A field investigation of a modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocol designed for fixed-time artificial insemination of Brahman heifers

Edwards, S. A. A.; Boe-Hansen, G.; Satake, Nana; Chandra, Kerri A.; McGowan, Michael

doi:10.1016/j.anireprosci.2015.07.011

Cited by 4 publications

(3 citation statements)

References 22 publications

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“…Similar to the results obtained in the present work, no differences were reported between J-Synch and conventional protocols in studies carried out with Bos taurus heifers between 13 to 17 months of age without eCG administration at DIB withdrawal (de la Mata and Bó, 2012;Dominicis et al, 2019). Likewise, the implementation of the J-Synch protocol did not produce differences compared with conventional protocol in Bos indicus (Edwards et al, 2015;Motta et al, 2016;Bonotto et al, 2017;Cedeño et al, 2019;Mion et al, 2019). Furthermore, the studies carried out on Braford heifers with 22 months of age and body conditions between 3 and 3.5, did not show significant differences between the J-Synch and conventional protocols (Bonotto et al, 2017;Mion et al, 2019).…”

Section: Discussionsupporting

confidence: 88%

Pregnancy rate to FTAI in Braford heifers submitted to J-Synch protocol

Reineri¹,

Coria²,

Principi

et al. 2020

Med. Vet. (UFRPE)

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The objective of the present work was to evaluate the effect of J-Synch protocol on pregnancy rate (PR) of heifers artificially inseminated after detected estrus (DEAI) or at fixed-time (FTAI). Two hundred ninety-three Braford heifers were used. On day 0, all animals received 2.0 mg of estradiol benzoate administered intramuscularly (IM) and an intravaginal progesterone-releasing device (DIB, 0.5 g). Heifers were assigned to the following group: 1) J-Synch: on day 6, DIB devices were removed and 500 µg of d-Cloprostenol sodium (d-CS) was administered IM and paint was applied on tail base (tail-paint). On day 9 (60 h after DIB removal), heifers with ≥ 40% of the tail-paint rubbed off were inseminated. Those not showing estrus by 72 h after DIB removal received 100 µg of GnRH at that time and were FTAI. 2) Conventional: on day 7, DIB devices were removed, and 500 µg of d-CS and 0.5 mg of estradiol cypionate were administered IM and tail-paint. Fortyeight hours after DIB removal, heifers with the tail-paint rubbed off were DEAI. Those not showing estrus by 54 h after DIB removal were FTAI. Pregnancy rate was diagnosed by ultrasonography 30 days after FTAI in all heifers and did not differ between protocols (44.28% and 42.48%, P = 0.673). In both protocols, higher PR was observed in DEAI heifers (P = 0.047). In conclusion, the use of the J-Synch protocol generated similar PR to the Conventional protocol, allowing its use with the same efficiency. Furthermore, the DEAI generated better PR than the FTAI, regardless of the protocol used.

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Section: Discussionsupporting

confidence: 88%

Pregnancy rate to FTAI in Braford heifers submitted to J-Synch protocol

Reineri¹,

Coria²,

Principi

et al. 2020

Med. Vet. (UFRPE)

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“…The 5-day Co-Synch+P4 protocol has also been investigated in Bos indicus cows in South America, with lower P/AI in suckled Nelore cows than those treated with the conventional 8-day estradiol/P4-based protocol (Ferraz Jr et al, 2016). An important difference was that 400 IU eCG was used in the estradiol/P4-based protocol but it was not used in the 5-day Co-Synch+P4 protocol.…”

Section: Extending the Proestrus Period In Gnrh/p4-based Protocolsmentioning

confidence: 99%

“…Although, more research is required in Bos indicus heifers, in one study, P/AI did not differ in Nelore and Nelore crossbred heifers treated with the J- Synch protocol or with the conventional protocol (both with 200 IU eCG at device removal; Motta et al ., 2016 ). A similar approach of a prolonged proestrus and FTAI at 72 h after device removal, but by giving 1 mg EB 36 h after device removal instead of GnRH at the time of FTAI was evaluated in Brahman heifers ( Edwards et al ., 2015 ). P/AI was significantly higher in heifers treated with the prolonged proestrus protocol than those treated with the conventional 8-day protocol in one farm, but no differences were detected in two other farms.…”

Section: Protocols That Prolong the Proestrus Periodmentioning

confidence: 99%

Programs for fixed-time artificial insemination in South American beef cattle

Bó¹,

Huguenine²,

Mata³

et al. 2018

Anim Reprod

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Fixed-time artificial insemination (FTAI) has been widely applied in South America within the last 20 years for the genetic improvement of commercial beef herds. Most FTAI treatments for beef cattle used in South America are based on the use of progesterone (P4) releasing devices and estradiol to synchronize follicle wave emergence, with pregnancies per AI (P/AI) ranging from 40 to 60%. More recent protocols focusing on extending the interval from device removal to FTAI (i.e. increasing the growing period of the ovulatory follicle) have been reported to improve P/AI in beef cattle. These new protocols and the more traditional FTAI protocols have also been adapted for use with sexed-sorted semen with acceptable P/AI in beef cattle. Finally, color-flow Doppler ultrasonography has been incorporated recently to determine the vascularity of the CL and thereby detect pregnancy as early as Day 22 after the first AI for resynchronization of ovulation for a second FTAI in nonpregnant animals. In summary, FTAI protocols have facilitated the widespread application of AI in South American beef cattle by allowing for the insemination and re-insemination of herds during a defined breeding season, without the necessity of clean up bulls to achieve high pregnancy rates.

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