Year: 2013 | Month: April | volume 3 | Issue 1
Effect of pre-treatment follicular size on reproductive response of dairy heifers after PG2α induced estrus and GnRH administration on the day of artificial insemination
Abstract: The present study was designed to investigate the influence of pre-treatment follicular size on the reproductive response of dairy heifers after PGF2á injection and GnRH administration on the day of artificial insemination (AI). After transrectal ultrasound examination, fifty-two dairy heifers bearing corpus luteum (CL) were selected and divided into three groups: Group I (n=19) with small follicles (2-5 mm); Group II (n=18) with medium follicles (6-9 mm) and Group III (n=15) with dominant follicle (10-12 mm). <br><br>Each group was administered 500 mg PGF2 &#945; immediately after ultrasound examination (Day 0) and 100 µg GnRH at the time of AI,performed 80 hours after PGF2&#945; injection. A second ultrasound examination was done early morning on Day 3 (72 h) after prostaglandin treatment and presence of a pre-ovulatory follicle and clinical estrus signs were recorded.
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