this important characteristic is the lactation stage when the cow is exited. There is, therefore, a need to evaluate the overall exiting reasons and the stage of lactation the cows exited the herd. The objective of this study was to study the days in milk at exiting in Iranian Holstein dairy cows.

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