RESUMO O objetivo deste estudo foi determinar o perfil termográfico escrotal e verificar a influência da temperatura e da umidade do clima tropical úmido na temperatura testicular e na qualidade seminal de garanhões Mangalarga Marchador. Os perfis térmicos das zonas proximal, média e distal dos testículos e a temperatura da superfície total (TSTT) foram registrados usando-se um termovisor FLIR E60bx. A temperatura média do ar (° C) e a umidade relativa (%) foram obtidas um, cinco, nove, 33 e 66 dias antes da coleta de sêmen e apresentaram valor médio de 26,5 ± 2,4 e 80,4 ± 6,0, respectivamente. A temperatura da superfície escrotal foi próxima a 34°C, e não houve variação com a idade do garanhão, a atividade reprodutiva e as características do ejaculado (P>0,05). As únicas correlações significativas obtidas foram entre TSTT e defeitos menores (R=0,41; P<0,05), entre TSTT e defeitos totais (R=0,46; P<0,01), e entre TSTT e porcentagem de espermatozoides morfologicamente normais (R=-0,46; P<0,05). Concluiu-se que os garanhões Mangalarga Marchador mantiveram a temperatura testicular dentro de condições favoráveis para a espermatogênese, demonstrando a eficiência dos mecanismos de termorregulação testicular no bioma Mata Atlântica.

ABSTRACT The objective of this study was to determine the scrotal thermographic profile and to verify the influence of temperature and humidity of the humid tropical climate on testicular temperature and seminal quality of Mangalarga Marchador stallions. The thermal profiles of the proximal, middle, and distal zones of the testicles and total surface temperature (TSTT) were recorded using an FLIR E60bx thermal imager. The average air temperature (°C) and relative humidity (%) were obtained 1, 5, 9, 33, and 66 days before semen collection and showed a mean value of 26.5±2.4 and 80.4±6.0 respectively. The scrotal surface temperature was close to 34°C and there was no variation with the age of the stallion, reproductive activity, and characteristics of the ejaculate (P>0.05). The only significant correlations obtained were between TSTT and minor defects (R = 0.41; P<0.05), between TSTT and total defects (R = 0.46; P<0.01), and between TSTT and percentage of morphologically normal sperm (R = -0.46; P<0.05). It was concluded that the Mangalarga Marchador stallions maintained the testicular temperature within favorable conditions for spermatogenesis, demonstrating the efficiency of testicular thermoregulation mechanisms in the Atlantic Forest biome.

RESUMO: O conhecimento das alterações fisiológicas que ocorrem quando os animais são submetidos a alterações climatológicas consideradas estressantes é fundamental para manter o bem-estar animal, e poder explorar o seu potencial reprodutivo de forma eficiente e racional. O presente estudo foi realizado com o objetivo de avaliar a influência de variáveis climáticas sobre parâmetros fisiológicos e de ejaculados de búfalos, da raça Murrah, criados em clima tropical úmido da Amazônia. As análises imediatas pertinentes às características físicas e morfológicas dos ejaculados foram realizadas e corresponderam no período chuvoso (PCh) o volume de 3,4±2,0mL, turbilhonamento de 4,4±0,5; motilidade de 80,4±5,6%; vigor de 4,4±0,4; concentração de 657.300±237.865,1 x 106sptz/mL; defeitos maiores de 9,0±2,6%; defeitos menores de 11,2±3,9%; defeitos totais de 20,2±5,3% e integridade da membrana plasmática (IMP) de 84,8±5,6%, enquanto que no período não chuvoso (PnCh), os resultados foram de 4,0±2,1mL; turbilhonamento de 3,0±1,0; motilidade de 56,2±13,4%; vigor de 3,0±1,0; concentração de 586.000±291.925,9 x 106sptz/mL; defeitos maiores de 20,8±9,9%; defeitos menores de 27,5±6,3%; defeitos totais de 48,3±9,3% e IMP de 57,9±12,4%. Observou-se diferença estatística (P<0,05) para os parâmetros movimento de massa, motilidade, vigor, defeitos maiores, defeitos menores, defeitos totais e integridade da membrana plasmática entre os dois períodos. Dados de frequência cardíaca, temperatura superficial (cabeça, dorso, virilha e bolsa escrotal) diferiram estatisticamente entre os períodos (P<0,05). Conclui-se que se faz necessário usar de um manejo específico no período não chuvoso para que o estresse térmico não seja um fator determinante na redução da qualidade reprodutiva dos búfalos, para isto se faz necessário utilizar de meios para melhorar o bem-estar animal, sendo uma das alternativas fazer uso de banhos regularmente para estes animais, ou disponibilizar acesso constante destes a áreas de rios ou lagos, assim como sombreamentos, evitando que os búfalos fiquem expostos diretamente ao ambiente térmico desfavorável.

