Ovarian and Estrous Response of Suckled Beef Cows to the Select Synch Estrous Synchronization Protocol

Geary, T. W.; Downing, E R; Bruemmer, J.E.; Whittier, J.C.

doi:10.15232/s1080-7446(15)31653-3

Cited by 70 publications

(6 citation statements)

References 13 publications

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“…After an initial GnRH injection in dairy cattle, PGF2α was administered at 7 days to induce luteolysis, followed by a second dose of GnRH given to provide ovulation synchronization [ 72 , 73 ]; this protocol is known as Ovsynch ( Figure 2 ). A variation, Co-Synch, is usually used in beef cattle because the cows are inseminated at the time of the second GnRH to minimize animal handling [ 74 ]. The first GnRH was responsible for a 44–54% ovulation rate in dairy cows [ 75 , 76 ], 60% in beef cows, and 56% in beef heifers [ 34 ].…”

Section: Application Of Exogenous Gnrh In Controlled Breedingmentioning

confidence: 99%

Application of Exogenous GnRH in Food Animal Production

Uddin

Petrovski

Song

et al. 2023

Animals

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Over several decades, exogenous GnRH and agonists have been employed for controlling reproductive cascades in animals, and treating some reproductive morbidities. The administration of GnRH is used in animals to counter ovarian dysfunction, induce ovulation, and to increase conception and pregnancy rates. GnRH and its agonists are used in the treatment of cystic ovarian degeneration and repeat breeder syndrome. The development of protocols for GnRH administration by intramuscular injection, intramuscular or subcutaneous implants, and intravaginal deposition has empowered their clinical use worldwide. Currently, exogenous GnRH products are a central part of several pre- and post-breeding programs for the enhancement of fertility, including the control of estrous cycles and timing of ovulation, development of fixed-time artificial insemination protocols, improved embryo survival, and the treatment of reproductive morbidity. The aim of the present review is to summarize the application of exogenous GnRH agonists in food animal production.

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Section: Application Of Exogenous Gnrh In Controlled Breedingmentioning

confidence: 99%

Application of Exogenous GnRH in Food Animal Production

Uddin

Petrovski

Song

et al. 2023

Animals

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“…One of the main limitations for the application of protocols with GnRH in beef cows and heifers is the low response to the first dose of GnRH (Geary et al, 2000;Martinez et al, 2000). Recently, Bonacker et al (2020b) developed a new synchronization protocol called 7 & 7 Synch, using previous knowledge generated by Small et al (2009).…”

Section: Long Gnrh+p4-based Protocolsmentioning

confidence: 99%

Prohibition of hormones in animal reproduction: what to expect and what to do?

Bó,

Menchaca

2023

Anim. Reprod.

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As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. The development of Fixed-Time Artificial Insemination (FTAI) protocols at the end of the 20th century has increased exponentially the number of animals inseminated over the last 20 years. The main reasons for this growth were the possibility of obtaining acceptable pregnancy rates without heat detection and, above all, the induction of cyclicity in suckled cows in postpartum anestrus and prepubertal heifers at the beginning of the breeding season. Most FTAI treatments in South America have been based on the use of progesterone (P4) releasing devices and estradiol to synchronize both follicular wave emergence and ovulation, with pregnancy rates ranging from 40 to 60%. These protocols are implemented on a regular basis, allowing producers access to high-quality genetics, and increasing the overall pregnancy rates during the breeding season. In addition, it provided the professionals involved in these programs with a new source of income and the diversification of their practices into activities other than their usual clinical work. Many of these practices are now apparently at risk from restrictions on the use of estradiol by the European Union (EU) and other countries. However, the development of alternative protocols based on GnRH, with P4 devices and eCG and other new products that are not in the market yet will allow us to adapt to the new times that are coming. Logically, the challenge has already been raised and we must learn to use alternative protocols to try to continue increasing the use of this technology in beef and dairy herds. The objective of the present review is to describe the main aspects of banning estradiol in livestock production, the negative impacts on reproductive efficiency, and to present some alternative FTAI protocols for dairy and beef cattle.

