Evaluation of predictive ability of linear type gonadal traits on reproductive capacity of breeding dairy bulls.

Dimensions of linear type traits facilitate selection of livestock for breeding and rearing. To date, use of linear type traits for selection of breeding bulls is highly concentric to scrotal circumference (SC), with probable overlook to other important traits. Present study reported the importance of various gonadal linear type traits on spermatozoa production, age-related changes in gonadal linear type traits of bulls and predictive ability of these traits on bulls' reproductive potentials. Among all gonadal traits, testicular density (TD), scrotal volume (SV), paired testicular weight (PWT) and SC were found most important predictor variables in order, which can discriminate between good/poor breeding bulls, that is, produced frozen semen doses (FSD) or not. Dimensions of gonadal traits increased significantly up to 36 months age and thereafter, development became slow and negligible. In contrast, TD decreased by 30%, 51%, 64%, 68% and 71% at 12, 24, 36, 48 and >49 months age, respectively, from its base value at 6 months. Bulls of lower TD (≤0.88 g/cm3) had significantly higher ejaculate volume (+9%), sperm motility, sperm concentration (+100 million/mL) and sperm output (+26%)/ejaculate as compared to bulls of higher TD (>0.88 g/cm3). Discriminant function was developed using TD, SV, PWT and SC to identify bulls of superior reproductive potentials. It was concluded that among the investigated traits, TD was the strongest to discriminate between FSD and Non-FSD bulls. Therefore, our findings suggested that TD could be more potential trait than SC for dairy bulls' breeding soundness evaluation and assessment of reproductive ability.

Association between sperm morphology and sperm count of boar semen.

The number of spermatozoa in the ejaculate is important for its quality and that of the sperm contained in it. The number of ejaculated spermatozoa is also associated with sperm dimensions. The aim of this study was to assess the morphological structure of sperm and the frequency of morphological abnormalities in sperm on the ejaculation performance of boars, measured as the total number sperm per ejaculate. The study was conducted using 648 ejaculates collected from 31 Large White boars and 30 Landrace boars. All ejaculates were analysed for basic physical characteristics and the frequency of sperm with morphological abnormalities. In addition, morphometric measurements of the sperm were made and used to calculate their shape indexes. As a result of our study it was noted that sperm from ejaculates with the most spermatozoa have shorter heads with a smaller area than sperm from ejaculates with a small or intermediate number of spermatozoa. Landrace boars produce semen of better quality, with a smaller percentage of sperm with major abnormalities, and the differences between the breeds increase with the number of spermatozoa in the ejaculate. The sperm from Landrace boars have larger heads and longer flagella than the sperm from Large White boars. The differences in sperm dimensions between breeds decrease as the total number of spermatozoa in the ejaculate increases. The number of spermatozoa in the ejaculate was shown to influence the dimensions of the sperm. The effect of the number of ejaculated sperm on ejaculate characteristics and sperm morphology depends on the breed of the male.

Genetic analysis for semen quality traits in buffalo bulls.

This study was attempted to estimate the genetic parameters of semen quality traits in buffalo bulls. The study data consisted of 10975 ejaculates from 45 Murrah buffalo bulls (aged 24-72 months) used for breeding program during year 2010 to 2020. Semen quality traits (ejaculate volume, concentration of sperm, mass activity, initial and post-thaw motility, number of sperms per ejaculate, motile sperm number and discard rates) were studied. It was observed that average ejaculate volume was 2.82 ± 1.45 mL with mean concentration of 1040.12 ± 523.26 million/mL. Higher heritability was observed for number of sperms per ejaculate, number of motile sperm and sperm concentration. Significant phenotypic correlation was obtained between volume and number of sperms per ejaculate as well as volume and number of motile sperms. Likewise, significant phenotypic correlation was evident between sperm concentration with sperm number per ejaculate. Highest phenotypic correlation was obtained between sperm count per ejaculate and motile sperm count. Estimated genetic trends showed significant change in volume and motile sperm number. In conclusion, this study ascertains that genetic parameters of semen traits can be considered during the selection of buffalo bulls in breeding program.

Evaluation of sperm and hormonal assessments in Wagyu, Nellore, and Angus bulls.

