O estresse por calor diminui a fertilidade de fêmeas bovinas por afetar o esenvolvimento oocitário e o embrionário / Heat stress disrupts fertility of bovine females affecting the oocyte and embryo development

Para tentar minimizar as perdas provocadas pelo estresse por calor, os bovinos, principalmente oszebuínos que foram selecionados em clima tropical, conseguiram desenvolver mecanismos de tolerância aocalor. Entretanto, o desempenho reprodutivo de bovinos, principalmente de taurinos, é severamente afetado pelocalor dos meses quentes do ano. Desta forma, considerando que a diminuição da fertilidade devido ao estressepor calor constitui um problema multifatorial, esta revisão tem por objetivo compreender como e quando oestresse por calor afeta o desenvolvimento oocitário e o embrionário, a fim de desenvolver estratégias potenciaisque aumentem a fertilidade de rebanhos bovinos sob estresse por calor.(AU)

Bovines developed in tropical areas acquired genes that determine thermotolerance allowing theseanimals to reach success in reproductive performance. However, fertility, mainly in Bos taurus, is severelyaffected by heat stress in the hot months of the year. Thus, considering that the deleterious effect of heat stress isa multifactorial problem, this review aims to present the relevant and recent information to obtain a betterunderstanding of how and when heat stress affects the embryonic development, offering a basis for thedevelopment of potential strategies to increase fertility in a hot environment.(AU)

O estresse por calor diminui a fertilidade de fêmeas bovinas por afetar o esenvolvimento oocitário e o embrionário / Heat stress disrupts fertility of bovine females affecting the oocyte and embryo development

Para tentar minimizar as perdas provocadas pelo estresse por calor, os bovinos, principalmente oszebuínos que foram selecionados em clima tropical, conseguiram desenvolver mecanismos de tolerância aocalor. Entretanto, o desempenho reprodutivo de bovinos, principalmente de taurinos, é severamente afetado pelocalor dos meses quentes do ano. Desta forma, considerando que a diminuição da fertilidade devido ao estressepor calor constitui um problema multifatorial, esta revisão tem por objetivo compreender como e quando oestresse por calor afeta o desenvolvimento oocitário e o embrionário, a fim de desenvolver estratégias potenciaisque aumentem a fertilidade de rebanhos bovinos sob estresse por calor.

Bovines developed in tropical areas acquired genes that determine thermotolerance allowing theseanimals to reach success in reproductive performance. However, fertility, mainly in Bos taurus, is severelyaffected by heat stress in the hot months of the year. Thus, considering that the deleterious effect of heat stress isa multifactorial problem, this review aims to present the relevant and recent information to obtain a betterunderstanding of how and when heat stress affects the embryonic development, offering a basis for thedevelopment of potential strategies to increase fertility in a hot environment.

Assessment of different solutions and incubation times in the hypoosmotic swelling test of frozen/thawed semen in Piau boars

The objective of this study was to assess the effect of several solutions and incubation times in the hypoosmotic swelling test in predicting the in vitro quality of the frozen/thawed semen of Piau boars. Four samples of frozen semen from five different Piau boars were used. For the assessment of the hypoosmotic test, three incubation times were used (5, 30 and 60 min) in three different hypoosmotic solutions (BTS at 75 mOsm/Kg, sucrrose at 100 mOsm/Kg and fructose and sodium citrate at 100 mOsm/Kg), thus, samples were submitted to each hypoosmotic solution in three incubation times. The means of sperm motility spermatic vigor and live sperm by supravital staining for the assessed samples were respectively, 37.5 ± 7.2%, 2.8 ± 0.3 and 37.4 ± 7.8% in thawing and 15.5 ± 7.6%, 1.7 ± 0.5 and 22.6 ± 6.6% after 120 mm of thermoresistance test (P < 0.05). There was no difference between the mean values obtained for reactive sperm in the different incubation times and hypoosmotic solutions, and also no interaction between time ans solutions. The results obtained in the resent study demonstrated that quality of frozen/thawed semen, besides offering aliernatives for hypoosmotic solutions and different incubation times in performing the hypoosmotic test to predict the sperm plasmatic membrane quality in boats.

