Concentration of calcium, zinc, magnesium, potassium and sodium in the bovine cervical mucus during normal oestrus and oestrus induced by progesterone and/or PGF2α

Abstract

Ninety-two healthy Friesian cows were used to determine the concentration of calcium (Ca), zinc (Zn), magnesium (Mg), potassium (K) and sodium (Na) in bovine cervical mucus and to compare these concentrations in cervical mucus collected during spontaneous and induced oestrus. Cows were assigned to four groups: (1) no treatment (2) PRID for 12 days plus pregnant mare's serum gonadotrophin (PMSG; 1000 IU, i.m.) at the removal of the PRID (3) PGF_2α , two doses (6 mg, i.m.) 11 days apart, and (4) PRID for 7 days plus one dose of PGF_2α (6 mg, i.m.) 24 h before removal of the PRID. The cows of the three induced-oestrus groups received two artificial inseminations (AI), whereas those in the spontaneous-oestrus group received only one. Cervical mucus samples were collected from all cows 5 to 30 min before the first AI. The results of this study can be summarized as follows: (1) viscosity was significantly lower (P<0.001) and crystallization was significantly (P<0.001) higher in the cervical mucus of cows in the spontaneous-oestrus group compared with cows in the induced-oestrus groups; (2) Na concentration was similar in all groups; (3) concentration of all the other elements in the spontaneous-oestrus group was significantly lower (P<0.05) than in the induced-oestrus groups; (4) there was significant positive correlation (P<0.001) between viscosity and all elements, and significant negative correlation (P<0.05–P<0.001) between crystallization and all elements.