Microbiological evaluation of buck fresh and frozen semen

Abstract

The aim of this research was to evaluate the microbial flora in the fresh and frozen semen of goat reproducers, as well as the effectiveness of the antibiotics estreptomicin, penicillin and gentamicin in cryopreservation of semen. It were used 25 males of different breeds, submitted to two semen collect through the artificial vagina method after cleanliness of prepucial region. The first collection of semen aimed the microbiological exam. The second collection had as goal accomplish freezing, after dilution in skimmed milk, with penicillin + estreptomicin (A1), gentamicin (A2) or control (A3). After microscopic evaluation, it was evidenced average of 87.92 ± 7.76% of MIP and 4.96 ± 0.20 of spermatic vigor in fresh semen. Regarding bacterin evaluation, it was verified, mostly, bacteria of the gender Sthaphylococcus spp and Bacillus sp. After semen cryopreservation, it was observed that there wasn't difference (P>;0.05) among groups in MIP and spermatic vigor. However, in the microbiological evaluation of frozen-thawed semen, bacteria of Sthaphylococcus spp gender was present in great part of samples. Gentamicin (13.3mg/mL) promoted larger inhibition of the bacterial growth in the semen post-freezing, concluding that gentamicin can be the antibiotic used for freezing of goat semen.