Assessment of different solutions and incubation times in the hypoosmotic swelling test of frozen/thawed semen in Piau boars

The objective of this study was to assess the effect of several solutions and incubation times in the hypoosmotic swelling test in predicting the in vitro quality of the frozen/thawed semen of Piau boars. Four samples of frozen semen from five different Piau boars were used. For the assessment of the hypoosmotic test, three incubation times were used (5, 30 and 60 min) in three different hypoosmotic solutions (BTS at 75 mOsm/Kg, sucrrose at 100 mOsm/Kg and fructose and sodium citrate at 100 mOsm/Kg), thus, samples were submitted to each hypoosmotic solution in three incubation times. The means of sperm motility spermatic vigor and live sperm by supravital staining for the assessed samples were respectively, 37.5 ± 7.2%, 2.8 ± 0.3 and 37.4 ± 7.8% in thawing and 15.5 ± 7.6%, 1.7 ± 0.5 and 22.6 ± 6.6% after 120 mm of thermoresistance test (P < 0.05). There was no difference between the mean values obtained for reactive sperm in the different incubation times and hypoosmotic solutions, and also no interaction between time ans solutions. The results obtained in the resent study demonstrated that quality of frozen/thawed semen, besides offering aliernatives for hypoosmotic solutions and different incubation times in performing the hypoosmotic test to predict the sperm plasmatic membrane quality in boats.(AU)

Relação entre perímetro escrotal e características produtivas e reprodutivas em bovinos de corte: uma revisão / Relationship between scrotal circumference and productive and reproductive traits in beef cattle: a review

Os programas de melhoramento genético visam mudar a herança nas populações pelo aumento dos genes desejáveis ou aumento da frequência de genótipos desejáveis com o objetivo de aumentar a produtividade dos rebanhos. Para tanto, faz-se necessário o conhecimento de parâmetros genéticos (herdabilidades e correlações genéticas) que orientem a escolha dos métodos de seleção. Apesar de a seleção para aumento do perímetro escrotal (PE) não trazer benefício econômico direto, o PE é uma característica que possui herdabilidade de moderada a alta e que é correlacionada com o ganho de peso e com características reprodutivas de fêmeas e machos. O PE se torna, assim, um dos critérios de seleção mais utilizado para eficiência reprodutiva do gado de corte. Esta revisão discute estimativas de herdabilidade e correlações genéticas para PE em bovinos de corte, visando à precocidade reprodutiva e ponderal, além de maior ganho econômico com o rebanho. (AU)

The breeding programs aim changing the genetic heritage of animals by the incorporation of new genes that increase the productivity of herd. Therefore, it is necessary the knowledge of genetic parameters (heritability and genetic correlations) to guide the choice of selection methods. Despite selection for increased scrotal circumference (SC) does not bring direct economic benefits, the SC is a characteristic that has moderate to high heritability, correlated with weight gain and reproductive traits of females and males. The SC thus becomes one of the selections criteria most commonly used for reproductive efficiency of beef cattle. Thus, the objective of this review is to discuss estimates of heritability and genetic correlations for SC in beef cattle, aiming at early reproductive and weight as well as greater economic gain of the herd. (AU)

Relação entre perímetro escrotal e características produtivas e reprodutivas em bovinos de corte: uma revisão / Relationship between scrotal circumference and productive and reproductive traits in beef cattle: a review

Os programas de melhoramento genético visam mudar a herança nas populações pelo aumento dos genes desejáveis ou aumento da frequência de genótipos desejáveis com o objetivo de aumentar a produtividade dos rebanhos. Para tanto, faz-se necessário o conhecimento de parâmetros genéticos (herdabilidades e correlações genéticas) que orientem a escolha dos métodos de seleção. Apesar de a seleção para aumento do perímetro escrotal (PE) não trazer benefício econômico direto, o PE é uma característica que possui herdabilidade de moderada a alta e que é correlacionada com o ganho de peso e com características reprodutivas de fêmeas e machos. O PE se torna, assim, um dos critérios de seleção mais utilizado para eficiência reprodutiva do gado de corte. Esta revisão discute estimativas de herdabilidade e correlações genéticas para PE em bovinos de corte, visando à precocidade reprodutiva e ponderal, além de maior ganho econômico com o rebanho.

