Oestrus synchronization with short-term and long-term progestagen treatments in goats: the use of GnRH prior to short-term progestagen treatment

Abstract

The aim of the present study was to determine the efficacy of the synchronization of oestrus using short- and long-term progestagen treatments in Hair goats at the onset of the breeding season, and to evaluate the effect of the exogenous GnRH administration immediately prior to short-term progestagen treatment on the reproductive performance. A total of 75 Hair goats, aged 2.5-5 years-old were used in this experiment. Goats were divided equally into three groups (n=25 per group). Animals in LT-FGA (long-term progestagen treatment), ST-FGA (short-term progestagen treatment) and Gn-ST-FGA (GnRH-short-term progestagen treatment) groups received an intravaginal sponge (day 0) containing 30 mg fluorogestone acetate (FGA) for 14, 8 and 8 days, respectively, plus 75 μg cloprostenol i.m. 24 h before sponge removal and 400 I.U. equine chorionic gonadotrophin (eCG) i.m. at the time of sponge removal. In addition, the goats in the Gn-ST-FGA group received 10.5 μg busereline acetate i.m. at the time of sponge insertion (day 0). Oestrus response for all treatment groups was 100%. The mean interval from sponge removal and the onset of oestrus for the LT-FGA, ST-FGA and Gn-ST-FGA groups was 28.0±1.0 h, 28.83±1.1 h and 33.1±2.0 h, respectively. No significant difference in onset of oestrus among groups was recorded. The pregnancy rate, kidding rate, multiple kidding rates and litter size were 72.0, 61.1, 45.5% and 1.6 in the LT-FGA, 70.8, 76.5, 69.2% and 1.8 in the ST-FGA and 58.3, 78.6, 63.6% and 1.6 in the Gn-ST-FGA groups, respectively. The pregnancy rates were similar in the LT-FGA (72.0%) and ST-FGA (70.8%). However, the kidding rate, multiple kidding rates and litter size were numerically higher in the ST-FGA (76.5%, 69.2% and 1.8, respectively) group than in the LT-FGA (61.1%, 45.5% and 1.6, respectively) group. Although not statistically different, pregnancy rate and litter size was lower in the Gn-ST-FGA group (58.3% and 1.6, respectively) compared with the ST-FGA (70.8% and 1.8, respectively). In conclusion, it can be said that oestrus synhcronization with long-term progestagen treatment (14 d-FGA- PGF2α- eCG) could be replaced with short-term progestagen treatment (8 d-FGA-PGF2α- eCG) without a reduction in oestrus rate and fertility parameters in lactating goats at the beginning of breeding season. However, the use of GnRH prior to short-term progestagen treatment (8 d-FGAPGF2α- eCG) do not have a positive effect on fertility parameters in goats

Estrus Response and Conception Rate in Sangamneri and Osmanabadi Goat Does using different Estrus Synchronization Protocols

“…eCG protocol was employed. The mean percentage of goats exhibiting estrus when treated with progestagen + PGF 2 α + eCG in the present study corroborate with the findings of earlier workers (Freitas et al, 1996 a ; Leboeuf et al, 2003;Karaca et al, 2010;and Nogueira et al, 2011) and was higher when compared with the findings of Drion et al, 2001 (87 %), Fonseca et al, 2005 (86.8%), Fonseca et al, (2008) (88.1%) in goats. Around 80 % estrus behavior was observed in Damascus Baladi goats in studies of Telab and Ashmawy (2007) when GnRH was administered 24 h before sponge removal.…”

“…There was significant variation (P< 0.05) in the duration of onset of estrus between Sangamneri and Osmanabadi goats in Group II (46.51 vs 24.00 h). Whereas durations of onset of estrus were non-significant (P > 0.05) between two breeds in Groups I, III, IV and V. Similar observations when treatment of progestagen + PGF 2 α + eCG was employed in goats regarding the time for the interval from sponge removal to onset of estrus in goats have been reported by Freitas et al (1996 a ), Drion et al (2001), Leboeuf et al (2003), Fonseca et al (2008), Karaca et al (2010). Higher range of interval of onset of estrus from the time of sponge withdrawal in goats has been reported by Feritas et al (1996 b ), 32 ± 7.1 h; Kusina et al (1999), 11 to 96 h; Lymberopoulos et al (2002), 42 to 44 h; Dogan et al (2005), 12 -66 h; and Fonseca et al (2005), 49.7±15.7 h in synchronized goats.…”

Oestrous synchronisation and pregnancy rate following artificial insemination (AI) in South African indigenous goats

“…The pregnancy rate of the goats treated with short-term progestagen (43.6%) was significantly (p B0.05) higher compared to goats treated with long-term progestagen (34.3%). Similar tendencies have been reported (Vinoles et al 2001;Tibary 2009;Karaca et al 2010). The lower pregnancy rate in long-term progestagen treated does might be due to poor sperm cell transportation in the reproductive tract.…”

“…Poor sperm cell transportation is associated with increase amount of cervical mucus usually observed when this protocol is used (Tibary 2009). Though, the pregnancy rate of the goats treated with short-term progestagen was higher in this study, it was still lower compared the pregnancy rate of 72% reported by Karaca et al (2010) during short-term progestagen treatment when FGA sponges were used.…”

“…Pregnancy rate following oestrous synchronisation using this long-term protocol has generally been low (52%) in South African indigenous goats (Motlomelo et al 2002). Although, shortterm progestagen treatments have been reported to be effective in synchronising oestrous in other goat breeds (Karaca et al 2010) it is not usually used in South Africa. Whether a similar response in the South African indigenous goats could be obtained, is uncertain.…”