Relationship between semen characteristics and fertility in electroejaculated mice

Ejaculates were obtained from C57BL mice by applying two successive series of electrical stimuli which were delivered via a bipolar rectal probe. The ejaculates thus collected contained fertile spermatozoa as indicated by results from in-vitro fertilization. Once separated from the seminal plasma, ejaculated spermatozoa possessed the same in-vitro fertilization rate as epididymal sperm. Ejaculates were analysed for coagulum weight, ejaculate volume, sperm count, sperm motility, acid phosphatase content and fructose content. Significant differences were present between several of these values for fertile and infertile mice, and values were therefore empirically assigned to represent minimal amounts for 'normal' fertility (1.5 microliters ejaculate volume; 10.2 mg coagulum weight; 2.5 x 10(6) spermatozoa/ml; 2.3 x 10(3) motile spermatozoa/ejaculate). One half of the fertile animals had no deficiencies in any of the characteristics measured, whereas 97% of the infertile animals had at least one deficiency. No fertile male had more than 2 deficiencies. These data show that the characteristics of mouse semen obtained by the present method of electroejaculation are related to the fertility status of the animal.     

Effect of ejaculation frequency and season on donkey jack semen

Semen characteristics of first and second successive ejaculates from 6 jacks were evaluated weekly for 12 mo. The semen was collected at 4-h intervals, using an artificial vagina with a female in either natural or induced estrus. The statistical analysis was done by factorial delineation 2 x 2 in randomized blocks. Due to some ejaculation failures, the data had to be divided into 2 Groups (A and B) for statistical analysis: Group A - ejaculates preceded by 2 ejaculates in the previous week and Group B - ejaculates preceded by only 1 ejaculate in the previous week. If no statistical difference was observed between the groups in a given parameter, the data was grouped together. Semen characteristics for the first and second ejaculates, respectively, showed the following mean +/- SEM: gel-free semen volume 29.2 +/- 2.2 and 31.7 +/- 2.2 ml; progressive motility 71.0 +/- 1.6 and 72.9 +/- 1.6%; sperm vigor 3.8 +/- 0.1 and 4.1 +/- 0.1; live spermatozoa for Group A 82.6 +/- 2.1 and 82.3 +/- 2.1%, and for Group B 84.6 +/- 1.4 and 86.6 +/- 1.4%; total number of spermatozoa for Group A 10.6 +/- 0.8 x 10(9) and 5.8 +/- 0.8 x 10(9), and for Group B 13.3 +/- 1.2 x 10(9) and 9.6 +/- 1.2 x 10(9); head abnormalities for Group A 1.2 +/- 0.3 and 1.4 +/- 0.3%, and for Group B 1.6 +/- 0.3 and 1.9 +/- 0.3%; mid piece abnormalities 7.7 +/- 0.7 and 6.1 +/- 0.7%; tail abnormalities 7.3 +/- 0.7 and 6.8 +/- 0.7%; pH 7.6 +/- 0.0 and 7.6 +/- 0.0. Significant differences (P < 0.05) were observed between the animals for all sperm characteristics except for sperm vigor. The means for the first and second ejaculates were significantly different (P < 0.05) for the total number of spermatozoa in all the animals, while the percentage of mid piece abnormalities was significantly different in only 1 jack. Seasonal effects on sperm parameters were observed only for semen pH.     

Influence of ejaculation frequency on semen characteristics in chimpanzees (Pan troglodytes)

