RESUMO

Despite being the most important form of biotechnology in animal reproduction, artificial insemination was used in about 23% of Brazilian bovine herds in 2021. This is due to the variability of results caused by varying bull fertility and body condition of the cows. This study aimed to correlate the fertility indices of bulls with qualitative attributes of the semen. Semen samples from 28 bulls (Nellore and Angus) were used to evaluate postthaw sperm morphology and kinetics using conventional analysis, image-based flow cytometry (IBFC) and computer-assisted semen analysis (CASA). The fertility index was effective in separating bulls into 4 different fertility classes (P < 0.001), and fertility rates in timed artificial insemination (TAI) remained constant between the cows' fertility categories (P < 0.001) and in the different grades of female body condition (P < 0.005). After partial least squares regression (PLS) analysis, four models were proposed with different variables. The coefficients of determination for the conventional analysis, CASA, and IBCFC models were 0.154, 0.380, and 0.259, respectively. The composite model, including select IBFC and CASA parameters, showed a greater R2 (0.481) with progressive motility, average speed (VAP, µm/s), membrane integrity, and mitochondrial potential, showing a positive effect. Linear speed (VSL, µm/s) and acrosomal integrity had a negative effect on bull fertility indices. Bulls classified by the fertility index attained dispersed pregnancy rates in different cow body condition score (BCS) classes, and the sperm quality pattern was consistent with this classification. In conclusion, this novel composite model including CASA and IBFC parameters improves the prediction of bull fertility used in TAI.

RESUMO

The objective of this study was to reduce the effects of cryoinjury caused in bovine semen by cryopreservation. Ejaculates were collected from Nellore bulls and subjected to freezing in C (control), ozone (15, 30, and 60 µg mL-1 of ozone), quercetin (25, 50, and 100 µg mL-1 of quercetin), and carnosine groups (100, 200, and 300 ng mL-1 of carnosine). Samples were evaluated post-thaw (M0) and post-rapid thermoresistance test (M30) for sperm kinetics (total motility, progressive motility, curvilinear speed, linearity and amplitude of lateral head displacement) and cell structure viability (plasma membrane integrity, acrosomal integrity, mitochondrial potential, membrane fluidity, and lipid peroxidation). There were no differences (P > 0.05) between the control, quercetin, and carnosine-treated groups for the parameters evaluated at M0 and M30. In turn, supplementation with ozone resulted in lower values for sperm kinetics (P < 0.05) and lower mitochondrial potential at M30 (P < 0.05). Quercetin and carnosine at the concentrations used did not promote significant gains in frozen semen, nor did they demonstrate cytotoxicity. We expected to obtain positive results with the use of ozone. Nonetheless, the addition was harmful to the parameters of sperm kinetics, and its effect was not observed as a possible pro-antioxidant. We believe that the fact that the gas did not harm the sperm structure opens avenues for tests with lower dosages, since, by reducing its concentration, we could minimize the damage to sperm kinetics.

RESUMO

The objective of this study was to reduce the effects of cryoinjury caused in bovine semen by cryopreservation. Ejaculates were collected from Nellore bulls and subjected to freezing in C (control), ozone (15, 30, and 60 µg mL-1 of ozone), quercetin (25, 50, and 100 µg mL-1 of quercetin), and carnosine groups (100, 200, and 300 ng mL-1 of carnosine). Samples were evaluated post-thaw (M0) and post-rapid thermoresistance test (M30) for sperm kinetics (total motility, progressive motility, curvilinear speed, linearity and amplitude of lateral head displacement) and cell structure viability (plasma membrane integrity, acrosomal integrity, mitochondrial potential, membrane fluidity, and lipid peroxidation). There were no differences (P > 0.05) between the control, quercetin, and carnosine-treated groups for the parameters evaluated at M0 and M30. In turn, supplementation with ozone resulted in lower values for sperm kinetics (P < 0.05) and lower mitochondrial potential at M30 (P < 0.05). Quercetin and carnosine at the concentrations used did not promote significant gains in frozen semen, nor did they demonstrate cytotoxicity. We expected to obtain positive results with the use of ozone. Nonetheless, the addition was harmful to the parameters of sperm kinetics, and its effect was not observed as a possible pro-antioxidant. We believe that the fact that the gas did not harm the sperm structure opens avenues for tests with lower dosages, since, by reducing its concentration, we could minimize the damage to sperm kinetics.(AU0

