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1.
The importance of standardizing the procedures of sample and slide preparation for computer‐assisted morphologic analysis has been emphasized in human and veterinary andrology. The purpose of this study was to optimize slide preparation (dilution grade and sperm washing), staining procedures and analysis conditions (colour of light source and objective magnification) for the morphometric analysis of bull spermatozoa using the Hamilton Thorne morphology analyzer integrated visual optical system (IVOS). For experiment 1, one ejaculate was collected from one bull and diluted to 200 000–300 000 spermatozoa/μl. Slides were prepared and stained using seven different procedures: rapid Papanicolaou (PAP), rapid Papanicolaou with prolonged staining times (PAP+), Diff‐Quik (DIF), haematoxylin (HEM), Farelly (FAR), Spermac (SPER) and the modified GZIN (MGZIN) staining. All slides were analysed using a Hamilton Thorne Morphology Analyser IVOS equipped alternatively with a red, green or blue light source, and a 40× or 100× oil immersion objective. Recognition and digitization errors as well as morphometric parameters were determined. The IVOS was unable to detect DIF‐stained spermatozoa. The GZIN and the SPER staining as well as the blue light source led to unsatisfactory results. Among the staining methods examined, the FAR, HEM, PAP+, and PAP staining, preferably in combination with the green light source, and the 40× objective yielded optimal results concerning sperm recognition and digitization. The 100× objective did not allow reliable analysis of the sperm heads because of a frequently appearing digitization error. For experiment 2, three ejaculates were collected from each of three bulls and diluted to five dilution grades (100 000–500 000 spermatozoa/μl). An aliquot of each dilution grade was washed additionally. The percentage of correctly digitized sperm heads decreased with increasing spermatozoal concentration. However, the evaluation speed increased. The range of 200 000–300 000 spermatozoa/μl appeared to be a reasonable compromise for both criteria. Sperm washing failed to further improve the analysis results. Sperm head dimensions were influenced significantly by all variations of the methods in both experiments. In conclusion, using the proposed methods, the IVOS allows precise and reliable morphometric analyses of bull spermatozoa. The consistent application of these procedures may lead to an inter‐laboratory standardization and to further establishment of generally accepted morphometric criteria used in human andrology (e.g. World Health Organisation or strict criteria).  相似文献   

2.
Assisted sperm morphometry analysis (ASMA) was used in this study to determine the effects of cryopreservation on bull spermatozoa distribution in morphometrically distinct subpopulations. Ejaculates were collected from five bulls and were divided. One portion was diluted at 30 degrees C in a skim milk-egg yolk medium, containing glycerol. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours. After thawing, sperm smears were prepared as described above. All slides were air dried and stained with Hemacolor. The sperm-head dimensions for a minimum of 200 sperm heads were analysed from each sample by means of the Sperm-Class Analyser (SCA), and the mean measurements recorded. Our results showed that applying the ASMA technology and multivariate cluster analyses, it was possible to determine that three separate subpopulations of spermatozoa with different morphometric characteristics coexist in bull ejaculates (large, average and small spermatozoa). The mean values of each sperm head dimension among the three subpopulations of spermatozoa were significantly different (p < 0.001). Besides, there were significant (p < 0.001) differences in the distribution of these three sperm subpopulations between fresh and thawed samples. Thus, the percentage of representation of the subpopulation that includes those spermatozoa whose dimensions are the biggest, decreased from 52.06% in extended fresh samples to 15.51% in the thawed ones. Contrarily, the percent of representation of the subpopulation containing the smallest spermatozoa, increased from 8.70% in extended fresh samples to 34.04% in the thawed ones. In conclusion, the present study confirms the heterogeneity of sperm head dimensions in bull semen, heterogeneity that vary through the cryopreservation procedure.  相似文献   

