Some biochemical parameters for qualification of bull semen

Summary

Since the macroscopical and microscopical examination of bull semen does not in all cases appear to give conclusive indications concerning the fertilizing capacity, an investigation of some biochemical parameters was undertaken. It was shown that the following biochemical examination could furnish some more information about the quality of the semen: 1. Determination of the phenylalanine‐ α‐ketoglutarate transaminase activity both in the seminal plasma and in the whole semen. A high transaminase activity in the plasma points to leakage out of the spermatozoa, thus indicating an affection of the spermatozoa. In that case larger amounts of basic amino acids and of leucine were often found in the seminal plasma than would normally be observed.

2. Gas chromatographic examination of the steroids occurring both in the seminal plasma and in the spermatozoa. In a number of infertile bulls small peaks of progesterone were found together with those of other, unidentified compounds.

3. Investigation of the carbohydrate metabolism in the semen. In a number of fertile bulls the following deviations were found: a. the presence of quite a lot of fructose in the spermatozoa;

b. the presence of glucuronic acid and / of other foreign compounds in the spermatozoa or in the plasma;

c. an elevated pH in the seminal plasma some 2 to 3 hours after ejaculation;

d. a low phenylalanine‐α ‐ketoglutarate transaminase activity in the whole semen (the spermatozoa had been disrupted by freezing).

4. Investigation of the presence of reducing aldehydes (glycolaldehyde and glyceraldehyde) inside the spermatozoa.

The determinations mentioned under 1, 3c and 3d can easily be carried out in the laboratories of each District Animal Health Service and of the A.I. stations; the same is true of the occurrence of amino acids in the seminal plasma and of fructose and aldehydes inside the spermatozoa if facilities are available for electrophoresis and chromatography.     

Insulin-like growth factors and IGF-binding proteins in bovine seminal plasma.

Insulin-like growth factor-I (IGF-I) is an important factor for germ cell development and maturation of spermatozoa. Actions of IGFs are modulated by IGF-binding proteins (IGFBPs) that may, depending on their concentration and site of expression, inhibit or enhance effects of IGF-I. We characterized IGFs and IGFBPs in seminal plasma from bulls routinely used for artificial insemination (AI) and from bulls producing poor-quality semen (low mass and individual motility of spermatozoa). IGFs were measured by specific radioimmunoassay in 22 samples of seminal plasma from nine different AI bulls with high (> 76.8%), average (72.8-73.4%), or low (< 69.5%) nonreturn rate (NRR). IGF-I and IGF-II levels were 144 +/- 9 ng/ml (mean +/- SE; range, 79-238 ng/ml) and 144 +/- 10 ng/ml (range, 55-221 ng/ml), respectively, and did not correlate with NRRs. IGF-I concentrations in seminal plasma from bulls producing poor-quality semen (n = 10) were significantly (P < 0.05) greater (194 +/- 26 ng/ml; range, 94-370 ng/ml), whereas IGF-II levels were significantly (P < 0.05) lower (93 +/- 17 ng/ml; range, 38-183 ng/ml) than in AI bulls. Ligand blot analysis of seminal plasma for IGFBPs revealed the presence of a 38-/45-kDa doublet band and a 30-kDa IGFBP. These IGFBPs were identified as IGFBP-3 and IGFBP-5, respectively, by immunoprecipitation using specific antibodies. In addition, a low amount of IGFBP-4 was detected in bovine seminal plasma by immunoprecipitation. There was a marked difference in the activity of IGFBPs between individual bulls, with a relatively small within-bull variance. The differences in IGFBP activities did not correlate with the fertilization capacity of the bulls in vivo or in vitro nor with immunoreactive IGF-I and IGF-II levels in seminal plasma. Our results demonstrate the presence of IGFBPs in bovine seminal plasma. In contrast to human seminal plasma, high activity of IGFBP-3 was detected in seminal plasma of some bulls, suggesting species-specific regulation of IGFBP activity by proteases.     

