Relationship between certain physical properties of cervical mucus and fertility in cows

The object of the present investigation was to determine several physical p roperties of cervical mucus in spontaneous oestrus cows in relation to fert ility. Because, it is very difficult to determine the exact time of the beg inning of oestrus in cows, the aim of the present study was to investigate if physical properties of cervical mucus at the time of artificial insemina tion (Al) are related to conception or not. A total of 93 cows of Friesian breed were used. The animals exhibited spont aneous oestrus, without being submitted to any hormonal treatment. Samples of cervical mucus were collected 5-30 min before Al and pH, viscosity, spin nbarkeit (spinability), crystallization and penetration were measured. Preg nancy diagnosis was performed by rectal palpation 3 months later. The resul ts obtained from cows that conceived (44 animals), compared to those obtain ed from cows that did not conceive (49 animals), were the following: a) viscosity had been significantly lower (p < 0.05), b) crystallization had been significantly higher (p < 0.05), and c) pH, spinnbarkeit and penetration of spermatozoa into cervical mucus did not differ. In conclusion, the best time for Al is when viscosity is below 20 mm H2O an d crystallization is above 3. Viscosity and crystallization could be relate d to ovulation time, but this needs further investigation.