A scanning electron microscope study of the structural component of the bovine vaginal fluid at oestrus.

The ultrastructure of the vaginal fluid of cows at oestrus was analysed by scanning electron microscopy. Samples of vaginal fluid were collected from 7 normally cycling and healthy cows, 3 to 4 years of age, in oestrus. Evaluation of the patterns of crystallization was used as a previous assessment of the quality of the samples. SEM images revealed a structure made up of non-oriented filaments constituting a network with a three-dimensional arrangement. These filaments were of different diameters and ranged between 50 and 400 nm. Mesh size, defined as the minimum distance measurement between strands, ranged between 2 to 8 microns.