Growth hormone treatment of breeding bulls used for artificial insemination improves fertilization rates

To evaluate new therapeutical concepts for male subfertility, we tested the effects of exogenous recombinant bovine growth hormone (rbGH) on various endocrine and metabolic parameters both in blood and in seminal plasma of bulls. Sperm quality was assessed morphometrically and by monitoring the number of successful artificial inseminations (AIs) defined as non-return rates (NRR). Aliquots of 450 semen samples were used from each bull and each experimental period (4 wk before, 14 weeks during and 6 wk after treatment). Six out of ten sires (average age 8.4 years) were treated every two weeks with 640-mg depot formulated rbGH (Eli Lilly). Four bulls received vehicle only. Blood plasma bGH, IGF-I, insulin and glucose concentrations were increased with rbGH treatment. In seminal plasma there was no effect of rbGH treatment on fructose and citrate or on testosterone concentrations. With one exception, rbGH-treated bulls had greater IGFBP-3 concentrations in seminal plasma. Motility of spermatozoa after freezing and thawing was increased compared with pretreatment rates. Most interestingly, the number of successful AIs was increased by an average of 6.0% NRR when ejaculates from rbGH-treated bulls were used.     

Effect of organic and inorganic selenium supplementation on semen quality and blood enzymes in buffalo bulls

The present study aimed to evaluate the effect of organic and inorganic selenium (Se) supplementation on semen quality and blood serum profiles of buffalo bulls. Nine mature buffalo bulls were divided into three groups: control (non‐supplemented); organic Se (10 mg Sel‐Plex®/head twice weekly) and inorganic Se (10 mg sodium selenite/head twice weekly). Semen was collected twice a week for 3 months during Se supplementation. Semen properties were evaluated from fresh ejaculate. Moreover, fructose concentration, aspartate and alanine transaminase (AST and ALT) activities, total protein and total cholesterol were assayed in seminal plasma. Additionally AST, ALT, testosterone and Se levels were determined in the blood serum. Results showed that Se supplementation significantly (P < 0.05) influences the semen parameters during 3 months of treatment. Organic Se significantly (P < 0.05) increased the percentage of viable sperms compared to inorganic Se and the control group. Fructose concentration was significantly higher (P < 0.05) in the seminal plasma of organic Se‐treated bulls. Serum testosterone and Se concentrations were significantly (P < 0.05) increased in the Se supplemented groups than the control group. In conclusion, Se supplementation improved the parameters of buffalo bull semen and more precisely, organic Se was more effective for the improvement of semen quality and some blood components than inorganic Se.     

Effects of a metabolic endurance test developed for the constitution examination of young bulls on spermatologic and endocrine parameters

The purpose of this study was to examine the influence of an eight day starvation period on semen characteristics and some endocrine parameters of young bulls. The experiments were performed with 18 bulls in two trials showing the following set-up: pre-treatment period (7 or 20 days), starvation period (8 days), realimentation period (3 days) and control period (64 days). During the pre-treatment period and the control period the bulls obtained a well-balanced food-ration, during the period of starvation only 2 kg straw daily. During the starvation period the bulls lost 6% of their bodyweight. No influence on general health could be noticed. The concentrations of testosterone, LH, bovine growth hormone, insulin and insulin-like growth factor decreased significantly during or after the period of starvation. There was no clear influence in volume, sperm density and total number of sperm due to the metabolic stress during the hunger period. The initial progressive motility of sperm was not affected. The percentage of morphological abnormal spermatozoa increased 45-55 days after the hunger period. Simultaneously the semen freezability was decreased. An influence on the acrosomal morphology of frozen/thawed spermatozoa could not be obtained. The concentration of fructose, citric acid and glycerylphosphorylcholine (GPC) of the seminal plasma was insignificantly influenced during the period of starvation. The realimentation caused a stimulating effect on the secretion mainly of GPC.     

Biochemical observations on beagle dog semen.

Semen samples were collected at weekly intervals for six weeks from eight sexually mature beagles previously shown to produce normal ejaculates. Seminal plasma and sperm fractions were separated by centrifugation and the sodium, potassium, alanine and aspartate aminotransferases, acid and alkaline phosphatase concentrations in the two fractions determined. Regression analysis of the mean weekly values obtained from physical and biochemical examination of the ejaculates showed that sodium ion concentration was highest in seminal plasma. The highest levels of aminotransferases were found in sperm fractions. Those enzymes may be indices of abnormal or damaged spermatozoa. Acid and alkaline phosphatase activity was 100 times greater in seminal plasma than in sperm fractions. Phosphatase concentrations are likely to be dependent on prostate activity. Measurement of acid phosphatase in canine semen therefore may be a useful index of prostate function. The motility of the semen samples was independent of the potassium concentration in seminal plasma. However, there was some evidence of a correlation between sperm motility and the enzyme and sodium content of seminal plasma.     

