Abstract
Cystic ovarian follicle “COF” is a common ovarian disorder diagnosed in dairy cattle that cause significant economic losses in dairy industry. This study was designed to evaluate efficacy of different therapeutic protocols of COF without determining cyst type. The study was conducted on 104 Holstein-Friesian cystic cows that were divided randomly to the following treatments: Experiment Ι: 1) Group G, n=27, subdivided into A) n=13: treated with 20μg Buserelin-GnRH agonist and B) n=14: treated with 100μg Gonadorelin-GnRH agonist; 2) Group GP, n=23: received 20μg Buserelin on day 0- 500μg of PGF2α on day 10; 3) Group GGP, n=27: received 2 doses of 20μg Buserelin 7 ds apart followed by 500μg PGF2α 7ds from the 2nd Buserelin injection; 4) Group GPG (Ovsynch), n=17: received 20μg Buserelin on day 0- 500μg PGF2α on day 7- 48hrs later, 20μg Buserelin was injected; 5) Group C, n=10: no treatment received. 22 normal cycling cows were kept as a normal control-NC. Experiment ΙΙ: This part of the study was conducted on 34 cystic animals that did not respond to one of the previous treatments in experiment Ι and were divided into 2 groups: 1) Group CGP, n=19: CIDR+100μg Gonadorelin- (d 0), then 500μg of PGF2α on day 7, insert was removed on day 9; 2) Group PI, n=15: treated by oral administration of 5gm Potassium iodide dissolved in 500 ml sterile water for 7 successive days. Treated Cows were observed for 35 days from the end of treatment, females exhibited estrus was inseminated within 12 hours after detected heat. Pregnancy was confirmed by per rectum on day 50 post-insemination. Results showed that GP protocol achieved highest (P<0.05) estrus induction rate (EIR) recorded at 87%, followed by 70% for G and GGP group, and lowest (53%) obtained in GPG treated cows. Conception rate at 1st estrus and total conception rate did not differ significantly among treatment groups, while pregnancy rates (PR) were significantly different (P<0.05) with highest (65.21%) obtained in GP protocol. Other groups recorded 63%, 55.55%, and 41.17% PR for G, GGP, and GPG respectively. In experiment ΙΙ, EIR was 47.36% and 33.33% for CGP and PI respectively with no significant difference, all conceived after 3 estrous cycles by the end of the experiment. In conclusion, GnRH+ PGF2α 10ds later seems the most suitable treatment of COF regardless of cyst type, GGP protocol might be a profitable alternative to Ovsynch for treatment of cystic ovaries. Persistent cases of COF could be recruited to avoid culling for other treatment options such as CIDR or Potassium iodide with equal therapeutic efficacy.

Key words: cystic follicles, estrus, GnRH, pregnancy, dairy cow