ABSTRACT: Awareness of the physiological changes that occur when animals are subjected to climatic changes that are considered stressful is essential to maintain animal welfare and to be able to exploit their reproductive potential efficiently and rationally. The present study was carried out to evaluate climatic variables’ influence on physiological parameters, and Murrah buffalo ejaculates reared in a humid tropical climate in the Amazon. The immediate analyzes pertinent to the physical and morphological characteristics of the ejaculates were carried out and corresponded in the rainy season (RS) volume of 3.4±2.0mL; the mass activity of 4.4±0.5; motility of 80.4±5.6%; vigor of 4.4±0.4; concentration of 657,300±237,865.1 x 106sptz/mL; major defects of 9.0±2.6%; minor defects of 11.2±3.9%; total defects 20.2±5.3% and sperm plasma membrane integrity (SPMI) 84.8±5.6%, whereas in the non-rainy season (nRS), the results were 4.0±2.1mL; the mass activity of 3.0±1.0; motility of 56.2±13.4%; vigor of 3.0±1.0; concentration of 586,000±291,925.9 x 106sptz/mL; major defects of 20.8±9.9%; minor defects of 27.5±6.3%; total defects 48.3±9.3% and SPMI of 57.9±12.4%. Furthermore, a statistical difference (P<0.05) was observed for the parameters mass activity, motility, vigor, major defects, minor defects, total defects, and sperm plasma membrane integrity between both periods. The data on heart frequency, superficial temperature (head, back, groin, and scrotal pouch) showed a statistical difference between both periods (P<0.05). To conclude is necessary specific management in the non-rainy season that thermal stress is not a determining factor in reducing the reproductive quality of buffaloes; it is necessary to use means to improve animal welfare; one alternative is to use baths regularly for these animals or provide constant access to areas of rivers or lakes, as well as shading, preventing the buffaloes from being directly exposed to the unfavorable thermal environment.

RESUMO Objetivou-se estudar o efeito do ômega 3 e da vitamina B12 no espermograma, na histomorfometria dos órgãos reprodutivos e na temperaturas do corpo com termografia infravermelha em ratos Wistar. Utilizaram-se 16 ratos, em quatro grupos (n=4), que receberam injeções diárias por 30 dias, sendo: grupo controle - solução salina; grupo ômega 3 - óleo de peixe 1g/kg; grupo B12 - vitamina B12 3µg; e grupo ômega 3 + B12 - óleo de peixe 1g/kg e vitamina B12 3µg. Imagens termográficas de áreas do corpo foram obtidas. No 30º dia, os ratos foram sacrificados e realizaram-se as análises de morfologia espermática e histomorfometria. Os dados foram submetidos à análise de variância e ao teste de Tukey a 5%. A temperatura da superfície do escroto foi superior no grupo B12 (P<0,05). Não houve diferenças entre grupos (P>0,05) para temperaturas do globo ocular. Houve correlação entre temperatura da superfície do escroto e porcentagem de gota citoplasmática distal (P=0,678). A elevação da temperatura do escroto resulta no aumento da porcentagem de gotas citoplasmáticas distais. A temperatura do globo ocular não sofre influência significativa do ômega 3 e da vitamina B12. O ômega 3 reduz o epitélio seminífero, e a vitamina B12 minimiza esse efeito.

