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1.
The objectives of this study were to evaluate the effects of season in southeast of Brazil comparing genotypes on semen characteristics, freezability and peripheral plasma concentrations of testosterone. Ejaculates of five Bos indicus bulls and six Bos taurus bulls were evaluated over a period of 27 months, which was divided into winter (July, August, September), spring (October, November, December), summer (January, February, March) and autumn (April, May, June). Semen was evaluated according to standard procedures for ejaculate volume, sperm concentration, gross-motility, progressive motility and sperm morphology. After preparing and freezing the ejaculates according to commercial procedures, the straws were stored in liquid N2 until post-thaw evaluation. Ejaculate volume, sperm concentration, gross-motility, progressive sperm motility, vigor and morphological sperm defects were significantly influenced by season and genotype (p < 0.05). Heat tolerance was better in B. indicus bulls than in B. taurus bulls characterized by lower values of sperm abnormalities throughout the observation period. The highest values were recorded for abnormal heads followed by cytoplasmatic droplets in B. taurus bulls. The proportion of ejaculates which were eliminated before freezing for reasons of bad quality was lower in the B. indicus bulls. Temporal changes in peripheral plasma testosterone concentrations were higher in B. indicus bulls than in B. taurus bulls not revealing seasonal influences. The results of this study show clear genotype differences regarding semen quality. Freezability of B. taurus semen varies considerably throughout the year, leading to a high proportion of eliminated ejaculates. Collecting semen from B. taurus bulls during the summer in an artificial insemination centre may not be profitable.  相似文献   

2.
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   

3.
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   

4.
The consequences of the use of swirl assessment at a bovine artificial breeding centre were studied. Data relating to the amount of semen discarded, fertility of accepted semen, the relationship between discard rates and age of bull and ejaculate number have been presented. The overall differences in fertility between semen with swirl ratings, 5, 6 and 7 were very small. About 50% of all ejaculates collected in the period considered were discarded at the first inspection. The discard rate tended to be greater in young and in older bulls. The discard rate was significantly greater (P less than or greater to 0.001) for second ejaculates. It was considered that a proportion of rejected semen may have been of good fertility. Semen wastage after freezing was low.  相似文献   

5.
Contents Investigations on 3432 ejaculates from 57 A. I. sires showed that there were practically significant relations between semen traits and conception rate only between bulls but not within bulls. Therefore the first five ejaculates already provided a satisfactory estimate of the fertility of normal A. I. bulls. The conception rate could be estimated by five examinations with an accuracy of R = 0.65 and by 60 examinations per bull with an accuracy of R = 0.70.  相似文献   

6.
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   

7.
Sixteen bulls ranging in age from 2 to 11 years were experimentally inoculated with bluetongue virus to investigate the frequency and duration of seminal shedding of the virus. All bulls developed typical viremia, lasting 21 to 58 days, and they seroconverted 2 to 3 weeks after inoculation. Virus isolation was attempted from a total of 232 ejaculates, 163 (70%) of which were collected during the period of viremia. Bluetongue virus was not isolated from any of the ejaculates collected from 11 of the 16 bulls. Virus was isolated from 9 of 52 ejaculates collected from the other 5 bulls during the period of viremia. In no instance was virus isolated from semen without concurrent isolation from blood.  相似文献   

8.
Conservation decisions based on neutral genetic diversity have been observed to promote retention of useful quantitative variation in biological populations. An experiment was undertaken to determine the association between microsatellite marker polymorphisms and phenotypic variation in semen production and cryosurvival traits in bulls. Thirty-five ejaculates were collected from ten bulls of two breeds and evaluated before and after cryopreservation for several semen traits. The bulls were also genotyped using a set of sixteen bovine-specific microsatellite marker loci. Fixation indices (FST), heterozygosity and Nei's genetic distance measures were computed from allele frequency data for each of the bulls. Molecular and phenotypic data were used to compute tri-distance matrices for the ten bulls and correlated using Mantel's test in GenAIEx 6.5. The study revealed extensive heterogeneity in semen traits, heterozygosity and FST values among the bulls. Large pairwise phenotypic and genetic distances were also observed. Correlation between pairwise genetic distances and phenotypic distances was significant and highly positive for sperm viability (r = .61, p < .001) and moderately positive for sperm motility (r = .40–42, p < .05) variables. For sperm morphology, ejaculate volume and sperm concentration, correlation with genetic distances was positive, low and not significantly different from zero (p > .05). A tendency for a triangular-shaped relationship between genetic and phenotypic distances for post-thaw motility and viability traits was also observed. Accordingly, association with neutral genetic diversity was absent for semen production traits and moderate to highly positive for sperm cryosurvival traits. Given these findings, conservation decisions based on neutral genetic diversity may capture variation in some adaptive traits, but not others.  相似文献   