Wagyu bulls are known to have a highly exacerbated libido, as shown by the intense sexual interest of young calves. Therefore we believe that Wagyu male animals have specialized Sertoli and Leydig cells that are directly involved with the sexual precocity in this breed as mature bulls have a small scrotal circumference. This study aimed to evaluate whether there were differences in the hormone and sperm characteristics of Wagyu bulls compared with the same characteristics of subspecies Bos indicus and Bos taurus sires. Frozen-thawed semen from Wagyu, Nellore, and Angus sires were analyzed for sperm kinetics (computer-assisted sperm analysis), plasma membrane integrity, chromatin integrity, acrosome status, mitochondrial activity, lipid peroxidation and hormone [luteinizing hormone (LH) and testosterone] serum concentration. The results showed that Wagyu had lower total motility and an increased number of sperm with no motility when compared with Nellore and Angus bulls. Wagyu breed did not differ from those breeds when considering plasma and acrosome membranes integrity, mitochondrial potential, chromatin resistance, sperm lipid peroxidation or hormone (LH and testosterone) concentrations. We concluded that Wagyu sires had lower total motility when compared with Nellore and Angus bulls. Wagyu breed did not differ from these breeds when considering plasma and acrosome membranes integrity, mitochondrial potential, chromatin resistance, sperm lipid peroxidation, or hormone (LH and testosterone) concentrations.

Sperm concentration of boar semen doses and sperm quality: Novel perspectives based on the extender type and sperm resilience.

This study evaluated the effect of sperm concentration of boar semen doses on their capacity to maintain its motility over the thermo-resistance test (TRT; sperm resilience) and verified if the extender type (short or long-term) could influence this effect. Thirty ejaculates from five crossbred mature PIC® boars were used, and a factorial design was followed to produce semen doses with 1.5 billion cells in 45 or 90 mL, using Beltsville Thawing Solution (BTS) or Androstar® Plus (APlus). Then, low-concentration doses (16.7 × 106 cells/mL in 90 mL) and higher-concentration doses (33.3 × 106 cells/mL in 45 mL) with BTS or APlus were produced and stored at 17 °C for 168 h. At 72 h, during the TRT, the low-concentration doses (16.7 × 106 cells/mL) lost three-fold less motility than doses with 33.3 × 106 cells/mL (P < 0.01), regardless of the extender type (11. 5% vs. 30.5% of initial motility, respectively). Similar results were found when the TRT was carried out at 168 h, with low-concentration doses losing two-fold less motility (11.4%) than highly concentrated doses (25.9%; P < 0.01). No sperm concentration effect was observed on membrane integrity or mitochondrial membrane potential (P ≥ 0.23). The osmolarity was not affected by the sperm concentration (P = 0.56), only by the extender and the storage time (P < 0.01). In conclusion, the sperm concentration effect on sperm quality was not influenced by extender type, and the data suggest that a low concentration of semen doses positively affects sperm resilience.

Impact of inbreeding and genetic parameter estimates for seminal traits in Lusitano horses.

The objectives of this study were to establish baseline information for seminal traits in Lusitano stallions, to assess the impact of inbreeding, interval between collections and age on semen quality during the breeding and non-breeding seasons, and to estimate the corresponding genetic parameters. A total of 2129 ejaculates by 146 Lusitano stallions used for artificial insemination, obtained from four equine reproduction centers distributed throughout Portugal, over a period of 14 years (2008-2021), were included in the study. The seminal traits analyzed, and the corresponding means and standard deviations, were gel-free volume (56.95 ± 28.76 mL), concentration (186.48 ± 104.68 × 106), motility (64.1 ± 16.9%), total number of spermatozoa (TNS) (9.271 ± 4.956 × 109) and total number of motile spermatozoa per ejaculate (TNMS) (5.897 ± 3.587 × 109). These results are in the normal range of values described for other breeds. In the stallions analyzed, the mean value for the inbreeding coefficient was 7.93 ± 5.29%, and for age it was 12.70 ± 6.83 years. A significant decline in sperm concentration, motility, TNS, and TNMS was observed as inbreeding increased. The season also influenced sperm concentration, motility, TNS and TNMS, with the highest values observed during the breeding season. When considering the impact of age on Lusitano seminal parameters, results showed a nonlinear relationship, with a positive effect until 18 years of age for volume, motility, TNS and TNMS and a negative effect after this age, with a slow decrease. However, age had a markedly negative effect on sperm concentration. The interval between semen collections only affected (P < 0.05) sperm motility, with a regression coefficient of +1.89 ± 2.17% per additional day. Genetic parameters were estimated with an Animal Model, and the estimated heritability (repeatability) was 0.27 (0.35) for volume, 0.02 (0.38) for sperm concentration, 0.24 (0.44) for motility, 0.29 (0.39) for TNS and 0.41 (0.41) for TNMS. These results suggest that it is possible to improve semen quality by selection and that the properties of semen produced by a stallion tend to remain consistent throughout its lifetime. Furthermore, the impact of inbreeding should be taken into consideration when selecting Lusitano stallions for fertility.