ABSTRACT The objective of this study was to study the effect of Omega 3 and vitamin B12 on spermogram, histomorphometry of reproductive organs and body temperature with infrared thermography in Wistar rats. Sixteen rats were used in four groups (n= 4) who received daily injections for 30 days. Control Group - saline solution; Group Omega 3 - fish oil 1g/kg; Group B12 - vitamin B12 3μg and Group Omega 3 + B12 - fish oil 1g/kg and vitamin B12 3μg. Thermographic images of body were obtained. On the 30th day the rats were sacrificed and analyzes of sperm morphology and histomorphometry were performed. Data were submitted to analysis of variance and Tukey's test at 5%. The surface temperature of the scrotum was higher in group B12 (P< 0.05). There were no differences between groups (P> 0.05) for eyeball temperatures. There was a correlation between scrotal temperature and distal cytoplasmic droplet (P= 0.678). Elevation of scrotum temperature results in an increase in the percentage of distal cytoplasmic droplets. The temperature of the eyeball is not significantly influenced by Omega 3 and vitamin B12. Omega 3 reduces the seminiferous epithelium and vitamin B12 minimizes this effect.

Abstract: Seasonality and changes in climate and habitat dynamics lead ground squirrels to use resources during the most favorable seasons and avoid less favorable conditions by hibernating. The Perote ground squirrel (Xerospermophilus perotensis) is nationally and internationally classified as vulnerable to extinction; however, our knowledge of this species is scant. The aim of this study was to describe and analyze its annual cycle. Temperature and rainfall data (2008 to 2014) for the area were used. Animal frequencies were obtained for seven sites by capture-mark-recapture; captured animals were marked, and their sex, weight, age and reproductive status noted. Population structure was obtained for each site using the male:female sex ratio and age structure. Activity during the annual cycle is statistically associated with temperature. Scrotal males were most abundant while females with signs of pregnancy and those lactating were recorded least often. The number of adults and juveniles differed statistically, with adults more abundant throughout the study. Weight varied throughout the study, and differed between adults and juveniles. The Perote ground squirrel exhibits phenological patterns similar to those of species of the genus Spermophilus, which respond to changes in temperature and its activity cycle begins in spring and ends in autumn. The weight of the squirrels was dynamic, probably resulting from reproduction, hibernation and their response to changes in environmental resources. The frequency of this species was low, with few juveniles recorded, indicating that X. perotensis is facing serious problems, likely from severe anthropogenic pressure and its own ecological characteristics.

Resumen: La estacionalidad y dinamismo del clima y hábitat inducen a que las ardillas terrestres exploten los recursos en las mejores estaciones y eviten la menos favorable a través de la hibernación. La ardilla endémica de Perote (Xerospermophilus perotensis) se encuentra clasificada a nivel nacional e internacional como vulnerable a la extinción, ya que su hábitat se ha reducido drásticamente por lo que su conservación se ha visto comprometida, a pesar de esto el conocimiento acerca de la especie es escaso. El objetivo de este estudio fue describir y analizar la fenología de la especie. Se obtuvieron las temperaturas y precipitaciones del área de estudio del año 2008 al 2014; la frecuencia de capturas se obtuvo a través del método de captura-marcaje-recaptura. Los animales capturados fueron marcados y se registró el sexo, edad, peso y estado reproductivo en el que se encontraban. La estructura poblacional se obtuvo para cada sitio usando la proporción de sexos, edad y estado reproductivo. Los resultados indicaron que la actividad durante el ciclo anual está relacionada estadísticamente con la temperatura, ya que cuando desciende ocurre la hibernación; así como de las condiciones reproductivas debido a que se presentaron cuando las temperaturas fueron las más altas. En lo que respecta a las características reproductivas, los machos escrotados fueron los más abundantes y las hembras con signos de preñez o lactantes fueron las menos registradas. Para la categoría de edad, el número de adultos y juveniles difirieron estadísticamente, siendo los adultos los más abundantes. Con relación al peso de las ardillas, fue variable a lo largo del estudio y sólo existió diferencia estadística entre el peso de los adultos y juveniles. La ardilla de Perote exhibe patrones fenológicos similares a las del género Spermophilus, ya que la especie responde a los cambios de temperatura y la actividad de su ciclo empieza en la primavera y termina en el otoño. El peso de los organismos fue dinámico, probablemente causado por la reproducción, hibernación y por su respuesta a los cambios en los recursos ambientales. En general, las frecuencias de los organismos fueron bajas y con pocos registros de juveniles, lo que indica que la especie está enfrentando serios problemas para persistir debido a las severas presiones antropogénicas a las que se enfrenta y a sus propias características ecológicas.

