Influência da progesterona injetável na taxa de prenhez e perda gestacional de fêmeas nelore de distintas categorias reprodutivas submetidas a inseminação artificial em tempo fixo / Influence of injectable progesterone on the pregnancy rate and gestational loss of Nellore females of different reproductive categories undergoing fixed-time artificial insemination

Progesterone (P4) is essential for embryonic development and maintenance of pregnancy when deficiency causes early embryonic loss. In this study, we investigated the ability of hormonal supplementation to improve the fertility of Nellore females subjected to fixed-time artificial insemination (IATF) protocols. Here, we evaluated the effect of long-acting injectable progesterone (iP4) supplementation in the D4 after IATF on pregnancy rate and pregnancy loss in Nellore females (Bos taurus indicus) from different reproductive categories in Western Amazonia. Eight hundred thirteen Nellore females from 5 farms were selected and distributed into 2 groups: control [GC; administration of 0.5 mL of 0.9% saline solution, intramuscularly - IM] (n = 407) and a group that received injectable progesterone (iP4) that was long-acting [GiP4; administration of 0.5 mL of iP4, 300 mg, via IM four days after IATF] (n = 406). Each group contained 3 subgroups: heifers, primiparous cows, and multiparous cows. Of the 407 animals in the CG, 103 were heifers, 107 primiparous, and 197 multiparous. Of the 406 animals in the GiP4 group, there were 101 heifers, 107 primiparous, and 198 multiparous. On a random day of the estrous cycle (D0), an intravaginal device containing 1 g of P4 and 2 mg of estradiol benzoate (BE) was inserted by intramuscular injection. On D8, the P4 device was removed and 150 µg of D-cloprostenol (PGF2α), 300 IU eCG, and 1 mg BE were administered IM. Cows were inseminated at D10, 48-52 h after procedure on D8. Pregnancy diagnosis was made between 35 and 40 days after insemination through ultrasound examination. Between 80 and 90 days after insemination, a new ultrasound examination was performed to assess early pregnancy loss. The data were processed using the SAS 9.2. The conception rate, pregnancy loss, and final conception rate were analyzed using PROC GLIMMIX according to groups (CG and GiP4), categories (heifers, primiparous and multiparous), and their interactions as variables. The differences in the means of least squares were adjusted using the Tukey­Kramer method. Statistical significance was defined as P < 0.05. The general conception rate was 46% (375/816). Regardless of the animal class, GiP4 animals (51.97%) had higher conception rates (P < 0.05) than CG (40.29%). In the subgroups (heifers, primiparous and multiparous cows), there was a difference (P < 0.05) between animals treated with iP4 (52.48%, 57.94%, and 48.48%, respectively) and those who were not (39.81%, 41.12%, and 40.10%, respectively). Gestational losses, regardless of the animal class, were higher in females in the CG (7.93%) [P < 0.05] compared to those in the GiP4 group (2.84%). Regardless of treatment with iP4, the percentage of gestational loss in heifers was significantly higher (10.64%) than that in primiparous and multiparous cows (3.77% and 2.86%, respectively). The final conception rates were higher in animals that received long-acting iP4, which increased the final pregnancy in all parity categories. In the present study, the use of iP4 increased the pregnancy rate in Nellore females, regardless of the category. Although there has been no consensus on the use of iP4, there is an agreement that increases in the pregnancy rate are related to the moment of exogenous P4 application. In addition to influencing the pregnancy rate, reduction in pregnancy losses is also attributed to iP4 treatment, a fact demonstrated in the present study, where animals treated with iP4 had a lower pregnancy loss rate than normally occurs in beef cattle. Supplementation with long-acting iP4 increased the pregnancy rate at D35-40, reduced pregnancy losses, and increased the conception rate on D80-90 days in Nellore females reared in the Western Amazon, regardless of the animal category.(AU)

Diferentes protocolos de congelação de sêmen canino para melhoria de sua cinética e viabilidade / Different canine semen freesing protocols to improve kinetics and viability / Diferentes protocolos de congelación de semen canino para mejoría de su cinética y viabilidad

A maioria dos protocolos utilizados para a criopreservação de sêmen canino, se baseiam em metodologias descritas para outras espécies. Assim, este estudo tem como objetivo avaliar diferentes protocolos de congelação para sêmen desta espécie doméstica. Para tanto, foram utilizados 3 machos, adultos, da raça Buldogue Campeiro, com idades entre 2 a 5 anos e fertilidade comprovada. Foram realizadas 5 colheitas de sêmen de cada animal, pelo método de manipulação digital do bulbo peniano, priorizando a segunda fração do ejaculado. As amostras colhidas foram divididas em 2 grupos, com concentração de 100 x 106 espermatozoides por mL. No grupo 1, as amostras foram diluídas diretamente em meio de congelação comercial Botudog® (Botupharma Biotecnologia Animal). No grupo 2, as amostras foram centrifugadas a 600 g por 10 minutos e em seguida, o pellet foi ressuspendido em meio de congelação comercial Botudog®. As amostras foram envasadas em palhetas de 0,5 mL com concentração de 50 x 106 espermatozoides viáveis. Em seguida, as amostras permaneceram por 1 hora em estabilização a 5ºC. Logo após, transferidas para o vapor de nitrogênio durante 10 minutos, e por fim, mergulhadas em nitrogênio e armazenadas em botijão criogênico. As palhetas foram descongeladas a 46ºC por 15 segundos. Foram avaliados os parâmetros de cinética espermática e integridade de membrana plasmática e acrossomal (IMPA, %). Verificou-se que os parâmetros de motilidade total (%), velocidade linear progressiva (VSL; µm/s), velocidade curvilínea (VCL; µm/s), linearidade (%), percentagem de espermatozoides rápidos (%) e integridade de membrana plasmática e acrossomal avaliados por citometria de fluxo foram superiores no grupo 1, em que as amostras não foram centrifugadas. Estes dados demonstram que, o protocolo para congelação de sêmen canino, utilizando o diluente Botudog®, não preconiza a centrifugação do ejaculado, previamente a congelação.(AU)