Seasonal Variations in Seminal Plasma Proteins of Buffalo

The study was designed to evaluate the influence of season on semen characteristics and seminal plasma protein profile of buffalo bull semen. Thirty‐six ejaculates were collected in three seasons (winter, summer and rainy) from six adult Bhadawari bulls, and semen characteristics were evaluated immediately after collection. The seminal plasma was harvested by centrifugation and protein profiling, and percentage protein fractions were analysed by SDS‐PAGE. The significant effect of season was observed on ejaculate volume, sperm concentration, progressive motility, percentage live spermatozoa, hypo‐osmotic swelling test (HOST) and acrosomal integrity. The electrophoretogram of seminal plasma proteins revealed 20 protein bands in winter, 23 bands in rainy and 25 bands in summer seasons, illustrating the significant effect of seasons on seminal plasma proteins. Among these protein bands, 18 bands were observed common in semen samples of all three seasons while protein bands of 46, 55, 58, 144 and 160 kDa were found in rainy and summer seasons. The protein bands of 48 and 60 kDa were observed only in winter season, whereas 184 and 200 kDa were reported in summer season only. The protein fractions (protein%) of common protein bands observed in three seasons revealed a significant effect of season on protein bands of 24.5, 66, 70, 72, 84 and 86 kDa. From the study, it was pertinent that bull seminal plasma contains specific proteins in particular season, which may be associated with some of the semen characteristics, and these proteins could be used as markers of the semen quality of buffalo bulls.     

日粮补锌对荷斯坦种公牛精液品质的影响

试验选用６头荷斯坦种公牛,研究了锌对性反射时间、精液品质、精清酶活性及血、精清锌与睾酮浓度的影响。结果表明：添加锌能显著提高精液的鲜精活力、精子密度、冻后精子活力和顶体完整率（Ｐ＜０．０５）;性反射时间明显减少（Ｐ＜０．０１）;鲜精精清中ＡＫＰ和ＧＯＴ活性组间差异不显著,但ＬＤＨ活性２组显著高于１组（Ｐ＜０．０５）;冻后精清ＡＫＰ、ＧＯＴ和ＬＤＨ活性组间差异不显著（Ｐ＞０．０５）。添加锌能显著提高血清锌浓度（Ｐ＜０．０１）,但对精清锌含量的影响不明显（Ｐ＞０．０５）。血清睾酮浓度１组显著高于２组（Ｐ＜０．０５）,而精清睾酮浓度组间差异不显著（Ｐ＞０．０５）。     

不同季节肉用种公牛精液品质与生理常值、血清及精清生化指标相关关系研究

以利木赞和夏洛来种公牛为试验牛，研究不同季节对其精液品质、冻精产量、生理常值、血清及精清生化指标的影响。结果表明：（1）与其它季节相比，夏季肉用种公牛的原精活力、冻精活力、活精于百分数、顶体完整率均显著降低，而精于畸形率显著升高（P〈0．05）。精子密度以秋季最低。（2）冻精产量夏季处于最低水平，平均每月仅为7388支。（3）夏季肉用种公牛的血清LH、睾酮、T3、皮质醇的含量分别为48．12、4．15、1．11、4．89ng／L，显著低于春、秋、冬季（P〈0．01）。（4）夏季肉用种公牛血清钠、钾、钙、镁均处于最低水平，显著低于其它季节（P〈0．01）。（5）夏季肉用种公牛精清睾酮水平明显下降，显著低于春季、秋季和冬季。（6）精清钠、钾、钙夏季含量最低，分别为83．12mmol／L、18，77mmol／L和4．63mmol／L；精清镁含量由春季至秋季呈显著下降趋势；精清磷含量夏季最高，为4．65mmol／L，显著高于春季、秋季和冬季。（7）肉用种公牛精清ALP夏季含量为1784．3U／L，显著高于春、秋两季，但低于冬季。（8）精清睾酮与精液品质各指标存在显著相关；血清生化指标与精清生化指标存在显著相关；直肠温度、呼吸频率与精液品质及血清生化指标存在显著相关性，与精清生化指标相关性不大。     

高温对荷斯坦种公牛精液品质及精清生化指标的影响研究

以荷斯坦种公牛为试验牛研究了高温对其精液品质和精清生化指标的影响。结果表明:(1)高温可造成种公牛精液品质显著下降。使原精活力、精子密度、活精子百分数和顶体完整率分别比春季下降3·13%(P<0·05)、34·8%(P<0·01)、15·0%(P<0·01)和17·8%(P<0·01),精子畸形率比春季上升25·5%(P<0·01)。(2)夏季荷斯坦种公牛精清睾酮含量仅为4·31pg/mL,极显著低于非高温季节(P<0·01)。(3)高温环境使得荷斯坦种公牛精清钾、钙、镁处于最低水平(P<0·01),精清碱性磷酸酶(ALP)、酸性磷酸酶(ACP)处于最高水平(P<0·01),使精清钠由春季至夏季呈显著下降趋势。     

