Can cover sheath model influence semen retention in AI-gun trials and pregnancy rates of cows inseminated at a fixed-time? / A bainha utilizada na inseminação artificial (IA) pode influenciar a retenção residual de sêmen e as taxas de concepção de vacas inseminadas em tempo fixo?

The achievement of satisfactory results in fixed-time artificial insemination (FTAI) protocols depends on several factors, such as the quality of the materials used to perform the artificial insemination (AI). In this context, three experiments were conducted to evaluate the effect of the cover sheath model on the residual retention of semen during AI and the pregnancy rates of cows submitted to FTAI. In Experiment 1, 400 straws of cryopreserved bovine semen were thawed and repacked in samples with similar weight and volume characteristics. Each new dose of semen (n = 300) was mounted using one of three AI cover sheath models (n = 100 semen/sheath doses): the main brand in the global market (G1), the main model in the Brazilian market (G2), and a model marketed as having a low residual semen retention rate (G3), to determine the percentages of seminal elimination (PSEs) during AI. In Experiment 2, 464 Nelore cows were synchronized through intravaginal progesterone implants and inseminated using the same cover sheaths as those tested in Experiment 1, which were grouped into classes (conventional: G1 and G2 [n = 225]; and low reflux: G3 [n = 239]). In Experiment 3, 859 Nelore cows were synchronized and inseminated as described above, using the same cover sheaths previously tested. After each AI, cover sheaths were visually inspected for the presence of residual semen and pregnancy diagnosis was performed 35 days after FTAI (Experiments 2 and 3). The PSEs in Experiment 1 were 91.7%, 90.6% and 96.5% for groups G1, G2 and G3, respectively (P = 0.05). The pregnancy rates in Experiment 2 were 53.33% and 58.16% for the conventional and low reflux model, respectively (P > 0.05), but there were differences (P = 0.05) among the cover sheath models employed for AI (G1 - 57.72% [71/123]; G2 - 48.04% [49/102]; G3 - 58.16% [139/239]). Additionally, a lower semen reflux incidence (P < 0.05) was observed in the low residual sperm retention model (0.72%) in Experiment 3, compared to the main international (10.42%) and national (22.99%) market models. In conclusion, residual semen retention occurs regardless of the cover sheath model used for AI. However, the PSE is influenced by the model and quality of cover sheath used. According to the results, the cover sheath represents a factor that may compromise the pregnancy rates of synchronized cows for FTAI.(AU)

Diversos fatores podem influenciar os resultados de concepção dos programas de inseminação artificial em tempo-fixo (IATF), como por exemplo a qualidade dos materiais utilizados para a inseminação artificial (IA). Nesse contexto, três experimentos foram conduzidos para testar o efeito da bainha sobre o percentual de retenção residual de sêmen nos aplicadores de IA e nas taxas de concepção de vacas submetidas à IATF. No Experimento 1 foram descongeladas 400 palhetas de sêmen bovino criopreservado, que foram re-envasadas para compor amostras com características de peso e volume semelhantes. Cada nova dose de sêmen (n=300) foi montada em um dos três modelos de bainhas de inseminação artificial em teste (n=100 doses de sêmen/ bainha): marca líder no mercado global (G1), modelo líder no mercado brasileiro (G2), modelo comercializado como de baixa taxa de retenção residual de sêmen (G3), para determinação do percentual de eliminação seminal (PES). No Experimento-2 foram selecionadas 464 vacas Nelore, sincronizadas através de implantes intravaginais de progesterona e inseminadas empregando as mesmas bainhas do experimento anterior, porém agrupadas em classes (convencional: G1 e G2 [n = 225]; ou baixo refluxo: G3 [n = 239]). No Experimento-3 859 vacas Nelore foram sincronizadas e inseminadas com sêmen previamente selecionado, utilizando os mesmos modelos de bainhas testadas nos experimentos anteriores. Após cada IATF as bainhas foram inspecionadas visualmente para detecção de presença residual de sêmen e o diagnóstico de gestação foi realizado a partir de 35 dias após a IATF (Experimentos 2 e 3). O PES foi de 91,7%, 90,6% e 96,5%, respectivamente para os grupos G1, G2 e G3 (P = 0,05). As taxas de concepção no Experimento-2 foram de 53,33% e 58,16%, respectivamente para o modelo convencional e de baixo refluxo (P > 0,05), porém havendo diferenças (P = 0,05) de acordo com o modelo da bainha empregada para a IA (57,72% [71/123], 48,04% [49/102] e 58,16% [139/239], respectivamente para os grupos G1, G2 e G3). Menor incidência de refluxo de sêmen (P < 0,05) foi observado para o modelo de baixa retenção residual de espermatozoides (0,72%), frente aos modelos líderes do mercado internacional (10,42%) e nacional (22,99%; Experimento-3). Conclui-se que ocorre retenção residual de sêmen, independente do modelo de bainha utilizada para a IA. No entanto, a PES é influenciada pelo modelo e qualidade da bainha utilizada para inseminação artificial, fator que pode comprometer os índices de concepção de vacas sincronizadas para IATF.(AU)