Semen samples were obtained by masturbation from 6 chimpanzees and the spontaneously liquefied fraction and the remaining coagulum were studied separately. When semen was collected once or twice a week, large intra-individual variations were observed for all measures. The liquefied fraction represented 26.5 +/- 3.2% (weighted mean +/- s.d.) of the total ejaculate but contained 51.3 +/- 3.8% of all emitted spermatozoa. Fructose concentration was higher in the coagulum than in the liquefied fraction (29.3 +/- 3.0 mumol/ml vs 12.0 +/- 2.7 mumol/ml, P less than 0.001) whereas acid phosphatase was less concentrated in the coagulum than in the liquefied fraction (3.5 +/- 0.3 x 10(3) IU/ml vs 13.0 +/- 0.9 x 10(3) IU/ml, P less than 0.001). L-Carnitine and citrate concentrations did not differ between the two fractions of the ejaculate. When semen collection was repeated every hour for 5 h, the ejaculate volume increased from 2.6 +/- 0.7 to 4.7 +/- 0.6 ml (P less than 0.001), whereas total sperm count decreased from 1278 +/- 872 x 10(6) to 587 +/- 329 x 10(6) (P less than 0.05) between the 1st and the 6th ejaculate. In the spontaneously liquefied fraction, the sperm count decreased from 984 to 369 x 10(6). The 6 successive ejaculates gave a total of 20.2 +/- 7.6 ml and 4278 +/- 2884 x 10(6) spermatozoa. The increase of the ejaculate volume was essentially due to an increase of the volume of the coagulum which closely correlated with total amount of fructose (from seminal vesicles) (r = 0.913, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Studies of chemical components of Angora goat seminal plasma

Ejaculates were collected by artificial vagina from 11 Angora goats, once or twice weekly, between April and July in two successive years. The mean +/- SEM ejaculate volumes each year were 0.8 +/- 0.30 and 0.98 +/- 0.52 ml; the sperm concentrations were 3.33 +/- 0.49 and 2.94 +/- 0.45 x 10(9)/ml, and the pH values were 7.01 +/- 0.34 and 7.20 +/- 0.17. The concentrations (mg/100ml) of fructose (875 +/- 97) and lactic acid (73 +/- 17) in goat seminal plasma were sufficiently high to be important substrates for maintenance of sperm motility. Only trace amounts of glucose were present in seminal plasma. The glycerylphosphorylcholine (GPC) concentration of seminal plasma (809 +/- 154 mg 100 ml ) was correlated with whole semen sperm concentration (P < 0.001), indicating that GPC is of epididymal origin. Goat sperm are not likely to utilize GPC as a substrate and its metabolizable derivatives, glycerophosphate (3.3 +/- 1.1 mg 100 ml ) and glycerol (1.8 +/- 1.0 mg 100 ml ), were not present in sufficiently high concentrations to be significant as energy sources for the sperm. The mean concentration of citric acid was 331 mg 100 ml seminal plasma. Colored semen was consistently produced by eight bucks, and in yellow, light yellow and white ejaculates, the seminal plasma riboflavin (mug/ml) concentrations were 5.38 +/- 2.89, 3.09 +/- 0.85 and 1.73 +/- 0.88, respectively. This suggests that the color is due to riboflavin, which is probably produced by the vesicular glands since the concentration of riboflavin in the seminal plasma was correlated with fructose and citric acid levels.     

A preliminary technique for electro-ejaculation of agouti (Dasyprocta leporina)

This study focused on the effectiveness of electro-ejaculation of the agouti (Dasyprocta leporina) and analysis of the collected semen. Sexually mature male agouti were anesthetized with ketamine and electro-ejaculated. The means of ejaculation time was 5.48+/-0.31min, ejaculation voltage was 9.33+/-0.69V, ejaculation voltage range was 6-12V, amps was 0.5-1.5amps, ejaculation volume was 0.47+/-0.12ml and pH was 8.3+/-0.09. Mean spermatozoa concentration, motility and percentage abnormalities were (106.7+/-31.1)x10(6)spermatozoa/ml, 50.44+/-4.44%, and 35.14+/-2.76%, respectively. Thirty percent of the semen samples collected contained spermatozoa. The most significant result from these experiments was the inverse relationship between ejaculation time and ejaculate volume, which suggests that the maximum ejaculation time for electro-ejaculation of the agouti should not proceed beyond 6min. Secondly, the results indicate that the time of the off periods should be shortened to 3-4s.     

