Reporting of dystocia scores and effects of dystocia on production, days open, and days dry from dairy herd improvement data.

Dystocia and livability scores are collected through the Mid-States Dairy Records Processing Center. Thirty-four percent of the cows had dystocia scores reported. Least difficult births were scored 1 and the most difficult births scored 5. Days open in first parity were 14 d greater for births scored 5 versus 1. The differences were larger in later parities. There were 26 more d open in second parity and 19 more d open in third and greater parities for score 5 versus 1. Differences between cows scored 5 versus 1 were 465 kg milk and 20.7 kg milk fat in first lactations, 576 kg milk and 20.9 kg milk fat in second lactations, and 725 kg milk and 25 kg milk fat in third and greater lactations. Cows produced more in lactations following an easy birth. Frequency of difficult births was less in lactations other than the first.