输精时间和精液稀释比例对种蛋受精率的影响

采用1200只健康的海兰褐种鸡,随机分为4组,即A、B、C和D组。试验1分别在下午3:00～3:30、3:30～4:00、4:00～4:30和4:30～5:00进行输精,每组750枚种蛋,结果C、D组种蛋受精率显著高于A、B组(P<0.05),A、B组之间及C、D组之间无显著差异(P>0.05)。下午4:00以后输精种蛋的受精率最高。试验2分别用生理盐水将精液按1:1、1:2、1:3稀释和原精液对海兰褐种鸡进行人工授精,每组750枚种蛋,结果显示,1、2和3组的受精率显著高于原精液对照组(4组)(P<0.05),1、2和3组之间无显著差异(P>0.05)。     

Effect of green buffer storage on the fertility of fresh camel semen after artificial insemination

Artificial insemination (AI) is one of the most widely used reproductive technologies, and there is considerably interest in commercializing this technology in camels. Storage of semen extender frozen (at -20 °C) is of considerable interest to scientists working with camels, as transportation of diluents at refrigeration temperature is not always possible given the hot, arid and remote conditions that dromedary camels exist in. Therefore, this study was conducted to compare the fertility of fresh camel semen, after dilution in fresh or frozen-thawed green buffer (GB), after AI into single and multiple ovulating female camels. No differences were observed in any sperm characteristics (motility, membrane integrity, acrosome integrity or morphology) when semen was diluted in fresh or frozen-thawed GB (p>0.05). Sperm motility was increased by dilution (fresh: 70.7 ± 4.9% and frozen: 68.8 ± 3.1%) compared with the motility of sperm in neat semen (35 ± 2.85%; p<0.05), and sperm motility changed from oscillatory to forward progressive after dilution. Pregnancy rates were higher (p<0.05) for single ovulating camels inseminated with semen diluted in fresh (72.7%) compared with frozen-thawed GB (27.3%), and fertilization rates were also higher (p<0.05) for multiple ovulating camels inseminated with semen diluted in fresh (83.3%) compared with frozen-thawed GB (11.1%). These results clearly demonstrate the detrimental effect of freezing and thawing semen diluent on the fertility of fresh camel semen. However, further studies are required to elucidate the mechanism responsible for this reduction in fertility. Moreover, these results demonstrate that the fertility of fresh camel semen diluted in fresh GB is high enough to be considered commercially viable.     

Influence of PMSG and time of artificial insemination on fertility of progestogen-treated sheep in confinement

The need for pregnant mates' serum gonadotropin (PMSG) in breeding confined sheep by artificial insemination (AI) at progestogen-synchronized estrus was assessed in 152 adult crossbred ewes brought into season by a controlled light regimen. One-half of the ewes received 500 IU PMSG after intravaginal progestogen treatment; all ewes were inseminated either 54, 57 or 60 h after sponge removal or at 54 and again at 60 h. Based on progesterone determinations 18 d after AI, conception rates with single insemination 54, 57, or 60 h and double insemination at 54 and 60 h were 76, 72, 47 and 72%, respectively, among ewes receiving PMSG, compared to 17, 22, 47 and 43%, respectively, among ewes not give PMSG (P less than .01) Lambing rates were higher (P less than .01) with PMSG (67, 67, 37 and 61%) than without PMSG (11, 11, 26 and 33%). While there was only a small increase (.06 less than P less than .05) in litter size with PMSG, fecundity decreased (P less than .01) from 1.4 to .3 when PMSG was not used. These data indicate that, even with controlled lighting to induce estrous activity, additional stimulation of ovulation by PMSG at progestogen-synchronized estrus is necessary for normal fertility when confined sheep are bred by AI.     

Effect of insemination volume on uterine contractions and inflammatory response and on elimination of semen in the mare uterus-scintigraphic and ultrasonographic studies

