Effect of method of seminal collection on the retrograde flow of spermatozoa into the urinary bladder of rams

The effects of method of seminal collection and a diuretic on retrograde flow of spermatozoa into the urinary bladder of rams were examined. In experiment 1, semen and urine were collected from 8 rams during the nonbreeding season. Prior to seminal collection, all rams were given furosemide and a sample of urine was obtained during micturition. Semen was then collected from each ram with an artificial vagina or by electroejaculation in alternate weeks for 4 weeks, and the urine released during the first postseminal collection micturition was collected in 4 consecutive samples. The volume of electroejaculates was larger (P < 0.0001) than the volume of ejaculates, but the total number of spermatozoa in the electroejaculate or in the ejaculate were not different (P > 0.1). Urine obtained before seminal collection was azoospermic or contained few, nonmotile spermatozoa (mean +/- SD = 0.053 +/- 0.114 x 10(6)/ml). The adjusted spermatozoal concentration (mean +/- SD = 1.630 +/- 2.258 X 10(6)/ml) in the urine collected after seminal collection was 31 times higher (P < 0.0001) and there were motile spermatozoa in most (97%) of the samples. The spermatozoal concentration in sequential samples of urine was not different (P > 0.1) between samples and was not affected (P > 0.1) by the method of seminal collection. There was a trend, approaching significance (P = 0.052), for an effect of method of seminal collection on the percentage of retrograde flow. Retrograde flow ranged from 0.21 to 19.38% when semen was collected with an artificial vagina and from 0.03 to 94.60% when semen was collected by electroejaculation and varied (P = 0.02) among rams within the 2 methods of seminal collection. In experiment 2, the 8 rams used in experiment 1 were given injections of 0.9% physiologic saline solution or furosemide in alternate weeks prior to seminal collection with an artificial vagina. Furosemide increased (P = 0.009) the volume of urine voided during the first postejaculation micturition, but did not influence (P > 0.1) the time from exposure of rams to the teaser to ejaculation, seminal characteristics, number of spermatozoa in the urine, or the percentage of retrograde flow. There was a trend (P < 0.1) for more rams to have motile spermatozoa in the postejaculation urine after treatment with furosemide. Administration of furosemide prior to seminal collection facilitates the noninvasive collection of pre- and postejaculation samples of urine for the determination of retrograde flow.