The objective of this study was to examine if changes to the mammary gland are suitable for determining the precise time of parturition in suckler cows. The following parameters were examined in a total of 105 animals (heifers: 10, Simmental; cows: 95 - Simmental: 68; Simmental x Limousin: 27) every eight hours during the last seven days ante partum: mammary development, mammary edema and fore udder edema. Development of the udder and the number of animals with udder and fore udder edema increased with approaching parturition (p < 0.001). However, only 5.7 % of the animals had a completely developed udder with shiny teats filled with milk eight hours before parturition, whereas the teats of 32.4 % of the animals were not yet filled with milk at this time. 86.7% of the animals had an udder edema and 12.4 % of the animals had edema of the fore udder. The fore udder edema was observed in 50 % of the heifers and in 10.3 % of the cows. This difference is statistically highly significant (p < 0.001). No influence of the breed was detected on any of the three parameters. Changes of the mammary gland in cows are therefore not suitable for fixing the time of parturition precisely within the last seven days ante partum.