The effect of artificial insemination (AI) volume on uterine contractility and inflammation and on elimination of semen in the reproductive tract of mares was examined for 4 h after AI using two methods, scintigraphy and ultrasonography. The same doses were used in both methods: 2 and 100 ml of skim milk-extended frozen semen. In the scintigraphic study, the number of reproductively normal mares was four per group and in the ultrasonographic study five per group. For scintigraphy, the semen was radiolabelled with technetium-99m. The static scintigrams were acquired immediately before and 30, 60, 120, 180 and 240 min after AI. The activities in the vagina and uterus were calculated and the values for sperm that had been discharged from the mare were obtained by subtracting the counts for the uterus and vagina from the total radioactivity. The dynamic scintigrams were taken continuously for the first 30 min after AI and in 5-min periods immediately after having acquired the static scintigrams. The uterine contractions were counted. In the ultrasonographic study, the mares were scanned before AI and at 5, 10, 15, 20, 25, 30, 60, 120, 150, 180, and 240 min after AI, for at least 1 min each time. The examinations were videotaped and contractions counted per minute. More contractions were observed with the ultrasonographic method than with the scintigraphic method. No difference was present in the number of contractions between the groups, except in the ultrasonographic study at 4 h, when the mares inseminated with 100 ml showed more contractions than did the mares inseminated with 2 ml. The intraluminal fluid was sampled with a tampon and by uterine lavage 4 h after AI in the ultrasonographic study. The numbers of polymorphonuclear leukocytes and spermatozoa were counted, but the differences between the groups were not significant. Under our experimental conditions and with the number of mares examined, the volume of the AI dose had an insignificant effect on contractility - with the exception at 4 h - and inflammatory reaction and on semen elimination in the uterus.     

同期发情定时输精技术对经产奶牛繁殖力的影响

为了研究同期发情定时输精技术对牛群体繁殖力的影响,试验选取同一牛场内不同单元的经产奶牛,随机分为2个组,分别采用自然发情输精和同期发情定时输精两种方法对奶牛进行人工输精,比较两种方法对奶牛群体繁殖力的影响。研究结果显示:同期发情组和自然发情组的参配率分别为,产后54 d之前为96.3%VS 12.1%,55～90 d为64.6%VS 44.6%,91～130 d为48.1%VS 50.1%,131～170 d为39.9%VS 38.7%,180 d内的总参配率分别为249.1%VS 145.5%;相应时段的同期发情组的受胎率为39.2%、36.7%、36.5%、33.9%、92.6%,自然发情组的受胎率为44.8%、47.3%、46.2%、46.1%、 67.5%;2个组的年繁殖率分别为93.8%VS 84.6%、空怀天数为(91.6±18.3)d VS (131.7±26.8)d、配种次数分别为2.5 VS 1.8、淘汰率分别为29.1%VS 13.4%。以上结果表明,在奶牛生产中,使用同期发情定时输精技术,能显著提高牛群的繁殖力,缩短空怀时间。     

Comparison of fertility on intrauterine insemination between cryopreserved ejaculated and cauda epididymal sperm in dogs

The fertility was compared between ejaculated and cauda epididymal sperm sensitized with prostatic fluid in dog after freeze-thawing using the fertility of ova from the contralateral ovary after injection (2 × 10(8) sperm) into dog uterus on the unilateral ovariectomized side, on the basis of the presence or absence of conception. No significant difference was observed in sperm quality after freeze-thawing between the two groups and conception rates were equivalent and low. Therefore, to achieve a high fertility by intrauterine insemination of canine frozen-thawed ejaculated and cauda epididymal sperm, intrauterine insemination on both sides is recommended, rather than insemination with a lot of sperm of the uterine horn on one side.     

PCV2很可能会通过人工授精传染给母猪并会影响公猪精液质量

猪圆环病毒(Porcine Circovirus,PCV)于20世纪70年代初首次被发现.这种病毒后来被命名为PCV1型,并被证实能感染猪,但不会引发疾病.20世纪90年代末,PCV的变体毒株被发现,随后被命名为PCV2型(PCV2),现在已知其与多种疾病[共同被称为猪圆环病毒相关疾病(PCVAD)]相关.最近,研究的重点转向作为PCVAD之一的母猪特别是小母猪和低胎次母猪的繁殖障碍上.例如,PCV2的临床症状包括在配种和流产之后不定期返情、窝产仔数减少但死产数和木乃伊胎比例增加.繁殖障碍的确诊需要胎儿组织,如心脏组织的PCV2病理和检测.     

Effect of acrosomal defects on fertility of bulls used in artificial insemination and natural breeding

Four bulls that produced spermatozoa with a high percentage of abnormal acrosomes were individually placed in pens with females for 21 days. Frozen semen from 2 of the bulls was used for artificial insemination. One of the bulls was placed in a competitive mating situation with normal bulls at pasture. First service pregnancy rates were determined by transrectal ultrasonography 28 days after bull removal from breeding pens, or after the last artificial insemination. The results of competitive mating at pasture were determined from breeding observations, the phenotypic characteristics of calves sired, and blood typing for parentage. The results of these studies suggest that bulls that produce a high percentage of spermatozoa with indented acrosomes may have normal fertility when used in artificial insemination or in single sire mating; however, their fertility may be low when breeding competitively with bulls with normal spermiograms.     

