Swedish University of Agricultural Science, Faculty of Veterinary Medicine, Department of Animal Hygiene, 532 00, Skara, Sweden

Swedish University of Agricultural Sciences, Department of Economics and Statistics, Uppsala, Sweden

Swedish Friesian Breed (SLB) had a higher incidence than Swedish Red and White Breed (SRB). The incidence showed a linear increase with age, both when analysing the entire data set and when analysing the frequencies in cows negative for risk factors shown to increase the incidence of retained placenta, e.g., twinning, parturient paresis and dystocia. Male calves increased the risk. Loose-housed cows of both breeds had a lower incidence than tied zero-grazing cows, suggesting exercise to be a sparing factor. An increased recurrence risk ratio was found in second, third and fourth calvings for SRB and in second and third calvings for SLB.

SRB cows with a positive report of retained placenta had an increased risk of removal during the lactation. In dystocia and parturient paresis negative SLB cows, retained placenta increased the risk of removal, whereas a positive report of this disease in dystocia and/or parturient paresis positive cows did not further increase the risk removal.