RESUMO

The cryopreservation of jaguar semen must be improved to produce high-quality biobanking doses. Until now, the rare studies of semen freezing in the species have only evaluated glycerol, always with a significant reduction in sperm quality in thawed semen. The purpose of this study was to assess the efficacy of three cryoprotectants, dimethylsulfoxide (DMSO), glycerol (GLY), and methanol (MET), in the cryopreservation of jaguar semen in an LDL-based extender, as well as the effect of thawing temperature on dosage quality. Five mature males with a history of reproduction were used. On the males, an infrared thermal image (IRT) was captured, the spicules and testes were analyzed, and the CASA system was used to evaluate the quality of fresh and thawed sperm. The superficial IRT was 4.6 ± 1.2 °C cooler than the anal sphincter, and the semen measured between 27.3 and 28.7 °C shortly after exiting the urethra. The total motility of fresh sperm was 55.3 ± 22.6%, and progressive motility was 36.3 ± 18%. The total motility of thawed sperm was 5.28 ± 2.51%, 4.49 ± %2.49, and 0.51 ± 0.62% for DMSO, GLY, and MET, respectively. DMSO and GLY performed better than MET, and there was no difference in thawing temperature (37°C 30 s vs. 50°C 12 s). All animals exhibit a considerable level of morphological changes in sperm. Low amounts of total and progressive motility were found in the thawed sperm. Males with a high level of sperm morphological changes were found to be fertile, but the lone male with normospermia was infertile. Thus, we contest the applicability of the commonly used morphological classification for bovines to felid species.(AU)

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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

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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)

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Among the different methods used for semen collection from domestic cats, the pharmacological collection by urethral catheterization becomes disruptive. Medetomidine is the elected α2-adrenoceptor agonist for that, but in several countries, it is not commercially available. This study aimed to evaluate the efficacy of detomidine compared to medetomidine in collecting semen by urethral catheterization in domestic cats. Urethral catheterization was performed on 13 mongrel cats using a disposable semi-rigid tomcat urinary catheter. Of the 19 semen collections performed with medetomidine induction, 94.7% were successful, while with detomidine induction, only 56.3% of 16 were successful. The values semen samples variables were as follows for volume - 10.56 ± 0.4 vs 8.88 ± 0.5 mL, motility - 171.67 ± 0.79 vs 49.77 ± 3.45%, vigor 4.1 ± 0.03 vs 3.10 ± 0.1 and concentration - 3.24 ± 0.19 vs 2.15 ± 0.13 ×109 sperm/mL respectively for medetomidine and detomidine group. The failure in semen collections with detomidine was mainly due to azoospermic samples, poor urethral relaxation, insufficient volume, or contamination of urine. The sperm concentration was also lower in the detomidine group (P<0.05) when compared to medetomidine. However, when the volume of semen collected was compared, we found no statistical differences. Despite its low performance in collecting semen from cats, detomidine may be an alternative when medetomidine is not accessible.(AU)

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Selection for bulls that would reach puberty early reduces the generation interval and increases fertility and herd productivity. Despite its economic importance, there are few QTL associated with age at puberty described in the literature. In this study, a weighted single-step genome-wide association study was performed to detect genomic regions and putative candidate genes related to age at puberty in young Nelore bulls. Several protein-coding genes related to spermatogenesis functions were identified within the genomic regions that explain more than 0.5% of the additive genetic variance for age at puberty in Nelore bulls, such as ADAM11, BRCA1, CSNK2A, CREBBP, MEIOC, NDRG2, NECTIN3, PARP2, PARP9, PRSS21, RAD51C, RNASE4, SLX4, SPA17, TEX14, TIMP2 and TRIP13 gene. Enrichment analysis by DAVID also revealed several GO terms related to spermatogenesis such as DNA replication (GO:0006260), male meiosis I (GO:0007141), double-strand break repair (GO:0006302), base excision repair (GO:0006284), apoptotic process (GO:0006915), cell-cell adhesion (GO: 0098609) and focal adhesion (GO:0005925). The heritability for age at puberty shows that this trait can be improved based on traditional EBV selection. Adding genomic information to the system helps to elucidate genes and molecular mechanisms controlling the sexual precocity and could help to predict sexual precocity in Nelore bulls with greater accuracy at younger age, which would speed up the breeding programme for this breed.