Seasonal changes in reproductive parameters and seminal plasma constituents of rams in Afyon province of Turkey

The objective of the present study was to describe seasonal changes in semen quality, serum testosterone and seminal plasma constituents for 9 months in 10 rams from a mature local (Daglic) and imported breed (Chios) under Afyon province conditions typical for the internal Anatolian region. Sperm motility and sperm concentration and testosterone level were higher, percentage of abnormal spermatozoa was the lowest during autumn. The biochemical analyses of ram seminal plasma indicated that the highest values of total protein, albumin (A), globulin (G), total lipid and cholesterol were recorded in autumn while A/G ratio exhibited the lowest values. Aspartate amino transferase (AST) activity and AST/ALT ratio recorded the lowest values, while moderate values were recorded for alanine amino transferase (ALT) activity in autumn. The results suggest that the rams under Afyon province conditions show seasonal changes for some reproductive parameters and seminal plasma constituents.     

Effects of ovalbumin on the motility and fertilising ability of fowl spermatozoa stored for 24 H at 4 degrees C

1. The effects of 0.1, 0.5, 1 and 3 g ovalbumin/100 ml diluent on spermatozoa stored for 24 h at 4 degrees C in TES diluent or BPSE diluent with or without seminal plasma were studied. 2. There was no effect of ovalbumin on the motility of spermatozoa stored in whole semen, except at an incorporation rate of 3 g/100 ml, when motility was reduced for spermatozoa stored in TES diluent. When sperm were stored in the absence of seminal plasma, ovalbumin stimulated motility but this effect was transitory. 3. The effects of ovalbumin on fertilisation rates were diluent- and concentration-dependent. Ovalbumin concentrations of 0.1 and 0.5 g/100 ml increased the fertilising ability of whole semen stored in TES diluent but 1 g/100 ml ovalbumin decreased it. However, 0.5 g ovalbumin/100 ml had no effect on the fertilising ability of spermatozoa stored in BPSE diluent, irrespective of the presence or absence of seminal plasma.     

Korrelation zwischen spermatologischen Befunden and Hyaluronidase-Aktivität m Stiersamen

Inhalt Acht Stiere wurden nach der spermatologischen Qualität ihrer Ejakulate in 2 Versuchsgruppen unterteilt und von jedem Tier 8 Ejakulate als native, verdünnte und aufgetaute Samenproben für die spermatologischen and biochemischen Untersuchungen verwendet. Eine signifikant positive Korrelation bestand zwischen der geschätzten Motilität und dem durch die Supravitalfärbung ermittelten Prozentsatz lebender Spermien. Bei den Ejakulaten geringerer Qualität war ein rascher and stärkerer Verlust der Spermienbeweglichkeit infolge des Verdünnens und Gefrierens zu beobachten als bei Ejakulaten guter Qualität. Zwischen der Hyaluronidase-Aktivität und der Spermienmorphologie bestand kein gesicherter Zusammenhang. Wohl aber konnte eine statistisch signifikant positive Korrelation zwischen der Hyaluronidase-Aktivität and dem Prozentsatz unbeweglicher Samenzellen in verdünnten and aufgetauten Samenproben nachgewiesen werden. Contents Correlation between spermatological results and hyaluronidase activity in bull semen. Eight bulls were assigned to two groups according to the spermatological quality of their ejaculates. For spermatological and biochemical examination eight ejaculates from each animal were processed as undiluted, diluted and thawed samples. A significantly positive correlation was found between motility and percentage of living spermatozoa estimated by an eosine stain. Lower quality ejaculates displayed a quicker and more pronounced loss of motility upon dilution and freeze preservation than ejaculates with good quality. In diluted as well as in thawed semen samples a significantly positive correlation could be found between the percentage of hyaluronidase released into the seminal plasma and the percentage of immotile spermatozoa. There was no strict correlation between hyaluronidase activity and sperm morphology.     

