The use of Crestar in bos indicus heifers

Data reported in some publications suggest that due to the prolonged action of oestradiol valerate constituting an integral element of Crestar system has negative effect on follicular growth and resulting fertility in the induced oestrus in bos indicus heifers. These observations although not consistent should be considered.

Addition of 400 IU of eCG/PMSG (Folligon) at the time of implant removal, to stimulate follicular growth has been extensively used in postpartum cows giving very good results and facilitates the obtainment of acceptable pregnancy rates after FTAI in heifers. Apparently, the FSH-like activity of the eCG is sufficient to overcome the suppressive effect of the long acting EV.

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