Injectable progesterone in timed artificial insemination programs in beef cows

Abstract

The aims of this study were I) to compare the follicular diameter, corpus luteum diameter and serum progesterone (P4) concentrations in cows treated with conventional protocol vs. injectable P4 protocol; II) to determine the serum P4 profile in ovariectomized heifers; and III) to compare pregnancy rate between protocols. In experiment I, multiparous cows received a protocol for ovulation synchronization with an intravaginal P4 device (n = 38; device + EB day 0; device removal + PGF2α + eCG + EC day 8) or injectable P4 (n = 38; injection + EB day 0; PGF2α + eCG + EC day 8). In experiment II, ovariectomized heifers (n = 8) were treated with injectable P4 and blood samples were collected to determine the serum P4 profile. In experiment III, multiparous cows were timed AI with two different P4 approaches, intravaginal P4 device (n = 48) or injectable P4 (n = 47). In the first experiment, cows treated with P4 device had higher (P < 0.05) diameter of dominant follicle after ovulation induction (11.6 ± 1.8 vs.10.3 ± 1.8 mm) and ovulation rate (97%, 37/38 vs. 47.3%, 18/38) than cows treated with injectable P4. But, the follicular growth daily was higher (P < 0.05) in cows treated with injectable P4 than intravaginal device (1.3 ± 0.4 vs. 1.0 ± 0.3 mm/day, respectively). In experiment II, the P4 concentration peak occurred within 48 hours (6.54 ng/mL) and decreased after 96 hours (P < 0.05) after P4 injection. In experiment III, cows with P4 device had higher (P < 0.05) pregnancy rate than the injectable P4 group (60.4 vs. 34.0%, respectively). These results demonstrate that although the intravaginal P4 devices showed a higher pregnancy rate, a protocol with injectable P4 represents an easier method and a promising alternative for TAI in cattle.

Induction of puberty in Bos indicus heifers in the western Amazon region

“…Then, to cyclicity induction, there was no need for such precise control for circulating progesterone fall. Finally, similar to previous studies that have shown several positive aspects of injectable P4 (Morotti et al, 2013a,b;Campos et al, 2016a,b;Morotti et al, 2018), the present study also revealed that injectable P4 is efficient, low cost, and very promising for use in puberty induction programs in heifers.…”

“…The injectable form of P4 comes at a lower cost due to the lack of silicone and other materials used in the manufacture of devices and implants. In addition, it provides a reduction in the risk of sanitary problems associated with the use of intravaginal devices, such as the occurrence of vaginitis and vulvovaginitis (Morotti et al, 2013a(Morotti et al, ,b, 2018, especially in heifers. Furthermore, this P4 source may result in animal welfare improvements by avoiding vaginal/vulvar discomfort caused by the rod of the device.…”

“…Conversely, the use of injectable P4 in synchronization protocols has been related to low cost, easy management of animals, and hygienic benefits (Morotti, Campos, Oliveira, & Seneda, 2013a;Morotti, Campos, & Seneda, 2013b;Campos, Morotti, Bergamo, Costa, & Seneda, 2016a;Campos, Morotti, Costa, Bergamo, & Seneda, 2016b). For TAI programs, these benefits provide a reduction in the risk of health problems associated with intravaginal devices, such as loss of the device and the occurrence of vaginitis and vulvovaginitis (Morotti et al, 2013a(Morotti et al, ,b, 2018. Considering the sanitary particularity of nulliparous females, this P4 source represents an interesting strategy for reproductive programs in heifers.…”

>b<Fertilidade de touros e suas interações com fatores relacionados as fêmeas em programas de inseminação artificial em tempo fixo>/b<

“…Além disso, a baixa taxa de serviço, seja por deficiências de manejo na detecção do cio ou pelo anestro no período pós-parto, comprometem a eficiência de programas reprodutivos, de forma que, o uso de protocolos funcionais para fêmeas que apresentam anestro é essencial (SEVERO, 2009). A P4 pode ser administrada através de implantes auriculares, via oral pela alimentação (BARUSELLI et al, 2004) ou injetáveis (MOROTTI et al, 2018), porém a administração realizada com auxílio de dispositivo intravaginal bovino (DIB) para liberação lenta do hormônio tem sido a mais utilizada. Isso porque, para exercerem seu papel fisiológico, é necessário a administração desses hormônios com liberação lenta, continua e constante (MACHADO et al, 2020).…”

“…A administração de P4 injetável tem como benefícios a redução dos custos, manejo e descarte dos dispositivos, além das vantagens sanitárias e higiênicas (MOROTTI et al, 2018). No entanto, a ação da P4 injetável ainda não está totalmente elucidada.…”