Xylazine does not induce retrograde flow of spermatozoa into the urinary bladder of sexually rested boars.

The effect of xylazine on the retrograde flow of spermatozoa from their storage sites in the epididymides and vasa deferentia into the urinary bladder of sexually rested boars was examined. The bladder of four boars was evacuated through a surgically implanted urinary catheter and the urine was examined for the presence of spermatozoa. Boars were then given an injection of 2.2 mg of xylazine per kilogram of body weight and, immediately thereafter, 500 ml of saline was infused into the urinary bladder. Approximately 50 ml of the post-treatment mixture of urine and saline, referred to as 'urine', was collected through the catheter at 5, 10, 15, 20, 30 and 45 min after the injection of xylazine, and examined immediately for the presence and motility of spermatozoa. At 60 min, the urinary bladder was evacuated and the remaining 'urine' was examined for the presence and motility of spermatozoa. None of the pre-xylazine urine and post-xylazine fractions of 'urine' had motile spermatozoa and xylazine did not increase (P > 0.1) the concentration and the number of spermatozoa in the post-treatment 'urine'. Thus, in contrast to other species, xylazine does not induce retrograde flow of spermatozoa into the urinary bladder of boars.

Neural and behavioral teratological evaluation of rats exposed to ultra-wideband electromagnetic fields.

Several investigators have reported teratologic effects of electromagnetic field exposure. The majority of these studies have been performed at levels of exposure that could produce substantial heating of the animals. New and unique sources of ultra-wideband (UWB) electromagnetic fields are currently being developed and tested that are capable of generating nonthermalizing, high-peak-power, microwave (MW) pulses with nanosecond (ns) pulse widths, picosecond (ps) rise times, and an UWB of frequencies. Our study was performed to determine if teratological changes occur in rat pups as a result of (i) daily UWB exposures during gestation days 3-18, or (ii) as a result of both prenatal and postnatal (10 days) exposures. Dams were exposed either to (i) UWB irradiation from a Kentech system that emitted a 55 kV/m-peak E field, 300 ps rise time, and a 1.8 ns pulse width, average whole-body specific absorption rate 45 mW/kg; (ii) sham irradiation; or (iii) a positive control, lead (Pb) acetate solution (2000 microg/ml) continuously available in the drinking water. Offspring were examined for ontogeny (litter size, sex-ratios, weights, coat appearance, tooth-eruption, eye-opening, air-righting, and ultrasonic stress vocalizations). Male pups were tested on various performance measures (locomotor, water-maze learning, and fertilization capabilities). The pups postnatally exposed were examined for hippocampal morphology and operant behavior. Behavioral, functional, and morphological effects of UWB exposure were unremarkable with these exceptions: (i) The UWB-exposed pups emitted significantly more stress vocalizations than the sham-exposed pups; (ii) the medial-to-lateral length of the hippocampus was significantly longer in the UWB-exposed pups than in the sham-exposed animals; (iii) male offspring exposed in utero to UWB mated significantly less frequently than sham-exposed males, but when they did mate there was no difference in fertilization and offspring numbers from the sham group. There does not appear to be a unifying physiological or behavioral relationship among the significant differences observed, and our findings could be due to the expected spurious results derived when a large number of statistical comparisons are made. Significant effects found between our positive-controls and other groups on numerous measures indicates that the techniques used were sensitive enough to detect teratological effects. Bioelectromagnetics 21:524-537, 2000. Published 2000 Wiley-Liss, Inc.

Development of rabbit embryos during a 96-h period of in vitro culture after superovulatory treatment under conditions of elevated ambient temperature.