3.
Contents: Repeatability and heritability coefficients were estimated for ejaculate volume, mass movement, individual motility, sperm concentration, first and second post-freezing control of motility, number of doses frozen, total number of spermatozoa and total number of motile spermatozoa per ejaculate in the first ten ejaculates of 175 Swiss Holstein and 673 Simmental young bulls (200 pure Simmental, 473 Simmental x Red Holstein crosses). Data were analysed using the univariate individual animal model with effects of interval between consecutive collections, age of bull at collection, season of collection, breed group of Simmental bulls according to percentage of Red Holstein genes, bull (within breed group) and permanent environment. Crossbred bulls had a better performance in all traits. Repeatability coefficients ranged from 0.28 to 0.46. They indicate that the prediction of semen quality in young bulls of the Swiss Holstein and the Simmental breed is possible to some extent. Heritabilities in Swiss Holstein bulls were generally very low and did usually not exceed 0.10, but standard errors of these estimates were high. Relatively high heritabilities (0.18–0.30) were found for Simmental bulls, Differences in heritabilities between these two breed groups were probably a consequence of the low number of Swiss Holstein bulls.  相似文献   

4.
The aim of the study was to determine the relation between the semen quality, frequency of sperm defects, sperm dimensions and shape, and the ejaculate volume of Large White and Landrace boars. A total of 648 ejaculates collected from 31 Large White and 30 Landrace boars were divided into three groups according to the criterion of the ejaculate volume. In this study Landrace boars produced ejaculates with higher volume, sperm concentration, and total numbers of spermatozoa than Large White boars. Landrace boars also showed a lower frequency of sperm with morphological abnormalities (P < 0.05). Landrace boars sperm had larger heads, which were by 0.15 μm longer, and by a larger perimeter and area (P < 0.05). Landrace boar spermatozoa also had a longer flagellum and were generally larger and by 2.07 μm longer than Large White boar sperm (P < 0.05). Significant differences were also found in the shape of sperm of the two breeds (P < 0.05). Landrace boars sperm had more elongated heads, and the ratio of head size to flagellum length was lower than in Large White boars sperm (P < 0.05). Sperm from ejaculates with low volume had a shorter flagellum and a greater head length/flagellum length ratio than sperm from medium- and high-volume ejaculates (P < 0.05).  相似文献   

5.
The evaluation of spermatozoal morphology is an essential step to determine the fertility potential in male individuals. The method of computer-assisted morphometry provides an efficient tool to evaluate objectively morphological anomalies of the sperm head. This review describes the development and current status of morphometry systems and addresses the various problems associated with this method in veterinary medicine. Although there are some unanswered questions, a number of interesting results have been obtained. In all species investigated an individual influence on sperm head dimensions could be demonstrated. In the bull the extent of variability rather than absolute morphometric data is related to individual fertility. The method of computer-assisted morphometry will also help to develop well defined criteria for subjective evaluation of sperm morphology. Further research has to be directed towards the evaluation of the sperm mid-piece. The ultimate goal is the automatic determination of spermatozoal morphology.  相似文献   

6.
In the present study variability of bull sperm concerning percentages of sperm with intact plasma membranes (PMI), high mitochondrial membrane potential (HMMP) and positive acrosomal status (PAS) before and after cryopreservation (vKK; nKK) between bulls and between ejaculates within bulls was examined. Studies were performed on 4 semen samples each of 20 Deutsche Fleckvieh bulls. VKK-Values were 76.5% +/- 9.6% (PMI) 68.3% +/- 8.9% (HMMP) and 9.8 +/- 5.1% (PAS) and nKK-values were 38.1 +/- 14.0% (PMI), 38.2 +/- 14.0% (HMMP) and 30.9 +/- 12.1% (PAS). After freezing, variabilities in sperm parameter values between bulls (nKK: PMI: 49.8%, HMMP 52.1% and PAS: 56.6%) were nearly quite as high or higher than variabilities between ejaculates (nKK: 50.2%, 47.9% and 43.4%). VKK-values of PMI, HMMP and PAS were only fairly to moderately related (0.36 < r < 0.53; P < 0.05) to nKK-values. The results show that PMI, HMMP and PAS did not only vary between bulls, but also between ejaculates within bulls. As there are no high relationships in these sperm parameters between times before and after cryopreservation, each ejaculate should be examined after cryopreservation in order to receive a reliable information about the quality of cryopreserved sperm.  相似文献   

