Sperm Motility In Fresh Semen Research Articles

The effect of Thai ginger (Kaempferia parviflora) extract orally administration on sperm production, semen preservation, and fertility in Thai native chickens under heat stress

Thai indigenous roosters are exposed to unsuitable temperatures and humidity, resulting in a lower reproductive potential. Kaempferia parviflora (KP) extract containing methoxyflavones was fed to roosters to improve their reproductive performance. Thirty-two Thai native roosters were orally administered KP extract at 300, 450, and 600 mg, calculated according to their average body weight, for at least 14 d before semen collection and continued supplementation until the end of the experiment. The nonsupplemented group served as the control. Fresh semen in terms of semen volume, sperm concentration, mass movement score, and sperm viability were evaluated. Semen preservation at 5°C and fertility test were examined for total motility (MOT), progressive motility (PMOT), sperm viability, and lipid peroxidation up to 48 h of storage. Testosterone concentrations and testicular function were also determined. The results showed that the highest sperm concentration and sperm motility of fresh semen were observed in KP extract at 600 mg (P < 0.001). KP extract at 600 mg resulted in higher sperm viability than the control and KP extract at 300 mg (P < 0.05), but was not different from KP at 450 mg (P > 0.05). The highest MOT, PMOT, and viability were found in the roosters that received 600 mg oral KP extract (P < 0.05), while those of the roosters that received oral KP extract 300 mg and the control were the lowest (P < 0.05) at all storage times. Lipid peroxidation was significantly lower in the KP extract up to 24 h (P < 0.05). The fertility and hatchability of the KP extract at 600 mg at T48 showed a minor decrease compared to the control at T0. These results might be inferred as a result of good spermatogenesis, as revealed by the results of histological examination and testosterone activity. In summary, oral administration of 600 mg KP extract improved sperm production and successfully preserved rooster semen for a long duration of up to 48 h of storage.

Differential Expressions of Protamine 1 (PRM1) and Protamine 2 (PRM2) Genes as Markers of Semen Quality in Pasundan Bulls

Several gene expressions are related to the success of spermatogenesis. Protamine plays an important role in sperm DNA packaging, spermatogenesis, and sperm quality. This study aimed to isolate RNA from spermatozoa and determine the gene expression profiles of protamine 1 (PRM1) and protamine 2 (PRM2). Six Pasundan bulls aged 5-8 years with a body weight of 380 kg-430 kg were used for this study. The Pasundan bulls were classified into group A (70%-79%) and group B (80%-89%) based on their sperm motility in fresh semen. In this study, correlation analysis was performed between fresh semen characteristics (volume, motility, concentration, abnormality, viability, intact plasma membrane (IPM), DNA integrity) and frozen semen characteristics after thawing (motility, viability, IPM, and DNA integrity). Total RNA was isolated from the frozen sperm pellet, and cDNA was synthesized. Specific PCR primers were used for the transcription of PRM1 and PRM2 from sperm. PRM1 and PRM2 gene expressions were evaluated by qRT-PCR, and ACTB was used as a control. The results showed that progressive sperm motility in the fresh sperm positively correlated with sperm viability and IPM. PRM1 and PRM2 were higher (p<0.05) in group B than in group A. This condition indicates the existence and influence of protamine on the parameters of progressive sperm motility. The expression of PRM1 and PRM2 genes could use as markers of semen quality in Pasundan bulls.

Seasonal changes in sperm freezability of sex-reversed female rainbow trout

In order to obtain sex-reversed females of Salmonid fish (SRF; neomales, masculinized females) the hormonal treatment of fertilized eggs or larvae is used. As a consequence, masculinized fish possess less-developed testes without functional spermatic ducts. Therefore, the semen of sex-reversed females is generally characterized by low or highly variable quality and reflects testicular rather than ejaculated semen. The aim of our study was to evaluate the alterations in sperm freezability of sex-reversed female rainbow trout during the progression of the spawning season. Sperm concentration, seminal plasma osmolality, semen pH, gonadosomatic index (GSI) and total sperm production (TSP) were monitored in fresh semen. The sperm motility parameters, adenosine triphosphate (ATP) production and sperm viability were examined throughout the spawning season in fresh and frozen/thawed semen. The day of the spawning season did not affect sperm motility of fresh semen. During the equilibration of semen, 2–3-fold increase in the sperm motility compared to fresh semen on each day of the spawning season was recorded. A decrease in the sperm motility after cryopreservation compared to equilibrated semen on each day of the spawning season was recorded. The highest ATP concentrations in fresh semen were noted on the 21st day of the spawning season, whereas in cryopreserved semen, these values were the highest on the 16th and 21st days of the spawning season. The viability of fresh semen did not change during the spawning season; however, the highest sperm viability after cryopreservation was observed between the 11th and 21st days of the spawning season. These results should be taken into account during the planning of cryopreservation of semen of valuable SRF individuals, which will be further used for fertilization of eggs under hatchery conditions.