ABSTRACT This study analyzed seasonal variations in the testes, the concentration of sex hormones, the parameters of fresh and thawed semen, and the sexual behavior of male Alpine goats from a temperate region in a tropical climate and possible interference with fertility. The maximum and minimum temperature and luminosity were recorded daily, while seminal, hormonal, and behavioral assessments were carried out every fortnight. The maximum and minimum temperature (°C) and luminosity (h) were recorded daily always at 17.00 h. The scrotal circumference (cm), testicular volume (mL), volume (mL), appearance (creamy, milky, aqueous) and coloration (white, white-yellowish, and yellowish) seminal, turbulence or mass movement (0 to 5), progressive spermatic motility (0 to 100%), spermatic force (0 to 5), concentration (spermatozoids/mL), spermatic pathologies, hypoosmotic test (%), serum levels of FSH (mUI/mL), LH (mUI/mL), testosterone (ng/mL), and sexual behaviors were carried out every fortnight. There was a difference between the scrotal circumference evaluated monthly, testicular volume, volume and concentration of fresh semen, sperm vigor of the thawed semen, serum levels of testosterone, FSH and LH, and some sexual behaviors. Thus, the changes that occur in the quantity and quality of sperm, in the hormonal profile, and in sexual behaviors should not be regarded as an impediment to the use of male Alpine goats in tropical climates throughout the year. These variations do not lead to changes in the semen that may compromise the fertility of these animals.

Theaim ofthisstudywastoassessclinicalandseminal characteristicsand endocrine changes in rams with scrotal insulation. Twelve Merino rams were randomly distributed into a control group (n=4) and a group with scrotal insulation (n=8), that was done with a cotton bag coated with plastic to increase the temperature to 39.0 °C for 48 h. The volume of ejaculate, testicular consistency, scrotal circumference, sperm concentration, mass and individual motility, and sperm abnormalities were recorded for five weeks. Semen collection byelectroejaculation wasconducted threetimesper week. Theanimals were cannulated in the jugular vein and blood samples were taken for 6 hours at 10 minute intervalsfor testosteroneand LHdetermination byradioimmunoassay.Theresultsshowed changesin scrotalcircumference(from30.43±1.1 to25.00±0.5cmonweek 5);reduction of sperm concentration (week 2); mass motility: 0 (week 2); individual motility: 2.45±3.1 (week 2); and 82.3±29.3% sperm abnormalities at week 3. Testosterone concentration decreased (280±83 pg/ml) and LH concentrations increased (0.96±0.72 ng/ml) at week 2, including higher number of LH pulses. It is concluded that the increase of scrotal temperature causes changes in the clinical, seminal, and in the secretion of testosterone and LH.

El objetivo del estudio fue evaluar los cambios en características clínicas, seminales y endocrinas en carneros con aislamiento escrotal térmico. Doce carneros Merino adultos fueron distribuidos al azar en un grupo Control (n=4) y uno sometido a aislamiento escrotal (n=8). A este grupo se le cubrió el escroto con una bolsa de algodón cubierta con plástico para elevar la temperatura a 39.0 °C por 48 h. Se registró por cinco semanas el volumen del eyaculado, consistencia testicular, circunferencia escrotal, concentración espermática,motilidadmasal eindividualytasa deanormalidades.Elsemen fuecolectado tres veces por semana por electroeyaculación. La vena yugular fue canulada para colectar muestras por 6 h a intervalos de 10 min para la determinación de testosterona y LH plasmática mediante radioinmunoanálisis. Los resultados señalan cambios en circunferenciaescrotal(de30.43±1.1cmalinicioa25.00±0.5cmen lasemana5);reducción dela concentración espermática (semana 2); motilidad masal: 0 (semana 2); motilidad individual:2.45±3.1% (semana2);y82.3±29.3% deespermatozoidesanormales(semana 3).A partir de la semana 2 disminuyen los niveles de testosterona (280±83 pg/ml) y se incrementan los de LH (0.96±0.72 ng/ml), incluyendo un mayor número de pulsos. Se concluye que el incremento de temperatura escrotal produce cambios en las características clínicas, seminales y endocrinas en el carnero.

