Evaluation of reproductive potential of young and adult Blonel bulls

Blonel was developed to be a new race for meat production in tropical countries. Composed by 5/8 Blonde and 3/8 Nellore, Blonel was developed to unit Zebu rusticity to good reproductive characteristics of the Blonde race and is the newest bovine race recognized and registered by the Ministry of Agriculture, Livestock and Supply (MAPA) in Brazil. This study aimed to evaluate the reproductive performance of Blonel bulls of different ages by andrological examination. The experiment was conducted in Tres Furnas Farm in Buriti Alegre, Goias. For this survey, 14 animals aged 24 to 63 months were subjected to andrological examination during August and September of 2012. The andrological examinations were conducted by the same veterinarian. Scrotal circumferences were determined in cm. After the collection, were conducted the immediate analyzes of semen: gross motility, motility, vigor and sperm concentration. From a drop of semen, were made a smear microscopy slide for evaluation. Subsequently, in the laboratory, this slide was stained (Gram stain) for conducting the mediate analysis of sperm cells (sperm morphology) under microscopy, when were evaluated all types of defects and their frequencies. The results of these evaluations mentioned above are part of the andrological exam report. For statistical analysis, results of scrotal circumference, semen volume, turbulence, motility, FPM, concentration, total major defects and total minor defects evaluations were submitted to ANOVA at 5% of significance level. The results of this study did not differ between groups (p>0.05) and were: 30.14 ± 1.34 and 28.93 ± 1.69 cm for scrotal circumference, 5.50 ± 0.00 and 4.64 ± 0.80 ml for semen volume, 2.71 ± 0.49 and 2.57 ± 0.53% for turbulence, 54.28 ± 6.07 and 67.86 ± 9.51% for motility, 3.57 ± 0.79 and 3.28 ± 0.75 for FPM, 657.14 ± 97.59 and 678.57 ± 138.01% for concentration, 7.57 ± 1.27 and 5.71 ± 2.43% for total major defects, 5.43 ± 2.76 and 2.29 ± 1.60% for total minor defects for young and adult Blonel bulls, respectively. Results observed were just below the recommended by CBRA, except for total major and minor defects. Among total defects were observed no: acrosome defects, proximal cytoplasmic droplet, sperm underdeveloped, curled tail to the head, abnormal small, abnormal color, abnormal contour, pouch formation, teratological forms and pathological middle piece. This study indicates that young and adult Blonel bulls shows similar reproductive potential and both has to be more studied.