EN
There were analysed 658 cases of placenta retention in Low-Land-Black-and-White cows from 49 villages situated in the central-west region of the Ostrołęka voivodeship. Each year in 1.4—3.4% parturitions the retention of placenta was noted (a mean value 2.7%), mainly in cows ageing 3—8 years (79%), Comparing to the years 1984—1985 in 1986—1989 increased the number of parturitions with the retention of placenta by 61—143% of parturitions. Increased significantly also a percentage of abortions (from 6.8% to 11.4%), premature parturitions (from 2.4 to 4.5%) still born calves (from 11.4% to 18.9%) and multiple births (from 2.3% to 16.5%), monsters and developmental disturbances in newborns (from 0.6% to 4,5%) and complications after the retention of placenta (from 6.8% to 17.1%). Maximum number of parturitions was noted in autumn (29.4%) but the retention of placenta in spring (32.2%). It was not found any correlation between the intensity of calvings and frequency of the retention of placenta. In twin calvings cows spontaneously discharged one placenta and in the genital tract one placenta was retained.