Boas práticas aplicadas à colheita do semen bovino influenciam nos parâmetros espermáticos

Abstract

One of the limiting factors for the quality of bovine semen is bacterial contamination, which is usually controlled by adding antibiotic supplements to the diluents. The present work evaluated the influence of semen microbial load on quality parameters in the spermogram. Four sets of fresh semen from 25 bulls, donated by an artificial insemination plant, were diluted and plated superficially on 5% defibrinated sheep blood agar, Baird-Parker agar and MacConkey agar. At the same time, the freezing equipment was tested for microbiological contamination. The urease production score in urea broth, fructose fermentation in phenol red broth were evaluated for the isolated microorganisms. Bacterial counts were statistically correlated (p <0.05) with the percentage of major (r = 0.199) and minor (r = 0.202) total defects, folded or curled tail (r = 0.237), normal isolated head (r = 0.226), times when the artificial vagina was reused (r = 0.224), time to perform the breeding (r = 0.247) and the hour of semen collection (r = 0.202). Scores of urease production by Staphylocoocus was correlated with the percentage of defects in the intermediate part and motility in the thermoresistance test, and fructase with the percentage of minor defects. Possible cross contamination of the semen was detected with hygiene brushes, semen diluent and semen freezing circuits pre-filling, which were properly controlled with hygiene measures. The results indicate that the concentration of bacteria in the semen and the production of these enzymes can influence the quality of sperm and that the microbiological monitoring of equipment and materials should be performed routinely.