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The objective was to evaluate vaginal temperature as a thermoregulatory response of Nellore heifers under different microclimatic conditions. The study was conducted during one year in an experimental area located at 54°37'W, 20°27'S, and 530 m of altitude in Brazil. Twenty-four Nellore females were reared in integrated crop-livestock-forestry systems with different shading patterns. The randomized complete block experimental design was utilized with a sub subdivided plots scheme, with plot corresponding to the production systems, the subplot to the season of the year, and the sub subplot, the hours of the day. To characterize the microclimate, data regarding air and black globe temperatures, and air relative humidity were collected and from them, temperature-humidity index was calculated. Vaginal temperature was obtained by using a bottom-type temperature logger (i-button) attached to an adapted intravaginal device. The black-globe temperature explained the variation on vaginal temperature. Increases on vaginal temperature were only observed, on average, two hours after the increase of black-globe temperature. The microclimatic conditions found in the systems, resulting from the various tree densities, modify the vaginal temperature in different degrees, demonstrating that the shading effect is not always accompanied by improvements in thermal comfort. The system with intermediate density showed a better microclimatic condition and, consequently, a lower increase in vaginal temperature. The interaction between air temperature, humidity and solar radiation resulted in adverse environmental conditions, however, Nellore heifers showed good adaptation to the environment. In conclusion, vaginal temperature is a good indicator to evaluate the thermoregulatory response in Nellore heifers.

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O objetivo desta revisão foi apresentar e discutir os efeitos da sazonalidade nas características seminais de touros Bos taurus e Bos indicus antes e após o congelação, a fim de possibilitar maior rentabilidade econômica. Apesar da reprodução da espécie bovina não se caracterizar pela sazonalidade, estudos mostram a interferência das estações do ano na qualidade do sêmen de touros. O aumento da temperatura ambiente pode levar a elevação da temperatura testicular, das taxas metabólicas e das exigências de oxigênio, ocasionando alterações na espermatogênese e, por consequência, a um impacto negativo na reprodução. Touros Bos indicus obtêm melhor desempenho na estação mais quente do ano apresentando uma qualidade de sêmen satisfatória em relação a touros Bos taurus. Isso se deve à maior resistência dos zebuínos às altas temperaturas e a peroxidação lipídica causada pelo calor resultando em menor produção de espécies reativas ao oxigênio e menor aumento nos defeitos nas células espermáticas. Desse modo, touros de origem europeia não apresentam um bom desempenho durante alguns períodos mais quentes do ano o que leva a questionar se a relação custo-benefício de aproveitamento do sêmen para criopreservação justifica o processamento do mesmo pelas Centrais de Coleta e Processamento de Sêmen nesta época. Esse fato tem levado algumas empresas a suspender atividades em determinados meses do ano.(AU)

The objective of this review was to present and discuss the effects of seasonality in the semen characteristics of Bos taurus and Bos indicus bulls before and after freezing in order to enable greater economic profitability. Even though the bovine reproduction is not characterized by seasonality, studies have shown the interference of the season on semen quality in bulls. The increase of temperature may lead to increase in testicular temperature, metabolic rates and oxygen requirements. Both thermal and oxidative stress will cause changes in the normal development of spermatogenesis, changing volume, sperm concentration, progressive motility, vigor and morphology of sperm cells, resulting in an economically negative impact on reproduction. Bos indicus bulls presented better performance in the hottest season of the year, showing a satisfactory quality of semen when compared to Bos taurus bulls. This is due to the greater resistance to high temperatures of zebu bulls and lipid peroxidation caused by the heat resulting in lower production of species reactive to oxygen and smaller increases in defects in sperm cells. Thus, European bulls, such as Bos Taurus, do not present a good performance in some of the hottest periods of the year, which leads to questioning if the cost-effective use of semen cryopreservation justifies its processing by the Semen Collection and Processing Centers during these periods. This fact has led some national centers for semen suspend activities in certain months of the year.(AU)