9.
The purpose of this study was to estimate the heritability of scrotal circumference (SC) and semen traits, genetic correlations between SC and semen quality traits, and the effect of cytoplasmic line on SC and semen traits. Breeding soundness exam (BSE) data were collected on registered Angus bulls at 4 ranches over 7 yr. The American Angus Association provided historical pedigree information to estimate the effect of cytoplasmic line on SC and semen quality traits. After editing, the evaluated data set contained 1,281 bulls with breeding soundness exam data that traced back to 100 founder dams. Data were analyzed using a 2-trait animal model to obtain heritability, genetic correlation between SC and semen quality traits, as well as the effect of cytoplasmic line as a random effect for SC, percent motility (MOT), percent primary abnormalities (PRIM), percent secondary abnormalities (SEC), and percent total abnormalities (TOT) using multiple-trait derivative-free REML. Fixed effects included source ranch and collection year, and test age was used as a covariate. Estimates of heritability for SC, MOT, PRIM, SEC, and TOT were 0.46, 0.05, 0.27, 0.23, and 0.25, respectively. Genetic correlations between SC and MOT, PRIM, SEC, and TOT were 0.36, -0.19, -0.11, and -0.23, respectively. The proportions of phenotypic variance accounted for by cytoplasmic line for SC, MOT, PRIM, SEC, and TOT were <0.001, 0.013, 0.023, 0.002, and <0.001, respectively. Genetic correlations between SC and semen quality traits were low to moderate and favorable. Cytoplasmic line may have a marginal effect on MOT and PRIM, but is likely not a significant source of variation for SC, SEC, or TOT.  相似文献   

10.
To evaluate new therapeutical concepts for male subfertility, we tested the effects of exogenous recombinant bovine growth hormone (rbGH) on various endocrine and metabolic parameters both in blood and in seminal plasma of bulls. Sperm quality was assessed morphometrically and by monitoring the number of successful artificial inseminations (AIs) defined as non-return rates (NRR). Aliquots of 450 semen samples were used from each bull and each experimental period (4 wk before, 14 weeks during and 6 wk after treatment). Six out of ten sires (average age 8.4 years) were treated every two weeks with 640-mg depot formulated rbGH (Eli Lilly). Four bulls received vehicle only. Blood plasma bGH, IGF-I, insulin and glucose concentrations were increased with rbGH treatment. In seminal plasma there was no effect of rbGH treatment on fructose and citrate or on testosterone concentrations. With one exception, rbGH-treated bulls had greater IGFBP-3 concentrations in seminal plasma. Motility of spermatozoa after freezing and thawing was increased compared with pretreatment rates. Most interestingly, the number of successful AIs was increased by an average of 6.0% NRR when ejaculates from rbGH-treated bulls were used.  相似文献   

11.
Batches of straws often need to be thrown away after freezing because of a too few number of motile or progressive sperm cells after thawing. Our objective was to evaluate the possibility to predict before freezing the quality of the semen after freezing/thawing. Computer‐Aided Sperm Analysis was performed on motility parameters both before and after freezing of 20 ejaculates from different bulls. Significant variation between bulls was observed both before and after freezing for all the analysed traits (anova 2; p < 0.001): proportion of motile (%mot) and progressive (%prog) sperm, velocity on the curved line (VCL), velocity on the straight line (VSL), velocity on the average path (VAP), linearity (VSL/VCL), beat cross frequency and average orientation change of the head. Freezing significantly altered the motility parameters and correlations were found between samples analysed before and after freezing (Pearson coefficient: R = 0.43–0.72; p < 0.05). The mean VAP, VSL and the %prog obtained before freezing were highly correlated to the %mot and %prog observed after freezing (R = 0.75–0.82; p < 0.001). Applying thresholds on mean VAP and VSL values allowed us to predict respectively 6 and 7 of nine batches that would be rejected after freezing due to a too low %prog (<15%). Combining different traits did not add to the precision. In conclusion, analysis of velocity traits on fresh sperm seems more efficient than analysis of %mot or %prog to discard batches that will be of poor quality after freezing.  相似文献   

