Strategies to optimize reproductive efficiency by regulation of ovarian function

Thatcher, W.W.; Moreira, F; Pancarcı, Şükrü Metin; Bartolome, J.A.; Santos, J.E.P.

doi:10.1016/s0739-7240(02)00160-1

Cited by 87 publications

(61 citation statements)

References 37 publications

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“…Seven days after GnRH injection, PGF 2α is injected to suppress CL followed with a second GnRH injection for inducing ovulation and timed AI. In general, the ovsynch program increases the pregnancy rate, but the result varies depending on the stage of estrous cycle when the treatment is initiated, i.e., in the early stage of the estrous cycle, the recruited DF has not yet matured to respond to the 1 st GnRH injection [17]. Controlled internal drug releasing device (CIDR) increases estrous behavior, but the pregnancy rate varies depending on the duration of treatment.…”

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confidence: 99%

Estrous Synchronization using an Intravaginal Progesterone Device in Combination with GnRH or Estradiol Benzoate characterized by the Initial Ovarian Conditions in Japanese Black Cows

Ando

Kamimura

Hamana

2004

The Journal of Veterinary Medical Science

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confidence: 99%

Estrous Synchronization using an Intravaginal Progesterone Device in Combination with GnRH or Estradiol Benzoate characterized by the Initial Ovarian Conditions in Japanese Black Cows

Ando

Kamimura

Hamana

2004

The Journal of Veterinary Medical Science

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“…It produces pregnancy rates greater or comparable to control groups that depend on estrus detection (Britt and Gaska, 1998). In the last decade, conception rates are at an all-time low of approximately 40% (Pursley et al, 1997a;Peter, 2000;Thatcher et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…At this stage, spontaneous ovulation has already occurred, and the new dominant follicle is too small to ovulate in response to GnRH administration (Moreira, et al, 2000). As a consequence, at the second administration of GnRH the dominant follicle is considered aged (Thatcher et al, 2002) and cows that are included in the Ovsynch program in the early estrus cycle are less fertile (Vasconcelos et al, 1999b andMoreira et al, 2000). Moreover, conception rate is low if anestrus cows are subjected to the ordinary Ovsynch protocol (Thatcher et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Effect of Parity and Milk Production on Conception Rate After Two Synchronization Protocols in Dairy Cows

El-Razek¹,

Genedy²,

Zaghloul³

2018

AJVS

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Key words:G6G, Ovsynch, presynchronization, fertility, dairy cow.Our objective in this study the effect of parity and average milk production on the conception rate after resynchronization with G6G protocol or Ovsynch protocol. Lactating Holstein cows (n = 100) divided into two groups (Ovsynch and G6G) cows in this group1 (n = 50) were received the following treatment sequence, 12 µg Buserelin on day zero, 500 µg IM of Cloprostenol on day seven, 12 µg Buserelin IM on day nine and received timed artificial insemination (TAI) 16 hours later. Group II (G6G): were received 500 µg IM Cloprostenol on day zero, 12 µg Buserelin on day two and six days later these cows received the Ovsynch as previously explained in the first group. Conception rate was (40 vs. 30 %) for G6G and Ovsynch protocol respectively primiparous cows, conception rate to G6G program was 46.15%, compared to 28.57% in cows synchronized with Ovsynch program. In Multiparous cows, the similar trend was observed but the difference was smaller (conception rate 37.8 vs. 30.55% in cows synchronized with G6G and with Ovsynch, respectively). In high producers, conception rate was numerically higher in the Ovsynch group (40%) compared to the G6G group (36%). While, in low producers, conception rate to G6G protocol (48%) tended (P = 0.07) to be higher than that to Ovsynch protocol (20%) in conclusion Administration of PGF2α 8 d before initiation of Ovsynch increase the conception rate compared with the standard Ovsynch protocol in primiparous cows than in multiparous cows and in low producers than high producer cows