7.
Subjective microscopic sperm motility results have recently been demonstrated to differ between Holstein-Friesian (HF) and Belgian Blue (BB) bulls. However, such assessments are rather imprecise. In the present study, sperm motility was assessed objectively by means of the Hamilton Thorne CEROS version 12.2c computer-assisted sperm motility analyser (CASA), and differences between the BB and HF breed could also be demonstrated. Higher percentages of both totally (p < 0.0001) and progressively (p < 0.0001) motile spermatozoa were encountered in the HF breed compared with the BB breed. Furthermore, a lower kinetic efficiency of the BB spermatozoa, evidenced by a lower beat cross-frequency (p = 0.0007) combined with a higher lateral head displacement (p = 0.0015), was the basis for the lower velocity of BB sperm cells. Additionally, BB spermatozoa move less straight forward, resulting in a lower straightness (p < 0.0001). No sperm motility differences were observed between age groups within the BB breed. The breed differences were observed in the examined bull populations residing at AI centres, in Belgium for the BB bulls and in the Netherlands for the HF bulls. However, these bull populations are selected for fertility. A similar pattern was observed in an unselected bull population of both breeds, although these differences were mostly non-significant for the different CASA parameters. Nevertheless, these data suggest that a genetic component might be responsible for the observed sperm motility breed differences.  相似文献   

8.
The aim of this study was to evaluate the effects of breed and season on semen quality parameters of zebu bulls. Data (1,632 registers) of semen production from Gir (n?=?4) and Nelore (n?=?15) bulls were collected between October 2005 and November 2009. The ejaculates were collected twice a week during various seasons (summer, fall, winter, and spring) and evaluated for the following semen parameters: ejaculate volume, sperm concentration, sperm motility, forward progressive motility (FPM), and sperm morphology. Factor analysis was used to determine the relationship among variables. The effect of breed (Gir and Nelore) and season and their cross effect on each parameter and extracted factor were tested using ANOVA. A negative correlation (P?<?0.05) was observed between FPM and proximal droplet, as well as with abnormal loose head, abnormal small head, pouch formation, abnormal mid-peace, and strongly folded tail. Gir bull sperm showed more major defects, detached acrosome, and minor FPM (P?<?0.01), whereas Nelore bulls showed a higher number of sperm with normally loose head.  相似文献   

9.
The aim of the study was to evaluate semen quality in the two most popular colour morphs of the Arctic fox Alopex lagopus L., blue and white, based on ejaculate parameters, acrosin activity and analysis of sperm morphology. The research material consisted of ejaculates collected once by manual stimulation from 20 one‐year‐old male Arctic foxes (10 individuals of the blue morph and 10 of the white morph). Ejaculates were evaluated in terms of volume, sperm concentration, total number of spermatozoa and the percentage of spermatozoa with major and minor defects. The study revealed that male blue Arctic foxes produce ejaculates with much higher concentration (148.75 × 106/ml) and total number of spermatozoa (98.16 × 106) compared to white Arctic foxes (42.88 × 106/ml and 35.2 × 106 respectively). The level of acrosin activity from white foxes seemed to be higher compared to blue foxes but the difference was not statistically confirmed. Semen from Arctic foxes is characterized by high inter‐individual variability in sperm morphology. The frequency of morphological changes in sperm from Arctic foxes does not significantly depend on ejaculate volume, sperm concentration or the total number of spermatozoa in the ejaculate, but is associated with acrosin activity.  相似文献   