Failure to detect bovine immunodeficiency virus contamination of stud bull spermatozoa, blood leukocytes, or semen leukocytes in samples supplied by artificial insemination centers

OBJECTIVE: To determine whether bovine immunodeficiency virus (BIV) infection could be detected in spermatozoa, blood leukocytes, or semen leukocytes from stud bulls in artificial insemination centers. ANIMALS: 30 bulls at 3 artificial insemination centers. PROCEDURE: Polymerase chain reaction testing that used 3 sets of primer pairs targeting pol and env regions of the BIV proviral genome was performed on DNA extracted from semen leukocytes, spermatozoa, and blood leukocytes from each bull. Southern blot analysis was performed to increase sensitivity of detection. Western blot analysis of plasma samples was used to detect antibodies against BIV. RESULTS: BIV provirus was not detected in DNA samples obtained from semen leukocytes, spermatozoa, or blood leukocytes, and antibodies against BIV were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Contrary to our report of high point prevalence of BIV contamination of semen from a single artificial insemination center, bulls of the study reported here did not appear to be infected. Maximum risk of BIV infection in similar bulls was estimated at 10% with a confidence level of 95%.     

Effects of herbal preparation on libido and semen quality in boars

The objective of this study was to investigate the effects of a preparation from herbal extracts (PHE) on libido and semen quality in breeding artificial insemination boars. Ten fertile boars were divided into control and experimental groups according to significant difference of libido. There were no differences in semen quality between groups. Animals were fed a commercial feeding mixture for boars. The feeding mixture for the experimental group was enriched with PHE, which was prepared from Eurycoma longifolia, Tribulus terrestris and Leuzea carthamoides. Duration of the experiment was 10 weeks. Samples of ejaculate were collected weekly. Libido was evaluated according to a scale of 0-5 points. Semen volume, sperm motility, percentage of viable spermatozoa, sperm concentration, morphologically abnormal spermatozoa, daily sperm production and sperm survival were assessed. Amounts of mineral components and free amino acids were analysed in seminal plasma. Significant differences were found in these parameters: libido (4.05 ± 0.22 vs 3.48 ± 0.78; p < 0.001), semen volume (331.75 ± 61.91 vs 263.13 ± 87.17 g; p < 0.001), sperm concentration (386.25 ± 107.95 vs 487.25 ± 165.50 × 10(3) /mm(3); p < 0.01), morphologically abnormal spermatozoa (15.94 ± 11.08 vs 20.88 ± 9.19%; p < 0.001) and Mg concentration (28.36 ± 11.59 vs 20.27 ± 13.93 mm; p < 0.05). The experimental group's libido was increased by 20% in comparison with the beginning of the experiment. Results of this study showed positive effect of PHE on libido and some parameters of boar semen quality.     

Nickel seminal concentrations in various animals and correlation to spermatozoa quality

In this study, the concentration of nickel in stallion, bull, ram, boar and fox semen, and its relation with spermatozoa quality was analyzed. The concentration of nickel in semen was 0.20 mg kg(-1) in stallion, 0.12 mg kg(-1) in bull, 0.31 mg kg(-1) in ram, 0.06 mg kg(-1) in boar and 0.36 mg kg(-1) in fox. Seminal nickel concentration was significantly higher (P < 0.05) in foxes than that in bulls and significantly higher (P < 0.01) in rams and foxes in comparison with boars. Evaluation of total pathological spermatozoa revealed the highest number in stallions followed by rams, bulls, boars and foxes. In bull, ram and boar semen, separated flagellum, flagellum torso and knob-twisted flagellum were predominant. Knob-twisted flagellum, separated flagellum and flagellum torso were found in increased number in stallion semen and broken flagellum in fox semen. Correlation analysis in bulls indicated a high positive correlation between seminal nickel and separated flagellum (r = 0.76) and medium positive correlation between nickel and flagellum torso (r = 0.62), and in rams a high positive correlation between nickel and separated flagellum (r = 0.77). Medium positive correlation was found between nickel and separated flagellum (r = 0.43) and between nickel and other pathological spermatozoa (r = 0.45) in boars.     

Associations among age, scrotal circumference, and proportion of morphologically normal spermatozoa in young beef bulls during an initial breeding soundness examination.