Automated sperm morphometry and morphology analysis of canine semen by the Hamilton-Thorne analyser

Computer-assisted sperm morphometry has the potential to eliminate several drawbacks inherent to the current methods of sperm morphology evaluation, and allows for the identification of subtle sperm characteristics which cannot be detected by visual evaluation. In the present study, the Metrix Oval Head Morphology software implemented in the Hamilton-Thorne CEROS (version 12.1; HTR 12.1 Metrix) computer-aided semen analyser was evaluated for canine sperm morphometry and morphology analysis. Comparison of sperm morphometric measurements of 200 spermatozoa from pooled semen samples (n = 4) at 40x and 60x demonstrated a more accurate identification of the sperm head boundaries at a magnification level 60x. Dilution of pooled semen samples (n = 4) to a sperm concentration of 50 x 10(6) ml(-1) allowed for a correct evaluation of the sperm cell dimensions whereas 100 x 10(6) and 200 x 10(6) ml(-1) resulted in a higher percentage of rejected spermatozoa due to overlapping. No differences in morphometric dimensions were found when 100 or 200 spermatozoa were evaluated for each of 15 dogs. The mean morphometric parameters of canine spermatozoa, based on the fresh ejaculates of 23 dogs, were: major 6.65 +/- 0.20 microm; minor 3.88 +/- 0.14 microm; area 20.66 +/- 1.04 microm2; elongation 58.64 +/- 2.58 %; perimeter 17.57 +/- 0.43 microm and tail length 48.93 +/- 10.16 microm. Large variations in morphometric dimensions were detected among individual dogs. After cryopreservation, significantly lower morphometric dimensions were obtained for all the evaluated sperm samples (n = 12). Finally, a correlation of 0.82 (P < 0.05) was established for the percentage of normal spermatozoa assessed by subjective evaluation and by the HTR 12.1 Metrix (n = 39 semen samples). In conclusion, dilution of the semen samples to approximately 50 x 10(6) spermatozoa/ml and an objective lens magnification of 60x, analysing at least 100 spermatozoa, are the technical settings proposed to obtain reliable and objective sperm morphometric measurements by the HTR 12.1 Metrix in canine.     

Comparison of seminal quality in Holstein bulls as yearlings and as mature sires

Semen quality was compared in 5 Holstein bulls from samples collected as young sires (yearlings) and again as mature bulls after a mean interval of 1,265 d. At both sampling periods, the semen was examined for ejaculate volume, sperm numbers, post-thaw progressive motility and sperm viability. Sperm viability was assessed on cryopreserved samples with fluorescent SYBR-14 to stain living spermatozoa and propidium iodide (PI) to identify dead spermatozoa. The fluorescent populations of stained spermatozoa were quantified by flow cytometry. The percentages of living spermatozoa for the individual bulls, as determined by green fluorescence of SYBR-14, ranged from 44 +/- 3.1 to 54 +/- 0.3 for yearlings, and from 38 +/- 1.5 to 55 +/- 1.0 for mature sires. No differences in sperm viability were found between samples taken from yearling bulls and those of mature bulls. The percentage of spermatozoa stained with SYBR-14 was negatively correlated (r = -0.97; P = 0.0001) with the percentage of dead spermatozoa as indicated by PI staining. Comparisons of identical samples run on 2 different flow cytometers indicated that either flow instrument could be used to assess sperm viability. Although the individual bulls differed (P < 0.05) in ejaculate volume and sperm numbers as yearlings, they did not differ in these parameters as mature bulls. The average number of spermatozoa per ejaculate changed as a result of maturation, increasing from 6.2 +/- 1.0 to 10.7 +/- 1.1 x 10(9). Aging was significantly correlated with ejaculate volume (r = 0.76; P = 0.01) but not with the total number of spermatozoa per ejaculate (r = 0.51; P = 0.13). The maturational changes that occurred in the 5 bulls were minimal with the exception of the increased volume of the ejaculate and the number of spermatozoa per ejaculate.     

Dietary supplementation with a source of omega-3 fatty acids increases sperm number and the duration of ejaculation in boars

