Influence of the dry and rainy seasons upon plasma seminal (SDS-PAGE) and characteristics of the ejaculate from bulls Bos taurus indicus

Disruptions in sperm production include decreased sperm motility and increased of abnormal sperm. Seminal plasma appears to exert important effects on sperm function. The objective was to evaluate the dry and rainy season influence on the seminal characteristics and semen plasma proteins. Eleven bulls with ages ranging from 34 to 38 months were submitted each one to 12 semen collect with eletroejaculation 6 on dry season and 6 on rainy season with 14 days interval, totalizing 144 samples. Qualitative and quantitative semen characteristics were evaluated. Samples of semen were centrifuged (1.500 g / 15 minutes) and conditioned and stored (-20 degrees C) until further processing. The proteins were extracted and quantified to electrophoresis performed. Variance analysis and Tukey test 5% was used. The semen vigor (P < 0.01), minor defects and total defects (P < 0.05) showed statistical difference between seasons, while the volume, motility and minor defects did not (P > 0.05). The number of bands occurred between 6 and 125 kDa. The molecular band of 26 kDa was present in 100% of bulls in rainy season. The molecular bands of 6, 9 and 125 kDa showed a high frequency in dry and rainy season. In conclusion, these results showed a band distribution variation throughout the season and the year seasons changed the semen quality with increase sperm vigor and reduction of abnormal sperm on dry season.