Blocking serine protease activity prevents semenogelin degradation leading to hyperviscous semen in humans.

Prostate-specific antigen (PSA) is a prostate-specific serine protease enzyme that hydrolyzes gel-forming proteins (semenogelins) and changes the semen from gel-like to watery viscosity, a process called semen liquefaction. Highly viscous semen and abnormal liquefaction reduce sperm motility and contribute to infertility. Previously, we showed that nonspecific serine protease inhibitor (AEBSF) prevented proteolytic degradation of semenogelin in mice. However, it is unclear whether similar effect could be recapitulated in fresh human ejaculates. Therefore, in this study we evaluated the effect of AEBSF on the degradation of semenogelin (SEMG1) and its subsequent impact on semen liquefaction and sperm motility in fresh semen ejaculates collected from healthy men. We found that AEBSF showed a dual contraceptive action where it effectively 1) prevented degradation of SEMG1 resulting in viscous semen and 2) decreased sperm motility in human semen samples. However, the impact of AEBSF on sperm motility and viability could be due to its inhibitory activity toward other serine proteases or simply due to its toxicity. Therefore, to determine whether inhibition of PSA activity alone could disrupt SEMG1 degradation and contribute to hyperviscous semen, a neutralizing PSA antibody was used. We found that PSA antibody effectively prevented SEMG1 degradation with a subtle impact on sperm motility. These findings suggest that the target inhibition of PSA activity can prevent proteolytic degradation of SEMG1 and block liquefaction process, resulting in hyperviscous semen. As it is currently unknown if blocking semen liquefaction alone could prevent pregnancy, it needs further extensive studies before drawing any translational conclusions.

Supplementation of Pandanus conoideus Oil in Cryopreservation Diluents for Maintaining the Semen Quality of Ongole Grade Bull

Antioxidants such as tocopherol, ß-carotene, and polyunsaturated fatty acids (PUFA) from red fruit oil of Papua may be used to protect frozen semen. The study is aimed to test the effect of red fruit oil supplementation on motility, viability, and recovery rate of frozen sperm of Ongole-grade bulls. Semen was collected twice a month from eight 4-5-year-old male Ongole grade using an artificial vagina, followed by macro- and microscopical evaluations. Collected semen was divided into four tubes and diluted with tris egg yolk diluents (TEY) as a control, TEY supplemented with 0.5% red fruit oil (RFO) (TEY RFO0.5), TEY supplemented with 1% RFO (TEY RFO1.0), and TEY supplemented with 1.5% RFO (TEY RFO1.5). The diluted semen was then packed into the straw and equilibrated for 2, 4, and 6 h prior to frozen on liquid nitrogen vapor for 10 minutes. The observed variables in this study were sperm motility, sperm viability, and morphology after equilibration, after thawing, and recovery rate. The experimental design is a completely randomized factorial design. The data were analyzed using ANOVA and were further tested using Duncan multiple range test. The results showed that the sperm motility of fresh semen was 81.10±1.42%. The percentage of sperm motility in TEY RFO1.5 treatment at 6 h equilibration was 60.00±1.06%, significantly higher compared to TEY RFO1.0 and TEY RFO0.5. The percentage of post-thawing sperm motility in TEY RFO1.5 treatment was 62.40±1.09%. The best post-thawing sperm viability in TEY RFO1.5 was 80.70±1.20%, significantly increase from the treatment of TEY RFO1.0 and TEY RFO0.5. The recovery rate (RR) for TEY RFO1.5 treatment had the best percentage at 76.94%. In conclusion, RFO supplementation in semen diluents for 2 h of equilibration resulted in the best motility and viability at 0 h of post thawing observation.

