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

Abstract

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.

Use of long-acting injectable progesterone in fixed-time artificial insemination protocols

“…Apesar da eficácia dos protocolos existentes que utilizam estradiol e progesterona, a busca por métodos que facilitem o manejo produtivo e reduzam os custos continua relevante. Nesse contexto, o uso injetável da progesterona emerge como uma inovação interessante, oferecendo facilidade de aplicação e mitigando problemas associados aos implantes intravaginais convencionais, como ocorrência de infecções, perda do dispositivo e impacto ambiental decorrente da presença residual de progesterona nos implantes, além dos materiais utilizados nos dispositivos, predominantemente plástico e silicone (Reineri et al, 2020). Campos et al (2016) exploraram o uso de progesterona injetável (250 mg) em vacas Nelore submetidas a um protocolo de sincronização da ovulação, comparando-o com os implantes convencionais de P4, e observaram resultados semelhantes, com uma taxa de 33,33% (15/45), fortalecendo a ideia de que a progesterona injetável é uma alternativa viável.…”

Use of equine chorionic gonadotropin (eCG) in Mashona heifers, under a J-Synch synchronization protocol, and its effect in pregnancy rate

“…These protocols face the following limitations: an extended proestrus stage; an inadequate development of the follicle diameter or the age of the ovarian follicle (Menchaca et al, 2015); and a corpus luteum that can produce enough progesterone which can support pregnancy (Aréchiga-Flores et al, 2019;Bó et al, 2019). These principles were the basis for the development of the J-Synch protocol, a short 5-6 d methodology (Motta et al, 2016;Macmillan et al, 2020), during which equine chorionic gonadotropin (eCG) is administered at the time of the removal of the intravaginal device (Motavalli et al, 2017), replacing the estradiol cypionate and the administration of GnRH, 72 h after the vaginal device is removed (Menchaca et al, 2015;Reineri et al, 2020;Zwiefelhofer et al, 2021;Núñez-Olivera et al, 2022).…”