Abstract Single layer centrifugation (SLC) technique has been developed to select the best sperm population in the ejaculate in order to increase the fertilization rates by artificial insemination or in vitro fertilization. Normospermic ram semen samples containing 800 and 3,000 × 106 sperms/ml (C800 and C3000, respectively) were processed by SLC. Three sperm fractions were separated in each sample following silica-coloidal sperm centrifugation and sperm yield, quality and subpopulations were analyzed in each one. In C800 group, the sperm recovery rate did not vary in any studied fraction, but when samples were highly concentrated (C3000) the top fraction (F1) contained significantly higher spermatozoa than bottom fraction (F3). Also, it was observed that F1 in C3000 had got a significantly higher percentage of spermatozoa (53.2 %) than in C800, while the quantity of spermatozoa recovered in fraction 2 was lower (25.2 % vs 45.4 %). Based on the sperm motility parameters, three sperm subpopulations were identified: SP1, low velocity spermatozoa showing no progressive movement (19.1 %); SP2, rapid and progressive spermatozoa (43.7 %); and SP3, rapid spermatozoa but non-linear movement (37.2 %). While SLC has been implemented for sperm separation in suboptimal and/or low concentrated sperm samples, this trial demonstrates that SLC is not efficient to separate different sperm populations in normospermic ram sperm samples containing high concentrations of spermatozoa.

Resumen La técnica de centrifugación de una sola capa (SLC) ha sido desarrollada para seleccionar la mejor población de espermatozoides en un eyaculado con la finalidad de aumentar las tasas de fertilización mediante la inseminación artificial o fertilización in vitro. Se procesaron muestras normospérmicos de semen de carnero que contenían 800 y 3000 × 106 espermatozoides/ml (C800 y C3000, respectivamente) utilizando SLC. Se separaron tres fracciones de espermatozoides en cada muestra y se analizó el rendimiento, la calidad y las subpoblaciones de espermatozoides en cada una. En las muestras de C800, la tasa de recuperación de espermatozoides no varió entre las fracciones. Sin embargo, en las C3000, la fracción superior (F1) contenía más espermatozoides que la fracción inferior (F3). La F1 en las C3000 tenía un porcentaje mayor de espermatozoides (53.2 %) que, en las C800, mientras que en la F2 de las C3000 el porcentaje de espermatozoides recuperados fue menor (25.2 %) que en la F2 de las C800 (45.4 %). Aplicando los parámetros de motilidad de los espermatozoides se identificaron tres subpoblaciones de espermatozoides: SP1, de baja velocidad y sin movimiento progresivo (19.1 %); SP2, rápidos y progresivos (43.7 %); y SP3, rápidos, pero con movimiento no lineal (37.2 %). Si bien SLC se ha utilizado para la separación de espermatozoides en muestras de semen subóptimas y/o de baja concentración de espermatozoides, los resultados indican que SLC no es eficiente en la separación de diferentes poblaciones de espermatozoides en muestras normospérmicas de semen de carnero con altas concentraciones de espermatozoides.

The objective of this work was to establish the genetic relationship between Guabalá and Guaymi cattle populations and some native ones of Latin America. Factorial correspondence analysis, analysis of molecular variance, genetic distances, average number of migrants per population and Wright's F statistics were performed. Population structure was assessed by a Bayesian model, assuming an unknown number of K genetically distinct groups. The correspondence analysis showed that the populations of Guabalá and Guaymí cluster with Mexican creole cattle and Texas Longhorn. Lower genetic differentiation of Panamanian creole with Mexican and Texas Longhorn was also observed. The analyses of genetic distances have also shown similar results to those obtained by Amova and by the factorial correspondence analysis, and the less distance was observed between north populations and Panamanian ones, in comparison with southern populations. Bayesian clustering permitted the assignment of individuals to their respective groups, based on their genetic similarity, and provided information on the number of cluster from which they originate. There is a close historical, genetic, and geographic relationship of Panamanian, Mexican, and Texas Longhorn populations due to the migration of precursors from the Caribbean islands to Panama and Mexico.

El objetivo de este trabajo fue establecer la relación genética entre poblaciones bovinas panameñas Guabalá y Guaymí y algunas poblaciones criollas de Latinoamérica. Se practicó un análisis factorial de correspondencias, análisis de varianza molecular, distancias genéticas, número medio de migrantes por población y los estadísticos F de Wright. Se evaluó la estructura de la población mediante un modelo Bayesiano, suponiéndose un número desconocido de K grupos diferentes genéticamente. El análisis factorial de correspondencias mostró que las poblaciones Guabalá y Guaymí se agrupan con los bovinos criollos mexicanos y el Texas Longhorn. Igualmente se observó menor diferenciación genética de las criollas panameñas con mexicanos y el Texas Longhorn. Los análisis de distancia genética también mostraron dados similares a los obtenidos por el Amova y por el análisis factorial de correspondencia, y se observó menor distancia entre poblaciones del norte y las panameñas, en comparación con las poblaciones del sur. La agrupación bayesiana permitió la asignación de los individuos a su respectivo grupo, con base en su semejanza genética, y proporcionó información acerca del número de poblaciones bajo el cual se originan. Hay una estrecha relación histórica, genética y geográfica de las poblaciones panameñas, criollas mexicanas y Texas Longhorn, a partir de las migraciones de sus precursores desde las Antillas hacia Panamá y México.