Development of nutritional strategies to increase the production of fertile sperm would further enhance the distribution of superior genetic material by AI. The objective was to determine the effects of a dietary source of omega-3 fatty acids in boars on semen characteristics and sexual behavior. Boars were fed daily 2.2 kg of a diet top-dressed with 0.3 kg of corn (controls; n=12) or 0.3 kg of a supplement containing 31% omega-3 fatty acids (n=12) for 16 weeks. Semen was collected weekly and for boars that received the supplement containing omega-3 fatty acids, total sperm per ejaculate averaged 84.3+/-2.3 x 10(9) (mean+/-S.E.M.) during Weeks 0-7, and increased (P=0.02) to 95.6+/-2.3 x 10(9) during Weeks 8-15. Control boars averaged 86.3+/-2.3 x 10(9) sperm per ejaculate during Weeks 0-7 and 86.4+/-2.3 x 10(9) during Weeks 8-15. Other semen characteristics were similar (P>0.1) between groups. Duration of ejaculation was affected by treatment (343.9s for controls and 388.8s for boars fed omega-3 fatty acids; S.E.M.=15.7; P=0.05). In summary, semen characteristics and sexual behavior were altered in boars fed a supplement containing omega-3 fatty acids. Boar semen is typically diluted to create AI doses containing 3 x 10(9) sperm each; therefore, use of the supplement increased the number of potential AI doses by approximately three per ejaculate after the initial 7 week supplementation period.     

Seminal carnitine and acetylcarnitine content and carnitine acetyltransferase activity in young Maremmano stallions

The reproductive characteristics and seminal carnitine and acetylcarnitine content as well as carnitine acetyltransferase activity of young Maremmano stallions (n=25) are reported. The stallions were subjected to semen collection in November and January; in each trial two ejaculates were collected 1h apart. The total motile morphologically normal spermatozoa (TMMNS) and the progressively motile spermatozoa at collection and during storage at +4 degrees C were evaluated. Seminal L-carnitine (LC), acetylcarnitine (AC), pyruvate and lactate were measured using spectrophotometric methods, whereas carnitine acetyltransferase activity was measured by radioenzymatic methods. Since there were no major significant differences in seminal and biochemical characteristics between the November and January trials, data were also pooled for the first and second ejaculates. Significant differences (P<0.001) were observed between the first and second ejaculates for sperm count (0.249+/-0.025 versus 0.133+/-0.014x10(9)/ml), total number spermatozoa by ejaculate (12.81+/-1.23 versus 6.36+/-0.77x10(9)), progressively motile spermatozoa (48.6+/-3.0 versus 52.6+/-3.0%) and TMMNS (3.35+/-0.50 versus 2.02+/-0.37x10(9)). In the raw semen the LC and AC were significantly higher in the first ejaculate than in the second (P<0.001), whereas, pyruvate and pyruvate/lactate ratio were higher in the second ejaculate (P<0.05). Seminal plasma AC and LC concentrations resulted higher in the first ejaculate (P<0.001). The pyruvate/lactate ratio was higher in the second ejaculate (P<0.05). Both raw semen and seminal plasma LC and AC concentrations were positively correlated with spermatozoa concentration (P<0.01); in raw semen AC was also correlated to TMMNS (P<0.01). Lactate levels of raw semen was correlated to progressively motile spermatozoa after storage (P<0.01). In the second ejaculate, significant correlations were also observed among AC/LC ratio in raw semen and progressively motile spermatozoa after 48 and 72h of refrigeration. Furthermore, AC levels were correlated to lactate concentration. The positive correlation between LC, AC and spermatozoa concentration, and between AC and TMMNS indicated carnitine as potential semen quality marker. Moreover, the correlation between AC/LC ratio and progressive spermatozoa motility after refrigeration, suggests that carnitine may contribute towards improving the maintenance of spermatozoa viability during in vitro storage.     

Influence of ejaculation frequency of stallions on characteristics of semen and output of spermatozoa.

Approximately 1 week was required to stabilize the extragonadal sperm reserves in stallions ejaculated daily for 10 weeks. The true daily sperm output of a stallion was equal to the mean daily sperm output of seven ejaculates +/- 1-35 X 10(9) spermatozoa. Mean concentrations of spermatozoa/ml and number of spermatozoa/ejaculate were higher (P less than 0-01) for X1 and X3/week ejaculation frequencies than for a X6/week frequency. Sperm output/week was nearly identical for a X6/week frequency. Sperm output/week was nearly identical for the X3 and X6 frequencies and higher (P less than 0-01) than the X1 frequency. Increase of ejaculation frequency from one to two ejaculates/day twice weekly significantly (P less than 0-01) raised the output of spermatozoa/week. Gel-free semen volume, spermatozoa/ml, and number of spermatozoa/ejaculate were higher (P less than 0-01) in the first, than in the second, ejaculate. Collection of semen on alternate days would be a practical ejaculation frequency for inseminating mares. Two ejaculates collected twice a week would be a practical ejaculation frequency for long-term storage of stallion semen.     