12.
为探索非遗传因素对中国美利奴羊（新疆型）主要经济性状的影响,试验对拜城种羊场1992-2010年共19年周岁母羊鉴定记录进行统计分析,利用最小二乘方差分析法研究出生年份、群别及出生月份3个非遗传因素对周岁母羊鉴定记录的6个主观鉴定性状（头毛评分、毛密度评分、毛弯曲评分、毛细度评分、体型外貌评分、品种等级评分）和4个客观测定性状（毛长度、鉴定时体重、剪毛后体重、剪毛量）共10个经济性状的影响。结果表明,出生年份和群别对10个性状均有极显著影响（P<0.01）;出生月份对除毛密度评分、毛细度评分、品种等级评分外的其他7个性状均有极显著影响（P<0.01）。从毛细度、毛长度和剪毛量3个最主要的性状来看,2008年毛细度评分最高,显著高于2006、2007和2010年（P<0.05）;1996年毛长度最长,显著高于1994、2002、2004、2006、2007、2008和2010年（P<0.05）,与1995、2003和2009年差异不显著（P>0.05）;1995年剪毛量最多,显著高于1994和2009年（P<0.05）,与1992年差异不显著（P>0.05）;除此之外,其他年份的毛细度评分、毛长度和剪毛量均极显著低于最高值（P<0.01）。除2号群外,不同群别各有优势。1、2月份出生的羊较3、4月份好。由此可见,出生年份、群别和出生月份非遗传因素对中国美利奴羊（新疆型）的主要经济性状存在显著影响,因此,在遗传参数估计和遗传评定时应该综合考虑这些因素,从而为获得更为全面、准确的育种值及制定育种方案提供参考依据。  相似文献   

13.
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   

14.
In this work, we investigated the influence of age and seasonality on sperm motility and DNA fragmentation in post-thawing semen from Chilean Purebred Stallions (CPS), a horse breed presenting the oldest genealogy record in South America with an interesting reproductive industry. Despite that semen from aged CPS is frozen all year round, there is a lack of studies characterizing the breed semen freezability in accordance with age and seasonality. Twenty fertile CPS were grouped into the young group, the middle group, and the aged group. Ten ejaculates from each stallion were obtained by using an artificial vagina during summer (December) and winter (July) and directly frozen. Subsequently, the frozen semen was thawed and analyzed by a computer-assisted semen analysis and flow cytometer assessing progressive motility, mean velocity, and DNA fragmentation spermatozoa. Kruskal–Wallis test and Pearson’s correlation were used to determine statistical differences among groups and correlation among variables (P ≤ .05). Both spermatozoa motility traits decreased progressively in accordance with age and seasonality, showing the lowest values in the aged group during winter and the highest values in the young group during summer. Deoxyribonucleic acid fragmentation increased significantly in accordance with age and seasonality being highest in the aged group during winter and lowest in the young group during summer. Post-thawing sperm quality showed a negative correlation with the age of the stallions and a positive correlation with the normal sperm morphology before freezing. These results allow the conclusion that age and seasonality are important factors that need to be considered during the selection of CPS for reproductive programs.  相似文献   

15.
In the present study, the correlations among age, body weight, scrotal circumference (SC), semen quality and peripheral testosterone and estradiol-17beta (E(2)) concentrations were investigated in pubertal (n=5) and postpubertal (n=7) groups of Holstein bulls over a 6 week period. There were significant positive correlations (P<0.01) among age, body weight and SC in both groups, and similar significant correlations between sperm motility and SC in pubertal bulls (P<0.01) and between sperm concentration and SC in postpubertal bulls (P<0.05). The sperm motility after collection (P<0.05) and after freezing and thawing (P<0.01) of the postpubertal bulls correlated positively with the E(2) concentration. Estrogen may be important for the function of postpubertal bull testes, in which it may regulate spermatozoa motility in vivo.  相似文献   

16.
Inhalt Die Spermatozoen von Bullen, deren Ejakulate gut, mangelhafl and nicht einfrierbar waren, wurden vor and nach dem Einfrieren elektronenmikroskopisch untersucht. Als Ursache der mangelha f ten Fin f rierbarkeit der Ejakulate von zwei Bullen wurden Veränderungen der Spermatozoen im Bereich des Akrosoms festgestellt, die bereits beim Frischsamen, vermehrt aber nach dem Einfrieren nachzuweisen sind. Diese Veranderungen (Schwellungen, Ablösungen, Brüche) entsprechen denen, die im Frostsperma von Tierarten gefunden werden, deren Ejakulate generell schlecht einfrierbar sind (Eber, Schafbock, Chinchilla). Bei einem Bullen, dessen Ejakulate trotz guter Beweglichkeit nicht einfrierbar waren, konnten Hinweise für feinste Schädigungen des Membransystems als Ursache gefunden werden. Contents Spermatozoa from bulls whose ejaculates were well frozen, partly frozen and unfreezable were examined in the electron microscope before and after freezing. The ejaculates of two bulls which were imperfectly freezable had spermatozoa which showed consistent damage to the acrosome complex. The alterations (swelling, detachment, rupture) were seen in fresh semen and to a greater extent in semen frozen in liquid nitrogen and then thawed. They correspond to the changes found in the frozen semen of these species of animals, whose ejaculates are in general poorly freezable (rain, boar, chinchilla). In the ejaculate of one bull which was not freezable in spite of good motility the cause was found to be slight damage to the membranous system.  相似文献   