El objetivo de esta revisión ha sido presentar y discutir los efectos de la estacionalidad en las características del semen de toros Bos taurus y Bos indicus pre y post congelación, con el fin de proporcionar mayor rentabilidad económica. A pesar de la reproducción vacuna no caracterizarse por la estacionalidad, estudios muestran la interferencia de las estaciones del año en la calidad del semen de toros El aumento de la temperatura ambiente puede conducir a elevada temperatura testicular, de las tasas metabólicas y de las exigencias de oxígeno, ocasionando alteraciones en la espermatogénesis y, por lo tanto, a un impacto negativo en la reproducción. Toros Bos indicus presentaron mejor rendimiento en la temporada más calurosa del año, presentando calidad de semen satisfactoria en comparación con toros Bos taurus. Esto es debido a mayor resistencia del ganado cebú a las altas temperaturas y la peroxidación de lípidos causada por el calor, que resulta en menor producción de especies reactivas al oxígeno y menos defectos en las células espermáticas. Así, toros de origen europea no presentan buen desempeño durante algunos períodos más calurosos del año, lo que lleva a cuestionar si la relación costo beneficio de aprovechamiento del semen para criopreservación justifica la tramitación del mismo por las Centrales de Recogida y Procesamiento de Semen en este periodo. Este hecho ha llevado a algunas empresas a suspender las actividades en ciertos meses del año.(AU)

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RESUMO

Addition of polyunsaturated fatty acids and/or cholesterol to a freezing diluent can modify the sperm plasma membrane composition, influencing its behavior during cryopreservation, thus, favoring seminal cryoresistance. The present study aimed to evaluate the effects of the addition of oleic-linoleic acid, (OLA); beta-sitosterol (beta-sit), a plant analog of cholesterol; and OLA + beta-sit in combination to a freezing diluent, on the cryopreservation bull and stallion semen. The following variables were analyzed: motility/vigor, plasma and acrosomal membrane integrity (by Trypan Blue/Giemsa staining), mitochondrial activity (by DAB staining), and lipid peroxidation (by a TBARS assays). The lipids were added according to experimental treatments: C control group, A1 and A2 OLA at concentrations of 37 uM and 74 uM, B1 and B2 beta-sit at concentrations of 1 ug mL-1 and 2 ug mL-1; AB1 and AB2 OLA 37 uM + beta-sit 1 g mL-1 and OLA 74 uM + beta-sit 2 ug mL-1, respectively. The study was divided into three experiments; in Experiment 1, the concentrations of the groups A1, B1, and AB1 were evaluated, whereas in Experiment 2 the concentrations of the groups A2, B2, and AB2 were analyzed, both experiments were performed with bull semen. We conducted Experiment 3 using equine semen with the addition of lipids at all of the concentrations described. Data were subjected to analysis of variance, using the GLM procedure of SAS, with treatment means compared by Duncan test considering 5% significance. These variables differed significantly after thawing the semen post-collection. However, there was no significant difference between treatments when variables were compared within the same time point, except for Experiment 2, where there was a decrease in motility and vigor decrease post-thaw in the groups following β-sit addition (C 51.0 ± 13.7%/2.9 ± 0.4; B2 35.8 ± 15.8%/2.3 ± 0.6; AB2 38.5 ± 16.6%/2.5 ± 0.5, respectively; p < 0.05).(AU)

