A. L. R. S. Maia

Autoclaved, previously used intravaginal progesterone devices induces estrus and ovulation in anestrous Toggenburg goats

Intravaginal progesterone devices are used worldwide for estrus induction in goats. Reused devices are able to induce estrus; however, this can be a health risk within a flock. The objective was to compare new and previously used (and autoclaved) progesterone-releasing intravaginal devices for induction of estrus and ovulation in seasonally anestrous Toggenburg goats. Anestrous goats (n=42) received new intravaginal devices containing 0.3g progesterone (CONTROL), or similar devices previously used for either 6 (USED6) or 12d (USED12) and subsequently autoclaved. All goats received 5mg dinoprost at device insertion and 200 IU eCG 5d later, and all devices were removed after 6d. After device removal, estrus was monitored and females displaying signs of estrus were mated by fertile bucks. Transrectal ovarian ultrasonography was performed after device removal until detection of ovulation. Blood samples were collected for determination of plasma progesterone concentration at different times. There was no difference (P>0.05) among groups CONTROL, USED6 or USED12 for: estrus response (87, 100 or 100%, respectively); duration of estrus (32.3±2.3, 25.2±3.4 or 27.3±4.1h); ovulation rate (100, 88 or 100%); number of ovulations (1.5±0.2, 1.9±0.3 or 1.7±0.3); and pregnancy rate (60, 58 or 67%). Plasma progesterone (P4) concentrations were greater (P<0.05) in CONTROL than in USED6-treated and USED12-treated goats (7.2±1.2, 4.7±0.7 and 4.3±0.6 ng/mL, respectively) at 6h after device insertion; these differences were maintained until 4d after device insertion (3.4±0.4, 2.3±0.2, and 2.5±0.2 ng/mL). Overall, plasma progesterone concentrations were greater (P<0.05) in nulliparous than in lactating goats (3.1±0.8 compared to 2.4±0.6 ng/mL, respectively). In conclusion, autoclaved, previously used intravaginal progesterone-releasing devices resulted in significant lesser plasma progesterone concentrations than new devices, but were similarly effective in inducing estrus and ovulation in anestrous goats.

Reproductive parameters of dairy goats after receiving two doses of d-cloprostenol at different intervals

This study evaluated the efficiency of two d-cloprostenol injections at different intervals on the reproductive parameters of dairy goats. Trial 1 comprised 54 goats allocated to receive two 37.5μg d-cloprostenol doses at intervals of seven (T7, n=19), 10 (T10, n=18), and 11.5 (T11.5, n=17) days. Trial 2 comprised 62 goats allocated to receive injections at T7 (n=30) and T11.5 (n=32). Ultrasonography was done and blood was collected just before d-cloprostenol injections. After the second dose, goats were artificially inseminated (AI) with frozen-thawed semen at 18-24h (Trial 1) or at 10-24h (adjusted according to the time of estrus onset in Trial 2) after estrus detection. Estrus response rate did not differ (P>0.05) among groups in Trials 1 (T7=94.7%; T10=88.9%; T11.5=88.2%) and 2 (T7=90.0%; T11.5=96.9). All females showed progesterone concentrations >1ng/mL before both d-cloprostenol injections. The largest follicle diameter present on ovaries was similar (P>0.05) among treatments at the first and second dose. The second largest follicle diameter was superior (P<0.05) to T7 than to T10 and T11.5 goats at first dose only. This possibly resulted in lower interval to estrus (P<0.05) in T7-treated goats than other treated goats in both trials. The conception rate was similar among treatment groups in Trials 1 (T7=55.6%; T10=18.8%; T11.5=26.7%) and 2 (T7=85.2%; T11.5=93.6%). The three treatments efficiently synchronized estrus. T7 and T11.5 protocols resulted in high estrus synchrony and conception rates when adjusting the AI time according to interval of estrus.

Hydrometra in dairy goats: Ultrasonic variables and therapeutic protocols evaluated during the reproductive season

Hydrometra is characterized by the accumulation of fluid within the uterus due to the persistence of corpus luteum. The diagnosis of this disorder occurs with an ultrasonic exam. This study evaluated uterine drainage and fertility rates in goats after the use of d-cloprostenol in association or not with Gonadotropin-releasing hormone (GnRH) treatment. Twenty Saanen goats, diagnosed with hydrometra, received three 37.5-μg doses of d-cloprostenol laterovulvarly at 10-day intervals. On D5, the goats were assigned into two groups receiving 1 mL of GnRH or saline solution intramuscularly. Ultrasonography (US) was performed from D0 to D25. An US approach was used to rank hydrometra in scores. The pregnancy rate was assessed 45 and 90 days after the end of treatment. The uterine fluid was totally drained after the first and second administration of d-cloprostenol in 50% and 95% of the goats, respectively. In one female, full emptying of the uterus occurred only after D20. US performed at 45 and 90 days after the end of treatment indicated there was a pregnancy rate of 45.0% and 55.0%, respectively. Fertility did not differ between the GnRH-treated and control goats. Those goats not pregnant at 45 days had a follicular cyst, hydrosalpinx or hydrometra. At 90 days, no change was observed in the hydrosalpinx, and four goats had hydrometra. The use of three doses of d-cloprostenol 10 days apart was efficient for induction of draining the contents of the uterus, resulting in a relatively acceptable pregnancy rate. This treatment associated with the US approach can be important when applied in the field.

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

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.