10.
Computer-automated sperm-head morphometry was used in this study to determine the effects of cryopreservation on red deer sperm-head morphometry. Epididymal sperm samples were collected from 40 mature stags and were divided. One portion was diluted at room temperature in a Tris-citrate egg yolk medium, containing 6% glycerol. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours. After thawing, sperm smears were prepared as described above. All slides were air dried and stained with Hemacolor. The sperm-head dimensions for length, width, area, perimeter and shape factor (length/width), for a minimum of 135 spermatozoa were determined for each slide by means of the Sperm-Class Analyser (SCA). Firstly, our results show that cryopreservation substantially reduced (p < 0.001) sperm motility and plasma membrane and acrosome integrities. In addition, sperm heads were significantly smaller in cryopreserved spermatozoa than in the companion extended samples for area (32.05 microm2 vs 32.56 microm2; p < 0.05), length (8.46 microm vs 8.53 microm; p < 0.0001) and shape factor (1.833 vs 1.849; p < 0.0001) for all stags. These differences were found within 29 of 40 stags (75%) for at least three of the morphometric parameters. The individual variability (CV) of sperm head measurements from extended samples was negatively correlated (p < 0.005) with the per cent of change in sperm head measurements after cryopreservation for area (r = -0.465), width (r = -0.483) and perimeter (r = -0.375). Thus, the lower the sperm head variability in the extended samples, the greater the sperm change as a consequence of the cryopreservation. These results suggest that the variability (heterogeneity) in sperm head dimensions of individual stags may be a good indicator of sperm freezability.  相似文献   

11.
Factors influencing boar sperm cryosurvival   总被引：1，自引：0，他引：1  
Optimal sperm cryopreservation is a prerequisite for the sustainable commercial application of frozen-thawed boar semen for AI. Three experiments were performed to identify factors influencing variability of postthaw sperm survival among 464 boar ejaculates. Sperm-rich ejaculate fractions were cryopre-served using a standard freezing-thawing procedure for 0.5-mL plastic straws and computer-controlled freezing equipment. Postthaw sperm motility (assessed with a computer-assisted semen analysis system) and viability (simultaneously probed by flow cytometry analysis after triple-fluorescent stain), evaluated 30 and 150 min postthaw, were used to estimate the success of cryopreservation. In the first experiment, 168 unselected ejaculates (1 ejaculate/boar), from boars of 6 breeds with a wide age range (8 to 48 mo), were cryopreserved over a 12-mo period to evaluate the predictive value of boar (breed and age), semen collection, transport variables (season of ejaculate collection, interval between collections, and ejaculate temperature exposure), initial semen traits, and sperm quality before freezing on sperm survival after freezing-thawing. In Exp. 2, 4 ejaculates from each of 29 boars, preselected according to their initial semen traits and sperm quality before freezing, were collected and frozen over a 6-mo period to evaluate the influence of interboar and intraboar ejaculate variability in the survival of sperm after cryopreservation. In Exp. 3, 12 ejaculates preselected as for Exp. 2, from each of 15 boars with known good sperm cryosurvival, were collected and frozen over a 12-mo period to estimate the sustainability of sperm cryosurvival between ejaculates over time. Boar and semen collection and transport variables were not predictive of sperm cryosurvival among ejaculates. Initial semen traits and sperm quality variables observed before freezing explained 23.2 and 10.9%, respectively, of the variation in postthaw sperm motility and viability. However, more that 70% of total variance observed in postthaw sperm quality variables among ejaculates was explained by boar. This indicates that boar is the most important (P < 0.001) factor explaining the variability among ejaculates in sperm cryosurvival, with most (14 of the 15 boars in Exp. 3) showing consistent (P > 0.05) sperm cryosurvival over time.  相似文献   