Com a finalidade de avaliar o efeito do sombreamento artificial sobre as características testiculares e seminais de ovinos deslanados, foram utilizados 12 carneiros (½ sangue Santa Inês x SRD) com peso vivo médio de 38.06 ± 5.24 kg e faixa etária de cerca de oito meses. Os tratamentos foram disponibilidade ou não de sombreamento artificial, utilizando tela preta de polietileno com malha para bloquear 50% da radiação solar global. Duas vezes na semana entre 14h e 15h realizou-se a medição da circunferência escrotal (CE), comprimento escrotal (CC), volume escrotal (VE), temperatura retal (TR) e temperatura escrotal (TE). Quinzenalmente, foram realizadas análises quantitativas e qualitativas do sêmen. Os resultados obtidos permitem concluir que o sombreamento proporcionou menores temperaturas escrotais e maior concentração espermática, não influenciando o volume escrotal e a porcentagem de espermatozoides normais. Medidas testiculares como circunferência e comprimento escrotal foram mais elevadas ao sol. A ausência de diferenças em algumas variáveis analisadas nos grupos com e sem sombreamento, pode ser reflexo da rusticidade natural dos animais.

The purpose of this study was to evaluate the effects of availability of artificial shading on testicular and seminal characteristics of Santa Ines crossbred rams. Twelve 8 month old rams at 38.1 ± 5.2 kg average weight, were used in a total random design with two treatments: areas with and without available artificial shading (black polyethylene mesh screen for a 50% reduction of solar radiation). The scrotal circumference, scrotal length, scrotal volume, rectal temperature and scrotal temperature were measured twice a week. Also a biweekly analysis of the semen was carried out, measuring the volume and spermatic concentration as well as the percentage of normal spermatozoa. The results show that available shading provided for lower scrotal temperatures and higher sperm concentration, without influencing the scrotal volume and the percentage of normal spermatozoa. The testicular measures, such as the scrotal circumference and length were higher in the rams that were subjected to the no available shading treatment. The absence of differences, in some of the analyzed variables, between the two treatments, with and without available shading, could be due to high adaptability of the animals.

O objetivo deste trabalho foi avaliar a influência do grau de bipartição escrotal e do período do ano sobre a termorregulação escroto-testicular em caprinos criados no Estado do Piauí. Foram utilizados 18 reprodutores caprinos machos, divididos em três grupos de seis animais: O Grupo I contendo caprinos com escroto simples, o Grupo II, caprinos com escroto bipartido até 50% do comprimento testicular e o Grupo III, caprinos com bipartição superior a 50% do comprimento testicular. Os parâmetros avaliados foram as temperaturas do escroto, testículo e funículo espermático, obtidas de forma invasiva, com um termômetro digital termoacoplável, e não invasiva, com um pirômetro, nos terços proximal, médio e distal. Os dados foram coletados nos períodos seco (outubro-novembro) e chuvoso (fevereiro-março) do ano, bem como, nos turnos da manhã (6h00 às 7h00) e tarde (14h00 às 15h00). Os resultados foram submetidos à análise de variância (ANOVA) seguida do teste SNK para comparação das médias (p<0,05). O período do ano interferiu na termorregulação escroto-testicular, pois no período seco as temperaturas do escroto, testículo e funículo espermático foram mais elevadas que as observadas no período chuvoso. O grau de bipartição do escroto foi outro fator que modificou a temperatura escroto-testicular, já que os caprinos que apresentaram escroto com maior grau de bipartição demonstraram as menores médias das temperaturas escroto-testiculares em ambos os períodos e turnos avaliados. Conclui-se, portanto, que tanto o período do ano quanto o grau de bipartição do escroto influenciaram o processo de termorregulação escroto-testicular em caprinos.