The effects of elevated ambient temperature on the response to exogenous gonadotropins were evaluated in female New Zealand White rabbits exposed to 33+/-1 degrees C (mean +/- SE) and 10-30% relative humidity (8 h/day) during a 5-day period. Does were treated with pFSH (0.3 mg/0.3 ml Standard Armour) twice daily during three consecutive days with a minimum interval of 8 h between injections. Six hours after the last FSH injection all does were removed from the experimental chamber, given hCG (25 IU/kg) and paired overnight. Nineteen hours after pairing, embryos were flushed from the reproductive tracts, evaluated, and subjected to in vitro culture during a 96-h period. The ovulatory responses to exogenous gonadotropins and fertilization rates did not differ significantly under conditions of elevated ambient temperature, whereas fewer blastocysts and increased number of degenerate embryos were observed after culture. We conclude that although hyperthermia was induced during exposure to elevated ambient temperature, it did not alter the ovulatory responses to gonadotropin treatment and plasma concentrations of FSH and LH compared with does in a thermoneutral environment. Exposure of donor rabbits to elevated ambient temperature before mating, however, increased embryonic degeneration.

Effect of mitochondrial DNA (mtDNA) type on pregnancy rate after embryo transfer in rats.

Because the mtDNA is maternally inherited, embryos resulting from matings or artificial inseminations have the same type of mtDNA as that of the mother. However, when embryos are transferred the mtDNA of the embryos may be different to that of the recipient and this may interfere with maternal recognition and the establishment of pregnancy. This study was done to determine whether differences in the mtDNA between embryos and recipients would influence the survival to term of transferred embryos.A total of 1,220 rat embryos were recovered from non-superovulated donors of known mtDNA type. The number and distribution of developmental stages of embryos collected from 51 rats of mtDNA type A (n = 595) were not different (P>0.05) from those collected from 50 rats of mtDNA type B (n = 625). The overall pregnancy rate after transfer of embryos to pseudopregnant rats was 54% (26 48 ). The pregnancy rate was not affected (P>0.05) by the type of mtDNA of the recipient or of the embryo, and the interaction between mtDNA type of embryos and recipients was also not significant (P>0.05). Embryonic survival to birth was low (78 622 , 12.5%) but was not affected (P>0.05) by the type of mtDNA of the recipient (A = 28 250 ; B = 50 372 ) or of the embryo (A = 41 306 ; B = 37 316 ). Survival of pups to weaning was affected by the type of mtDNA of the embryo (P < 0.01) but not by the type of mtDNA of the recipient (P>0.05) and the interaction between mtDNA type of embryos and recipients was also not significant (P>0.05). More pups (P < 0.005) derived from donor rats of mtDNA type A (34 41 ) survived to weaning age than pups from donor rats of mtDNA type B (18 37 ). These results indicate that differences in the type of mtDNA between embryos and recipients do not interfere with establishment of pregnancy in pseudopregnant recipients.

Yohimbine prevents the retrograde flow of spermatozoa into the urinary bladder of dogs induced by xylazine.

This study was carried out to determine whether yohimbine antagonizes the retrograde flow of spermatozoa into the urinary bladder of dogs caused by xylazine. Adult dogs were assigned to one of four groups of six dogs each and treated as follows: saline control, xylazine (2.2 mg/kg, i.m.), yohimbine (0.2 mg/kg, i.m.), yohimbine/xylazine (yohimbine, 0.2 mg/kg, i.m., followed 10 min later by xylazine, 2.2 mg/kg, i.m.). Pre- and post-treatment urine were collected by cystocentesis from all dogs. The mean (+/- SD) adjusted total number of spermatozoa in the post-treatment urine of xylazine-treated dogs (141.02 +/- 136.75 x 10(6)) was 15 times higher (P < 0.05) than the number in the post-treatment urine of control dogs (9.16 +/- 20.26 x 10(6), 1763 times higher (P < 0.05) than the number in the urine of yohimbine-treated dogs (0.08 +/- 0.20 x 10(6), and 56 times higher (P < 0.05) than the total number in the post-treatment urine of yohimbine/xylazine-treated dogs (2.54 +/- 4.54 x 10(6)). These results confirm that xylazine induces a significant (P = 0.007) displacement of spermatozoa into the urinary bladder of dogs and demonstrate that pre-treatment with yohimbine prevents this effect.

Retrograde flow of spermatozoa into the urinary bladder of boars during collection of semen by electroejaculation.

