[Practice-oriented approach to secondary retention in cattle].
Veterinary practice research carried out from 1983 to 1986 showed that the incidence of retained placenta in cows decreased from 13.6% in 1983 to 9% in 1986. A possible relationship with the use of Holstein-Friesian breed during this period has been mentioned but not substantiated. Detailed data were collected for 503 cows treated for retained placenta with the aim of gaining insight into the cause of the problem. The data showed that there are two types of retained placenta (1). The type that cannot be 'peeled off', which occurs in animals that have given birth unexpectedly and too early and in cattle that calved unexpectedly after a normal or extended gestation; and (2) the type that can be 'peeled off', which occurs in animals with a normal parturition after a normal or extended gestation. Some cows were fed silage in the last month of gestation; 67% was of moderate-to-poor quality and 37% was of good quality.