title: Induction of ovulation of ovulatory size non-ovulatory follicles and initiation of ovarian cyclicity in summer anoestrous buffalo heifers (Bubalus bubalis) using melatonin implants.
abstract: This study was conducted on summer anoestrous buffalo heifers to monitor the efficacy of melatonin for induction of ovulation and ovarian cyclicity. During pre-treatment period of 24 days, the ovarian dynamics of five cycling and 10 summer anoestrous heifers was monitored on each alternate day using a transrectal ultrasound scanner. Thereafter, during treatment period, these 10 anoestrous heifers along with additional seven anoestrous heifers were randomly allocated into non-implanted (n = 5) and implanted (n = 12, one melatonin implant/50 kg, 18 mg melatonin/implant) group. Non-implanted heifers were monitored on each alternate day till the confirmation of second-ovulation in implanted heifers. Pre-treatment period revealed the presence of dominant follicles in anoestrous heifers which attained the diameter comparable with ovulatory follicles of cycling heifers but failed to ovulate and regressed. Between 6 and 36 days (15.3 +/- 2.9 days) post-treatment, all the implanted heifers (p < 0.05) exhibited ovulation of dominant follicles; however none of the non-implanted heifers ovulated during the corresponding period. The first-interovulatory period in implanted heifers ranged between 8 and 28 days (18.0 +/- 1.8 days). The implanted heifers with short (<or=16 days) interovulatory period had short-lived corpus luteum (CL) that had smaller diameter and secreted less progesterone (p < 0.05). The diameter of CL was large (p < 0.05) and plasma progesterone was high (p < 0.05) following second-ovulation compared with first-ovulation in implanted heifers. In conclusion, using melatonin implants, ovulatory size nonovulatory follicles observed in summer anoestrous buffalo heifers can be successfully ovulated to initiate ovarian cyclicity.
authors.affiliation: Department of Animal Reproduction, Gynaecology and Obstetrics, College of Veterinary Sciences, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India. ghuman_s@yahoo.co.in
authors.forename: S P S
authors.initials: SP
authors.lastname: Ghuman
authors.forename: J
authors.initials: J
authors.lastname: Singh
authors.forename: M
authors.initials: M
authors.lastname: Honparkhe
authors.forename: D
authors.initials: D
authors.lastname: Dadarwal
authors.forename: G S
authors.initials: GS
authors.lastname: Dhaliwal
authors.forename: A K
authors.initials: AK
authors.lastname: Jain
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D002020:Buffaloes / Q000502:physiology*; D004334:Drug Administration Schedule; D004971:Estrus / Q000502:physiology*; D005260:Female; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000187:drug effects*; D010062:Ovulation Induction / Q000662:veterinary*; D012621:Seasons
chemical_list: D008550:Melatonin