USE OF OXYTOCIN IN GIROLANDO CATTLE: EVALUATION OF THE VAGINAL ROUT AS AN ALTERNATIVE TO INTRAVENOUS ROUT

Abstract

The aim of this study was to test the feasibility of vaginal route in order to apply oxytocin in female bovines using specific formulations. The oxytocin was used in its injectable form (as a comparison standard) and associated with absorption enhancers. Seven formulations containing 5 IU/ml of oxytocin each were used. The experimental design was an 8x8 latin square (eight days, eight treatments and eight cycling heifers). The formulations were delivered in vaginal route and the injectable oxytocin was applied intravenously, all of them having 10 IU of oxytocin. Blood samples (n=7) were collected from each animal, the first at time 0, prior to the administration of the treatment, and the following every three minutes until 18 minutes. Oxytocin was extracted from plasma using the C18 Sep-Pak column and measured with the commercial kit Oxytocin EIA. The responses were evaluated using the nonparametric ANOVA and the Kruskal Wallis test was used to compare the means. Statistical difference was observed between times 0 and 12 (p<0,05) for the oxytocin plus glycerin formulation, showing that absorption did occur. Nonetheless, it does not suppress the need for further research before it can be effectively used in female bovine management. 
Key-words: cows, milk yield, milking, milk ejection