Most protocols used for canine semen cryopreservation are based on methodologies described for other species. Thus, this study aims at evaluating different freezing protocols for semen of this domestic species. To this end, 3 adult Bulldog Campeiro males aged 2 to 5 years and proven fertility were used. Five semen samples were collected from each animal using the digital manipulation of the penile bulb method, prioritizing the second fraction of the ejaculate. The collected samples were divided into 2 groups, with a concentration of 100 x 106 sperm per mL. In group 1, the samples were diluted directly into Botudog® commercial freezing medium (Botupharma Animal Biotechnology). In group 2, the samples were centrifuged at 600 g for 10 minutes and then the pellet was resuspended in commercial Botudog® freezing medium. The samples were packed in 0.5 mL straws with a concentration of 50 x 106 viable sperm. Then, the samples remained for 1 hour in stabilization at 5ºC. Afterwards, they were transferred to nitrogen vapor for 10 minutes, and finally, dipped in nitrogen and stored in cryogenic cylinder. The straws were thawed at 46ºC for 15 seconds. Parameters for spermatic kinetics, and plasma and acrosomal membrane integrity (IMPA, %) were evaluated. Total motility (%), progressive linear velocity (VSL; µm/s), curvilinear velocity (VCL; µm/s), linearity (%), percentage of rapid sperm (%) and membrane integrity were found. Plasma and acrosomal samples evaluated by flow cytometry were higher in group 1, where samples were not centrifuged. These data demonstrate that the protocol for canine semen freezing using Botudog® diluent does not recommend centrifugation of the ejaculate prior to freezing.(AU)

La mayoría de los protocolos utilizados para la criopreservación de semen canino se basan en metodologías descritas para otras especies. Por lo tanto, esta investigación tiene como objetivo evaluar diferentes protocolos de congelación para el semen de esta especie doméstica. Con este fin, se utilizaron 3 machos, adultos, de la raza Bulldog Campero, con edades entre 2 a 5 años y fertilidad comprobada. Se realizaron cinco recolecciones de semen de cada animal mediante el método de manipulación digital del bulbo del pene, priorizando la segunda fracción de la eyaculación. Las muestras recolectadas se dividieron en 2 grupos, con una concentración de 100 x 106 espermatozoides por mL. En el grupo 1, las muestras se diluyeron directamente en medio de congelación comercial Botudog® (Botupharma Animal Biotechnology). En el grupo 2, las muestras fueron centrifugadas a 600 g durante 10 minutos y luego el pellet fue resuspendido en medio de congelación comercial Botudog®. Las muestras se envasaron en paletas de 0,5 mL con una concentración de 50 x 106 espermatozoides viables. Luego, las muestras permanecieron durante 1 hora en estabilización a 5ºC. Posteriormente, se transfirieron al vapor de nitrógeno durante 10 minutos y, finalmente, se sumergieron en nitrógeno y se almacenaron en un cilindro criogénico. Las paletas se descongelaron a 46ºC durante 15 segundos. Se han evaluado los parámetros de la cinética espermática y la integridad de la membrana plasmática acrosomal (IMPA, %). Se verificó que los parámetros de motilidad total (%), velocidad lineal progresiva (VSL; µm/s), velocidad curvilínea (VCL; µm/s), linealidad (%), porcentaje de espermatozoides rápidos (%) e integridad de la membrana plasmática y acrosomal evaluadas por citometría de flujo, fueron mayores en el grupo 1, donde las muestras no fueron centrifugadas. Estos datos demuestran que, el protocolo para la congelación de semen canino, usando el diluyente Botudog®, no preconiza la centrifugación del eyaculado, previamente a la congelación.(AU)

Estrus synchronization and Fixed Time Artificial Insemination (FTAI) in dairy buffaloes during seasonal anestrus

The aim of this work was to study estrus synchronization and fixed time artificial insemination (FTAI) in dairy buffaloes during season anestrus. One hundred thirty-nine dairy buffaloes in seasonal anestrus were divided in two groups as G1(n=66) and G2(n=73). The protocols for both the groups were the same until day (D)14:D0 administration of 2.0 mg estradiol benzoate and implantation of progesterone device (P4) for 14 days; D14 removal of P4 plus 150 mg of cloprostenol and 400 IU of equine chorionic gonadotropin. On D16, G1 received 10 mg of buserelin and G2 100 mg deslorelin acetate. On D17, both the groups were submitted to FTAI. Ultrasonographic examinations of ovaries were performed on D0, D14, D16 and D17. Results showed that pregnancy rates in G1 and G2 were 20 and 41% (p<0.05) and the ovulation rates were 16.6 and 37%, respectively (p<0.05). The dominant follicle (DF) diameter on D16 was 7.9 mm in G1 and 8.9 mm in G2 (p>0.05). Thirty-five percent of the animals in G1 and 54.1% in G2 showed a diameter DF greater than 8.0 mm on D16 (p>0.05). Thus, it could be concluded that the protocols synchronized the estrus, leading the concentration of the parturitions in the period of low milk production. Deslorelin was more efficient than buserelin due the higher percentage of DF ovulation and higher pregnancy rates.