Mark E. Carson BSc. (Agr). MSc., Gencor Herd Reproduction Analyst A difficult calving can effect a cow's performance throughout the entire lactation. An examination of calving ease performance of first lactation cows from five dairy herds shows the impact it can have on first service conception. Dairy Comp 305 calving ease data provided by DHI was compared with first service conception on first lactation cows. Calving Difficulty 1st Service Conception Rates # of First Lactation Cows Unattended or Easy 38% 195 Hard 22% 64 First lactation cows that had an Unattended or Easy Calving (U or E) were found to have a first service conception of 38%, while cows with a Hard Calving (H) had a conception rate of 22%. From these herds, having a trouble-free calving made the cows twice as likely to get pregnant on the first breeding! To reduce calving troubles, work to manage body condition scores, age at first calving and appropriate sire selection. Also, make sure you are providing proper assistance to cows that need help at the time of calving. Managing all of these things will help to ensure your cows have a better start and make the most out of their lactations.