Microbiology of bovine semen and artificial breeding practices under New Zealand conditions

摘要

Abstract The total number of viable micro-organisms in semen from 42 bulls used for artificial breeding varied between 20 and 534000/ml, with a mean of 4630/ml. Most were bacteria of the genera Bacillus, Corynebacterium, and Micrococcus; also represented were Aerobacter, Alkaligenes, Escherichia, Flavobacterium, Herellea, Nocardia, Proteus, Sarcina, and Staphylococcus and the yeasts Rhodotorula rubra and Candida guilliermondi. Seminal plasma contained natural inhibitors effective against 80% of the Gram positive and 40% of the Gram negative organisms isolated. There was no correlation between total viable count of semen and concentration of inhibitor in the seminal plasma. The high proportion of organisms in semen which were sen,itive to natural inhibitors and the lack of correlation between total viable count and concentration of inhibitor are consistent with the view that semen bacteria are transient invaders derived from the urethra and preputial cavity. However, no consistent difference was found betw...