Physical Properties and Ionic Concentration of the Bovine Cervical Mucus at the Moment of Inseminating: Spontaneous Estrous and Induced Estrous

Abstract

Objective of the investigation was to characterize biochemically the cervical mucus collected prior to the artificialinsemination of Holstein heifers comparing spontaneous oestrus with induced oestrus. The concentration of sodiumand potassium was determined through flame photometry, chlorine ions by Schoenfeld reaction, magnesium andcalcium was determined through colorimetry in micro plates. pH (reactive tape) and degree of crystallization (opticalmicroscope) were also evaluated. Natural estrous was detected by observing the behavior of the heifers twice a dayand by observing the characteristics of the vulva. In order to induce oestrous, an intra vaginal device was placedwith 1 gm of progesterone and 2 mg of estradiol benzoate were injected (Day 0). On day 8 the device waswithdrawn and 0-150 mg of D-Cloprostenol and 1 mg of Estradiol Cypionate were provided. 56 hours afterwithdrawal, the device was inseminated and at 60 days of pregnancy determined. The cervical mucus of heifers withspontaneous oestrus showed lower content of sodium and potassium, higher magnesium and chlorine, and biggerproportion of sodium/potassium from that obtained by induce oestrus. When comparing the pregnant with the emptyheifers, it was discovered that at the moment of insemination, the pH value and the degree of crystallization ofpregnant heifers was significantly lower, same as the concentrations of potassium and magnesium. Sodium washigher in this group. Pregnancy was always related to high ionic level generating an osmotic force that draws waterto the cervical mucus, characteristic fundamental in transport of sperms.