Testicular needle aspiration: Is it a safe method for breeding soundness evaluation in bulls?

The aim of this study was to evaluate the impact of successive bovine testicular punctures using different needle sizes. Fifteen bulls were submitted to testicular needle aspiration (TNA) in the left and right testis using 18-gauge (40×12mm) or 22-gauge (25×7mm) needles, respectively, once every 30 days. Animals were randomly divided into three groups, which were submitted to bilateral orchiectomy two days after the last puncture. Group 1 (G1): only one puncture (n=5); Group 2 (G2): three consecutive punctures in a period of three months (n=5); Group 3 (G3): six consecutive punctures in a period of 6 months (n=5). Fragments from the medial portion of the testicular parenchyma were excised and fixed in Bouins fluid for histological analysis. No differences were observed in the percentage of seminiferous tubules degeneration between G1, G2 and G3 (P>0.05). Higher amounts of erythrocyte were found in G1 and G2 groups compared to G3, in the intra- and intertubular tissue (P<0.05). There was no interaction between the needle gauge and the occurrence of testicular damage in animals submitted to one (G1) or three (G2) punctures. However, a higher percentage of tubular degeneration was associated to 18-gauge compared to 22-gauge fine needles in G3. In conclusion, multiple testicular needle aspiration can be safely conducted using fine needles. Large needles are recommended only for a single TNA, since multiple punctures may result in increased tubular degeneration and compromise testicular architecture and functionality.(AU)

Testicular needle aspiration: Is it a safe method for breeding soundness evaluation in bulls?

The aim of this study was to evaluate the impact of successive bovine testicular punctures using different needle sizes. Fifteen bulls were submitted to testicular needle aspiration (TNA) in the left and right testis using 18-gauge (40×12mm) or 22-gauge (25×7mm) needles, respectively, once every 30 days. Animals were randomly divided into three groups, which were submitted to bilateral orchiectomy two days after the last puncture. Group 1 (G1): only one puncture (n=5); Group 2 (G2): three consecutive punctures in a period of three months (n=5); Group 3 (G3): six consecutive punctures in a period of 6 months (n=5). Fragments from the medial portion of the testicular parenchyma were excised and fixed in Bouin’s fluid for histological analysis. No differences were observed in the percentage of seminiferous tubules degeneration between G1, G2 and G3 (P>0.05). Higher amounts of erythrocyte were found in G1 and G2 groups compared to G3, in the intra- and intertubular tissue (P<0.05). There was no interaction between the needle gauge and the occurrence of testicular damage in animals submitted to one (G1) or three (G2) punctures. However, a higher percentage of tubular degeneration was associated to 18-gauge compared to 22-gauge fine needles in G3. In conclusion, multiple testicular needle aspiration can be safely conducted using fine needles. Large needles are recommended only for a single TNA, since multiple punctures may result in increased tubular degeneration and compromise testicular architecture and functionality.