17.
The aim of the present study was to determine the suitability of using two egg yolk-free commercial extenders, Andromed and Biociphos Plus as compared with the Tris-egg yolk based diluent Biladyl, for the cryopreservation of bull spermatozoa when the freezing protocol involved holding the extended semen at 4 degrees C for 18 h before the freezing. Six ejaculates from each of 10 Holstein bulls were collected by using artificial vagina. The ejaculates were evaluated for volume, sperm concentration and motility, divided in to three equal volumes, and diluted, respectively, with the three extenders as specified above. Extended semen was equilibrated for 18 h at 4 degrees C and frozen in 0.25-ml straws. After thawing, 100-mul aliquots of semen were labelled with SYBR-14, PI and PE-PNA (Phycoerythrin-conjugated Peanut agglutinin) and analysed by flow cytometry at 0, 3, 6 and 9 h after incubation at 37 degrees C. A General Lineal Model procedure for repeated measures was used to determine the effects of extender, bull, replicate and the interaction between them, on sperm viability and acrosomal integrity. Semen samples frozen with Biladyl showed higher (p < 0.001) sperm survival after 0 h (47.9%) and 9 h (30.3%) of incubation than those frozen with Andromed (38.5% and 17.3%, after 0 and 9 h respectively) or Biociphos Plus (34.9% and 21.6%, after 0 and 9 h respectively). The bull and replicate had significant effects (p < 0.001) on both sperm viability and acrosomal integrity, but the interactions between bull and extender and between replicate and extender were not significant. It was concluded that, when holding the semen overnight before freezing, the use of Biladyl results in higher sperm survival and longevity than the use of Andromed or Biociphos Plus.  相似文献   

18.
本文利用5个国家级种畜场和8个家畜冷冻精液中心站1979～1998年间的338头西门塔尔公牛的1275头女儿与其所配母牛的繁殖性状资料和重要的生产性状记录,以及有一定数量后裔的61头公牛的915条精子形态性状测定记录,对西门塔尔母牛的配妊时间、产犊间隔、305d产奶量,和公牛的精子形态性状(头长、最大头宽、中段长、主段长、总长)、精子解冻后活力、密度等共计15个性状进行了遗传统计分析。结果表明:场、年度(配种年度、分娩年度、制精年度)、季节(配种季节、分娩季节、采精季节)、与配公牛、胎次等环境因素对母牛主要繁殖性状影响非常显著,而对公牛精子形态性状的影响小于遗传因素。公牛精子形态性状在个体间差异极显著(P<0.01),这种差异代表了真正的遗传差异。  相似文献   

19.
Dairy bulls, 322 Ayrshires (Ay) and 85 Friesians (Fr), were studied at the age of 11 months. Of the bulls, 286 Ay-bulls and 80 Fr-bulls produced semen of acceptable quality for use in A.I. Scrotal circumference, tonometer measure, scrotal fold thickness, 1-year body weight and testicular palpation were used to predict unsuitable bulls for A.I. Non-return rate was used as a measure of fertility. Scrotal fold thickness and 1-year weight had no significant correlation with fertility or semen quality. Scrotal circumference had a significant positive correlation with fertility. Tonometer ratio had a significant negative correlation with fertility. Testicular palpation was the best basis for predicting bulls with poor semen quality in this study. Twelve bulls were recorded as having testicles of different sizes, 1 testicle being more than 20% bigger than the other. Only 2 of these 12 bulls produced semen of acceptable quality. One of these 2 bulls was, after slaughter, diagnosed as having a hereditary testicle disease. Friesians were shown to have significantly higher fertility than Ayshires.  相似文献   

20.
Evaluation of two seminal collection regimens for mature Holstein bulls   总被引：2，自引：0，他引：2  
Twenty mature Holstein bulls (3 to 10 yr old) were used to test the effect of two semen collection regimens on spermatozoal output, post-thaw percentage spermatozoal motility, and time needed to make the collections/week. For both regimens, six ejaculates/wk were collected using either three ejaculates/d, 2 d/wk, or two ejaculates/d, 3 d/wk. A three-period switchback experimental design was used. Each collection period for which measurements were taken was 3 wk and was preceded by a 2 wk period of acclimation. The total number of spermatozoa harvested per week was not significantly different (P greater than .05): 33.2 X 10(9) when the bulls were collected two ejaculates 3 d/wk, compared with 33.9 X 10(9) three ejaculates 2 d/wk. Post-thaw progressive spermatozoal motility was 50.3 and 52.1% (P greater than .05), respectively. The average time per week to collect each bull was 73.6 and 83.7 min (P less than .05), respectively.  相似文献   

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