Boars that had a catheter implanted in the urinary bladder (n = 11) were used to determine the magnitude of retrograde flow of spermatozoa into the urinary bladder during electroejaculation. The overall mean (+/- SD) number of spermatozoa in the electroejaculate of boars was 22 +/- 20 x 10(9), with a mean range for individual boars of 3 +/- 3 to 48 +/- 13 x 10(9). The overall mean adjusted total number of spermatozoa in the post-electroejaculation urine was 1.038 +/- 2.656 x 10(9), and the mean percentage of retrograde flow of spermatozoa into the urinary bladder among boars ranged from 0% to 32.69%, with an overall mean percentage of retrograde flow of 7.51 +/- 17.82%. These findings indicate that in boars electroejaculation is associated with retrograde flow of spermatozoa into the bladder.

Urinary losses of spermatozoa during ejaculation are negligible in boars.

Boars that had a catheter implanted surgically in the urinary bladder (n = 10) were used to determine the magnitude of retrograde flow of spermatozoa into the urinary bladder during ejaculation (Experiments 1 and 2) and the post-ejaculatory retention of spermatozoa in the urethra (Experiment 2). The overall mean (+/- SD) total number of spermatozoa in the ejaculates of boars used in Experiments 1 and 2 was 62 +/- 25 x 10(9) and 65 +/- 33 x 10(9), respectively. The overall mean adjusted total number of spermatozoa in the post-ejaculation urine of boars was 106 +/- 537 x 10(6) in Experiment 1, and 41 +/- 242 x 10(6) in Experiment 2. The overall mean percentage of retrograde flow of spermatozoa into the urinary bladder was 0.15 +/- 0.78% for the boars used in Experiment 1, and 0.03 +/- 0.16% for boars used in Experiment 2. In Experiment 2, the overall mean percentage of urethral loss of spermatozoa was 0.45 +/- 1.02%, and the overall mean percentage of total urinary losses was 0.48 +/- 1.03%. These findings demonstrate that in boars, in contrast to bulls, rams, dogs, and cats, urinary losses of spermatozoa during ejaculation are negligible.

Retrograde flow of spermatozoa into the urinary bladder of cats during electroejaculation, collection of semen with an artificial vagina, and mating.

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 micrograms/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 x 10(6) (range, 0.22 x 10(6) to 76.05 x 10(6) spermatozoa).(ABSTRACT TRUNCATED AT 250 WORDS)

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 non-breeding 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 less than 0.0001) than the volume of ejaculates, but the total number of spermatozoa in the electroejaculate or in the ejaculate were not different (P greater than 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 less than 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 greater than 0.1) between samples and was not affected (P greater than 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.(ABSTRACT TRUNCATED AT 250 WORDS)

Retrograde flow of spermatozoa into the urinary bladder of dogs during ejaculation or after sedation with xylazine.

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 X 10(6)/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 X 10(6)/ml) was higher (P less than 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 X 10(6)/ml), whereas urine collected after administration of xylazine had more (P less than 0.025) and motile spermatozoa (3.717 +/- 4.273 X 10(6)/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.

Retrograde flow of spermatozoa into the urinary bladder of rams.

Retrograde flow of spermatozoa into the urinary bladder of rams during electroejaculation (EE) was examined. In experiment 1, semen and 4 consecutive samples of the urine released during the first post-EE micturition were collected once a week from 6 rams for 5 weeks during the nonbreeding season. The overall mean concentration per milliliter and the mean total number of spermatozoa in the urine ranged from 3.06 to 4.32 X 10(6) and from 80 to 2,865 X 10(6), respectively. The spermatozoal concentration in sequential urine samples was not different between samples, indicating that these spermatozoa had mixed with the urine before micturition. The percentage of the total number of spermatozoa displaced during EE, which flowed into the urinary bladder (retrograde flow), varied among rams (range 3.9% to 80%). The overall mean percentage of retrograde flow during the nonbreeding season was 28.3%. In experiment 2, a catheter was implanted into the urinary bladder of 6 rams (4 rams were from experiment 1), and semen was collected over 4 weeks during the subsequent breeding season. A urine sample was collected from the implanted catheter before EE. Immediately after semen collection, urine was collected by evacuating the bladder. The spermatozoal concentration in the pre-EE urine ranged from 0 to 1.3 X 10(6) (mean +/- SD, 0.17 +/- 0.38 X 10(6)) and was significantly (P less than 0.0001) lower than the spermatozoal concentration in the post-EE urine, which ranged from 1.10 to 22.55 X 10(6) (mean +/- SD, 9.46 +/- 11.30 X 10(6)).(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for retrograde flow of spermatozoa into the urinary bladder of bulls during electroejaculation.