Effects of heat stress on sperm quality of French Bulldogs.

This study aimed to evaluate the effects of heat stress (HS) and its duration on semen quality, serum testosterone, pulsatility and resistibility index of the testicular artery of French Bulldogs. Eight male French Bulldogs, 3-7 years old, 12.63 ± 1.8 Kg were adapted and trained for two months. Room temperature was 21 °C. Semen was collected by digital stimulation. The median of four andrological evaluations was T0. Heat was applied to the scrotum using an electrical heat pad at 40 °C for 11 min. Rectal temperature (RT) and scrotum temperature were evaluated using a mercury thermometer and an infrared thermography camera before and after HS. Semen was evaluated immediately (T1) and after seven (T7), 14 (T14), 21 (T21), 28 (T28) and 60 (T60) days after HS. Semen parameters included macroscopic (volume, color and viscosity) and microscopic (sperm motility and vigor, percentage of morphologically normal or defected spermatozoa, sperm concentration and total number of sperm cells) aspects. A pulsed colored doppler ultrasound was performed on the testicular artery at the spermatic cord and epididymis region before and immediately after HS. Serum testosterone was analyzed before, 48 and 96 h after HS. Data was analyzed by ANOVA using SAS. There was a 1.23 °C increase on RT and a 4.98 °C increase on thermograph after HS. Sperm motility decreased at T1 (P < 0.05) and tended to stay lower at T7 (P = 0.056). It improved at T14, but reduced again at T21 (P < 0.05). At T28 and T60 motility was normal. Vigor was lower at T1 (P < 0.05), normal at T7 and T14, but decreased at T21 (P = 0.054), at T28 and T60 it was not different than T0. Sperm concentration was lower at T1 (P < 0.05) and not different from T0 at other timepoints. Volume color and viscosity were not different. Total sperm per ejaculate was reduced at T1 and T7 (P < 0.05) and tended to be lower at T14 (P = 0.057). T21, T28 and T60 were not different than T0. There was a decrease in normal sperm cells and an increase in defected sperm at T7. There was no difference within T14, T21, T28 and T60. The raise in pathologies at T7 was from an increase in minor defects (P < 0.05). There was no difference in serum concentration of testosterone nor pulsatility and resistivity index before and after HS. In conclusion, induction of HS directly to the testis reduces sperm quality in French Bulldog. This impairment is immediately and transitory.

Age-dependent genetic and environmental variance of semen quality in Nordic Holstein bulls.

The aim of this study was to estimate genetic and environmental parameters, across bull's age, for semen quality traits including pre- and postcryopreservation semen concentration, sperm motility, and sperm viability as well as ejaculate volume and number of doses per ejaculate. A data set on 96,595 ejaculates from 2,831 Nordic Holstein bulls collected between 2006 and 2019 was used. Genetic and environmental parameters were estimated using a random regression model and applying the average-information REML approach. Spline functions were chosen to fit the additive genetic and permanent environmental effects across bull's age, and the optimal number of knots was chosen using cross validation. Residual variance heterogeneity was assumed in different bull age classes. The estimated repeatabilities of semen quality traits ranged from 0.16 to 0.85 across different ages of bulls. The estimated heritabilities of semen quality traits ranged from 0.02 to 0.56 across different ages of bulls. The results indicate possibilities for genetic improvement of semen quality traits through selective breeding.

The use of machine learning methods to predict sperm quality in Holstein bulls.