Individual Variation in Semen Characteristics of Murrah Buffalo Bulls

This study evaluated the variation in semen characteristics between two individual Murrah buffalo bulls. Two hundred and ninety semen samples were involved in this study. The results showed that most of the semen had a milky white color with moderate consistency. The Bull B1 tended to have higher proportion of creamy color and moderate consistency than the Bull B2. The ejaculatory volume is varied (P&lt;0.01) between Bull B1 and Bull B2. However, semen pH and sperm concentration of Bull B1 and B2 were equal (P&gt;0.05). The individual bull had a highly significant effect (P&lt;0.01) on sperm motility of fresh semen. The individual variation (P&lt;0.05) also found on sperm motility of before freezing. Whereas, sperm motility of post-thawing semen and recovery rate value were not significantly influenced (P&gt;0.05). Moreover, it was found that the frozen semen production differed (P&lt;0.01) between two individual bulls, with bull B1 had higher production than the bull B2. This study clearly demonstrates that the frozen semen production of Murrah buffalo is highly dependent on the individual bull. However, the variation in frozen semen production between two bulls studied here is still qualified to be used for artificial insemination.

Cryopreservation and quality assessment of boar semen collected from bulk samples

The purpose of this study was to examine sperm quality after cryopreservation of ejaculates collected as a bulk sample, which is routinely part of semen collection, and to compare this quality with the sperm-rich fraction in boars. Ejaculates were collected as sperm-rich fractions (SRF) and bulk samples (BE) using a gloved-hand technique. Fresh semen quality in terms of semen volume, sperm concentration, total sperm motility and pH were conventionally evaluated. Then, semen was cryopreserved using the liquid nitrogen vapour method. The post-thaw sperm quality was evaluated by assessing sperm motility, live sperm with normal apical ridge and high mitochondrial energy status, lipid peroxidation was evaluated using CASA and fluorescent multiple staining and MDA levels were determined using a spectrophotometer, respectively. In terms of fresh semen quality, sperm motility in fresh semen did not differ significantly between the two groups. The treatment with the greater mean volume (BE; P &amp;lt; 0.05) had a lower mean sperm concentration (P &amp;lt; 0.05); meanwhile, the mean ejaculate pH collected as BE was more basic compared with SRF (P &amp;lt; 0.05). However, there were no significant post-thaw quality changes between sperm-rich fractions and bulk samples of semen. In conclusion, ejaculates can be collected as bulk samples without the need to classify fractions for boar semen cryopreservation.

Missense mutation within cystic fibrosis transmembrane conductance regulator (CFTR) gene is associated with selected parameters of the frozen-thawed spermin Holstein-Friesian bulls

In our previous Genome-wise Association Study we found that Cystic Fibrosis Transmembrane Conductance Regulator gene (CFTR) is a candidate gene for sperm motility in fresh semen of Holstein-Friesian bulls. Since in cows thawed semen is commonly used for the artificial insemination (AI) we have decided to find out whether functional polymorphism within CFTR gene coding sequence is associated with selected parameters of thawed sperm, including their motility evaluated by computer-assisted sperm analysis (CASA), the activity of three antioxidant enzymes: glutathione peroxidase (GPx) catalase (CAT), superoxide dismutase (SOD), ATP content and integrity of sperm membranes. One hundred twenty Holstein Friesian bulls kept in uniform environmental conditions (one AI company) were included in the study. Significant associations between genotypes of missense mutation within exon 11 of the CFTR gene (Met468Leu) and the activity of antioxidant enzymes and sperm mitochondrial function were revealed. No effect of CFTR genotypes on sperm motility was observed. Significant differences in CAT and SOD activity were found between AA and TT homozygous individuals. Bulls with TT genotype had the lowest activity of both antioxidant enzymes. The same bulls also showed the lowest number of sperm with active mitochondria. Our results demonstrate that missense mutation Met468Leu within CFTR gene is associated with antioxidant enzyme activity and mitochondrial function of bovine thawed sperm without affecting their motility.

