Ultrasonography of Pyometra.
Pyometra in the cow manifests itself by the accumulation of pus in the uterus while the cervix is closed and the corpus luteum is maintained, with the result that the cow is anestrous. The cow is not systemically ill. On palpation per rectum the fluid can be made to move from one horn to another, in contrast with a gravid uterus of comparable size. There are no positive signs of pregnancy such as a membrane slip, presence of an amniotic vesicle or fetus or caruncles.
Pieterse MC (1999)