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“…A commonly used FTAI protocol in dairy cattle that utilizes two GnRH treatments given 9 d apart and a PG treatment given 7 d after the first GnRH has been called Ovsynch [5]. The CO-Synch is a modification of the 7-day Ovsynch protocol in which the second GnRH treatment is given concurrently with FTAI [6]. The latter protocol is more commonly used in beef cattle because it requires animal handling only 3 times.…”

Section: Introductionmentioning

confidence: 99%

“…With regard to physiology, the concentration of circulating steroid hormones and the size of the dominant follicle are determining factors in the release of LH and ovulation in response to GnRH administration [7]. It has been reported that 49 to 66% of beef cows ovulated following GnRH administration at random stages of the estrous cycle [6,8] and follicular wave emergence was synchronous only when GnRH induced ovulation [9].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Gonadotropin-Releasing Hormone versus Estrogen-Based Fixed-Time Artificial Insemination Protocols in Grazing Bos taurus Suckled Beef Cows

Ferré,

Jaeschke,

Gatti

et al. 2023

Animals

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Fixed-timed artificial insemination (FTAI) protocols for beef cattle in South America are primarily based on estradiol esters and intravaginal progesterone-releasing devices (IVPD). The objective of this study was to determine the optimal gonadotropin-releasing hormone (GnRH)-based protocol as an alternative to the use of estrogen-based protocols in grazing Bos taurus suckling beef cows. All cows received an IVPD on the day of protocol initiation and prostaglandin F2α (PG) plus equine chorionic gonadotropin (eCG) treatments at the time of IVPD removal. In Experiment 1, cows (n = 235) were randomly assigned to one of four treatments: (i) 7-day estradiol = 2 mg of estradiol benzoate (EB) at IVPD insertion on Day 9 and 1 mg of estradiol cypionate (ECP) at IVPD removal on Day 2; (ii) 7-day GnRH = 10 µg of GnRH at IVPD insertion on Day 10, IVPD removal on Day 3 and GnRH at FTAI; (iii) 7 & 7 estradiol = PG at IVPD insertion on Day 16, EB on Day 9 and ECP at IVPD removal on Day 2; (iv) 7 & 7 GnRH = PG at IVPD insertion on Day 17, GnRH on Day 10, IVPD removal on Day 3 and GnRH at FTAI. In Experiment 2, cows (n = 462) were randomly assigned to one of four treatments: (i) 6-day estradiol = EB at IVPD insertion on Day 9, IVPD removal on Day 3 and GnRH at FTAI; (ii) 7-day estradiol; (iii) 7-day GnRH; (iv) 7 & 7 GnRH. In Experiment 1, plasma progesterone concentrations and percentage of cows with a corpus luteum (CL) at IVPD removal, and pregnancy per AI (P/AI) were greater for cows subjected to GnRH-based protocols compared with cows subjected to estrogen-based protocols (p < 0.01). In Experiment 2, cows subjected to the 7 & 7 GnRH protocol had the greatest P/AI (p < 0.01). In summary, GnRH-based FTAI protocols resulted in similar or greater P/AI compared to estrogen-based FTAI protocols in grazing postpartum Bos taurus suckled beef cows. The greatest P/AI was attained with the 7 & 7 GnRH protocol.

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Ovarian and Estrous Response of Suckled Beef Cows to the Select Synch Estrous Synchronization Protocol

Cited by 70 publications

References 13 publications

Application of Exogenous GnRH in Food Animal Production

Application of Exogenous GnRH in Food Animal Production

Prohibition of hormones in animal reproduction: what to expect and what to do?

Comparison of Gonadotropin-Releasing Hormone versus Estrogen-Based Fixed-Time Artificial Insemination Protocols in Grazing Bos taurus Suckled Beef Cows

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