Intrauterine application of flavonoids in puerperal dairy cows: reproductive tract involution and fertility at high-altitude environments

The main objective of the present study was to evaluate the effects of postpartum intrauterine administration of flavonoids in order to hasten reproductive tract involution and to shorten the parturition-to-conception interval in dairy cows. A total of 40 Holstein cows (2nd-3rd lactation; BC: 3-3.5) were divided randomly into 4 groups [1 control group (T1) and 3 treatment groups (T2, T3 and T4)]. Treatments consisted of one single intrauterine administration on day 10 postpartum of 90 mg (T2), 180 mg (T3) and 360 mg (T4) of ultrapure flavonoids (20 ml). Ultrasonographic measurements of different reproductive tract anatomical structures were scored from cervix (length, width and thickness), uterus (diameter and thickness) and ovaries (length and width) during the postpartum period (day 10, 15 and 21 postpartum). As fertility parameters rate of return to estrus, pregnancy rate and calving-to-conception interval were scored as well. Pregnancy status was performed using ultrasonography (day 35 post-insemination). There were multiple differences (p < 0.05) among reproductive tract structure dimensions (cervix and uterus) in values obtained from T1, T2, T3 and T4 groups after ultrasonographic analysis at day 10, 15 and 21. No significant differences were observed (p > 0.05) in ovarian dimensions from T1, T2, T3 and T4 groups during the postpartum period after ultrasonographic analysis at day 10, 15 and 21. Return to estrus index, pregnancy rate and calving-to-conception interval differed between T1 and T2-T3-T4 groups (p < 0.05), however, no differences were observed among T2, T3 and T4 groups (p > 0.05). In conclusion, intrauterine application of flavonoids enhanced the cervical and uterine involution. Finally, although no significant differences among treatments, theintrauterine application of flavonoids improved the return to estrus index, pregnancy rate and calving-to-conception interval compared with non-treated dairy cows.