12.
Inhalt Es Wurde versucht, 276 Ejakulate von 50 Bullen der Rasse Deutsche. Fleckvich mit Hilfe eines einfachen Objekträgertestes ohne die im Ruutineverfahren üblichen Maβnahmen (Adaption, Einfrieren) auf ihre Gefriertauglichkeit zu testen. Dies erfolgte durch einen Vergleich der Auftauraten von verdünnten Spermaproben gleich nach dem Tiefgefrieren ohne Adaption auf Objektträgern und von solchen die nach 6–8stündigcr Adaption routinemäβig in Ampullen bzw. Pailletten eingefroren wurden. Die Untersuchungen führten zu folgenden Ergebnissen: 1. Die Auftaurate von Spermaproben, die ohne Adaption auf Objektträgern im Stickstoffdampf eingefroren wurden, lassen bis zu einem gewissen Grade eine Vorausbestimmung des Einfrierergebnisses und damit der Tiefgefriertauglichkeit eines Ejakulates zu. Bullen, deren Sperma im Objektträgertest ein Auftaurate von über 20% zeigt, werden als gefriertauglich, jene mit einer Spermienmotilität nach dem Auftauen der Objektträgerproben von unter 5% als gefrieruntauglich und solche, deren aufgetautes Sperma 5% bis 20 % motile Spermien aufweisen, als bedingt tauglich angesprochen. 2. Zur Beurteilung eines Bullen hinsichtliclz der Gefriertauglichkeit seines Spermas reicht die Testung von 3 Ejakulaten aus. 3. Der Objektträgertest ist leicht durchführbar und zeitsparend. Er ist für die Auswahl der Bullen hinsichtlich der Gefriertauglichkeit ihres Spermas für die Praxis allerdings nur bedingt einsatzfähig, da ein groβer Teil der Stiere doch noch routinemäβig nachgetestet werden muβ. Er bringt eindeutige Ergebnisse nur dann, wenn die Auftaurate höchstens 5% und deutlich mehr als 20 % beträgt. Contents (The determination of the suitability for deep freezing of bull semen using a slide test) . 276 ejaculates from 50 bulls of ther German Fleckvieh breed were studied for deep freezing suitability using a simple slide test without the routinely used mea.rures (adaptation, freezing). A comparison was made of the thawing rates of diluted semen samples immediately after deep-freezing without adaptation on slides and after 6–8 hours adaptntion in ampoules or paillettes. The following results were obtained: 1. The thawing rate of semen samples frozen without adaptation on slides in the vapour phase of nitrogen allow a certain degree of predetermination of the freezing result and therefore of the suitability of an ejaculate for deep freezing. Bulls whose semen shows a thawing rate of over 20% by the slide test are taken as being suitable for freezing; those with a sperm motility after the slide test of less than 5% are unsuitable; those with a sperm motility of 5–20% are considered as conditionally suitable. 2. 3 ejaculates are sufficient to test a bull for suitability of semen for deep-freezing. 3. The slide test is easy to carry out and saves time. However, for the selection of bulls on the basis of deep freezing of semen in practice it is limited, since a large proportion of bulls still have to be tested further. The test only gives unequivocal results if the thawing rate is less than 5% or more than 20%.  相似文献   

13.
Using pedigree data, the inbreeding coefficients of 715 Austrian dual‐purpose Simmental (Fleckvieh) bulls stationed in two artificial insemination (AI) centres in Upper and Lower Austria were calculated and incorporated in statistical models for the analysis of semen quality. Five semen quality parameters (volume, concentration, motility, number of spermatozoa per ejaculate and percentage of viable spermatozoa) of approximately 30 000 ejaculates, used in two separate data sets, were investigated. The mixed model included the fixed effects age class of the bull, bull handler, semen collector, month and year of collection, number of collection per bull and day, time interval since last collection, the linear continuous effect of the inbreeding coefficient of the bull, interactions between age class and month, and age class and interval since last collection, respectively, as well as the random effect of the bull and the random residual effect. Non‐linear effects of inbreeding were significant for motility only. Despite the quite low inbreeding coefficients (mean 1.3%), all semen quality traits showed inbreeding depression, in four of the five traits significantly in at least one of the data sets. The magnitude of inbreeding depression was small, which might partly be caused by the low inbreeding levels and a potential pre‐selection of the bulls in the AI centres. However, monitoring of inbreeding depression on fertility traits is recommended to avoid unrecognized deterioration of such traits.  相似文献   