Influência da bipartição escrotal sobre a capacidade de termorregulação e hemodinâmica testicular em caprinos / Influence of bipartite scrotum on the thermoregulatory and hemodynamic testicular capacity in male goats / Influencia de la bipartición escrotal sobre la capacidad de termorregulación y hemodinámica testicular en caprinos

O objetivo do estudo foi avaliar a influência da bipartição escrotal sobre a capacidade de termorregulação do testículo caprino, testando-se a hipótese de que animais com bipartição possuem menor temperatura testicular, maior capacidade hemodinâmica local, maior número de células germinativas e maior produção espermática. Foram selecionados 8 bodes, divididos de acordo com a conformação escrotal: G1 (n=4) animais com até 50% de bipartição; GC (n=4) grupo controle, sem bipartição. Todos foram submetidos à mensuração da temperatura retal, termografia corporal e escrotal. Exames ultrassonográficos Doppler foram conduzidos no plexo pampiniforme. Adicionalmente os animais foram submetidos à punção biópsia aspirativa testicular (PBA) e 2 ejaculados de cada reprodutor foram colhidos para avaliação espermática. Não foram observadas diferenças para os resultados da PBA, da termografia escrotal e do espermograma comparando-se os dois grupos. Na avaliação hemodinâmica apenas o IR (0,53a+-0,11 e 0,46b+- 0,06; p=0,0108) foi superior para os animais bipartidos. Conclui-se que caprinos que possuem até 50% de bipartição escrotal possuem qualidade espermática semelhante a animais não bipartidos, não possuem menor temperatura testicular e maior número de células germinativas primordiais como se supunha na hipótese inicial da pesquisa.(AU)

The objective of this study was to evaluate the influence of the bipartition of the scrotum on the thermoregulatory capacity of the goat testicle, testing the hypothesis that bucks with bipartition of the scrotum have minor testicular temperature, greater local hemodynamic capacity, more germ cells and higher sperm production capacity. Eight male goats were used and divided according to the conformation of the scrotum: G1 (n=4) animals with scrotal bipartition below 50%; CG (n=4) control group without scrotal bipartition. All the animals were submitted to the evaluation of rectal temperature and scrotal and body surface thermography. Doppler ultrasonography held at the spermatic cord region was performed. In addition, the animals underwent fine needle aspiration testicular cytology (FNAC) and two ejaculates from each buck were collected. There were no significant differences between G1 and GC for FNAC and for testicular thermography. On the hemodynamics evaluation the IR was higher for the animals with scrotal bipartition than to control group (0.53a+-0.11 and 0.46b+- 0.06; P=0.0108). In conclusion, goats up to 50% of the scrotum bipartition have the same sperm quality than the control group, and the bipartition was not related to more efficiency on the thermoregulation process or number of testicular primordial cells in this study.(AU)

El objetivo del estudio fue evaluar la influencia de la bipartición escrotal sobre la capacidad de termorregulación del testículo caprino, probándose la hipótesis de que animales con bipartición tienen menor temperatura testicular, mayor capacidad hemodinámica local, mayor número de células germinativas y mayor producción espermática. Se seleccionaron 8 machos, divididos de acuerdo con la conformación escrotal: G1 (n=4) animales con hasta 50% de bipartición; GC (n=4) grupo de control, sin bipartición. Todos ellos fueron sometidos a la medición de la temperatura rectal, termografía corporal y escrotal. Los exámenes ultrasonográficos Doppler se realizaron en el plexo pampiniforme. Adicionalmente los animales fueron sometidos a la punción biopsia aspirativa testicular (PBA) y 2 eyaculaciones de cada reproductor fueron cosechados para evaluación espermática. No se observaron diferencias para los resultados de la PBA, de la termografía escrotal y del espermograma comparando los dos grupos. En la evaluación hemodinámica sólo el IR (0,53a +- 0,11 y 0,46b +- 0,06, p = 0,0108) fue superior para los animales bipartidos. Se concluye que los caprinos que tieren hasta 50% de bipartición escrotal tienen calidad espermática similares a animales no bipartidos, no tienen menor temperatura testicular y mayor número de células germinativas primordiales como se suponía en la hipótesis inicial de la investigación.(AU)