Neste estudo, foram avaliados os efeitos ambientais sobre o peso corporal do nascimento aos 150 dias de idade de caprinos na Tunísia com base em 1.656 registros obtidos em caprinos localizados em zonas áridas do Instituto de Medenine-Tunísia, durante 2001-2005. Exceto para peso ao nascimento, registros individuais foram ajustados à idade-padrão (30, 60, 90, 120 e 150 dias) usando interpolação ou extrapolação sobre os dados de campo. Os dados foram analisados pelo procedimento GLM e as médias comparadas pelo teste SNK (α = 0,05). Ano de nascimento (2001-2005), mês de nascimento (janeiro, fevereiro, março e dezembro), tipo de parto (simples e duplos), sexo (macho e fêmea), cor do pelame e idade da mãe (2 a 10 anos) foram definidos como fatores não-genéticos. Os valores médios e os desvios-padrão de peso corporal ao nascimento e aos 30, 60, 90, 120 e 150 dias de idade foram 2,57 ± 0,52 kg, 4,06 ± 1,16 kg, 6,99 ± 1,87 kg, 8,90 ± 2,46 kg, 11,48 ± 3,35 kg e 13,53 ± 4,80 kg para os machos e 2,29 ± 0,44 kg, 4,76 ± 1,13 kg, 3,09 ± 1,33 kg, 8,08 ± 2,02 kg, 10,24 ± 2,36 kg e 12,15 ± 6,54 kg para as fêmeas. O ano de nascimento, tipo de nascimento e sexo tiveram efeito no peso dos cabritos em todas as idades. Os cabritos machos e de partos simples foram sempre mais pesados que os de partos múltiplos e que as fêmeas. O mês de nascimento teve efeito nos pesos corporais em todas as idades, exceto aos 30 dias de idade. A idade da mãe teve efeito no peso corporal aos 60 e aos 150 dias de idade. No entanto, a cor do pelame não teve qualquer efeito em nenhum dos pesos. Os efeitos ambientais estimados neste estudo são importantes e devem ser considerados na gestão e no melhoramento genético de caprinos locais em condições severas da Tunísia.

It was evaluated in this study the environmental effects on body weights of goat kids from birth to 150 days of age of Tunisian local goat population, on the basis of 1,656 records obtained from the Arid Areas Institute of Médenine, Tunisia, during 2001-2005. Except for birth weight, individual records were adjusted for standard ages (30, 60, 90, 120 and 150 days) using either extrapolation or interpolation on field data. Data were analyzed by GLM procedure and SNK (α = 0.05) means comparison test. The kidding year (2001-2005), kidding month (December, January, February, and March), birth type (single and twins), sex (male and female), coat colour of kid and age of dam (2-10 years) were definied as non-genetic factors. Results showed that mean values and standard deviation (SD) of body weight at birth (0), 30, 60, 90, 120 and 150 days of age were 2.57 ± 0.52 kg, 4.06 ± 1.16 kg, 6.99 ± 1.87 kg, 8.90 ± 2.46 kg, 11.48 ± 3.35 kg and 13.53 ± 4.80 kg for male and 2.29 ± 0.44 kg, 4.76 ± 1.13 kg, 3.09 ± 1.33 kg, 8.08 ± 2.02 kg, 10.24 ± 2.36 kg and 12.15 ± 6.54 kg for female. The kidding year, birth type and sex had effect on body weights of Tunisian local kids at all ages. The single and male was always heavier than the twins and the females. The birth month had effect on all body weights except for weight at 30 days of age. The age of dam had effect on body weights from 60 to 150 days of age. However, the coat color had no significant effect on all body weights. Environmental effects estimated in this study are important and need to be taken into account for Tunisian local goat management and breeding improvement under harsh conditions.

We investigated the genealogy of the in situ conservation nucleus of the Pantaneiro horse using DNA microsatellites by evaluating 101 horses, the group consisting of 71 adult horses (3 stallions, 40 male and 31 mares) and 27 foals (14 colts and 13 fillies). Genomic DNA was extracted from hair roots and genotyped using 12 microsatellite markers (AHT4, AHT5, ASB2, ASB17, ASB23, HMS3 HMS6, HMS7, HTG4, HTG10, LEX33 and VHL20). The number of alleles per locus varied from 6 to 13, with a mean of 7.8 and the expected heterozygosity ranged from 0.544 to 0.734 (mean 0.644). The VLH20, ASB2, HTG10, ASB23 markers had a high (> 0.8) polymorphism information content and the total exclusion probability of the 12 microsatellite loci was 0.99. The genealogical study of the Pantaneiro horse using genetic markers was efficient in detecting mistakes during paternity and maternity designation and is an important tool which can be used together with traditional systems of animal identification. The use of genetic markers is recommended in the systematic control of the genealogical registrations and conservation plans to improve genetic aspects of the Pantaneiro horse.