14.
A total of 35 ejaculates were studied in order to assess the suitability of porcine semen for freezing according to the ejaculate characteristics. The effects of the freezing procedure were identified; a decrease in motility and acrosome quality was found after thawing. The best results on motility were linked to the ejaculates with a volume of less than 100 ml of the sperm‐rich fraction, a concentration lower than 450 × 106 spermatozoa/ml and an agglutination score below 2. However, the best normal apical ridge (NAR) was found when the volume of the sperm‐rich fraction was greater than 150 ml. For this reason, an intermediate volume of the sperm‐rich fraction of the ejaculate for the best motility and the best NAR, a concentration lower than 450 × 106 spermatozoa/ml and a rate of agglutination below 2 should provide the best quality after freezing. This study also attempted to determine whether a positive effect of ejaculate selection on the overall freezing performance might be expected.  相似文献   

15.
The knobbed acrosome defect was found at levels of 25 to 100 percent of spermatozoa from 16 of 2054 beef bulls. The incidence of this defect appeared to be particularly high in the Charolais breed. Pedigree analysis of some of the affected Charolais bulls indicated there may be a genetic predisposition for this sperm defect. In eosin-nigrosin stained semen smears the most common form of the abnormality was a flattened or indented apex of the sperm head. A refractile bead at the apex of the sperm head was seen less commonly. Electron microscopy of the spermatozoa from one bull showed that the abnormality was similar to the knobbed sperm defect previously described in Friesian bulls. A breeding trial confirmed that bulls producing spermatozoa with a high incidence of knobbed acrosomes are infertile.  相似文献   

16.
Contents
The value of routine evaluation of bull semen was analysed for 117 AI bulls placed in two studs. Data from semen analysis of a total of 1635 ejaculates was compared statistically with the nonreturn rates of the bulls. The semen parameters which were significantly correlated to nonreturn rates were the motility of the freshly collected ejaculates (p = 0.0140) and post-thaw motility (p = 0.0075). The total number of motile sperm in the inseminate ranged from 10.9 to 19.3 × 106 and according to previous reports the effects of low motility should be fully 'compensated' when doses above 10 × 106 sperm/dose are used for insemination. In conclusion, the motility of freshly collected semen does not appear to be 'compensation' and a low percentage of motile sperm in an ejaculate may indicate other dysfunctions of the population of motile cells. Furthermore, post-thaw motility appears to correlate significantly with nonreturn rates. The largest proportion of the variation was explained by the breed of the bull and stud (42.2% of the variation), whereas the two motility parameters explained 10% of the total variation in nonreturn rates. Objective and precise evaluation of sperm motility in combination with other semen traits are needed to improve breeding efficiency. Although microscopic evaluation of sperm motility correlates with nonreturn rates of bulls, the methods are subjectively assessed and inaccurate and therefore do not allow a satisfactory prediction of fertility.  相似文献   

17.
Genetic parameters were estimated for semen production traits collected in an Austrian AI centre in the years 2000-2004. In total, 12,746 ejaculates from 301 Austrian dual-purpose Simmental (Fleckvieh) AI bulls were examined considering different effects on ejaculate volume, sperm concentration, percentage of viable spermatozoa in the ejaculate, total spermatozoa per ejaculate and motility. The model for genetic parameter estimation included the fixed effects age of bull, collection interval, number of collections on collection day, bull handler, semen collector, year and month of collection, a random additive genetic component and a permanent environmental effect. Correlations between estimated breeding values for semen traits and male fertility from the routine evaluation were calculated. The fertility trait considered in the routine evaluation is non-return rate 90 for the first insemination. All semen production traits were moderately heritable. Heritabilities for volume, concentration, percentage of viable spermatozoa, total number of spermatozoa and motility were 0.18, 0.14, 0.10, 0.22 and 0.04, respectively. Correlations between breeding values for semen quality traits and routinely estimated breeding values for male fertility were low and ranged from 0.08 to 0.17 indicating that semen production traits are rather poor predictors of male fertility.  相似文献   

