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SUMMARY

The effect of methoxamine on retrograde flow of spermatozoa into the urinary bladder of domestic cats during electroejaculation and the incidence of retrograde flow during the collection of semen with an artificial vagina, or during mating was examined. In experiment 1, urine collected by cystocentesis prior to electroejaculation was azoospermic or contained few, nonmotile spermatozoa, whereas urine collected after electroejaculation contained more (P = 0.002) spermatozoa, and motile spermatozoa were evident in urine obtained from 6 of 8 cats. Administration of methoxamine hydrochloride (200 μg/kg of body weight, iv) did not affect spermatozoal output or percentage of retrograde flow. Percentage of retrograde flow for control cats ranged from 61.18 to 92.95% (mean ± sd, 80.00 ± 14.28%) and for methoxamine-treated cats, ranged from 15.25 to 92.49% (mean ± sd, 58.10 ± 32.28%), but the difference was not significant.

In experiment 2, an artificial vagina was used to collect semen from 5 of the 8 cats used in experiment 1. Urine collected by cystocentesis after ejaculation contained spermatozoa, and motile spermatozoa were evident in the urine from 4 of 5 cats. The mean (± sd) percentage of retrograde flow for these 5 cats was 46.82 ± 31.67% (range, 14.56 to 90.32%).

In experiment 3, each of the 5 cats that were used in experiments 1 and 2 were mated. Spermatozoa were recovered from the vagina of each mated female, and motile spermatozoa were also present in postejaculation urine obtained by cystocentesis from each of the 5 male cats. Mean total number of spermatozoa in the postmating urine was 29.42 ± 33.58 × 106 (range, 0.22 × 106 to 76.05 × 106 spermatozoa).

Anesthesia of cats with ketamine facilitated the obtention of urine by cystocentesis, but did not cause spermatozoal displacement into the urinary bladder. Results of this study confirm the fact that, in cats, appreciable numbers of spermatozoa are lost because of retrograde flow into the urinary bladder during electroejaculation. Recovery of spermatozoa from the urinary bladder after collection of semen with an artificial vagina or following natural mating, indicates that retrograde flow of spermatozoa is not an artifact derived from electrical stimulation, but is a component of the ejaculatory process in cats.

Free access
in American Journal of Veterinary Research

SUMMARY

Retrograde flow of spermatozoa into the urinary bladder of dogs during ejaculation or after administration of xylazine was examined. In experiment 1, the mean (± SD) spermatozoal concentration in urine collected by cystocentesis before ejaculation was 0.322 ± 0.645 × 106/ml. After ejaculation, motile spermatozoa were present in the urine collected by cystocentesis from 12 of 15 dogs, and the concentration of spermatozoa in the urine (5.139 ± 7.014 × 106/ml) was higher (P < 0.025) than the concentration in the urine collected before ejaculation. The percentage of the total number of spermatozoa that were displaced during ejaculation and flowed into the urinary bladder (retrograde flow) ranged from 0 to 99.75% (24.67 ± 33.98%).

In experiments 2 and 3, administration of xylazine to sexually rested dogs induced retrograde flow of spermatozoa into the urinary bladder. In experiment 2, all dogs had spermatozoa in urine collected after xylazine administration, with motile spermatozoa present in the urine from 9 of 10 dogs. In experiment 3, urine collected from dogs before administration of xylazine was azoospermic or contained few, nonmotile spermatozoa (0.063 ± 0.135 × 106/ml), whereas urine collected after administration of xylazine had more (P < 0.025) and motile spermatozoa (3.717 ± 4.273 × 106/ml).

In experiment 4, administration of xylazine to dogs after ejaculation did not increase the concentration of spermatozoa in the urine. Results indicate that spermatozoa flow into the urinary bladder of dogs during ejaculation or after administration of xylazine to sexually rested dogs.

Free access
in American Journal of Veterinary Research

Summary

Three doses of an α2-adrenoreceptor antagonist, atipamezole, were administered to reverse xylazine-induced sedation, bradycardia, and ruminal atony in calves. Once a week for 4 weeks, each of 6 calves was administered iv 1 treatment of: 0.3 mg of xylazine/kg of body weight, followed in 10 minutes by 1 ml of 0.9% NaCl; 0.3 mg of xylazine/kg, followed in 10 minutes by 3 μg of atipamezole/kg; 0.3 mg of xylazine/kg, followed in 10 minutes by 10 μg of atipamezole/kg; or 0.3 mg of xylazine/kg, followed in 10 minutes by 30 μg of atipamezole/kg. The order of the 4 treatments in each calf was selected at random. Xylazine alone caused lateral recumbency for 33.6 ±7.1 minutes (mean ± sem-). Atipamezole administered at dosages of 3, 10, and 30 μg/kg shortened xylazine-induced lateral recumbency to 20.5 ± 3.0, 10.2 ± 0.2, and 9.3 ± 0.5 minutes, respectively. Calves given xylazine alone stood at > 60 minutes after the onset of recumbency. Atipamezole given at 3, 10, and 30 μg/kg shortened the time from onset of lateral recumbency to standing to 40.2 ± 6.9, 12.8 ± 1.1, and 10.0 ± 0.7 minutes, respectively. Drowsiness was found in calves given the lowest dosage of atipamezole (3 μg/kg) after the calves stood.

Atipamezole given at dosages of 10 and 30 μg/kg reversed xylazine-induced ruminal atony in a dose-dependent manner. In addition, 30 μg of atipamezole/kg reversed xylazine-induced bradycardia, but the lower dosages of this antagonist did not. Results indicated that 30 μg of atipamezole/kg should be a useful antidote for xylazine overdose in cattle.

Free access
in American Journal of Veterinary Research