Effects of age and environmental factors on semen production and semen quality of Austrian Simmental bulls

More than 90% of the breeding stock of Austrian dual purpose Simmental cows is artificially inseminated. Knowledge of factors affecting sperm production and semen quality is of importance with regard to reproductive efficiency and thus genetic improvement as well as for the productivity and profitability of AI centers. Hence, semen data from two Austrian AI centres collected in the years 2000 and 2001 were evaluated. In total, 3625 and 3654 ejaculates from 147 and 127 AI bulls, respectively, were analysed regarding ejaculate volume, sperm concentration, percentage of viable spermatozoa in the ejaculate, total spermatozoa per ejaculate and motility. Effects accounted for were the bull (random), age of bull, collection interval, number of collection on collection day, bull handler, semen collector, temperature on day of semen collection, in the course of epididymal maturation (average temperature of days 1-11 before collection) and during spermatogenesis (average temperature of days 12-65 before collection). Age of bull significantly affected all traits (P<0.01 to P<0.001) except motility score in center 2. Ejaculate volume and total number of spermatozoa increased with age of bull while sperm concentration was lower in higher age classes (center 1). The collection team was also found to significantly influence semen quality traits. With increasing collection interval ejaculate volume and total number of spermatozoa increased significantly (P<0.05 to P<0.001) while collection intervals between 4-9 days and 1-6 days were superior with regard to sperm concentration and percentage of viable spermatozoa, respectively (P<0.10 to P<0.001). First ejaculates were superior with respect to ejaculate volumes, sperm concentrations and total number of spermatozoa per ejaculate (P<0.001). Temperature, either on day of semen collection or during epididymal maturation or spermatogenesis, had important but inconsistent effects on semen production and sperm quality. Overall, however, ambient temperatures in the range of 5-15 degrees C were found to be optimal for semen production.     

Semen characteristics of Muturu Bulls--Bos brachyceros

Six mature Muturu Bulls were elecroejaculated once a week for nine weeks to study their semen quality and ejaculate characteristics. The semen volume was 1.8 ml +/- 0.1, the sperm concentration 2.16 x 10(8)/ml +/- 0.29, and the progressive sperm motility 36.2% +/- 2.6. Morphologically normal sperm averaged 70.0% +/- 3.1, primary abnormalities 13.4% +/- 1.0 and secondary abnormalities 15.1% +/- 2.3. Except in one bull, no measurable levels of fructose were observed. The contents of major cations and chloride ions in whole semen and seminal plasma were also determined.     

Cellular and biochemical characteristics of semen obtained from pubertal chimpanzees by masturbation

Semen characteristics were studied in 6 wild-born chimpanzees with dental ages ranging approximately from 6 to 12 years. The animals formed 2 groups, early pubertal (EP, N = 3, 6-9 years) and late pubertal (LP, N = 3, 11-12 years). Mean body weight, testicular volume and serum androgen concentration were significantly lower in Group EP (32.2 +/- 1.6 kg, 34.0 +/- 7.7 cm3, 2.1 +/- 0.1 ng/ml) than in Group LP (55.7 +/- 5.7 kg, P less than 0.01; 100.5 +/- 11.9 cm3, P less than 0.01; 3.6 +/- 0.7 ng/ml, P less than 0.05). Ejaculates were obtained by masturbation in all subjects. The mean ejaculate volume was lower in Group EP (0.56 +/- 0.20 ml) than in Group LP (3.77 +/- 0.73 ml, P less than 0.01). In Group EP, 2 animals were azoospermic while the third produced semen with means of 57.1 x 10(6) spermatozoa per ml, 20% motility and 40% vitality. These values were low when compared with the mean values of Group LP (376 x 10(6) spermatozoa per ml, 67% motility and 78% vitality). Mean total sperm count was correlated with testicular volume (r = 0.84) and serum androgen concentration (r = 0.96). The mean concentrations of L-carnitine, fructose, citrate and acid phosphatase for the two groups were not significantly different; but, related to the differences in ejaculate volumes, their total amounts in total ejaculate were lower in Group EP than in Group LP. These results suggest that, in chimpanzees, mechanisms of seminal plasma production and ejaculation are functional early in the reproductive life and that the emission of spermatozoa occurs later.     

