The Effectiveness of Progesterone-Releasing Intravaginal Device with Daily GnRH Injections on the Reproductive Parameters of Mares in Diestrus

Aksoy O. A., Ay S. S., Kaya D., Handler J., Aslan S.

Animal Health, Production and Hygiene, vol.2, no.1, pp.145-151, 2013 (Peer-Reviewed Journal)

  • Publication Type: Article / Article
  • Volume: 2 Issue: 1
  • Publication Date: 2013
  • Journal Name: Animal Health, Production and Hygiene
  • Journal Indexes: TR DİZİN (ULAKBİM)
  • Page Numbers: pp.145-151
  • Dokuz Eylül University Affiliated: No


This study examines the effectiveness of PRID solely and combined with GnRH treatment on fertility parameters of mares. At day seven after ovulation, PRID (1.55 g P4 +10 mg E2 -benzoate) was inserted intravaginally for nine days in G1 (n=8) and G2 (n=7). In the same period, G1-mares received GnRH (2.5ml/mare, Receptal®) on a daily basis. At day 16 (day of PRID removal) PGF2 a (500μg/mare, Estrumate® ) was administered to G1 and G2. Mares of G3 (n=8) served as controls. Follicle controls were started at day 16 in G1 and G2, and when the mares showed positive response to stallions in G3. After day 16 in G1 and G2, mares that did not show signs of oestrus and ovulation within eight days were considered to be non-responder (NR). Mating was performed every other day until ovulation occurred after determination of preovulatory follicle (POF). NR mares were found to be 12.5% (G1) and 14.3% (G2). The pregnancy rate was not statistically significant between the groups. Interval from PRID removalovulation was determined to be 6.4 days in G1 and 5.7 days in G2. Interval from POF-ovulation in G1 (1.2 day) was found to be significantly lower than in G2 (3.2 day) and G3 (3.6 day) (P<0.05). Diameter of POF (G1: 38.5 mm ; G2: 38.2 mm ; G3: 40.8 mm) and ovulatory follicle (G1: 41.5 mm ; G2: 42.7 mm ; G3: 43.0 mm) were not found significantly different among groups (P>0.05). The significance between P4 concentrations of G1 and G2 was not found throughout PRID treatment (P>0.05), except second day of PRID insertion (P<0.05). It was concluded that application of PRID solely or combined with daily GnRH injection has no effect on fertility parameters in diestrus mares.