Assuntos

RESUMO

Esta revisão pretende discorrer sobre a estrutura social dos bovinos e sua relação com o comportamento sexual, a fisiologia reprodutiva e a fertilidade de touros a campo e em regime de coleta de sêmen, levando em consideração as diferentes fases do desenvolvimento sexual, os processos de aprendizado envolvidos e os efeitos do estresse social. À luz do conhecimento etológico serão feitas reflexões sobre o fitness (sucesso reprodutivo) de touros mantidos em manejo extensivo de criação e touros em Centrais de Coleta e Processamento de Sêmen (CCPS), a organização arquitetônica dos piquetes e área de coleta e a influência da proximidade de outros touros sobre a qualidade de todo o processo.(AU)

This review intends to discuss the cattle social structure and its relationship with sexual behavior, reproductive physiology, and fertility of bulls in the field and under semen collection regime, taking into account the distinct stages of sexual development, the learning processes involved and the effects of social stress. In the light of ethological science, we will reflect on the fitness (reproductive success) of bulls in extensive breeding management or bulls in Semen Collection and Processing Centers, their architectural organization of paddocks and collection area, and the influence of the proximity of other bulls on the quality of the entire process.(AU)

Assuntos

RESUMO

It was aimed to evaluate anti-GnRH vaccine efficiency on productive characteristics, seminal performance, size, and histology of testicles of lambs submitted to immunocastration. Twenty contemporary Texel lambs were evaluated, being 10 animals received two doses of 1 mL of anti-GnRH vaccine and 10 received two doses of 1 mL of saline, with an interval of 30 days. Seminal characteristics, weight and histological cut for the testicles, productive performance, and blood parameters were analyzed. Andrological monitoring was carried out every 30 days. All animals were kept on pasture of Urochloa spp. receiving daily supplementation protein-energetic by 90 days. There was effect of immunocastration on slaughter weight (44.3 vs. 48.3 kg),total gain (9.9 vs. 10.3 kg), daily gain (104.5 vs. 108.9 g/day), and feed conversion (5.83 vs. 5.97) respectivelyto immunocastrated and intact lambs. There was immunocastration effect on testicle weight (0.09 vs. 0.35g), motility (4.5 vs. 61.0%), vigor (0.40 vs. 3.00), volume (0.09 vs. 0.74 mL) and swirling (0.20 vs. 2.70) in the third semen collection. Immunocastration through two doses of 1 mL of anti-GnRH vaccine with a 30-day interval between doses, causes infertility in sheep and can be adopted for lambs.(AU)

O objetivo foi avaliar a eficiência da vacina anti-GnRH quanto às características de desempenho produtivo e seminais, tamanho e histologia dos testículos de cordeiros submetidos à imunocastração. Foram avaliados 20 cordeiros contemporâneos cruzados SRD x Texel, dos quais 10 animais receberam duas doses de 1 mL de vacina anti-GnRH e 10 receberam duas doses de 1 mL de soro fisiológico, com intervalo de 30 dias entre doses. As variáveis analisadas foram concentração espermática, motilidade, vigor, turbilhonamento e volume de ejaculado para o sêmen, peso e corte histológico para os testículos, peso ao abate, ganho de peso total, ganho médio diário, consumo médio de suplemento e conversão alimentar para o desempenho produtivo e GGT, AST, albumina, creatinina, proteínas totais e ureia para o sangue. A cada 30 dias foi realizado o acompanhamento andrológico para verificação do efeito da vacina sobre características seminais e testiculares dos animais. Durante os 90 dias de duração do experimento, os animais foram mantidos a pasto de Urochloa spp., com suplementação diária, sendo abatidos ao final deste período. Houve diferença entre animais imunocastrados e inteiros respectivamente, para o peso ao abate (44,3 vs. 48,3 kg), ganho de peso total (9,9 vs 10,3 kg), ganho médio diário (104,5 vs. 108,9 g/dia) e conversão alimentar (5,83 vs. 5,97). Houve efeito significativo para motilidade (4,5 vs. 61,0%), vigor (0,40vs. 3,00), volume (0,09 vs. 0,74 mL) e turbilhonamento (0,20 vs. 2,70) na terceira colheita de sêmen, que foi 30 dias após a segunda dose da vacina. Houve efeito significativo para peso dos testículos (0,09 vs. 0,35g). No perfil bioquímico do sangue dos animais não houve alterações significativas durante o experimento em ambos os tratamentos. A imunocastração através de duas doses de 1 mL de vacina anti-GnRH com 30 dias de intervalo entre as doses, [...].(AU)