Influência da bipartição escrotal sobre a capacidade de termorregulação e hemodinâmica testicular em caprinos / Influence of bipartite scrotum on the thermoregulatory and hemodynamic testicular capacity in male goats / Influencia de la bipartición escrotal sobre la capacidad de termorregulación y hemodinámica testicular en caprinos

O objetivo do estudo foi avaliar a influência da bipartição escrotal sobre a capacidade de termorregulação do testículo caprino, testando-se a hipótese de que animais com bipartição possuem menor temperatura testicular, maior capacidade hemodinâmica local, maior número de células germinativas e maior produção espermática. Foram selecionados 8 bodes, divididos de acordo com a conformação escrotal: G1 (n=4) animais com até 50% de bipartição; GC (n=4) grupo controle, sem bipartição. Todos foram submetidos à mensuração da temperatura retal, termografia corporal e escrotal. Exames ultrassonográficos Doppler foram conduzidos no plexo pampiniforme. Adicionalmente os animais foram submetidos à punção biópsia aspirativa testicular (PBA) e 2 ejaculados de cada reprodutor foram colhidos para avaliação espermática. Não foram observadas diferenças para os resultados da PBA, da termografia escrotal e do espermograma comparando-se os dois grupos. Na avaliação hemodinâmica apenas o IR (0,53a+-0,11 e 0,46b+- 0,06; p=0,0108) foi superior para os animais bipartidos. Conclui-se que caprinos que possuem até 50% de bipartição escrotal possuem qualidade espermática semelhante a animais não bipartidos, não possuem menor temperatura testicular e maior número de células germinativas primordiais como se supunha na hipótese inicial da pesquisa.

The objective of this study was to evaluate the influence of the bipartition of the scrotum on the thermoregulatory capacity of the goat testicle, testing the hypothesis that bucks with bipartition of the scrotum have minor testicular temperature, greater local hemodynamic capacity, more germ cells and higher sperm production capacity. Eight male goats were used and divided according to the conformation of the scrotum: G1 (n=4) animals with scrotal bipartition below 50%; CG (n=4) control group without scrotal bipartition. All the animals were submitted to the evaluation of rectal temperature and scrotal and body surface thermography. Doppler ultrasonography held at the spermatic cord region was performed. In addition, the animals underwent fine needle aspiration testicular cytology (FNAC) and two ejaculates from each buck were collected. There were no significant differences between G1 and GC for FNAC and for testicular thermography. On the hemodynamics evaluation the IR was higher for the animals with scrotal bipartition than to control group (0.53a+-0.11 and 0.46b+- 0.06; P=0.0108). In conclusion, goats up to 50% of the scrotum bipartition have the same sperm quality than the control group, and the bipartition was not related to more efficiency on the thermoregulation process or number of testicular primordial cells in this study.

El objetivo del estudio fue evaluar la influencia de la bipartición escrotal sobre la capacidad de termorregulación del testículo caprino, probándose la hipótesis de que animales con bipartición tienen menor temperatura testicular, mayor capacidad hemodinámica local, mayor número de células germinativas y mayor producción espermática. Se seleccionaron 8 machos, divididos de acuerdo con la conformación escrotal: G1 (n=4) animales con hasta 50% de bipartición; GC (n=4) grupo de control, sin bipartición. Todos ellos fueron sometidos a la medición de la temperatura rectal, termografía corporal y escrotal. Los exámenes ultrasonográficos Doppler se realizaron en el plexo pampiniforme. Adicionalmente los animales fueron sometidos a la punción biopsia aspirativa testicular (PBA) y 2 eyaculaciones de cada reproductor fueron cosechados para evaluación espermática. No se observaron diferencias para los resultados de la PBA, de la termografía escrotal y del espermograma comparando los dos grupos. En la evaluación hemodinámica sólo el IR (0,53a +- 0,11 y 0,46b +- 0,06, p = 0,0108) fue superior para los animales bipartidos. Se concluye que los caprinos que tieren hasta 50% de bipartición escrotal tienen calidad espermática similares a animales no bipartidos, no tienen menor temperatura testicular y mayor número de células germinativas primordiales como se suponía en la hipótesis inicial de la investigación.