OBJECTIVE: To evaluate age and scrotal circumference as predictors of semen quality in young beef bulls. DESIGN: Cohort study. ANIMALS: 1,173 beef bulls < 15 months old. PROCEDURE: During initial breeding soundness examination, variables for bulls producing > or = 70% morphologically normal spermatozoa were compared with those for bulls producing < 70% morphologically normal spermatozoa. Mean and 95% confidence interval for age and scrotal circumference were constructed to detect differences between groups of bulls over all observations and within the 5 most common breeds. For these 5 breeds, chi 2 analysis was used to evaluate differences in the proportion of bulls that had values less than the population mean for scrotal circumference, age, and percentage of morphologically normal spermatozoa. Multivariate regression was used to quantify variation in the proportion of morphologically normal spermatozoa that could be explained by age and scrotal circumference. RESULTS: Mean (+/- SD) age and scrotal circumference differed significantly for bulls that produced > or = 70% morphologically normal spermatozoa (12.7 +/- 1.1 months and 35.6 +/- 2.7 cm) and bulls that produced < 70% morphologically normal spermatozoa (12.1 +/- 1.2 months and 34.8 +/- 3.3 cm). The proportion of bulls younger than mean age at first examination and the proportion producing > or = 70% morphologically normal spermatozoa differed among breeds. Age and scrotal circumference explained only 11% of the variation in semen quality. CLINICAL IMPLICATIONS: Among young beef bulls, those that were older and had larger testes were more likely to produce > or = 70% morphologically normal spermatozoa. Age and scrotal circumference were not sufficient predictors of semen quality.     

Influence of chicken native breeds on some physical and biochemical characteristics and short-term storage of semen

1. The major objective of this study was to examine the influence of 24-h storage of semen at low temperature on semen characteristics and fertilising ability of spermatozoa in two native breeds (Kadaknath-KN, Aseel Peela-AP) and White Leghorn (WL) chicken. 2. Various physical and biochemical properties of freshly ejaculated semen of KN and AP were investigated. Fertility was examined in freshly-ejaculated as well as 24-h-stored (3°C) semen diluted (1:3) with Beltsville Poultry Semen Extender. 3. No significant difference was observed in sperm motility among the different breeds whereas live counts were higher in WL than the native breeds. Body weight, semen volume and sperm concentration were highest in AP, followed by KN and WL. A similar trend was observed in the percentage of dead and morphologically-abnormal spermatozoa. 4. The activity of acid and alkaline phosphatase in seminal plasma were higher in WL than KN, whereas the opposite trend was recorded for glutamic oxaloacetic and pyruvic transaminases. The cholesterol content of semen was highest in AP, followed by KN and WL. Cholesterol was much lower in seminal plasma compared with whole semen but there were no differences between breeds. Mean values of the methylene blue reduction time test were higher in WL than in the native breeds. 5. Fertility and hatchability, using freshly-diluted semen, were poorer in the native breeds than in WL. The pattern of fertility deteriorated further, especially in native fowls, when the birds were inseminated with 24-h-stored semen. 6. In conclusion, variation in physical and biochemical characteristics of semen in native breeds compared to WL correlated with poor fertility after short-term storage of semen.     

Effect on fertility of low numbers of fowl spermatozoa inseminated in aqueous diluent or semen components of the fowl and turkey

A study was undertaken to compare the effect on fertility in the fowl of aqueous medium, natural homologous seminal plasma, heterologous turkey seminal plasma and whole turkey semen when whole fowl semen was excessively diluted with these media and inseminated fresh. High dilution with fowl seminal plasma resulted in the best fertility. Dilution with the turkey semen components produced fertility no different from that with aqueous diluent when the dose of spermatozoa was 5 X 5 or 10 X 10(6). The results of this study confirm that 5 X 5 to 10 X 10(6) good quality spermatozoa are sufficient to produce acceptable fertility in weekly inseminations of fresh semen. This enables good quality semen to be highly diluted. However, at high dilution rates there is a need to reconsider the composition of semen diluents, with respect to simulating as yet unknown properties provided by factor(s) in homologous ductus deferens seminal plasma.     

ATP content and sperm motility of extended bovine semen under different storage conditions.

The effects of incubation temperature (+20 degrees C vs +35 degrees C) and media type on the ATP content and motility of spermatozoa were determined in fresh bovine semen in order to develop a method for assaying post-thaw quality. Semen was obtained from 3 bulls at 2 occasions. The spermatozoa were washed using a Ficoll-containing medium before being resuspended in each of 4 different media (I. 0.9% NaCl; II. Tris-buffer solution; III. seminal plasma; IV. seminal plasma+Tris-buffer solution) and incubated for 6 h. The least-squares means for ATP content were higher (p less than or equal to 0.05) at +20 degrees C than +35 degrees C for all media except no. I. By contrast, the least-squares means for sperm motility were higher (p less than or equal to 0.05) at +35 degrees C than at +20 degrees C in media II and III. A decrease over time in ATP content and motility at both temperatures was also observed. The single most important factor responsible for changes in ATP content and sperm motility was the temperature and the medium, respectively.