The aim of this study was to develop prediction models for total sperm motility, morphological abnormalities and sperm output based on 1,551 ejaculate records of 58 Holstein bulls. The data was collected from September 2019 to November 2020 in a single artificial insemination (AI) center located in Eastern Germany. Factors considered for the prediction models include barn climate conditions, semen collector, number of false mounts, libido, semen collection frequency, breed and age (10-74 months). In this study, the prediction models Lasso, Group Lasso and Gradient Boosting were evaluated. The best model for each sperm quality parameter was chosen using cross validation. The models were estimated with five algorithms for sperm motility and sperm morphology and three algorithms for the number of total sperm per ejaculate (sperm output). For sperm motility and morphology a binary classification algorithm was applied, reaching an accuracy of over 80% for all models. For sperm output, no such classification was used and the only variable selected by all three algorithms was age. Furthermore, for sperm morphology, climate variables were frequently selected. Additionally, network diagrams from Group Lasso show the interdependencies between the major variable groups influencing sperm motility and morphology. In conclusion, the implementation of such prediction tools could help AI centers to optimize management factors and stabilize bull semen production in the future.

Exploring the metabolome of seminal plasma in two different horse types: Light versus draft stallions.

The application of the 'omics' studies in the field of animal reproduction has been aimed at identifying novel biomarkers of fertility since the last few years. When assessing reproductive efficiency in horses, breed should also be taken into account as it can influence semen quality and fertility. Considering the growing interest in metabolomic analysis to evaluate male fertility, we aimed to investigate the metabolomic profile of seminal plasma in two different horse breeds. Twelve healthy stallions, n.6 American Quarter Horse (AQH) and n.6 Italian Draft Horse (IDH) stallions, regularly used for artificial insemination, were included in the study. Two semen collections, performed 30-day apart, were considered for the assessment of semen parameters including gel-free volume, spermatozoa (spz) concentration, spz progressive motility and seminal plasma analysis by 1 H-NMR.Semen characteristics differed between IDH and AQH (p < .05) as well as the first cycle conception rate that was higher in AQH than IDH (p = .001). Metabolomic analysis quantified 56 molecules in equine seminal plasma, with 11 metabolites showing different concentrations in IDH compared to AQH (p < .05).This study provided evidence of differences in seminal plasma metabolites' concentrations between studied horse types, highlighting specific metabolomic fingerprints characterizing AQH and IDH sperm.

The benefits of Maca (Lepidium meyenii) extract administration for male rabbits affected by environmental heat stress.

Heat stress (HS) is the most substantial environmental issue in rabbit health status impairment, which can lower productivity. Maca is a common medicinal plant with important biological activities including antioxidant, anti-inflammatory, anti-fatigue, and neuroprotective effects. The present research explored the alleged protective role of Maca extract in alleviating the adverse impact of HS on rabbits. Growing V-line 6-week-old buck rabbits (N = 48) were orally administered Maca extract at levels of 0 (MAC0), 200 (MAC2), 400 (MAC4), or 600 (MAC6) mg/head twice per week. Compared to the control groups, rabbits provided Maca had better growth performance, feed intake and feed conversion ratio. Liver and tests weights were significantly higher (p < 0.05) in Maca treated groups compared to the control. hemoglobin, white blood cell, red blood corpuscles, platelet count, hematocrit, and lymphocytes were significantly increased in the MAC4 group compared with the control group. MAC4 treatment significantly reduced aspartate aminotransferase and malondialdehyde levels compared with other groups. Moreover, the concentrations of total bilirubin, creatinine, glucose, total cholesterol, and triglycerides were lower (p < 0.05) in the MAC4 group than in the controls. Oral administration of Maca improved cortisol and testosterone values, total antioxidant capacity, and superoxide dismutase. The MAC4 group exhibited significant improvement (p < 0.05) in sperm motility, survival, membrane functionality, concentration, and libido, with a significant decrease in abnormal sperm compared with the control group. Also, aforementioned group showed sperm cells with a normal structure and intact plasma membranes, acrosomes, and well-organised axonemal components. Histopathological screening of liver sections showed moderate to severe degenerative and necrotic changes in rabbits exposed to HS, which were alleviated with Maca oral administration. In conclusion, oral administration of Maca extract at 400 or 600 mg/head-weekly enhanced growth performance, hemato-biochemical attributes, antioxidant status, and semen quality in rabbits during the hot season.

Genetic evaluation of semen production potential in Indigenous bulls using random regression models in a Bayesian framework.

