Short, medium or long-term hormonal treatments for induction of synchronized estrus and ovulation in Saanen goats during the nonbreeding season

Abstract

-The objective of this study was to compare the effect of hormonal treatment duration through the use of intravaginal sponges impregnated with 60 mg MAP for 6 (G6; n = 10), 9 (G9; n = 10) or 12 (G12; n = 10) days. All nulliparous (n = 15) and lactating (n = 15) Saanen goats received 37.5 µg d-cloprostenol and 200 IU eCG 24 hours before sponge removal during the nonbreeding season. After sponge removal, estrus was monitored twice a day (06h00 and 18h00) by the use of fertile bucks. Transrectal ovarian ultrasonography was performed after device removal until ovulation detection. All goats were bred by artificial insemination (AI) or natural breeding (NB). All females received 250 IU hCG 5 d after AI or NB. No difference was observed among groups G6, G9 and G12 for: estrous response (90.0, 100.0 and 100.0%, respectively); interval from sponge removal to estrus (26.7±5.6, 25.2±2.8 and 25.2±3.3 hours), duration of estrus (28.5±7.1; 21.6±3.0 and 25.2±6.1 hours); ovulation rate (80.0, 100.0 and 70.0%); number of ovulations (1.9±0.2, 1.5±0.2 and 1.4±0.2); and pregnancy rate (60.0, 80.0 and 50.0%). Interval from sponge removal to ovulation was shorter in animals from G6 (44.6±2.2 hours) than for animals from G9 (52.8±2.7 hours) and G12 (60.0±4.5 hours). All treatments were effective in the induction of synchronized estrus in Saanen goats during the nonbreeding season, but ovulation occurred earlier when goats received sponges for 6 days.

Different progestagen treatment duration on estrous synchronization during the natural breeding season in non-lactating Anatolian black goats

“…Thus, various protocols have been developed to control reproduction activities throughout the year including the buck effect, photoperiod treatments and the use of exogenous hormone treatment (Whitley and Jackson, 2004;LopezSebastián et al, 2014). Exogenous hormones such as progesterone or its synthetic analogues, equine chorionic gonadotrophin (eCG) and prostaglandin F2α (PGF2α) are generally used in the reproductive season of goats (Dogan et al, 2005), outside the natural breeding season (Corteel et al, 1988;Souza et al, 2011;Pietroski et al, 2013) and in the transition period (Dogan et al, 2004(Dogan et al, , 2008a. Estrous synchronization in goats is achieved by control of the luteal phase of the estrous cycle, either by providing exogenous progesterone or by inducing premature luteolysis (Gordon, 1999).…”

“…injection of eCG alone or eCG with PGF2α given at the end of the treatment (Corteel et al, 1988;Gordon, 1999). Following treatment, a high rate of does show estrus within a relative short time, but fertility rate is generally low or variable (Dogan et al, 2004(Dogan et al, , 2008aPietroski et al, 2013). This phenomenon is related to lower concentration of progesterone/progestogen with abnormalities in follicular development, ovulation, oocyte health, luteal function, alteration in sperm transport and fertility (Corteel et al, 1988;Menchaca et al, 2007).…”

“…This phenomenon is related to lower concentration of progesterone/progestogen with abnormalities in follicular development, ovulation, oocyte health, luteal function, alteration in sperm transport and fertility (Corteel et al, 1988;Menchaca et al, 2007). Recently, with the objective to avoid prolonged progesterone exposure, the short term protocol using intravaginal devices during 5-7 days has been proposed for goats (Menchaca et al, 2007;Dogan et al, 2008b;Vilariño et al, 2011;Pietroski et al, 2013). The short term protocol uses progesterone/progestogen, PGF2α and eCG, and is effective for controlling both luteal activity and follicular dynamics (Menchaca et al, 2007) and also resulting in high pregnancy rates following fixed timed artificial insemination (AI; Vilariño et al, 2011) or after natural mating (Souza et al, 2011).…”

Pregnancy rate in dry and lactating goats after estrus synchronisation with artificial insemination and natural breeding (a field study)

“…Estrus synchronisation (ES), artificial insemination (AI) and ultrasound check of reproductive system are important management tools that have been used to improve reproductive performance in goats (Riaz et al, 2012;Pietroski et al, 2013;Fasulkov, 2014;Arredondo et al, 2015). One of the most important indicators for success after introduction of the aforementioned biotechnological methods is the increase in pregnancy and kidding rates (Leboeuf et al, 2008;Arrebola et al, 2012;Uzabaci et al, 2014).…”

Avaliação reprodutiva de ovelhas da raça Texel submetidas a diferentes protocolos de indução de estro na contraestação reprodutiva

“…Na literatura há uma tendência na diminuição do período de manutenção do progestágeno (UNGERFELD; FONSECA et al, 2005;MARTEMUCCI;D'ALESSANDRO, 2011;PIETROSKI et al, 2013), tradicionalmente utilizados por 12 a 14 dias (LEYVA et al, 1998), o que permite maior concentração do manejo reprodutivo e melhor aproveitamento dos dispositivos de progesterona, possibilitando sua reutilização (VILARINO et al, 2010;DIAS et al, 2012DIAS et al, , 2013 O crescimento folicular na ovelha é um processo lento, fazendo com que um folículo primordial se torne ovulatório (CAHILL, 1981). Nos estágios iniciais de desenvolvimento, os folículos possuem receptores de FSH e LH encontrados nas células da granulosa e teca, respectivamente, porém, não são dependentes de gonadotrofinas, mas influenciados por fatores parácrinos e autócrinos (FINDLAY et al, 2000).…”