Progesterone release profile and follicular development in Nelore cows receiving intravaginal progesterone devices.

This study aimed to evaluate the progesterone (P4) release profile provided by four commercially available intravaginal P4 devices, as well as the effect of circulating P4 concentrations exclusively from these devices on the development of the dominant follicle (DF) in Nelore (Bos indicus) cows. Therefore, non-lactating multiparous Nelore cows were enrolled in an experimental design, over three replicates, starting on Day -9 with the insertion of a reused P4 device (2 g - original P4 load) for 7 d, followed by two treatments of cloprostenol sodium (PGF; 0.482 mg), 24 h apart, on Days -3 and -2.

Progesterone release profile and follicular development in Holstein cows receiving intravaginal progesterone devices.

The aim of this study was to evaluate the progesterone (P4) release profile provided by eight commercial intravaginal P4 devices, as well as the effect of circulating P4 concentrations produced exclusively by these devices on the development of the dominant follicle (DF) in non-lactating multiparous Holstein cows. All cows were submitted to the same experimental design starting with the insertion of a reused P4 device (2 g - original P4 load) for 7 d, followed by two treatments of cloprostenol sodium (PGF; 0.482 mg), 24 h apart, 6 and 7 d after device insertion.