Genetic potential of indigenous bulls with respect to semen production traits over the age of the bulls at semen collection was analyzed using random regression models (RRMs). Data pertaining to 59,641 ejaculates from 189 bulls of 18 indigenous breeds collected from BAIF (Bharatiya Agro Industries Foundation) was utilized for this study. Six semen production traits, viz., ejaculate volume (EV, ml), sperm concentration (SC, 109/ml), initial sperm motility (ISM, %), post-thaw motility (PTM, %), the total number of spermatozoa per ejaculate (TNS, 109/ejaculate), and the theoretical number of semen doses (TNSD) were studied. Univariate and RRM were used to obtain variance components and genetic parameter estimates. Two hundred thousand Gibbs samples were generated for each trait with a burn-in of 20,000 and thinning interval of 50 in a Bayesian framework. Legendre polynomials with orders of fit up to 5 for additive and permanent environmental effects were used. RRM modeled the heritability and repeatability for all ages between 3 and 10 years (productive lifespan). Heritability estimates ranged from 0.18 to 0.36, 0.18 to 0.45, 0.02 to 0.06, 0 to 0.001, 0.09 to 0.32, and 0.14 to 0.42 while the repeatability estimates ranged from 0.41 to 0.72, 0.36 to 0.79, 0.04 to 0.10, 0 to 0.001, 0.37 to 0.56, and 0.32 to 0.57 for EV, SC, ISM, PTM, TNS, and TNSD, respectively. Variability of estimates over the age of the bulls obtained through RRM could be useful to further refine the breeding program for age at selection, deciding the production period and age at culling.

Birthweight leads to seminal and testicular morphofunctional commitment in sexually mature boars.

Given the importance of males as semen donors for artificial insemination (AI) and the high incidence of low birthweight piglets at commercial farms, the impact of birthweight on fertility in boars deserves special attention. The aim of this study was to evaluate testicular morphofunctional parameters and semen characteristics in different birthweight boars. Forty littermate males were selected at birth and divided into two experimental groups, according to birthweight: high (HW, birthweight ranging from 1.80 to 2.15 kg, n = 20) and low (LW, birthweight ranging from 0.75 to 1.10 kg, n = 20). At 170 days of age, a sub-set of 24 littermate boars (n = 12 HW and n = 12 LW) were randomly selected for semen collection, which was performed once a week, at a 15-day interval, during five weeks. At 300 days of age, boars were orchiectomized, and the testis processed for histological and molecular analyses. The HW group was heavier and presented larger testes compared to LW animals (P < 0.05). Despite that, birthweight did not significantly affect semen volume or sperm quality parameters (concentration, motility, vigor or morphology), although LW boars produced 38.2% fewer total sperm and 24% lower semen concentration, leading to 36.8% less inseminating doses. The histomorphometrical evaluation showed that seminiferous tubules diameter and germinal epithelium height were similar between experimental groups. However, LW boars presented shorter seminiferous tubules and, consequently, fewer Sertoli cells per testis (P 0.05). Even though plasma testosterone levels were equivalent in both birthweight groups, LW testis presented less androgen receptors (P < 0.05). Additionally, birthweight was positively correlated with total seminiferous tubule length and number of Sertoli cells (P < 0.01), and with body and testis weights (P < 0.01). Taken together, even though adult LW boars showed no evident semen pathologies or spermatogenesis commitment, mature HW males have the potential to produce more spermatozoa, consequently more semen doses per ejaculate, being more valuable to an industry that relies on AI.

Longitudinal genetic analysis of semen production traits in Holstein bulls according to a random regression animal models on age.

Here we used random regression animal models (RRAMs) to investigate genetic change over age in the semen volume (VOL) and sperm concentration (CON) of Holstein bulls. We used 35,294 collection records from 1284 Holstein bulls and their 4166 pedigree records. The models included year and month of collection, collection place, collection method, and number of collections attempted for each day and month of age (second-order regressions) as fixed effects; technician as a random effect; and additive genetic and permanent environment as random regressions (first-order regressions). We examined two RRAMs with homogeneous and heterogeneous residual variances (RRAM1 and RRAM2, respectively). By using RRAM1, heritability for VOL and CON increased from 0.08 to 0.61 and 0.18 to 0.57, respectively, between 10 and 126 months of age. By using RRAM2, heritability for VOL increased from 0.11 to 0.28 between 10 and 24 months of age for young bulls and increased from 0.08 to 0.48 between 25 and 126 months of age for mature bulls; heritability for CON ranged from 0.18 to 0.19 for young bulls and increased from 0.10 to 0.48 for mature bulls. Posterior genetic correlations between young ages and older ages were strongly positive for VOLs but weak for CONs.

