The effects of progesterone priming on reproductive performance of GnRH-PGF2α-treated anestrous goats

Abstract

-The objective of this experiment was to determine the effect of a 5-day progesterone priming prior to a GnRH-PGF 2α treatment on reproductive performance of anestrous goats. Thirtysix Mountain Black goats were randomly assigned in a 2 × 2 factorial arrangement and were administered intravaginally on day -12, either with 300 mg progesterone inserts (CGPE and CGP) or with 0 mg progesterone (GPE and GP) for 5 days. On day -6, the goats were injected with 100 µg GnRH, followed 6 days later by 15 mg PGF 2α (day 0), the time at which the goats in the CGPE and GPE groups were administered 300 IU eCG injections and those in CGP and GP groups were administered the control solution. The goats were exposed to four fertile bucks at 0 h and were checked for breeding marks at 6-h intervals for 72 h. Blood samples were collected from all goats for progesterone analysis. Progesterone concentrations increased only in CGPE and CGP during the period of device insertion but remained low in GPE and GP groups (P < 0.001). Progesterone levels at the time of GnRH injection on day -6 were basal (0.2 ± 0.04 ng·mL -1 ) among the groups and began to increase starting on day -2. Day 0 progesterone concentrations differed (P < 0.05) among groups and were significantly influenced by CIDR-G (P < 0.001). A similar proportion of goats expressed estrus and intervals to detected estrus were shorter (P < 0.05) in the CGPE and GPE groups than in GP with no difference between the CGPE, CGP and GPE or between CGP and GP groups. The number of goats ovulating based upon elevated progesterone levels on day 0 was significantly greater (P = 0.002) in CGPE (9/9) and CGP (9/9) than GPE (6/9) and GP (5/9) groups and was significantly influenced by CIDR-G (P = 0.03). All pregnant goats had elevated progesterone concentration on day 0 and none of the goats with basal progesterone levels became pregnant. Pregnancy and kidding rates, twinning percentage and the number of kids born per goat exposed were greater (P < 0.05) among goats treated with progesterone and eCG. In conclusion, progesterone priming and eCG are essential for producing higher rates of pregnancy and kidding in GnRH-PGF 2α -treated anestrous goats.

Efficiency of methods applied for goat estrous synchronization in subtropical monsoonal climate zone of Southwest China

“…The combination of Levonorgestrel treatment and PGF 2α injection was found to be an efficient method for estrous synchronization in cycling does during the breeding season, and the high estrous response (95.0%) was obtained. However, there was a significant longer time in the onset of estrus (57.8 h), which was similar to or little longer than that reported in other studies (Romano 1996;Husein et al 2005). A longer duration (33.5±9.4 h) was recorded in does subjected to the Levonorgestrel/PGF 2α treatment, which is within the range of that reported by researchers (Romano 1996;Freitas et al 1997).…”

Influence of sexually inactive bucks subjected to long photoperiod or testosterone on the induction of estrus in anovulatory goats

“…Even at latitude 25°N, native breeds are capable to breed in spring (Mellado et al 2006); however, indiscriminate crossbreeding of native goats with dairy breeds originated in the Alps has led to seasonal anoestrous in crossbred goats at this latitude, although this seasonal anestrous is less marked than that observed in temperate zones (males: Todini et al 2007;Zarazaga et al 2009;females: Carcangiu et al 2009;Arrebola et al 2010). Induction of fertile estrus for out of season breeding is important for goat producers in many countries in order to overcome the seasonality of the goat milk supply; thus, a considerable research has been carried out to enable yearround kidding of goats (Husein et al 2005;López-Sebastian et al 2007). Several methods are available to induce off-season cyclicity and estrous synchronization in does.…”

Estrus Synchronization in Sheep and Goats Using Combinations of GnRH, Progestagen and Prostaglandin F2α

“…Hormonal treatment to control ovulation and reproduction is a perquisite for successful breeding and increasing the number of pregnant females (Motlomelo et al. 2002; Husein et al. 2005), resulting in short breeding period and more uniform newborn crop (Husein and Kridli 2003).…”

“…2005). Husein et al. (2005) reported that 4‐day progesterone priming ahead of the treatment was essential for the effectiveness of this procedure to maintain follicular response to GnRH.…”

“…(2005) reported that 4‐day progesterone priming ahead of the treatment was essential for the effectiveness of this procedure to maintain follicular response to GnRH. Results of their work showed increased responsive in estrus and improved pregnancy rates of treated ewes and goats (Husein and Kridli 2003; Husein et al. 2005).…”