The breeding programs aim changing the genetic heritage of animals by the incorporation of new genes that increase the productivity of herd. Therefore, it is necessary the knowledge of genetic parameters (heritability and genetic correlations) to guide the choice of selection methods. Despite selection for increased scrotal circumference (SC) does not bring direct economic benefits, the SC is a characteristic that has moderate to high heritability, correlated with weight gain and reproductive traits of females and males. The SC thus becomes one of the selections criteria most commonly used for reproductive efficiency of beef cattle. Thus, the objective of this review is to discuss estimates of heritability and genetic correlations for SC in beef cattle, aiming at early reproductive and weight as well as greater economic gain of the herd.

Hypoosmotic swelling test in young Nelore bulls classified as sound and unsound for breeding

This work aimed to study the correlations between the physical characteristics of semen, sperm morphology and the biochemical integrity of the plasmatic membrane of raw sperm in young Nelore bulls (Bos taurus indicus). A total of 420 bulls between 18 and 22 months of age were examined for breeding soundness according to the criteria established by the Brazilian College of Animal Reproduction. After physical and morphological evaluation, semen was tested with a hypoosmotic test. To accomplish this, 10 µl of fresh semen was incubated in 1 ml of hypoosmotic solution (150 mOsm/kg) for 60 min at 37°C. After the breeding soundness evaluation, 83% (350/420) of the bulls were classified as sound for breeding. There were no significant differences between the mean testicular biometry, scrotal circumference and the percentage of spermatozoa reactive to the hypoosmotic test (43.9 ± 21.1% vs. 43.6 ± 19.3%) in bulls classified as sound and unsound for breeding (P > 0.05), although there were significant differences between the averages for all physical and morphological aspects of the sperm between the two groups (P 0.05). In this study, the hypoosmotic test was not an efficient predictor of the reproductive potential of young Nelore bulls.

Hypoosmotic swelling test in young Nelore bulls classified as sound and unsound for breeding

This work aimed to study the correlations between the physical characteristics of semen, sperm morphology and the biochemical integrity of the plasmatic membrane of raw sperm in young Nelore bulls (Bos taurus indicus). A total of 420 bulls between 18 and 22 months of age were examined for breeding soundness according to the criteria established by the Brazilian College of Animal Reproduction. After physical and morphological evaluation, semen was tested with a hypoosmotic test. To accomplish this, 10 µl of fresh semen was incubated in 1 ml of hypoosmotic solution (150 mOsm/kg) for 60 min at 37°C. After the breeding soundness evaluation, 83% (350/420) of the bulls were classified as sound for breeding. There were no significant differences between the mean testicular biometry, scrotal circumference and the percentage of spermatozoa reactive to the hypoosmotic test (43.9 ± 21.1% vs. 43.6 ± 19.3%) in bulls classified as sound and unsound for breeding (P > 0.05), although there were significant differences between the averages for all physical and morphological aspects of the sperm between the two groups (P < 0.05). The hypoosmotic test did not correlate with the main characteristics of semen quality (P > 0.05). In this study, the hypoosmotic test was not an efficient predictor of the reproductive potential of young Nelore bulls.(AU)

Aplasia segmentar bilateral do epidídimo na espécie bubalina: relato de caso / A case of bilateral segmental aplasia of the epididymis in a buffalo