Association of linear type pelvic traits with testicular characteristics and reproductive capability of breeding dairy bulls.

Associations of pelvic linear type traits (PLT) on production and reproduction of cows were widely documented; in contrast, importance of PLT on bulls' reproductive ability, semen quality, semen cryo-preservability, frozen semen doses (FSD) production etc. was inadequately reported. The present study was conducted on Frieswal bulls (N = 378, age: 6-91 months, m) to assess age-wise growth dynamics of pelvic dimensions, classifying age into 6 groups (6 m, 7-12 m, 13-24 m, 25-36 m, 37-48 m, >48 m). Iso-age group bulls' (N = 100; 25-36 m) records were analysed after classifying seasons (summer/rainy/winter) of semen collection, if pelvic morphometric traits had any practical associations with testicular traits, semen quality and FSD production or not. A discriminant function was developed based on PLT, which showed poor predictive ability to distinguish FSD/non-FSD category bulls. Age significantly influenced growth and dimensions of gonadal and external pelvic morphometry traits. The dimensions of PLT increased at higher rate up to 36 m age and thereafter enhancement became insignificant. Pelvic linear type traits were positively (p < .01) associated with testicular/scrotal traits. Among PLT studied, pelvic triangle area (PTA) was the strongest discriminating variable to distinguish between good and poor breeding bulls. Bulls of larger PTA (≥1000 cm2 ), at average 30 m age, produced relatively inferior-quality semen, viz. lower volume (-3%), sperm concentration (-48 × 106 /mL), motility, semen quality index, total sperm counts/ejaculate (-601 × 106 ), motile sperm counts/ejaculate (-474 × 106 ) and total post-thaw motile sperm counts (-226 106 ), than bulls of lesser PTA (<1000 cm2 ). It was concluded that external PTA could be a useful addition to the bulls' breeding soundness evaluation.

Seasonal semen quality of a local and commercial taurine cattle breeds, raised in a subtropical climate: Relationship between external morphology of the animals and climate.

Livestock production is considered an important factor influencing global warming; however, climate change has also been considered one of the major factors affecting livestock production and reproduction. The present study was carried out in the Southern region of Brazil and aimed to assess the seasonal influence of climatic factors and external morphology of the animals on the semen quality. Three ejaculates were obtained from each bull (Crioulo Lageano and Angus) in summer and winter seasons. Motile cells, sperm vigor, sperm concentration, sperm membrane status, and sperm abnormalities were analyzed in fresh and post-thawed semen. In addition, the sperm kinetics using CASA was assessed on post-thawed semen. Environmental data such as air temperature (AT), relative humidity (RH), mean radiant temperature (MRT) and temperature-humidity index (THI) were measured. Furthermore, body and testicular metrics, as well as hair coat characteristics, were recorded in each season on all bulls. Environmental traits differed significantly between seasons. Results of the PLS regression and Spearman's correlations confirmed a negative relationship between climatic variables and sperm traits in both seasons. Semen quality between breeds and seasons was similar, satisfactory, and heat stress was not sufficient to impair spermatozoa viability. External morphological traits were considered non-important in the final model. The findings of this study suggest that AT, MRT, and THI were the most important factors that could affect seminal characteristics of bulls raised in a subtropical climate.

Semen characteristics of ganders kept as genetic resources conservation programme.

The creation of genetic reserves of domesticated animal species and breeds almost become a necessity in the recent years, but there is a question what is the value of semen of males kept ex situ in vivo as gene conservation flocks. Presented studies assessed the response to semen collection by dorso-abdominal massage and the quantitative and qualitative semen characteristics of six goose breeds (Pomorska, Garbonosa, Kuban, Landes, Roman and Slovakia) covered by the genetic resources' protection programme. Fourteen semen collection attempts were performed per male. In each breed there were ganders with low and high sensitivity to massage. The most positive reactions were stated in Pomorska ganders (67.9%) and the least in Kuban breed (52.60%). Individual male evaluation showed that only in three breeds (Pomorska, Garbonosa and Kuban) there were individuals showing 100% susceptibility to semen collection, in some breeds only one to four positive reactions (ending with ejaculation) were noted. Results obtained indicated breed and male effect on analysed semen traits, with the exception of sperm motility. The highest number of live normal sperm (44.2% on average), sperm concentration (530 × 106 ml-1 ), the highest Semen Quality Factor (92.9) and sperm motility (50.30%) were found in semen of Kuban ganders, while the lowest values of these traits (28.7%; 230 × 106 ml-1 ; 11.4 respectively) in Slovakia ganders. The lowest sperm motility (38.3%) was observed in ganders of Roman breed, but comparing to the other breeds existing differences were not significant. Significant differences in sperm morphology between individual ganders were also observed.