The influence of the scrotal bipartition and of the year period on the scrotal-testicular thermal regulation was evaluated in male goats raised in Piaui State, Brazil. Eighteen male goats at mating age were accomplished in this study and arranged into three Groups (6 animals each) obeying the classification as goats presenting no scrotal bipartition (Group I), goats showing scrotal bipartition at 50% of the testicular length (Group II), and goats with more than 50% of scrotal bipartition (Group III). The scrotal, testicular and spermatic funiculi temperatures were evaluated invasively with the aid of a digital thermometer and non-invasive with a pyrometer in the proximal, medial and distal portion. The data were acquired during the dry (October-November) and rainy (February-March) period of the year, measured in two shifts: morning (6h00-7h00) and afternoon (14h00-15h00). The results were submitted to variance analysis (ANOVA) following the SNK test for average comparison (p<0.05). The year period interfered on the scrotal-testicular thermal regulation, due to increased temperatures of the scrotal, testicular and spermatic funiculi during the dry period in comparison with the rainy period. The bipartition level was also a factor which contributed to the influence of scrotal-testicular temperature regulation, due to lower average scrotal-testicular temperature rates observed during both periods in the goats with higher levels of scrotal bipartition (>50%). It is possible to conclude that with the experimental conditions applied on this study, the level of scrotal bipartition and the climatic conditions interfere with the scrotal-testicular thermal regulation in goats.

Genetic diversity among breeds of cattle allows producers to select animals for specific environments or market conditions. Reproductive efficiency is a multi-component trait that is largely influenced by environmental influences such as health and nutritional status; however, there are clearly genetic components to reproductive efficiency, and breed differences in a number of indicator traits associated with fertility and cow productivity have been identified. Historical indicators of fertility include scrotal circumference, age at puberty, and postpartum interval. Both age at puberty and postpartum interval are laborious traits to collect in heifers and cows because they require many days of detection of behavioral estrus. In recent years, the addition of ultrasonography to management practices has allowed for the collection of female traits such as follicle diameter, antral follicle counts, and fetal age that are not as labor intensive. These additional diagnostic traits provide novel phenotypes for the identification of genetic markers of fertility and cow productivity, which would be the ultimate goal. Genetic markers of the number of follicles in the bovine ovary have the potential to identify heifers that will be highly productive cows. Furthermore, identifying and understanding the genes that control various reproductive traits and the response to stressors, such as temperature and nutrient availability, could improve production efficiency by improving management and breeding decisions in a wide range of production environments.

We studied the reproductive cycle in males of the cricetid rodent species Oligoryzomys flavescens (Waterhouse, 1837), collected in northern Uruguay. From February 2001 to February 2002, specimens were captured in grasslands and exotic forests. Determination of the reproductive condition was based on external characteristics of gonads as well as histological and histometric analysis. The testicular volume was measured and testes position (whether scrotal or intra-abdominal) was verified by dissection. Correlations between these anatomical features and some environmental factors that included temperature, precipitation and photoperiod, were analyzed using linear regression analysis. The annual reproductive cycle of O. flavescens was characterized by a period of quiescence during winter months (June to August) and a main period of reproductive activity from spring to early fall (October to April). Spermatogenic activity ceased completely in winter and was gradually restored in early spring (September). Reproductively active animals had larger testes and thicker seminiferous tubules than non-reproductive individuals. In addition the epididymides of the former were filled with sperm. Ambient temperature and photoperiod appear to be the main environmental factors that are directly correlated with the reproductive cycle. Finally, in spite of its wide use, it is shown that testes position is an inaccurate predictor of reproductive activity since many individuals showing full spermatogenic activity had intra-abdominal testes. Testicular volume and histological analysis are more appropriate in determining the male reproductive condition of the species.

El ciclo reproductivo masculino de Oligoryzomys flavescens (Waterhouse, 1837) fue establecido en una población del norte de Uruguay. Los animales fueron colectados entre Febrero 2001 y Febrero 2002 en praderas y áreas forestales. La determinación del estado reproductivo se basó en la posición testicular, así como en el análisis histológico e histométrico de las gónadas. La posición testicular (escrotal o intra-abdominal) se verificó mediante disección. Las correlaciones entre estas características anatómicas y algunos parámetros ambientales -temperatura, precipitación y fotoperíodo- fueron analizadas empleando regresiones lineales. El ciclo reproductivo anual de O. flavescens se caracterizó por un período de quiescencia durante los meses de invierno (junio-agosto) y un periodo de máxima actividad desde primavera hasta principios de otoño (octubre-abril). Durante el invierno cesó completamente la actividad espermatogénica, la cual se restableció gradualmente en primavera (setiembre). Los animales reproductivamente activos presentaron testículos más grandes y túbulos seminíferos de mayor diámetro en relación con los no activos, además de presentar abundante esperma en el epidídimo. La temperatura ambiental y el fotoperíodo parecen estar directamente correlacionados con el ciclo reproductivo. No obstante su amplio empleo, la posición de los testículos no resultó ser un buen indicador de la actividad reproductiva, observándose varios animales con testículos intra-abdominales y actividad espermatogénica. El volumen testicular y el análisis histológico son más apropiados para determinar el estado reproductivo en esta especie.

