Resumen de Efecto del invierno y verano sobre el comportamiento reproductivo de toros cruzados

Esperanza Prieto Manrique, P. Amado Espitia, Jaime Cardozo

• español

  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.

• English

  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.