Este estudo reporta um bubalino mestiço, com 27 meses de idade, 188 kg de peso de carcaça, sem histórico reprodutivo. Sangue foi coletado para posterior determinação hormonal. Testículos e epidídimos foram avaliados macroscopicamente e microscopicamente. Os testículos apresentaram-se simétricos, caudas dos epidídimos ausentes e cabeças com presença de cistos. Parênquima testicular e mediastino demonstraram edema. Concentrações de testosterona e androstenediona foram de, respectivamente, 9,88 pg/mL e 3,00 ng/mL. Observou-se alto grau de degeneração testicular. Considerando-se a esterilidade do animal, associada à origem genética da patologia, sugere-se que machos acometidos sejam descartados da reprodução.(AU)

This case report involves a slaughtered cross-breed buffalo, age 27 months, carcass weight, 188 kg, without reproductive history. Blood was collected for later hormone determination. Testes and epididymes were evaluated macroscopically and microscopically. The testes were symmetrical. However, the epididymal tails were absent and the epididymal heads had cysts. Testicular parenchyma and mediastinum were swollen. Testosterone and androstenedione concentrations were 9.88 pg/mL and 3.00 ng/mL, respectively. A high degree of testicular degeneration was observed. That this condition causes esterility, coupled with the genetic origin of the disease, it is suggested that affected animals are culled.(AU)

Aplasia segmentar bilateral do epidídimo na espécie bubalina: relato de caso / A case of bilateral segmental aplasia of the epididymis in a buffalo

Este estudo reporta um bubalino mestiço, com 27 meses de idade, 188 kg de peso de carcaça, sem histórico reprodutivo. Sangue foi coletado para posterior determinação hormonal. Testículos e epidídimos foram avaliados macroscopicamente e microscopicamente. Os testículos apresentaram-se simétricos, caudas dos epidídimos ausentes e cabeças com presença de cistos. Parênquima testicular e mediastino demonstraram edema. Concentrações de testosterona e androstenediona foram de, respectivamente, 9,88 pg/mL e 3,00 ng/mL. Observou-se alto grau de degeneração testicular. Considerando-se a esterilidade do animal, associada à origem genética da patologia, sugere-se que machos acometidos sejam descartados da reprodução.

This case report involves a slaughtered cross-breed buffalo, age 27 months, carcass weight, 188 kg, without reproductive history. Blood was collected for later hormone determination. Testes and epididymes were evaluated macroscopically and microscopically. The testes were symmetrical. However, the epididymal tails were absent and the epididymal heads had cysts. Testicular parenchyma and mediastinum were swollen. Testosterone and androstenedione concentrations were 9.88 pg/mL and 3.00 ng/mL, respectively. A high degree of testicular degeneration was observed. That this condition causes esterility, coupled with the genetic origin of the disease, it is suggested that affected animals are culled.

Teste de ligação de espermatozoides de suínos da raça Piau à membrana perivitelina da gema do ovo / Sperm-binding assay in Piau swine breeds to the hens egg perivitelline membrane

O objetivo deste trabalho foi avaliar a utilização do teste de ligação de espermatozoides à membrana perivitelina da gema do ovo de galinha como uma alternativa de predizer a qualidade espermática pós-descongelamento em suínos da raça Piau. Foram utilizadas cinco partidas de sêmen congelado de um varrão, as quais foram subdivididas em quatro tratamentos, de acordo com o meio (BTS ou B-TALP) e as concentrações espermáticas utilizadas (20 ou 40 x 106 espermatozoides/mL). Além disso, utilizaram-se 25 partidas de sêmen congelado de cinco varrões (cinco partidas de cada animal), sendo que 10 μL de sêmen na concentração de 20 x 106 espermatozoides/mL foram incubados em meio BTS ou B-TALP. No experimento 1, o número médio de espermatozoides aderidos/mm2 variou de 157,0 ± 81,3 a 249,4 ± 119,3 (P > 0,05). No experimento 2, o número médio de espermatozoides ligados/mm2 foi de 339,3 ± 255,5 e 275,4 ± 164,0, respectivamente, para os meios BTS e B-TALP, sem diferença entre eles (P > 0,05). Concluiu-se que a concentração espermática, assim como os meios de incubação utilizados, não interferiu na capacidade de adesão de espermatozoides à membrana perivitelina da gema do ovo em animais da raça Piau. (AU)