Spermatozoa were not found in the urine collected from 12 bulls before electroejaculation, whereas spermatozoa were found in the urine collected after electroejaculation. The concentration of spermatozoa in four consecutive samples of urine collected during the first postelectroejaculation micturition did not differ (P > 0.80) within bulls, suggesting that the spermatozoa found in the urine were those that had flowed into the urinary bladder during electroejaculation. The mean percentage of retrograde flow was 21% and ranged from 1 to 50% for the 12 bulls. These findings demonstrate that there was a significant urinary loss of spermatozoa during electroejaculation.

Effect of method of collection on seminal characteristics of the domestic cat.

The effect of level of voltage and method of collection on seminal characteristics were studied in the domestic cat. A Latin square design was used to determine the effects of voltage (1, 2, 4, or 6 V) on seminal characteristics of electroejaculates for 8 cats (experiment 1). There was a significant effect of cat on the total volume (P less than 0.005), number of spermatozoa (P less than 0.05), pH (P less than 0.05), and osmolality (P less than 0.025). There was an effect of week for the pH (P less than 0.05) and osmolality (P less than 0.005) of semen. Voltage of stimulation affected the total volume (P less than 0.005), total number of spermatozoa (P less than 0.025), and osmolality (P less than 0.005) of semen. There were trends (P less than 0.1) for an effect of cat and an effect of voltage on spermatozoal motility. Urine contamination was not observed in any of the electroejaculates. A 2, 2 X 2 Latin square design was used in experiment 2 to determine the effect of method of collection (artificial vagina or electroejaculation) on seminal characteristics for 4 cats. Electroejaculation was performed, using the 6-V electrical stimulus selected from experiment 1. There was a significant (P less than 0.025) effect of cat on the motility of the spermatozoa in the viability preparation and a trend (P less than 0.1) for an effect of cat on spermatozoal viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of flushing the vasa deferentia at the time of vasectomy on the rate of clearance of spermatozoa from the ejaculates of dogs and cats.

Flushing the vasa deferentia (ductus deferentes) at the time of vasectomy reduced to zero the number of intact spermatozoa by postvasectomy day 6 in the dog and by postvasectomy day 7 in the cat and shortened the time from vasectomy to azoospermia in the dog, but not in the cat. The fluid used to flush the vasa deferentia was not eliminated through the penile urethra, but flowed into the urinary bladder, indicating that the least resistant pathway for the exit of vasal content in the anesthetized dog and cat is toward the urinary bladder. Both control and treated dogs and cats had spermatozoa in the urine obtained by cystocentesis immediately after ejaculation or ejaculation and flushing of the vasa deferentia. Flushing the vasa deferentia at the time of vasectomy is easy to do, safe, and can be used in clinical practice to decrease the time from vasectomy to the safe utilization of dogs and cats as teasers. The procedure has potential application to males of other species.

Effects of voltage and order of voltage application on seminal characteristics of electroejaculates of the domestic cat.