18.
Single layer centrifugation (SLC) has been shown to select the most robust spermatozoa from the ejaculate in several species. Here the effects of SLC prior to freezing on various parameters of frozen‐thawed bovine sperm quality are reported. Semen from 8 bulls was layered on top of a species‐specific colloid, Bovicoll. After centrifugation for 20 min at 300 g, the resulting sperm pellet was resuspended in OPTIXcell® (IMV Technologies, l′Aigle, France); the SLC‐selected sperm samples and uncentrifuged controls were frozen. On thawing, all sperm samples were analysed for membrane integrity, production of reactive oxygen species, mitochondrial membrane potential (MMP) and chromatin integrity. The SLC‐treated samples had a higher percentage of live, superoxide‐positive spermatozoa than uncentrifuged samples (27.9 ± 5.1% versus 21.7 ± 6.7%; p = .03). They had a higher proportion of spermatozoa with high mitochondrial membrane potential than uncentrifuged samples (55.9 ± 8.2% versus 40.5 ± 15.1%; p = .03) and also a lower proportion of spermatozoa with low mitochondrial membrane potential than non‐treated samples (42.0 ± 8.5% versus 55.9 ± 14.4%; p = .04). No significant effects of treatment were found for membrane integrity or chromatin integrity. The effect of bull was significant on the proportions of dead, superoxide‐positive spermatozoa and live, hydrogen peroxide‐negative spermatozoa, as well as on membrane integrity, but it was not significant for mitochondrial membrane potential or chromatin integrity. These results suggest that SLC selects the most metabolically active bull spermatozoa from the rest of the population in normal ejaculates; the pattern of reactive oxygen species production may be different in SLC‐selected spermatozoa compared to unselected samples.  相似文献   

19.
Reasons for performing study: An improvement in sperm quality after single layer centrifugation (SLC) has been seen in previous studies using small sample sizes (for example, n = 10 stallions). There is a need to investigate whether this improvement is repeatable over several breeding seasons with a larger number of stallions (n ≥ 30 stallions). Objective: To make a retrospective analysis of the results of SLC performed on more than 250 sperm samples (176 ejaculates) from 31 stallions in 3 consecutive breeding seasons. Methods: Sperm quality (motility, proportion of morphologically normal spermatozoa and the proportion of spermatozoa with undamaged chromatin) was assessed before and after SLC. Results: All parameters of sperm quality examined were significantly better in sperm samples after SLC than in their unselected counterparts (P<0.001 for each parameter). The yield of spermatozoa obtained after SLC was influenced by the type of extender used and also by the concentration of spermatozoa in the original ejaculate, with fewer spermatozoa being recovered when the loading dose contained a high concentration of spermatozoa. The optimal concentration was approximately 100 × 106/ml. Sperm concentration in the samples loaded on to the colloid influenced the sperm yield while the type of semen extender affected sperm quality and survival. Furthermore, the scaled‐up SLC method was found to be suitable for use with a range of ejaculates, with similar sperm kinematics being observed for standard and scaled‐up preparations. Conclusions: SLC consistently improved the quality of stallion sperm samples from a large number of ejaculates. The method could be scaled‐up, allowing larger volumes of ejaculate to be processed easily from a wide range of stallions.  相似文献   

20.
Two ejaculates were harvested by electroejaculation on each of 3 d per week for 14 wk from 14, 12- to 24-mo-old Holstein bulls. Ejaculates during the first 2 wk served to stabilize sperm output. Data for the remaining ejaculates were used in a components of variance approach to determine the number of bulls per treatment and ejaculates per bull that would be needed to provide adequate sensitivity and precision for assessing treatment effects on seminal characteristics. The latter included the number of sperm (total and motile), volume and sperm concentrations of the sperm-rich fraction, and the percentage of progressively motile sperm in first and second ejaculates or per day. Replication requirements declined as the number of ejaculates per bull was increased to about 15 to 25 but declined minimally thereafter. The number of bulls needed per treatment varied in relation to the size of the treatment response to be detected but was much greater than the replication used in typical experiments. Replication for assessing sperm output in first ejaculates or per day was approximately one-half as great for experiments in which pretreatment information was used to adjust post-treatment data. Tables should be useful as a guide for designing efficient, cost-effective studies of known sensitivity and precision.  相似文献   

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