Bovine sperm selection procedure prior to cryopreservation for improvement of post-thawed semen quality and fertility

Background: The application of cryopreservation and artificial insemination technology have contributed to the advancement of animal reproduction. However, a substantial proportion of spermatozoa undergoes alterations and loses their fertility during cryopreservation, rendering the frozen-thawed semen impractical for routine use.Cryopreservation is known to reduce sperm lifespan and fertility. Variation in cryosurvival of spermatozoa from different sires and even with the individual sire is common in artificial insemination(AI) centers. Our goal is to improve post-thawed semen quality by optimization of cryopreservation technique through sperm selection prior to cryopreservation process.Results: Our strategy of sperm selection based on rheotaxis and thermotaxis(SSRT) on macrosale in a rotating fluid flow demonstrated the ability to maintain the original pre-freezing structural integrity, viability and biological function related to fertilization competence. This strategy has a positive effect on the cryosurvival and fertilizing abilities of spermatozoa as supported by the improvement on pregnancy rate of Japanese Black heifers and Holstein repeat breeders. This technique protected further sublethal damage to bovine spermatozoa(higher %cryosurvival than the control) and resulted in the improvement of DNA integrity. Prefreeze selected spermatozoa demonstrated slower and controlled capacitation than unprocessed control which is thought to be related to sperm longevity and consequently to appropriate timing during in vivo fertilization.Conclusions: These results provide solid evidence that improvement of post-thawed semen quality by SSRT method is beneficial in terms of cryosurvival, longevity of post-thawed sperm, and optimization of in vivo fertilization, embryo development and calving as supported by the favorable results of field fertility study.     

Threshold-linear analysis of measures of fertility in artificial insemination data and days to calving in beef cattle

Mating and calving records for 47,533 first-calf heifers in Australian Angus herds were used to examine the relationship between days to calving (DC) and two measures of fertility in AI data: 1) calving to first insemination (CFI) and 2) calving success (CS). Calving to first insemination and calving success were defined as binary traits. A threshold-linear Bayesian model was employed for both analyses: 1) DC and CFI and 2) DC and CS. Posterior means (SD) of additive covariance and corresponding genetic correlation between the DC and CFI were -0.62 d (0.19 d) and -0.66 (0.12), respectively. The corresponding point estimates between the DC and CS were -0.70 d (0.14 d) and -0.73 (0.06), respectively. These genetic correlations indicate a strong, negative relationship between DC and both measures of fertility in AI data. Selecting for animals with shorter DC intervals genetically will lead to correlated increases in both CS and CFI. Posterior means (SD) for additive and residual variance and heritability for DC for the DC-CFI analysis were 23.5 d2 (4.1 d2), 363.2 d2 (4.8 d2), and 0.06 (0.01), respectively. The corresponding parameter estimates for the DC-CS analysis were very similar. Posterior means (SD) for additive, herd-year and service sire variance and heritability for CFI were 0.04 (0.01), 0.06 (0.06), 0.14 (0.16), and 0.03 (0.01), respectively. Posterior means (SD) for additive, herd-year, and service sire variance and heritability for CS were 0.04 (0.01), 0.07 (0.07), 0.14 (0.16), and 0.03 (0.01), respectively. The similarity of the parameter estimates for CFI and CS suggest that either trait could be used as a measure of fertility in AI data. However, the definition of CFI allows the identification of animals that not only record a calving event, but calve to their first insemination, and the value of this trait would be even greater in a more complete dataset than that used in this study. The magnitude of the correlations between DC and CS-CFI suggest that it may be possible to use a multitrait approach in the evaluation of AI and natural service data, and to report one genetic value that could be used for selection purposes.     