Candidates for reproductive biomarkers: Protein phosphorylation and acetylation positively related to selected parameters of boar spermatozoa quality

Protein post-translational modifications (PTMs) have been reported to be involved in various functions of sperm, yet the exact correlation between PTMs and sperm motility remains unclear. With the goal of contributing to this subject, motility variables were measured by computer-assisted sperm analysis system (CASA), and the amount of PTMs were evaluated using Western blot and immunofluorescence in fresh sperm and liquid stored sperm. Results of the present study indicate that the amount of the phosphorylated substrates of PKA (P-PKAs), protein tyrosine phosphorylation (PTP), global protein acetylation (Pan-Kac) and α-tubulin acetylation (Tub-Kac) was greater in sperm of fresh semen samples with relatively greater motility than in sperm of fresh semen samples with relatively lesser motility. Similarly, the amounts of phosphorylation and acetylation gradually decreased with the reduction in the motility of sperm in liquid stored semen samples. Interestingly, the P-PKAs (r = 0. 634, P < 0. 01) and Pan-Kac (r = 0. 380, P < 0. 05) were positively correlated with sperm motility in fresh semen, whereas only P-PKAs (r = 0.607, P < 0. 01) were positively correlated with sperm motility during liquid storage. Furthermore, it is noteworthy that the amounts of phosphorylation and acetylation were positively correlated with the acrosome integrity and mitochondrial membrane potential of fresh sperm and liquid stored sperm. This study is the first to explore the correlation between PTMs and sperm motility, and it may provide a new reproductive biomarker for evaluating semen quality and predicting sperm capacity for enhancing reproductive performance, which is meaningful for the pig breeding industry.

Supplementation of freezing/thawing media with GSK3 inhibitor alsterpaullone does not bypass the harmful effect of cryopreservation on boar spermatozoa

Frozen-thawed boar sperm have less motility and fertility capacity in comparison to fresh sperm. Glycogen Synthase Kinase 3 (GSK3) contributes to sperm motility in fresh semen. In addition, GSK3 inhibition in boar spermatozoa in fresh semen improves motility variables. The role of GSK3 on boar cryopreserved sperm, however, is still unknown. The hypothesis in the present study was that GSK3 pathway inhibition by alsterpaullone (AST) could result in enhancement of the quality of sperm afer cryopreservation. Two different strategies were evaluated: i) AST supplementation to the freezing medium (AST + Cryo); ii) AST supplementation after sperm thawing (AST + Thaw). Sperm motility was evaluated using the CASA system and different sperm quality variables were evaluated using flow cytometry, as well as amount of GSK3 phosphorylation of thawed spermatozoa after 30 and 90 min incubation at 38.5 °C. Results indicate that AST supplementation had detrimental effects on sperm viability (live spermatozoa) and mitochondrial membrane potential when it was added after thawing (P < 0.05) The AST supplementation after thawing, however, had a protective effect on plasma membrane lipid disorganization (P < 0.05). The percentage of motile spermatozoa was not modified by AST supplementation. Nonetheless, after 30 min post-thawing, STR and LIN variables (related to straightness of the movement) as well as the percentage of rapid lineal spermatozoa were increased with both AST supplementation protocols. The GSK3α phosphorylation was not modified through the incubation time in boar thawed sperm. In summary, results do not support the idea of adding AST to the cryopreservation/thawing medium to improve boar sperm quality after cryopreservation.

Freezing of rabbit semen after the addition of glycerol and dimethylsulfoxide in the extender

In this study, semen from 10 rabbits was frozen after it was diluted in two different extenders, A and B. Extender A consisted of Tris-buffer in which 20% of egg yolk and 3% of glycerol were added, while extender Β had the same composition, plus 3% of dimethylsulfoxide (DMSO). The semen of the buck exhibiting the best post-thaw motility in the two extenders, was used for the insemination of two corresponding groups (I and II) of 20 does each. The average sperm motility of fresh semen (77%) was significantly reduced (P&lt;0.05) after it was frozen in the extender A (47%) and Β (54%). The post-thaw sperm motility in extender Β was significantly higher (P&lt;0.05) than that in extender A. The percentage of the animals that gave birth in group II (60%) was increased compared to that of the animals in group I (50%), but not significantly (P&gt;0.05). Also, no significant difference (P&gt;0.05) was observed between the average litter size of group I (6,8±1,7) and group II (7,0±1,9). Thereafter, it is concluded that freezing rabbit semen in an extender that contains a combination of the cryoprotective agents glycerol and DMSO, in the proportion of 3% and 3%, respectively, results in a significant improvement of post-thaw sperm motility, while it doesn't affect significantly its fertility value neither the size of the litters.