Assuntos

RESUMO

It was aimed to evaluate anti-GnRH vaccine efficiency on productive characteristics, seminal performance, size, and histology of testicles of lambs submitted to immunocastration. Twenty contemporary Texel lambs were evaluated, being 10 animals received two doses of 1 mL of anti-GnRH vaccine and 10 received two doses of 1 mL of saline, with an interval of 30 days. Seminal characteristics, weight and histological cut for the testicles, productive performance, and blood parameters were analyzed. Andrological monitoring was carried out every 30 days. All animals were kept on pasture of Urochloa spp. receiving daily supplementation protein-energetic by 90 days. There was effect of immunocastration on slaughter weight (44.3 vs. 48.3 kg),total gain (9.9 vs. 10.3 kg), daily gain (104.5 vs. 108.9 g/day), and feed conversion (5.83 vs. 5.97) respectivelyto immunocastrated and intact lambs. There was immunocastration effect on testicle weight (0.09 vs. 0.35g), motility (4.5 vs. 61.0%), vigor (0.40 vs. 3.00), volume (0.09 vs. 0.74 mL) and swirling (0.20 vs. 2.70) in the third semen collection. Immunocastration through two doses of 1 mL of anti-GnRH vaccine with a 30-day interval between doses, causes infertility in sheep and can be adopted for lambs.

O objetivo foi avaliar a eficiência da vacina anti-GnRH quanto às características de desempenho produtivo e seminais, tamanho e histologia dos testículos de cordeiros submetidos à imunocastração. Foram avaliados 20 cordeiros contemporâneos cruzados SRD x Texel, dos quais 10 animais receberam duas doses de 1 mL de vacina anti-GnRH e 10 receberam duas doses de 1 mL de soro fisiológico, com intervalo de 30 dias entre doses. As variáveis analisadas foram concentração espermática, motilidade, vigor, turbilhonamento e volume de ejaculado para o sêmen, peso e corte histológico para os testículos, peso ao abate, ganho de peso total, ganho médio diário, consumo médio de suplemento e conversão alimentar para o desempenho produtivo e GGT, AST, albumina, creatinina, proteínas totais e ureia para o sangue. A cada 30 dias foi realizado o acompanhamento andrológico para verificação do efeito da vacina sobre características seminais e testiculares dos animais. Durante os 90 dias de duração do experimento, os animais foram mantidos a pasto de Urochloa spp., com suplementação diária, sendo abatidos ao final deste período. Houve diferença entre animais imunocastrados e inteiros respectivamente, para o peso ao abate (44,3 vs. 48,3 kg), ganho de peso total (9,9 vs 10,3 kg), ganho médio diário (104,5 vs. 108,9 g/dia) e conversão alimentar (5,83 vs. 5,97). Houve efeito significativo para motilidade (4,5 vs. 61,0%), vigor (0,40vs. 3,00), volume (0,09 vs. 0,74 mL) e turbilhonamento (0,20 vs. 2,70) na terceira colheita de sêmen, que foi 30 dias após a segunda dose da vacina. Houve efeito significativo para peso dos testículos (0,09 vs. 0,35g). No perfil bioquímico do sangue dos animais não houve alterações significativas durante o experimento em ambos os tratamentos. A imunocastração através de duas doses de 1 mL de vacina anti-GnRH com 30 dias de intervalo entre as doses, [...].

Assuntos

RESUMO

Dispersed ovulation at the breeding (BS) and anestrus at non-breeding season (NBS) are major impediments to embryo transfer and insemination programmes. The present study aimed to evaluate a hormonal P4/E2-based synchronisation protocol in mares during both the BS and the NBS on ovarian/follicle behaviour. Mares underwent a hormone protocol to synchronise their ovulation during the BS (n = 8) and NBS (n = 10), starting (D0) with the insertion of an intravaginal device containing 1 g of P4 and 7 mg Estradiol Benzoate IM. (EB). On D9, the device was removed and injected with 0.25 mg of cloprostenol sodic IM and 2 mg of EB IM. Follicular behaviour was evaluated using a daily transrectal ultrasound (24/24 h) from D0 until ovulation. When the dominant follicle (DF) measured at least 35 mm, females were injected with 0.25 mg of gonadorelin acetate IM to induce ovulation. The DF on D0 were similar in animals between BS (18.9 ± 8.4 mm) and NBS (23.7 ± 9.2 mm; p = 0.2700). However, in the BS the DF was smaller (14.2 ± 4.7 mm) on D9 than during NBS (22.0 ± 7.1 mm; p = 0.0177). During the BS, the ovulatory follicle is smaller (p = 0.0042) than during NBS, measured at 33.5 ± 4.6 mm and 41.3 ± 2.8 mm, respectively. Ovulation time after P4 removal was similar during BS (173.1 ± 68.8 h) and NBS (192 ± 58.2 h; p = 0.3507). There was no difference towards an ovulation rate during BS (88%) and NBS (60%; p = 0.0978). There was no difference in spontaneous ovulation during BS (43%) and NBS (0%; p = 0.6085). This hormonal protocol would be an effective tool for inducing cyclicity/ovulation in mares during BS and NBS.