A adição de ácidos graxos poli-insaturados e/ou colesterol ao diluidor pode modificar a composição da membrana plasmática do espermatozoide, influenciando seu comportamento frente à criopreservação e favorecendo, assim, a crioresistência seminal. O presente trabalho teve como objetivo avaliar o efeito da adição do ácido oleico-linoleico (AOL), beta-sitosterol (beta-sit), um análogo vegetal do colesterol, e da associação AOL + beta-sit, ao diluente de congelação de sêmen bovino e equino. As variáveis analisadas foram motilidade/ vigor, integridade das membranas plasmática e acrossomais (Trypan Blue/Giemsa), atividade mitocondrial (DAB) e nível de peroxidação lipídica (TBARS). Os lipídios foram adicionados de acordo com os tratamentos experimentais: C grupo controle; A1 e A2 AOL nas concentrações de 37 uM e 74 uM; B1 e B2 beta-sit nas concentrações de 1 ug ml-1 e 2 ug ml-1; AB1 e AB2 AOL 37 uM + beta-sit 1 ug ml-1 e AOL 74 uM + beta-sit 2 ug ml-1, respectivamente. O trabalho consistiu de três experimentos, sendo que o Experimento 1 testou as concentrações dos grupos A1, B1 e AB1, e o Experimento 2 as concentrações dos grupos A2, B2 e AB2, ambos utilizando sêmen de touro. Para o Experimento 3 utilizou-se sêmen equino, sendo a adição dos lipídios feita em todas a concentrações descritas. Os dados foram submetidos à análise de variância, através do procedimento GLM do SAS, sendo as médias dos tratamentos comparadas pelo teste de Duncan em nível de 5% de significância. Os valores das variáveis avaliadas pós-descongelação diferiram significativamente daqueles obtidos pós-colheita, porém não foi observada diferença significativa entre os tratamentos quando as variáveis foram comparadas dentro do mesmo momento, exceto no Experimento 2, em que os valores de motilidade / vigor pós-descongelação nos grupos acrescidos do β-sit foram menores que os do controle (C 51,0 ± 13,7% / 2,9 ± 0,4; B2 35,8 ± 15,8% / 2,3 ± 0,6; AB2 38,5 ± 16,6% / 2,5 ± 0,5, respectivamente; p < 0,05).(AU)

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Thirty Brangus bulls were used in a 90-d study to assess the effect of artificial shading on the performance and reproductive characteristics of semi-confined cattle. Animals were kept in four one-ha paddocks in two groups of eight for shade treatment (5 m²/animal of 80% solar block shade cloth) and two groups of seven animals in no-shade treatment. Each treatment had two homogeneous groups, each divided into heavy-bulls (351-450 kg) and light-bulls (300-350 kg). Time spent under shade, time standing, average daily gain, testicular development and sperm quality were investigated. Animals spent 24% of the daylight under the shade and no-shaded bulls spent more time standing (P < 0.05). No difference was found in average daily gain (P > 0.05) and testicular development between shaded and no-shaded animals. However, scrotal perimeter was higher for shaded light animals compared to no-shaded light bulls (P < 0.10). Sperm motility increase during the experimental period for shaded animals (P < 0.05) and sperm abnormalities were higher for the shaded ones (P < 0.05). Although the results did not indicate pronounced benefits on cattle performance, this resource was an important alternative because it appears to provide an improvement in some reproductive parameters and ensure a better thermal comfort to the animals.

Foi avaliado o efeito do sombreamento artificial sobre o desempenho produtivo e reprodutivo de animais semiconfinados em trinta novilhos Brangus durante o período de 90 dias. Os animais foram mantidos em quatro piquetes de 1 ha cada, divididos em dois grupos de oito animais cada no tratamento sombra (5 m2/animal de tela de sombreamento de polipropileno com 80% de retenção solar) e dois grupos no tratamento sem acesso à sombra com sete animais em cada. As variáveis analisadas foram: o tempo gasto na sombra, o tempo em pé, ganho de peso, desenvolvimento testicular e qualidade espermática. Os animais passaram 24% do dia sob a sombra e os que não tiveram acesso à sombra permaneceram mais tempo em pé (P < 0,05). Não foi encontrada diferença no ganho de peso (P > 0,05) e no desenvolvimento testicular entre animais com acesso à sombra e os que não tinham acesso. No entanto, o perímetro escrotal foi maior para os animais submetidos ao sombreamento comparado com novilhos sem acesso à sombra (P < 0,10). A motilidade espermática aumentou durante o período experimental para os animais com acesso a sombra (P < 0,05), porém as anormalidades espermáticas também foram maiores para este grupo (P < 0,05). Embora os resultados não indiquem claramente os benefícios relacionados ao uso de sombreamento no desempenho produtivo de bovinos semiconfinados, este recurso se mostra como uma alternativa importante, pois proporcionou melhoria de alguns parâmetros reprodutivos e propiciou um melhor conforto térmico para os animais.