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“…Thus, one of the ways to obtain the largest follicle responsive to the 2 nd GnRH injection prior to TAI would be to clarify the physiological conditions of the animals that ovulated after the 1 st GnRH injection. While a positive correlation between plasma progesterone concentrations at the 1 st GnRH injection of the Ovsynch protocol and the rate of synchronization of ovulation has been reported [31,32], a negative correlation between the two parameters has also been found [19,21,22,33]. The effects of anovulatory conditions or a low progesterone environment on the responsiveness of the largest follicle to GnRH has not been well elucidated.…”

mentioning

confidence: 99%

Effect of Follicular Aspiration at the Onset of Progesterone-based Timed Artificial Insemination on the Follicular Dynamics and Fertility of Early Postpartum Japanese Black Cows

Hirata

Kon

Sugiyama

et al. 2011

Journal of Reproduction and Development

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Abstract. The effect of gonadotropin-releasing hormone analogue (GnRH-A) or follicular aspiration at the onset of progesterone-based timed artificial insemination (TAI) on subsequent follicular growth and synchronization of ovulation was examined in early postpartum Japanese Black cows. A total of 40 (22 in Exp. 1 and 18 in Exp. 2) Japanese Black cows at 20-30 days postpartum were fitted with a progesterone releasing internal device (PRID) for 7 days, injected with a prostaglandin F2α analogue upon removal of the PRID and GnRH-A 48 h later, and inseminated 18 h after GnRH-A injection. In Exp. 1, the animals were divided into three groups (untreated control, GnRH-A injection or follicular aspiration) of different treatments on the first day of PRID insertion (day 0), and the synchronized ovulation rate in the follicular aspiration group (100%; 8/8) tended to be higher (P=0.077) than that in the control group (42.9%; 3/ 7). In Exp. 2, follicular growth in the GnRH (n=9) and follicular aspiration (n=9) groups was monitored by ultrasonography. Four out of the nine animals in the GnRH group had a corpus luteum on either day 4 or day 7 (OV group), and the other five animals had no induced ovulation (NOV group). The diameter of the ovulatory follicle on day 9 in the OV group (1.44 ± 0.11 cm) tended to be greater (P=0.078) than that in the NOV group (1.13 ± 0.07 cm). Follicular aspiration at the onset of PRID-based TAI of early postpartum Japanese Black cows, regardless of the resumption of ovarian cyclicity, tended to result in a higher rate of synchronization of ovulation than that of the untreated controls. Key words: Early postpartum, Japanese Black cows, Ovum pick-up, PRID, Timed artificial insemination (J. Reprod. Dev. 57: [613][614][615][616][617][618][619] 2011) t is economically beneficial to impregnate cows as early as possible postpartum in a beef production system. A number of protocols controlling timing of estrus and ovulation followed by timed artificial insemination (TAI) have been developed to save labor costs and improve reproductive efficiency in the cow [1][2][3]. One of the key points in designing these protocols is how to control follicular growth. Options to control follicular growth include administration of progesterone, estradiol-17β or gonadotropinreleasing hormone (GnRH) [4][5][6][7][8][9][10][11][12][13] and ultrasound-guided transvaginal follicle ablation [14,15]. While progesterone inhibits ovulation of a dominant follicle, it allows the dominant follicle to maintain dominance, leading to low fertility due to an aged ovum being maintained for an extended period in a high-progesterone environment [4,16]. To improve conception rates with TAI, it is effective to administer estradiol-17β or GnRH to reset a follicular wave at the time of progesterone insertion [4]. However, previous studies have reported animals in which ovulation was induced and in which ovulation was not induced by the 1 st GnRH injection under the TAI protocol, and the conception rates in those that had no induced ovulati...

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Strategies to optimize reproductive efficiency by regulation of ovarian function

Cited by 87 publications

References 37 publications

Estrous Synchronization using an Intravaginal Progesterone Device in Combination with GnRH or Estradiol Benzoate characterized by the Initial Ovarian Conditions in Japanese Black Cows

Estrous Synchronization using an Intravaginal Progesterone Device in Combination with GnRH or Estradiol Benzoate characterized by the Initial Ovarian Conditions in Japanese Black Cows

Effect of Parity and Milk Production on Conception Rate After Two Synchronization Protocols in Dairy Cows

Effect of Follicular Aspiration at the Onset of Progesterone-based Timed Artificial Insemination on the Follicular Dynamics and Fertility of Early Postpartum Japanese Black Cows

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