Utilização do dispositivo intravaginal de progesterona, em até três usos, para inseminação artificial em tempo fixo de fêmeas Bos indicus

Abstract

Objetivou-se avaliar o efeito do número de utilizações (até três) do CIDRÒ, manifestação de estro e ordem de parição sobre a taxa de prenhez em vacas Bos indicus. Utilizou-se 1176 vacas pluríparas e primíparas, lactantes, 30 a 60 dias pós-parto. Os grupos receberam CIDRÒ de primeiro, segundo ou terceiro usos, mais 2,0 mg de benzoato de estradiol no dia de introdução (D0) e, 500 μg de dinoprost trometamina, 300 UI de eCG e 0,6 mg de cipionato de estradiol na retirada dos dispositivos (D8), com a IATF 48 horas após (D10). Em 30 dias realizou-se o diagnóstico de gestação (D40). Analisaram-se as variáveis pelo PROC LOGISTIC (SAS) e pela regressão logística binária, considerando-se significância quando p < 0,05. A quantidade de usos do implante influenciou a taxa de gestação (1 uso < 2 usos – p<0,05; 1 uso < 3 usos – p < 0,01; 2 usos = 3 usos; p > 0,1), de 44,8%, 51,1% e 51,1% para CIDRÒ 1, 2 e 3 usos, respectivamente, bem como a ordem de parição (pluríparas 50,85% > primíparas 34,48%; p<0,01), e manifestação de estro (com estro 44,02% > sem estro 33,06%; p<0,01). O CIDRÒ pode ser utilizado por até três vezes, mas as taxas de gestação mostram-se mais baixas no primeiro uso em relação ao segundo e terceiro usos e com melhores resultados em pluríparas e com manifestação de estro.

Resynchronization of ovulation with new and reused intravaginal progesterone‐releasing devices without previous pregnancy diagnosis in Bos taurus indicus cows subjected to timed‐artificial insemination

“…In the present study, we found similar P/AI in the two groups (56.2% for GRN and 57.0% for GRU; p > 0.05), because both groups were subjected to the same hormonal protocol (Table ). While working with Bos taurus indicus cows, Medalha et al () obtained significantly lower P/AI values (44.8%) using new intravaginal devices with P4. Therefore, significant variations in the P/AI of cows subjected to the TAI protocol were found in several studies, and these variations have persisted over time, with few exceptions.…”

Impact of breed, body score and animal category on the pregnancy rate of bovine females under IATF management

“…There is no effect of intravaginal progesterone implant of up to third use on the pregnancy rate of heifers 2 and 3), demonstrating that intravaginal progesterone(P4) devices can be reused, allowing the start of the synchronization of the cycle from lower concentrations of this hormone, without reducing conception rates, being a viable and efficient way to perform the TAI Medalha et al, 2015). The results of this work corroborate those published in the literature on the reuse of heifer progesterone device implants up to 3 times (Carvalho et al, 2019;Medalha et al, 2015;Gottschall et al, 2012).…”

“…There is no effect of intravaginal progesterone implant of up to third use on the pregnancy rate of heifers 2 and 3), demonstrating that intravaginal progesterone(P4) devices can be reused, allowing the start of the synchronization of the cycle from lower concentrations of this hormone, without reducing conception rates, being a viable and efficient way to perform the TAI Medalha et al, 2015). The results of this work corroborate those published in the literature on the reuse of heifer progesterone device implants up to 3 times (Carvalho et al, 2019;Medalha et al, 2015;Gottschall et al, 2012). The use of fourth-use intravaginal progesterone devices is an effective alternative for inducing puberty in heifers, thus, the authors reported a pregnancy rate of 35.14% in this category (Coelho et al (2021), and in the same In this sense, Figueredo et al, (2019) found a pregnancy rate of 48.18% also in beef heifers and under conditions similar to those observed in this study.…”

“…The results presented here corroborate those reported by Silva et al, (2017) who found a pregnancy rate of 61.88% and 61.49% among multiparous and primiparous females, respectively. Usualty primiparous females are less efficient when compared to multiparous and secundiparous females, due to the higher nutritional requirements of this category (Patterson et al, 1992;Medalha et al, 2015). For this reason, the return to cyclic luteal activity of these animals becomes compromised, which increases the calving interval and service period (Cunha et al, 2013).…”

“…For this reason, the return to cyclic luteal activity of these animals becomes compromised, which increases the calving interval and service period (Cunha et al, 2013). Medalha et al (2015) when synchronizing primiparous and multiparous cows, concluded that primiparous cows had lower chances of conceiving compared to multiparous cows. However, Castilho et al, (2018) reported a 55.2% gestation rate in primiparous Red Angus cows calved and submitted to TAI protocols.…”