Free gossypol supplementation frequency and reproductive toxicity in young bulls

The aim of the present study was to analyze seminal quality of young bulls subjected to different frequencies of gossypol supplementation. Forty-eight Nellore bulls, with 19 months of age and weighing 357.8 ± 7.2 kg, were used in this study. Animals were fed with 10.5 kg of standard supplement containing free-gossypol from whole cottonseed (WCS) at the following frequency: 3x/week (G3x), 5x/week (G5x) or 7x/week (G7x - Control). Additionally, a negative control was provided, and the treated animals received only mineral supplement (MM) ad libtum. The experiment lasted for 84 days and semen was collected at the beginning and at the end for analysis and cryopreservation. Fresh semen was used for initial analysis and plasma membrane integrity and sperm morphology were also determined. General motility using computer assisted sperm analysis (CASA), plasma and acrosomal membranes integrity, mitochondrial activity, and induced oxidative stress were assessed in post-thawed semen. The study design was completely randomized. Parametric data were analyzed by ANOVA and non-parametric data by the Wilcoxon test, using the statistical program SAS. Level of significance was set at 5%. Supplementation with WCS, regardless the frequency, increased total (P = .009) and head (P = .005) defects in comparison to animals receiving only forage and mineral supplement. Infrequent supplementation, particularly 5 times in the week (G5X), increased head (P = .026) and midpiece (P = .014) abnormalities. Sperm motility in fresh semen was lower in animals that received daily supplementation than those supplemented on alternate days (P = .021). Additionally, animals supplemented daily showed lower percentage of spermatozoa with intact acrosome compared to those supplemented on alternate days (P = .005). Thus, regardless the frequency of supplementation, free-gossypol supplementation affects sperm quality. Although the amount of free gossypol supplied weekly was the same among treatments, daily supplementation compromised sperm kinetics, differently from infrequent supplementation that led to sperm defects developed during spermatogenesis.

Quality parameters of fresh and cryopreserved whitefish (Coregonus lavaretusL.) semen

The aim of this study was to characterize the fresh and cryopreserved whitefish semen and to verify the usefulness of fresh semen parameters in order to qualify the cryopreserved semen. The relationship between DNA microsatellite genotyping and quality parameters of fresh and cryopreserved semen was also examined. Whitefish semen was characterized by high quality parameters values, mainly sperm motility and viability. After cryopreservation an intense decrease of the percentage of motile cells was noticed whereas viability decreased in a lower degree. Low regressions were found between quality parameters for both fresh and cryopreserved semen, except for the regression between the amplitude of lateral head displacement and curvilinear velocity. A significant but low regression was found between the percentage of heterozygotic microsatellite loci and the percentage of sperm motility of fresh semen and seminal plasma osmolality. Differences in sperm motility and linearity of cryopreserved semen between homozygotes and heterozygotes at locus Sfo-292A (P < 0.05) were noticed. The parameters of fresh semen demonstrated little usefulness for predicting the quality of cryopreserved whitefish semen. Genetic characterization of male whitefish by microsatellite variability seems to be a promising tool for the study of genetic background of male reproduction in fish.

Soy Lecithin Interferes With Mitochondrial Function in Frozen‐Thawed Ram Spermatozoa

Egg yolk and milk are the 2 major membrane cryoprotectants commonly used in freezing media for the long-term preservation of semen (alone or in combination with others). However, in recent years, there have been increasing arguments against the use of egg yolk or milk because of the risk of introducing diseases through the use of cryopreserved semen. In this study, we analyzed the protective effect of lecithin as an alternative to egg yolk for the cryopreservation of ram semen, using a range of functional markers for sperm viability, motility, apoptosis, and mitochondrial functionality analyses (mitochondrial inner membrane surface [MIMS], mitochondrial inner membrane potential [MIMP], and cell membrane potential) as methods of assessment in samples diluted in 3 different media: Tris-citrate-glucose as control and 2 media supplemented with soy lecithin or egg yolk. The results showed that lecithin was able to effectively protect certain sperm quality characteristics against freezing-induced damage. However, lecithin induced loss of mitochondrial membrane potential or mitochondrial loss that was not reflected by modifications in sperm motility in fresh semen. MIMS and MIMP values decreased in thawed lecithin-treated samples, concomitant with a lower (P < .05) percentage of total and progressively motile cells, compared with those in egg yolk-containing samples. Further incubation of thawed samples revealed changes in motility and mitochondrial functionality that otherwise would not have been detected. These results indicated that lecithin may have affected the inner mitochondrial membrane in frozenthawed spermatozoa and confirmed that sublethal damages that seriously affect sperm functionality, not detected by classic sperm quality analyses, can be evidenced by changes in the inner mitochondrial membrane surface. These findings strengthen the relationship between mitochondrial membrane potential and motility and show that the mitochondrial alterations induced by the cryopreservation process could be specific targets for the improvement of semen cryopreservation protocols.

