Follicular Changes and Reproductive Performance in Postpartum Noncyclic Dairy Cows After Treatment with Progesterone and Estradiol or with Progesterone, GnRH, Prostaglandin F2α and Estradiol

The aim of this study was to investigate the effects of treatment methods including GnRH, PGF2α and estradiol hormones on follicular development and progesterone concentrations in postpartum noncyclic cows. The study material consisted of 20 noncyclic, Holstein breed cows (n= 20), which were randomly allocated to three groups according to the treatment protocols. In Group I (n=7), PRID with estradiol capsule was inserted for 12 d. Cows in Group II (n=6) were treated with 10 mcg of GnRH and PRID without estradiol capsule on Day 0 and 25 mg of PGF2α on Day 7 when PRID was removed. Cows in Group III (n=7) were treated same as Group II until PRID removal, then they were received estradiol benzoate 10 h after PRID removal. In response to GnRH treatment on Day 0, all six cows in Group II and 5 of 7 cows in Group III ovulated 2,5±0,2 d and 2,2±0,2 d after GnRH treatment with 12,0±0,7 mm and 11,0±0,9 mm follicle diameter. All cows (7/7) in Group I had a persistent follicles on the ovary following 12 d PRID treatment. Ovulations after PRID removal were detected on Day 4,8±0,6 and 3,5±0,3 d in Group II(4/6) and III (6/7), respectively. In conclusion, PRID (with capsule) treatment for 12 d was not successful to resume cyclicity and cause persistent follicle in noncyclic cows. However, resumption of cyclicity was similarly high in Group II and III in response to treatmens. In addition, cows in Group III ovulated earlier than Group II due to estadiol benzoate treatment (P<0.05)