Comparison of two staining techniques on the manual and automated canine sperm morphology analysis.

Detailed and direct analysis of semen, including sperm morphology, enables a diagnosis of male fertility. This study aimed to describe an economical and verified protocol for canine spermiograms and compare the effectiveness of Sperm Stain® and Sperm Blue® (Microptic, Spain) in veterinary practice. Sperm assessment was conducted manually, using a standard optical microscope, and via computerized semen analysis using the SCA® CASA (Sperm Class Analyzer® CASA System-MICROPTIC, Spain). This study showed that Sperm Blue® is a better solution for computerized sperm quality analysis of healthy dogs. At the same time, Sperm Stain® turned out to be more helpful in identifying specific morphological defects of sperm. Automated canine sperm morphology analysis worked better with Sperm Blue stain, but Sperm Stain simplified manual evaluation of various organelles' defects. Standard, manual examination is more error-prone for an inexperienced andrology technician, but it seems to be still a gold standard technique for canine sperm assessment.

The effects of female-male friendships on male postcopulatory levels of oxytocin and vasopressin, and sperm parameters in Macacaarctoides.

Male and female stump-tailed macaques (Macaca arctoides) form close relationships akin to human friendships. Oxytocin and vasopressin modulate these and other social relationships and reproductive behavior and physiology in various mammal species. Besides the behavioral effects of oxytocin, this hormone plays an essential role in the ejaculatory process, favoring sperm transport upward the female reproductive tract. Therefore, we investigated the influence of friendships on postcopulatory serum levels of oxytocin and vasopressin in the stump-tailed macaque (Macaca arctoides). In addition, we searched for a correlation between this kind of social relationship and sperm transport in the vagina during the periovulatory and luteal phases. Six female and six male adult macaques having different friendship indices served as experimental animals. Allocated in 57 mating pairs combinations, these animals were allowed to copulate once in the luteal and periovulatory phases. Blood samples were collected from each animal finishing copulation to measure oxytocin and vasopressin. Afterward, we profoundly sedated the females and collected three semen samples from the vagina every 10 min to perform spermatobioscopies. Males' post-copulation oxytocin values increased along with the friendship index, while vasopressin behaves oppositely. Sperm concentration and immotile and motile sperm decreased from one sample to another as male-female closeness increased. Finally, in the periovulatory phase, only in the first vaginal sample, sperm velocities significantly increased with friendship indices. Our results showed that in stump-tailed macaques, heterosexual friendships promote higher postcopulatory oxytocin concentrations and better physiological conditions to males, which probably enhance reproductive success.

Genetic evaluation of semen traits in Friesian bulls raised in Egypt.

A total of 14696 semen records were collected from Friesian bulls, kept at International Livestock Management Training Center belonging to Animal Research Institute, Ministry of Agriculture, Dokki, Cairo. Traits studied were volume, motility, livability and sperm concentrates in other to construct selection indexes by using all combination between different traits of semen to improve semen traits in a herd of Friesian bull cattle. Data were analysed by using four traits repeatability model and includes effects of the following fixed factors: the age of animal at semen collection, the combined effect of the month and year of semen collection, and the number of times semen were collected per month. Semen motility, volume and livability were highly influenced (p < 0.001) by all the fixed factors. Heritability estimates for semen traits were moderate and ranged from 0.29 to 0.33. All phenotypic and genetic correlations between different traits are positive and ranged from 0.09 to 0.67 for phenotypic correlations and from 0.02 to 0.68 for genetic correlations, while permanent environmental correlations ranged from -0.69 to 0.12. Estimated Breeding Values ranged from -0.68 to 0.78 ml for semen volume, from -13.17 to 7.34% for motility, from -259.42 × 10-6 to 239.64 × 10-6 for concentrates and from -6.83 to 6.09% for livability. Eleven selection indexes were calculated, selection Indexes not including livability showed a reduced accuracy. This study demonstrated that selection index (I3) which includes sperm volume, motility and livability or selection index (I8) which includes sperm volume and livability are the best and both are recommended for Friesian bulls' selection.