Re-used progesterone devices efficiently synchronise oestrus and ovulation after autoclaving process in Toggenburg goats during the breeding season

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

This study compared new and previously used (and autoclaved) progesterone devices for synchronisation of oestrus during the breeding season in Toggenburg goats. Nulliparous (n = 17) or lactating (n = 50) received new intravaginal devices containing 0.3 g progesterone (CONTROL), or similar devices previously used for either 6 (USED6) or 12 (USED12) days and subsequently autoclaved. All goats received 5 mg dinoprost at device insertion and 200 IU equine chorionic gonadotropin 5 days later and all devices were removed after 6 days. After device removal, females were mated by fertile bucks. Ovarian ultrasonography was performed every 12 h after device removal until ovulation detection. Blood samples were collected for determination of plasma progesterone concentration in different moments and intervals (from 7 days before device insertion to 3 days after its removal). There was no difference (P > 0.05) among groups CONTROL, USED6 or USED12 for: oestrus response [75% (18/24), 77% (17/22) or 71% (15/21), respectively]; duration of oestrus (30.7 +/- 3.4, 31.8 +/- 1.7 or 32.8 +/- 3.4 h), percentage of ovulating goats [67% (6/9), 78% (7/9) or 56% (5/9)], ovulation rate (1.3 +/- 0.2, 1.4 +/- 0.2 or 1.8 +/- 0.4 units of corpora lutea), average follicle diameter (6.2 +/- 0.1, 6.7 +/- 0.1 or 6.8 +/- 0.3 mm) and pregnancy rate [54% (13/24), 50% (11/22) or 48% (10/21)]. Plasma progesterone concentrations were not different (P > 0.05) for does among treatments and between nulliparous and lactating females. In conclusion, autoclaved, previously used intravaginal progesterone devices are effective in synchronising oestrus and ovulation in cyclic goats during the breeding season.