定时输精对母猪繁殖性能的影响

为了研究同期发情+定时输精对母猪发情率、妊娠率及产仔数的影响。试验1:将200头后备母猪随机分成两组,每组100头。所有后备母猪连续饲喂四烯雌酮(ATL)(15 mg/d)14 d,第15 d开始查情。试验组后备母猪停止饲喂ATL 24 h后肌注促性素(PMSG)、再过72 h肌注生源(Gn RH),肌注Gn RH 24 h后开始输精1次,过24 h再输精1次;对照组后备母猪停止饲喂四烯雌酮后有发情就开始输精,过24 h再输精1次(如还发情,第2次输精过24 h后再输精1次);试验2:将200头断奶母猪随机分成两组,每组100头,断奶第2 d开始查情。试验组断奶母猪断奶24 h后肌注促性素(PMSG),再过72 h肌注生源(Gn RH),肌注Gn RH 24 h进行输精1次,过24 h再输精1次;对照组断奶母猪发情就开始输精,过24 h再输精1次(如还发情,第2次输精过24 h后再输精1次);精液剂量为80 ml(2×109个精子细胞)。试验1结果显示,试验组的后备母猪的静立率(P>0.05)、妊娠率(P<0.05)、分娩率(P<0.05)、窝产仔数(P>0.05)均高于对照组。试验2结果显示,试验组的断奶母猪的发情率、妊娠率、分娩率均高于对照组(P>0.05),窝产仔数也高于对照组。试验结果表明,母猪肌注PMSG和Gn RH,可改善母猪的发情率、分娩率、窝产仔数,减少隐性发情母猪的漏配率。     

The incidence of agglutination and its influence on sperm quality and fertility of boar semen

The aim of this study was to examine the incidence of sperm agglutinations and their relationships with sperm quality and fertility. Semen samples of 40 boars of an AI-station were investigated. Nineteen of the 40 investigated boars showed a constantly low (< 10% agglutinated sperm), 3 an intermediate (10-20%) and 6 boars a high level (> 20%) of agglutination in raw semen. The degree of agglutination in sperm samples of 12 boars varied distinctly during the investigation period. During summer more (P < 0.05) agglutinated sperm were observed (11.0 +/- 11.6%) than during winter (6.2 +/- 7.3%). There was no association between bacterial contamination and incidence of agglutinations (P > 0.05). After dilution in extender the percentage of agglutinated sperm decreased from 6.2 +/- 7.3% to 1.1 +/- 1.4% (P < 0.0001). Twenty-four hours after dilution the percentage of progressively motile sperm was 7.4% lower (P < 0.05) in ejaculates with an initially high degree of agglutination (> 20% agglutinated sperm) compared to samples with an initially low degree of agglutinated sperm (< 10%). Plasma membrane integrity, mitochondrial membrane potential, acrosome reaction and chromatin structure were independent (P > 0.05) from the level of agglutination. Fertility data did not differ (P > 0.05) between boars with low and high numbers of agglutinated sperm in raw semen. The results show that there are individual, ejaculatory and seasonal variations in the incidence and degree of agglutination. Agglutinations have a negative effect on motility of sperm and disappear to a large extent after dilution in sperm extender. They have no negative consequences on fertility.     

Effect of breed and other animal-related factors on conception rate to artificial insemination with frozen semen in mares in Ethiopia

Equine reproduction is unique by having long behavioral estrus and differences in time of breeding between breeds and individuals of mares. An experimental study was conducted at the Balderas Sport Horses and Recreational Center, Addis Ababa, Ethiopia, from January to June, 2018, to evaluate conception rate to frozen semen in local and exotic crossbreed mares. Mares were teased to characterize estrus behavior and examined by ultrasound in determining imminent ovulation. Inseminations were done post ovulation within an average of 6–9 h using frozen-thawed semen. The overall conception rate to frozen semen was 15/21 (71.43%) with 8/11 (72.73%) in crossbreed and 7/10 (70%) in local breed mares. Age and body condition score (BCS) of animals had no significant effect on conception rate to AI with frozen semen. A slightly higher conception rate was obtained when ovulation was from the right ovary than when ovulated from the left ovary. A higher conception rate was obtained when the diameter of the preovulatory follicle was ≤ 45 mm than above diameter. The conception rate increased significantly with increased number of services/conception with an overall mean ± (SEM) of 2.2 ± 0.2 services/conception. A more number of services/conception were required for local breed (2.7 ± 0.2) than crossbreed mares (1.8 ± 0.3) and again for lower body condition scores than higher condition scores of mares. In conclusion, the increased number of services improved the conception rate with significant difference between breed of mares, whereas good management of mares for improved body conditions could be required to decrease the number of services per conception.