The objective of this study was to verify the use of sperm-binding assay in Piau swine breeds to the hens egg perivitelline membrane as an alternative to predict semen post-thawing fertilizing capability. It were used five matches of frozen semen from a boar, and the matches divided into four treatments, according to media (BTS or B-TALP) or sperm concentration (20 or 40 x 106 sperm/ml). Moreover, Twenty five frozen semen samples were used from five males (five semen samples from each male), using 10 μL of sperm with the concentration of 20 x 106 spermatozoa/mL and incubated BTS or B-TALP. In experiment 1, the average number of sperm-binding/mm2 varied from 157.0 ± 81.3 to 249.4 ± 119.3 (P > 0.05). In experiment two, The average number of sperm-binding/mm2 was 339.3 ± 255.5 and 275.4 ± 164.0, respectively for BTS and B-TALP media, with no difference between themselves (P > 0.05). It was concluded that sperm concentration, as well as the incubation media used did not affect the sperm adhesion to hens egg perivitelline membrane in Piau breed animals. (AU)

Teste de ligação de espermatozoides de suínos da raça Piau à membrana perivitelina da gema do ovo / Sperm-binding assay in Piau swine breeds to the hen’s egg perivitelline membrane

O objetivo deste trabalho foi avaliar a utilização do teste de ligação de espermatozoides à membrana perivitelina da gema do ovo de galinha como uma alternativa de predizer a qualidade espermática pós-descongelamento em suínos da raça Piau. Foram utilizadas cinco partidas de sêmen congelado de um varrão, as quais foram subdivididas em quatro tratamentos, de acordo com o meio (BTS ou B-TALP) e as concentrações espermáticas utilizadas (20 ou 40 x 106 espermatozoides/mL). Além disso, utilizaram-se 25 partidas de sêmen congelado de cinco varrões (cinco partidas de cada animal), sendo que 10 μL de sêmen na concentração de 20 x 106 espermatozoides/mL foram incubados em meio BTS ou B-TALP. No experimento 1, o número médio de espermatozoides aderidos/mm2 variou de 157,0 ± 81,3 a 249,4 ± 119,3 (P > 0,05). No experimento 2, o número médio de espermatozoides ligados/mm2 foi de 339,3 ± 255,5 e 275,4 ± 164,0, respectivamente, para os meios BTS e B-TALP, sem diferença entre eles (P > 0,05). Concluiu-se que a concentração espermática, assim como os meios de incubação utilizados, não interferiu na capacidade de adesão de espermatozoides à membrana perivitelina da gema do ovo em animais da raça Piau.

The objective of this study was to verify the use of sperm-binding assay in Piau swine breeds to the hen’s egg perivitelline membrane as an alternative to predict semen post-thawing fertilizing capability. It were used five matches of frozen semen from a boar, and the matches divided into four treatments, according to media (BTS or B-TALP) or sperm concentration (20 or 40 x 106 sperm/ml). Moreover, Twenty five frozen semen samples were used from five males (five semen samples from each male), using 10 μL of sperm with the concentration of 20 x 106 spermatozoa/mL and incubated BTS or B-TALP. In experiment 1, the average number of sperm-binding/mm2 varied from 157.0 ± 81.3 to 249.4 ± 119.3 (P > 0.05). In experiment two, The average number of sperm-binding/mm2 was 339.3 ± 255.5 and 275.4 ± 164.0, respectively for BTS and B-TALP media, with no difference between themselves (P > 0.05). It was concluded that sperm concentration, as well as the incubation media used did not affect the sperm adhesion to hen’s egg perivitelline membrane in Piau breed animals.