Assuntos

RESUMO

Gynecological examination is essential to assess the reproductive tract of mares and can provide important information about the uterine environment. It includes physical, vaginal, and rectal examination, ultrasound, cytology, culture, and endometrial biopsy. The present study aimed to perform gynecological examination and fertility to assess the fertility prognosis of Pantaneiro mares that have not been reproductively active and to determine their reproductive ability. Eight mares underwent ultrasound and gynecological examination and artificial insemination. Ultrasound revealed changes only in one mare. Histopathological findings were mild, such as periglandular and perivascular inflammatory cell infiltrates, fibrotic areas, glandular dilation, glandular island formation, and edema due to the phase of the estrous cycle. One animal was classified in category I and the others in category IIA. Cytological changes were found in only one mare. Endometrial culture from five mares resulted in isolation of Pseudomonas sp., Bacillus sp., Escherichia coli and Candida sp. Only four mares resulted pregnant through artificial insemination, using the same stallion with fresh semen, which has been proving fertility. Thus, mares with better uterine conditions will not always become pregnant and those with mild changes will not always be barren.

RESUMO

Plasma membrane composition has impact on phase transition from liquid crystal to gel state of cooled sperm cell. The incorporation of polyunsaturated fatty acids increases its fluidity and can contribute to sperm motility. The aim of this study was to compare the effect of adding docosahexaenoic acid (DHA) and α-tocopherol (α-Toh) to the cooling extender, singly or combined, to the equine sperm parameters, submitted to cooling, up to 72 hours. Two ejaculates of ten stallions collected with artificial vagina were used, and evaluated for motility, plasma membrane integrity, chromatin fragmentation, mitochondrial activity and lipid peroxidation, according to the following treatments: C; DHA; α-Toh; DHA/α-Toh; EtOH 100: and EtOH 140 (corresponding to control; 10 ng mL-1 of DHA; 2 mM of α-Toh; : 10 ng mL-1 of DHA + 2 mM of α-Toh; 100 µL of ethanol and 140 µL of ethanol respectively). DHA treatment showed higher motility (68.2 ± 12.3; p < 0.05) when compared to control (62.1 ± 16.2), DHA/α-Toh (61.3 ± 12.7) and EtOH (58.1 ± 8.6) groups. In lipid peroxidation assay, the control group showed 2,506.2 ± 796.4 ng of MDA 108 spermatozoa-1, being significantly higher (p < 0.05) than the groups treated with DHA (2,036.0 ± 687.0), α-Toh (1,890.8 ± 749.5) and DHA/α-Toh (1,821.1 ± 627.2). In conclusion, α-Toh was effective in diminishing lipid peroxidation of equine sperm subjected to cooling, and DHA improved sperm motility and, in spite of being a polyunsaturated fatty acid with high susceptibility to peroxidation, reduced lipid peroxidation.(AU)

A composição da membrana plasmática tem impacto na transição de fase do estado cristal líquido para o estado gel das células espermáticas submetidas à refrigeração. A incorporação de ácidos graxos poliinsaturados aumenta sua fluidez e pode contribuir para a motilidade espermática. O objetivo deste estudo foi comparar o efeito da adição de ácido docosahexaenóico (DHA) e α-tocoferol (α-Toh) ao diluidor de refrigeração, isoladamente ou combinado, aos parâmetros do sêmen equino, submetidos à refrigeração por até 72 horas. Foram utilizados dois ejaculados de dez garanhões coletados com vagina artificial e avaliados quanto à motilidade, integridade da membrana plasmática, fragmentação da cromatina, atividade mitocondrial e peroxidação lipídica, de acordo com os seguintes tratamentos: C; DHA; a-Toh; DHA / a-Toh; EtOH 100: e EtOH 140 (correspondentes ao controle; 10 ng mL-1 de DHA; 2 mM de α-Toh;: 10 ng mL-1 de DHA + 2 mM de α-Toh; 100 µL de etanol e 140 µL de etanol, respectivamente). O tratamento com DHA mostrou maior motilidade (68,2 ± 12,3; p < 0,05) quando comparado aos grupos controle (62,1 ± 16,2), DHA/α-Toh (61,3 ± 12,7) e EtOH (58,1 ± 8,6). Na análise de peroxidação lipídica, o grupo controle mostrou 2.506,2 ± 796,4 ng de MDA 108 espermatozoides-1, sendo significativamente maior (p < 0,05) do que os grupos tratados com DHA (2.036,0 ± 687,0), α-Toh (1.890,8 ± 749,5) e DHA / a-Toh (1.821,1 ± 627,2). Em conclusão, α-Toh foi eficaz na diminuição da peroxidação lipídica de espermatozoide equino submetido ao resfriamento, e o DHA melhorou a motilidade espermática e, apesar de ser um ácido graxo poliinsaturado com alta suscetibilidade à peroxidação, reduziu a peroxidação lipídica.(AU)