Objetivo. Evaluar el efecto del verano e invierno sobre la calidad seminal de toros cruzados en el Valle del Sinú. Materiales y métodos. Se utilizaron 8 toros 75% Bos indicus x 25% Bos taurus, 4 con edades entre 20.5 - 27 meses (menores de 30 meses), con edades entre 32 - 37.5 meses (mayores de 30 meses), mantenidos bajo pastoreo. Cada 28 días se evaluó ganancia de peso, condición corporal, circunferencia escrotal (CE) y viabilidad espermática (MPIR, MPIL, A). Resultados. Las variables climáticas en invierno y verano fueron temperatura máxima 33.2 Vs, 35.1°C, temperatura mínima 24.1 Vs, 23.9°C, humedad relativa 81.8 Vs, 75.4%, precipitación 516.4 Vs, 24.1 mm y brillo solar 6.3 Vs, 5.6. Hubo diferencias significativas por época para la ganancia de peso (p<0.01) y para la condición corporal (p<0.01) en ambos grupos. En el grupo de toros menores de 30 meses, se presentaron diferencias significativas para MPI rápido (p<0.02), MPI lento (p<0.0001) y anormalidades secundarias (AS) (p<0.02). En el grupo de toros mayores de 30 meses, solo se presentaron diferencias significativas para AS (p<0.02). La CE, volumen del eyaculado, motilidad y espermatozoides normales, no presentaron diferencias significativas en verano-invierno (p>0.05), en los grupos estudiados. Las correlaciones entre variables climáticas con variables espermáticas en los dos grupos de edades en estudio fueron bajas (r<0.2). Conclusiones. La época afecta la morfología espermática (MPIR, MPIL y AS), especialmente en toros jóvenes. No obstante, el efecto principal está confundido entre el verano y el régimen alimenticio deficiente.

Objective. To evaluate summer and winter effect on the seminal quality of crossbred bulls in the Sinu valley river. Materials and methods. Eight bulls of genetic composition 75% Bos indicus and 25% of Bos taurus, were included, four of them were 20.5 and 27 months (group smaller than 30 months), and the remained four with an age among 32 to 37.5 months (group bigger than 30 months). Corporal weight increase, score of condition corporal, scrotal circumference (CE) as well as their sperm viability were assessed every 28 days. Results. Weather variations during the rainy season and the dry season showed a maximun temperature of 33.2 Vs 35.1°C and a minimum temperature of 24.1 Vs, 23.9°C, a relative humidity of 81.8 Vs, 75.4%, precipitation rain of 516.4 Vs, 24.1 mm and sunshine measures of 6.3 Vs, 5.6. Differences were found in terms of weight increase (p<0.01) and body of condition score (p<0.01). In the group of the bulls under 30 months of age, some differences were found for fast MPI (p<0.02). In the group of bulls over 30 moths of age, there were only statistical differences for secondary abnormalities, AS (p<0.02). There were no statistical differences for scrotal circumference, the ejaculated volume, motility and normal spermatozoids during the dry season and rainy season (p>0.05). The correlations between the weather variables with sperm variables in the two age group are low (r<0.2). Conclusions. The season affects the sperm morphology (MPRI, MPIL, and AE), specially in young bulls. Nonetheless, the main effect is intermingled between the season (dry season) and the deficient forage offered to the animals.

Seasonal effects on semen quality of Gorno Altai cashmere goats and South African indigenous goats were studied in this experiment. A definite breeding season for the two breeds was determined. Semen quality parameters that were quantified include semen volume, sperm concentration, sperm motility, percentage live sperm, dead sperm and scrotal circumference. Scrotal circumference, semen volume, concentration and sperm concentration of the two breeds followed a seasonal pattern. These seasonal variations were significantly affected by changes in photoperiod, with subsequent effects on sperm production. The results suggest that environmental temperature plays a secondary role in terms of semen production compared to seasonal differences in photoperiod. experiment determined volume motility circumference pattern photoperiod