Evaluation of relative fertility of cryopreserved goat sperm

This study was designed to compare differences in the in vivo fertility of cryopreserved goat semen assessed by heterospermic insemination with differences in in vitro analyses. Five groups of does were inseminated with mixed frozen-thawed semen from different pairs of bucks. The percentage of offspring sired by each buck in the pair was compared with the relative ability of spermatozoa from that frozen-thawed ejaculate to penetrate zona-free hamster ova, relative post-thaw acrosomal integrity, ability to undergo an acrosome reaction during in vitro capacitation, and assessments of sperm motility. In 4 of the 5 different insemination pairs, the ratio of offspring born was other than 1:1. Acrosomal integrity, ability of spermatozoa to undergo an acrosome reaction, and parameters of sperm motility were not correlated with differences in relative fertility in this experiment using ejaculates from fertile bucks. The ability of spermatozoa to fuse with the oocyte plasma membrane was highly correlated with relative in vivo fertility (R(2) = 0.78, P = 0.04). This suggests that fusion with the oocyte plasma membrane is an event in the fertilization process in which significant variation exists among fertile bucks. Assessment of ability of spermatozoa to fuse with zona-free hamster ova may contribute to analysis of post-thaw fertility of frozen-thawed buck semen.     

Biophysical and biochemical characteristics of bactrian camel semen collected by artificial vagina

Seminal characteristics were investigated in Bactrian camel in this study. Semen samples from ten mature Bactrian camel bulls were collected using a modified bovine artificial vagina. The biophysical parameters including volume, color, sperm concentration and fast forward progressive motility, percentage of live sperm and the biochemical parameters including osmolarity, pH, glucose, calcium, phosphorus, chloride, triglycerides, phospholipids, total protein, albumin and non-protein nitrogen concentrations in seminal plasma were measured. The mean time for semen collection was 5.3 +/- 0.29 min. The volume of semen varies from 1.2 to 26 (8.2 +/- 0.7 mls). The majority of semen samples (83.6%) were milky in color and consistency. The average osmolarity of semen was 316.1 +/- 1.48 mOsm/kg H(2)O. The pH of semen was slightly alkaline (7.4 +/- 0.03). The mean concentration of spermatozoa was 414.8 +/- 25.04 x 10(6)cells/ml. The fast forward progressive motility of spermatozoa was 62.4 +/- 1.57%. The percentage of live spermatozoa was 85.6 +/- 1.15. Seminal plasma concentration of glucose was 35.8 +/- 0.9 mg/dl. Non-protein nitrogen, total protein and albumin were 32.5 +/- 2.5, 2200 +/- 100 and 1100 +/- 100mg/dl, respectively. The average concentrations of phospholipids and triglycerides in seminal plasma were 36.4 +/- 2.1 and 101.6 +/- 5.5mg/dl, respectively. The concentrations of calcium, phosphorus and chloride were 8.2 +/- 0.1, 2.9 +/- 1.7 mg/dl and 97.9 +/- 2.9 mEq./l, respectively.     

Semen quality of postpubertal boars during increasing and decreasing natural photoperiods