Assuntos

RESUMO

Plasma membrane composition has impact on phase transition from liquid crystal to gel state of cooled sperm cell. The incorporation of polyunsaturated fatty acids increases its fluidity and can contribute to sperm motility. The aim of this study was to compare the effect of adding docosahexaenoic acid (DHA) and α-tocopherol (α-Toh) to the cooling extender, singly or combined, to the equine sperm parameters, submitted to cooling, up to 72 hours. Two ejaculates of ten stallions collected with artificial vagina were used, and evaluated for motility, plasma membrane integrity, chromatin fragmentation, mitochondrial activity and lipid peroxidation, according to the following treatments: C; DHA; α-Toh; DHA/α-Toh; EtOH 100: and EtOH 140 (corresponding to control; 10 ng mL-1 of DHA; 2 mM of α-Toh; : 10 ng mL-1 of DHA + 2 mM of α-Toh; 100 µL of ethanol and 140 µL of ethanol respectively). DHA treatment showed higher motility (68.2 ± 12.3; p < 0.05) when compared to control (62.1 ± 16.2), DHA/α-Toh (61.3 ± 12.7) and EtOH (58.1 ± 8.6) groups. In lipid peroxidation assay, the control group showed 2,506.2 ± 796.4 ng of MDA 108 spermatozoa-1, being significantly higher (p < 0.05) than the groups treated with DHA (2,036.0 ± 687.0), α-Toh (1,890.8 ± 749.5) and DHA/α-Toh (1,821.1 ± 627.2). In conclusion, α-Toh was effective in diminishing lipid peroxidation of equine sperm subjected to cooling, and DHA improved sperm motility and, in spite of being a polyunsaturated fatty acid with high susceptibility to peroxidation, reduced lipid peroxidation.

A composição da membrana plasmática tem impacto na transição de fase do estado cristal líquido para o estado gel das células espermáticas submetidas à refrigeração. A incorporação de ácidos graxos poliinsaturados aumenta sua fluidez e pode contribuir para a motilidade espermática. O objetivo deste estudo foi comparar o efeito da adição de ácido docosahexaenóico (DHA) e α-tocoferol (α-Toh) ao diluidor de refrigeração, isoladamente ou combinado, aos parâmetros do sêmen equino, submetidos à refrigeração por até 72 horas. Foram utilizados dois ejaculados de dez garanhões coletados com vagina artificial e avaliados quanto à motilidade, integridade da membrana plasmática, fragmentação da cromatina, atividade mitocondrial e peroxidação lipídica, de acordo com os seguintes tratamentos: C; DHA; a-Toh; DHA / a-Toh; EtOH 100: e EtOH 140 (correspondentes ao controle; 10 ng mL-1 de DHA; 2 mM de α-Toh;: 10 ng mL-1 de DHA + 2 mM de α-Toh; 100 µL de etanol e 140 µL de etanol, respectivamente). O tratamento com DHA mostrou maior motilidade (68,2 ± 12,3; p < 0,05) quando comparado aos grupos controle (62,1 ± 16,2), DHA/α-Toh (61,3 ± 12,7) e EtOH (58,1 ± 8,6). Na análise de peroxidação lipídica, o grupo controle mostrou 2.506,2 ± 796,4 ng de MDA 108 espermatozoides-1, sendo significativamente maior (p < 0,05) do que os grupos tratados com DHA (2.036,0 ± 687,0), α-Toh (1.890,8 ± 749,5) e DHA / a-Toh (1.821,1 ± 627,2). Em conclusão, α-Toh foi eficaz na diminuição da peroxidação lipídica de espermatozoide equino submetido ao resfriamento, e o DHA melhorou a motilidade espermática e, apesar de ser um ácido graxo poliinsaturado com alta suscetibilidade à peroxidação, reduziu a peroxidação lipídica.

Assuntos