Two experiments were performed to determine the effects of voltage and order of voltage application on the volume and number of spermatozoa of electroejaculates collected sequentially from the domestic cat. An electro-ejaculate was defined as the seminal fluid and spermatozoa obtained during the application of 60 electrical stimuli. Four electroejaculates were obtained from each cat once a week for 4 weeks. In experiment 1, a stepwise increase in voltage (1, 2, 4, and 8 V) was used in a factorial design to obtain successive electroejaculates from 9 cats. The volume of electroejaculate was not affected by cat, voltage, or week of collection (P greater than 0.05) and the interactions cat X voltage and week of collection X voltage also were not significant (P greater than 0.05). Number of spermatozoa of electroejaculates was affected by cat (P less than 0.001) and voltage (P less than 0.025), and the interaction cat X voltage also was significant (P less than 0.001). The number of spermatozoa of electroejaculates was not affected by week of collection (P greater than 0.05), and the interaction week of collection X voltage also was not significant (P greater than 0.05). The number of spermatozoa in electroejaculates collected with 4 or 8 V were greater (P less than 0.05) than the number of spermatozoa in electroejaculates collected with 1 or 2 V. Stimulation with 8 V resulted in urine contamination of some electroejaculates. In experiment 2, a latin square design was used to determine the effects of voltage (1, 2, 4, and 6 V), electroejaculate sequence, and order of the 4 voltages in the sequence on seminal characteristics of electroejaculates from 8 cats. Volume of electroejaculate was not affected by cat, voltage, order of voltages, electroejaculate sequence, or week of collection (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term study on the effects of electroejaculation on seminal characteristics of the domestic cat.

Semen was collected by electroejaculation from 9 random-source cats. There were 22 seminal collections over 32 weeks. An electroejaculate was defined as the seminal fluid and spermatozoa collected during the application of 60 electrical stimuli--the 1st 40 stimuli at 2.0 V, and immediately afterward, 20 stimuli at 3.0 V. Four sequential electroejaculates were obtained from each cat at each seminal collection. The volume and number of spermatozoa for each electroejaculate were determined. There was a significant (P less than 0.005) effect of cat and sequence of electroejaculate for both the volume and number of spermatozoa in the electroejaculate . There was no effect of week of collection; however, there was a trend (P less than 0.1) for the volume of electroejaculate to increase with time. The interactions of cat X week of collection and electroejaculate sequence X week of collection for the volume and for the number of spermatozoa per electroejaculate were not significant (P greater than 0.05). The volume of the 1st electroejaculate of the sequence was lower (P less than 0.01) and the number of spermatozoa in the 2nd of the sequential electroejaculates was higher (P less than 0.05). There was considerable variation within and between cats in the volume and number of spermatozoa. Repeated anesthesia and electrical stimulation did not appear to alter the ejaculatory capacity of the cat.

Surgical and chemical vasectomy in the cat.

Ejaculates of surgically vasectomized cats had spermatozoa as long as 49 days after vasectomy, indicating that spermatozoa in the ejaculate from intact cats originated from the epididymides and vasa deferentia. Intraepididymal injections of an aqueous solution of 4.5% chlorhexidine digluconate into the caudae of the epididymides induced a lasting oligospermia or azoospermia in 7 of 8 cats. Of these 7 cats, 4 were azoospermic and 1 cat had no intact spermatozoa in his ejaculates 140 days after treatment. The method of chemical vasectomy by intraepididymal injection of sclerosing agents appears to be safe and may be suitable for large-scale sterilization programs for controlling the growth of the feline population.

An electroejaculator for the collection of semen from the domestic cat.

An electroejaculator for the collection of cat semen and for the evaluation of electroejaculation protocols is described. The electroejaculator contains an adjustable signal generator and allows for the precise control and monitoring of the electrical stimulus to the animal. The electroejaculator incorporates controls for the selection of the frequency, potential and waveform of the electrical stimulus and controls for either manual or automatic delivery of stimuli of specified characteristics to the rectal probe. In the automatic mode, the operator may also preset the rate and duration of stimulus application and the interval between successive stimuli. The electroejaculator output to the probe is controlled with an on-off foot-switch which allows for the collection of semen from an anesthetized cat by one operator. Diagrams of the functional block, the component circuits of the electroejaculator, and the accessories which facilitate the collection of cat semen are provided.