The present study analyses the effects of increasing and decreasing photoperiods on the semen quality of 20 selected postpubertal Landrace boars. The boars were exposed, throughout 75 days, to increasing and decreasing photoperiods of natural light, a constant temperature of 21 +/- 1 degrees C and 60-70% of humidity, fed with a nutritious diet and, submitted to a rhythm of semen collection of twice a week. During the last 2 weeks of each treatment, semen samples were analysed and the parameters measured were: ejaculate volume and pH, sperm concentration, sperm production and the number of semen doses per ejaculate, sperm vitality, sperm motility, osmotic resistance of spermatozoa and sperm morphology. The comparative analysis between increasing and decreasing photoperiods indicated that the semen quality of boars exposed to a decreasing photoperiod was reduced as a consequence of decreases in sperm concentration, sperm production and the number of semen doses. There was no difference between increasing and decreasing photoperiods in terms of sperm vitality and sperm motility, nor in the osmotic resistance of spermatozoa to isotonic and hypotonic media. The analysis of sperm morphology showed significantly lower frequencies of mature and immature spermatozoa with a distal cytoplasmic droplet, and significantly higher frequencies of immature spermatozoa with a proximal droplet in boars exposed to the decreasing photoperiod. These results indicate that the sperm quality of the selected boars decreased during decreasing photoperiods, in comparison with increasing photoperiods, mainly due to impaired testicular function.     

The collection and examination of semen of the Reindeer (Rangifer tarandus)

Semen was collected from all the mature Reindeer bulls (9) in the Glenmore herd, both normal and vasectomized. Nineteen samples of semen were obtained. Reindeer semen is a viscous fluid, generally amber in colour: after vasectomy its viscosity is much lower. The mean volume of the ejaculates was 0–5 ml. and mean sperm density 467 × 10⁴ spermatozoa. Motility was low in comparison with other mammals and the proportion of eosinophilic spermatozoa was high (74.5%). Other determinations included measurements of the size of unstained spermatozoa, and of fructose and citric acid concentration in the semen.     

Morphometry of stallion spermatozoa by computer-assisted image analysis

Metric measurements of stallion spermatozoal heads were determined for live, unfixed spermatozoa and for Feulgen-stained spermatozoa by videomicroscopy and computerized image analysis. Two ejaculates were collected from each of five stallions of normal fertility. Air-dried semen smears were Feulgen-stained, and live, unfixed spermatozoa were examined as wet-mount preparations. For Feulgen-stained spermatozoa, videoimages (x3850) were captured, and sperm heads were detected via image segmentation and particle analysis. For live, unfixed spermatozoa, phase contrast videoimages (x3850) were measured to determine width and length of the sperm head. For Feulgen-stained spermatozoa, there were significant effects (P < 0.001) of stallion and ejaculate on measured parameters of area, circumference, and the length and width of the sperm head. For live, unfixed spermatozoa, there were significant effects of stallion on length and width and of ejaculate on length of the sperm heads. There was a very poor correlation between length and width of sperm heads between Feulgen-stained and live, unfixed spermatozoa. Two indices of sperm shape (oval factor and aspect ratio) were also determined. Both aspect ratio and oval factor were significantly affected by stallion (P < 0.001); however, oval factor was not affected by ejaculate and therefore may represent a less variable determination of sperm head shape across stallions. Overall, length and width of stallion sperm heads were larger (P < 0.01) for live, unfixed spermatozoa than for Feulgen-stained spermatozoa (length: 6.3 +/- 0.4 vs 5.08 +/- 0.44; width: 3.08 +/- 0.34 vs 2.71 +/- 0.28 mum, respectively). Computerized image analysis may be useful as a means to objectively measure sperm head dimensions in the stallion and could be useful in future studies to determine associations with stallion fertility.     

Effects of season and breed on sperm acrosin activity and semen quality of boars

Acrosin activity and semen quality (sperm concentration, ejaculate volume and number of spermatozoa) were assessed from March 1997 to March 1998 in semen of Large White, Pietrain and Duroc x Pietrain boars. Semen quality varied with season, including high production of spermatozoa in autumn and winter and low production in summer. Semen quality also differed across breeds. Acrosin activity of boar spermatozoa was not affected by breed (range 3.16-3.32 mU/10(6) spermatozoa), but exhibited distinct seasonal changes. Monthly changes in acrosin activity were parallel to changes in number of sperm in the ejaculate from November to March. On the other hand, dramatic changes in acrosin activity between July and October (range 1.85-4.59 mU/10(6) spermatozoa) were not paralleled by similar changes in number of ejaculated sperm. These fluctuations in acrosin activity may reflect either changes in sperm acrosin production or disturbances to sperm membranes, probably related to effects of high summer temperatures during spermatogenesis. Results confirmed seasonal and breed-related differences in boar semen quality characteristics.