Immunoactive relaxin in boar seminal plasma and its correlation with sperm motility

Relaxin in boar seminal plasma ( n = 43) was assayed by an homologous radioimmunoassay. The seminal plasma levels of relaxin averaged 1.1 ± 0.38 ng/ml (±s.e.). The relaxin concentrations in seminal plasma were correlated with sperm motility ( n = 32, r = 0.33, P < 0.05) and the transmembrane migration ratio ( n = 11, r = 0.81, P < 0.01) of boar spermatozoa. Relaxin levels in seminal plasma of Yorkshire ( n = 19), Landrace ( n = 5), Duroc ( n = 10), and Poland China ( n = 4) boars were 1.3 ± 0.07, 0.9 ± 0.13, 0.8 ± 0.13, and 0.7 ± 0.03 ng/ml (mean ± s.e.), respectively. Seminal plasma relaxin levels differed among these breeds ( P < 0.05). The results in this study indicate the presence of immunoactive relaxin in boar seminal plasma which shows high positive correlations with sperm motility of fresh semen.

Fertilizing capacity of equine spermatozoa stored for 24 hours at 5 or 20°C

A breeding trial was conducted to evaluate the effect of in vitro storage time and temperature on fertilizing capacity of equine spermatozoa. Semen obtained from one stallion and diluted with skim milk-glucose extender was used to artificially inseminate 45 estrussynchronized mares. The mares were assigned to one of three treatment groups (15 mares per group): 1) insemination with fresh semen (collected within 0.5 h of use), 2) insemination with semen stored for 24 h at 20°C or 3) insemination with semen stored for 24 h at 5°C. The mares were inseminated daily during estrus, from the detection of a 35-mm follicle until ovulation, with 250 × 10 6 progressively motile spermatozoa (based on initial sperm motility of fresh semen). Semen samples (n = 35) were evaluated prior to insemination for percentages of total sperm motility (TSM), progressive sperm motility (PSM) and sperm velocity (SV). Single-cycle 15-d pregnancy rates. resulting from insemination with fresh semen, from fresh semen stored for 24 h at 20°C or from semen stored for 24 h at 5°C were the same ( 11 15 ; 73%). Mean diameters (mm) of 15-d embryonic vesicles were not different (P>0.05) among these three treatment groups (21.5 ± 2.9, 19.6 ± 2.6 and 20.5 ± 3.6, respectively). Ten pregnant mares were aborted on Day 15 of gestation for use in another project. The pregnancy status of the 23 remaining pregnant mares was again determined at 35 to 40 d and 55 to 60 d of gestation. No pregnancy losses occurred during this time period. Mean TSM percentages were different (P<0.05) among the three groups: the fresh semen percentage was 89 ± 2, semen stored for 24 h at 20°C was 57 ± 11 and semen stored for 24 h at 5°C was 80 ± 6. Similar differences were found for mean PSM and SV. Semen storage at either 20 or 5°C for 24 h had no apparent effect on the fertilizing capacity of the extended semen samples; however, the reduction in all motility parameters tested was more dramatic in semen stored at 20°C than that stored at 5°C.

Relationship between scrotal circumference and semen parameters in crossbred bulls

The relationship between the scrotal circumference and semen volume, sperm concentration and number of sperm per ejaculate of 12 crossbred bulls [4 Local × Friesian, 4 Local × Sahiwal] was studied. Semen of three consecutive collections at seven day intervals was evaluated. The age of bulls at first collection varied between 15 and 20 months. Soon after collection, volume, sperm concentration, number of spermatozoa per ejaculate and initial sperm motility of fresh semen were measured. Scrotal circumference was correlated with semen volume, sperm concentration and number of spermatozoa per ejaculate in both groups. A significant (P&lt;0.04) positive correlation (r = 0.72) was observed between scrotal circumference and volume of semen, and between scrotal circumference and number of sperm production per ejaculate. Significant (P&lt;0.05) variation was observed in different semen parameters between bulls within the same group, but no significant (P&gt;0.05) variation was found between the two groups. It is suggested that crossbred bulls aged 18 months or over, with scrotal circumference more than 30 cm, yielded good quality semen. DOI: 10.3329/bvet.v26i2.4952 Bangl. vet. 2009. Vol. 26, No. 2, 61-67