Postpartum factors and fertility in dairy cows

Abstract

Normal reproductive function should return by 50 days postcalving and depends on complete uterine involution, clearance of uterine pathogens, and resumption of ovarian cycling. Delays in resumption of ovarian cycling beyond 35 days postcalving, failure to clear uterine pathogens, excessive adipose tissue mobilization and body condition loss, increased blood ketones, and decreased serum glucose are associated with decreased pregnancy to first insemination and increased pregnancy loss in cows that do conceive. Overall, health issues and delays in ovulation have an odds ratio of conception to first insemination of 0.54 - 0.39 relative to cows with early ovulation and no infectious or metabolic health problems. Embryonic losses are approximately 16.5% in cows with no health problems and 27% in cows with postcalving health problems. Significant proportions of cows with health problems challenge the ability of farm managers to achieve pregnancy rates that result in economic optimal reproductive performance.