     

Synchronization of estrus in suckled beef cows for detected estrus and artificial insemination and timed artificial insemination using gonadotropin-releasing hormone, prostaglandin F2alpha, and progesterone

We determined whether a fixed-time AI (TAI) protocol could yield pregnancy rates similar to a protocol requiring detection of estrus, or estrous detection plus TAI, and whether adding a controlled internal device release (CIDR) to GnRH-based protocols would enhance fertility. Estrus was synchronized in 2,598 suckled beef cows at 14 locations, and AI was preceded by 1 of 5 treatments: 1) a CIDR for 7 d with 25 mg of PG F(2alpha) (PGF) at CIDR removal, followed by detection of estrus and AI during the 84 h after PGF; cows not detected in estrus by 84 h received 100 mug of GnRH and TAI at 84 h (control; n = 506); 2) GnRH administration, followed in 7 d with PGF, followed in 60 h by a second injection of GnRH and TAI (CO-Synch; n = 548); 3) CO-Synch plus a CIDR during the 7 d between the first injection of GnRH and PGF (CO-Synch + CIDR; n = 539); 4) GnRH administration, followed in 7 d with PGF, followed by detection of estrus and AI during the 84 h after PGF; cows not detected in estrus by 84 h received GnRH and TAI at 84 h (Select Synch & TAI; n = 507); and 5) Select Synch & TAI plus a CIDR during the 7 d between the first injection of GnRH and PGF (Select Synch + CIDR & TAI; n = 498). Blood samples were collected (d -17 and -7, relative to PGF) to determine estrous cycle status. For the control, Select Synch & TAI, and Select Synch + CIDR & TAI treatments, a minimum of twice daily observations for estrus began on d 0 and continued for at least 72 h. Inseminations were performed using the AM/PM rule. Pregnancy was diagnosed by transrectal ultrasonography. Percentage of cows cycling at the initiation of treatments was 66%. Pregnancy rates (proportion of cows pregnant to AI of all cows synchronized during the synchronization period) among locations across treatments ranged from 37% to 67%. Pregnancy rates were greater (P < 0.05) for the Select Synch + CIDR & TAI (58%), CO-Synch + CIDR (54%), Select Synch & TAI (53%), or control (53%) treatments than the CO-Synch (44%) treatment. Among the 3 protocols in which estrus was detected, conception rates (proportion of cows that became pregnant to AI of those exhibiting estrus during the synchronization period) were greater (P < 0.05) for Select Synch & TAI (70%; 217 of 309) and Select Synch + CIDR & TAI (67%; 230 of 345) cows than for control cows (61%; 197 of 325). We conclude that the CO-Synch + CIDR protocol yielded similar pregnancy rates to estrous detection protocols and is a reliable TAI protocol that eliminates detection of estrus when inseminating beef cows.     

靖西县推广牛冻精取得的效果及存在问题

我区黄牛杂交改良的方向问题 ,到底是发展乳用、肉用或兼用牛 ,现在还没有统一的意见 ,这里发表两篇不同看法的文章 ,希望能引起大家讨论、争鸣 ,以便统一见解和做法。在　　　讨论中 ,希望言之有据 ,用事实说话 ,比如杂种牛皮毛颜色问题怎么看待 ,是皮毛颜色重要还是　生产性能重要 ?又比如肉用牛的改良成果 ,特别是生产成本和国内外市场价格相比 ,经济效益　　　　如何 ,到现在还缺乏报道 ,有的又认为市场鲜奶过剩了 ,再多就难卖了 ,有的又以为地方鲜奶难敌进口货 ,特别是参加世贸组织以后。牛的改良 ,在我区家畜中比较滞后 ,而潜力又最大 ,希望大家踊跃赐稿     

Assessment of the morphology of frozen-thawed bull sperm in relation to its cryopreservation for artificial insemination

The morphology of sperm in raw semen was compared with that of the live sperm in semen which had been frozen and thawed. The thawed semen was stained with 6-carboxyfluorescein diacetate and propidium iodide and examined by fluorescence microscopy; smears of the raw semen were stained with eosin and nigrosin. Thirty-four ejaculates from 24 bulls of various breeds were examined. There were fewer abnormal heads, detached heads, coiled tails and proximal cytoplasmic droplets/pseudodroplets in the thawed semen than in the raw semen, there was no change in the number of bent tails, but the number of distal cytoplasmic droplets/pseudodroplets increased. There were no significant differences in morphology between ejaculates which passed or failed the osmotic resistance test after thawing, but failed batches tended to have more distal cytoplasmic droplets/pseudodroplets.