Event-time analysis of the effect of 60-day milk production on the parturition-to-conception interval in dairy cows.

OBJECTIVE To quantify the effect of early-lactation milk and milk fat production on time to conception. DESIGN Event-time analysis (survival analysis). SAMPLE POPULATION 44,450 cows delivering calves between September 1985 and September 1986, from 6,227 Ayrshire dairy herds in 80 Finnish communities. PROCEDURE Primiparous and multiparous cows were… CONTINUE READING