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RESUMO

Addition of polyunsaturated fatty acids and/or cholesterol to a freezing diluent can modify the sperm plasma membrane composition, influencing its behavior during cryopreservation, thus, favoring seminal cryoresistance. The present study aimed to evaluate the effects of the addition of oleic-linoleic acid, (OLA); beta-sitosterol (beta-sit), a plant analog of cholesterol; and OLA + beta-sit in combination to a freezing diluent, on the cryopreservation bull and stallion semen. The following variables were analyzed: motility/vigor, plasma and acrosomal membrane integrity (by Trypan Blue/Giemsa staining), mitochondrial activity (by DAB staining), and lipid peroxidation (by a TBARS assays). The lipids were added according to experimental treatments: C control group, A1 and A2 OLA at concentrations of 37 uM and 74 uM, B1 and B2 beta-sit at concentrations of 1 ug mL-1 and 2 ug mL-1; AB1 and AB2 OLA 37 uM + beta-sit 1 g mL-1 and OLA 74 uM + beta-sit 2 ug mL-1, respectively. The study was divided into three experiments; in Experiment 1, the concentrations of the groups A1, B1, and AB1 were evaluated, whereas in Experiment 2 the concentrations of the groups A2, B2, and AB2 were analyzed, both experiments were performed with bull semen. We conducted Experiment 3 using equine semen with the addition of lipids at all of the concentrations described. Data were subjected to analysis of variance, using the GLM procedure of SAS, with treatment means compared by Duncan test considering 5% significance. These variables differed significantly after thawing the semen post-collection. However, there was no significant difference between treatments when variables were compared within the same time point, except for Experiment 2, where there was a decrease in motility and vigor decrease post-thaw in the groups following β-sit addition (C – 51.0 ± 13.7%/2.9 ± 0.4; B2 – 35.8 ± 15.8%/2.3 ± 0.6; AB2 – 38.5 ± 16.6%/2.5 ± 0.5, respectively; p < 0.05).

A adição de ácidos graxos poli-insaturados e/ou colesterol ao diluidor pode modificar a composição da membrana plasmática do espermatozoide, influenciando seu comportamento frente à criopreservação e favorecendo, assim, a crioresistência seminal. O presente trabalho teve como objetivo avaliar o efeito da adição do ácido oleico-linoleico (AOL), beta-sitosterol (beta-sit), um análogo vegetal do colesterol, e da associação AOL + beta-sit, ao diluente de congelação de sêmen bovino e equino. As variáveis analisadas foram motilidade/ vigor, integridade das membranas plasmática e acrossomais (Trypan Blue/Giemsa), atividade mitocondrial (DAB) e nível de peroxidação lipídica (TBARS). Os lipídios foram adicionados de acordo com os tratamentos experimentais: C grupo controle; A1 e A2 AOL nas concentrações de 37 uM e 74 uM; B1 e B2 beta-sit nas concentrações de 1 ug ml-1 e 2 ug ml-1; AB1 e AB2 AOL 37 uM + beta-sit 1 ug ml-1 e AOL 74 uM + beta-sit 2 ug ml-1, respectivamente. O trabalho consistiu de três experimentos, sendo que o Experimento 1 testou as concentrações dos grupos A1, B1 e AB1, e o Experimento 2 as concentrações dos grupos A2, B2 e AB2, ambos utilizando sêmen de touro. Para o Experimento 3 utilizou-se sêmen equino, sendo a adição dos lipídios feita em todas a concentrações descritas. Os dados foram submetidos à análise de variância, através do procedimento GLM do SAS, sendo as médias dos tratamentos comparadas pelo teste de Duncan em nível de 5% de significância. Os valores das variáveis avaliadas pós-descongelação diferiram significativamente daqueles obtidos pós-colheita, porém não foi observada diferença significativa entre os tratamentos quando as variáveis foram comparadas dentro do mesmo momento, exceto no Experimento 2, em que os valores de motilidade / vigor pós-descongelação nos grupos acrescidos do β-sit foram menores que os do controle (C – 51,0 ± 13,7% / 2,9 ± 0,4; B2 – 35,8 ± 15,8% / 2,3 ± 0,6; AB2 – 38,5 ± 16,6% / 2,5 ± 0,5, respectivamente; p < 0,05).

Assuntos