Metabolites in the cervical mucus of dual purpose cows in natural and induced estrus
The objective was to quantify cholesterol, sorbitol, and total protein concentrations in cervical mucus obtained from Swiss x Zebu crossbreed cows (n = 40), in order to associate the same with reproductive capability. Two experimental treatment groups were formed to observe natural (n = 20) and Synchro-Mate B® induced estrus (n = 20). Cervical mucus samples were collected during estrous cycle stages of proestrus, estrus, metaestrus, and diestrus and the cholesterol, sorbitol, and total protein concentrations were quantified by enzymatic reactions and spectrophotometry. All experimental cows underwent artificial insemination and pregnancy diagnosis by rectal palpation. Additionally, the effects of body condition and the estrous cycle stages on cervical mucus chemical composition were studied. The experimental design was completely randomized. Treatment, body condition, and estrous cycle stage all modified the cervical mucus metabolites concentrations (P<0.01). The cholesterol and total protein concentrations as well as changes therein were different during estrus and diestrus (P<0.01). The cows having cholesterol concentrations less than 20 mg.dl-1 at estrus and higher than 50 mg.dl-1 at diestrus, as well as protein values less than 2.5 g.dl-1 at estrus, and higher than 3 g.dl-1 at diestrus; showed higher gestation percentage (P<0.05). In conclusion, the chemical composition of cervical mucus is a useful tool to detect females of high reproductive capability.