奶牛胚胎体外保存时间和温度对移植受胎率的影响

试验对胚胎在体外保存时间的长短及温度与移植妊娠率的关系进行统计分析，胚胎收集后分别在0-3h,3-6h和6h后冷冻，解冻后移植受胎率分别为46.07%,43.33%,30.56%,0-3h和3-6h冷冻的胚胎，移植受胎率没有明显差异（P〉0。05），6h后的冻胚与6h以前的冻胚移植受胎率差异显著（P〈0．05）。胚胎分别在室温和37℃保存5h后冷冻，解冻后移植受胎率分别为39．74％、42．24％（P〉0．05）。     

提高绵、山羊颗粒冻精品质的研究

用波德代羊和无角陶赛特羊品质良好的鲜精，研制出9个绵羊精液冷冻稀释液配方，同时对稀释、平衡、解冻、授配等方法和步骤进行相庆优化试验研究，获得冻精解冻后活力在0．45以上，冷冻保存409天的冻精解冻后活力在0．5以上，组织300只当地绵羊授配试验，30天的情期不返情率为65．57％。研制出波尔山羊（Boer)冻精的优化的稀释液配方和优化的冷冻工艺，授配试验结果表明母羊情期不返情率为65．77％。     

奶牛细管冷冻精液体内解冻与其受胎率关系的研究

为探索一种操作简单，适合广大牧区特点的奶牛细管冷冻精液的解冻方法，笔者对280头具有正常繁殖机能的黑白花奶牛进行了细管冻精体内解冻（试验组）与常规38－40℃水浴解冻（对照组）的受胎试验。结果表明，试验组的受胎率为60％（84／140），对照组的受胎率为57.85%（８１／１４０），试验组比对照组高２.１５％。故细管冻精体内解冻方法完全可以代替常规水浴解冻方法。     

公牛塑料细管冻精制作方法与应用效果的研究

本试验就细管冻精和颗粒冻精的冷冻效果和受胎情况进行了对比分析。结果表明，采用设定的工艺流程制作的细管冻精与颗粒冻精，其精子的解冻活率和复苏率没有显著差异（ｐ〉０．０５），采用水平冻结方式和垂直冻结方式生产的细管冻精，其精子的解冻活率和复苏率也无显著差异（ｐ〉０．０５）。但细管冻精的情期受胎率和一次输精受胎率却显著高于颗粒冻精。表明细管冻精的应用效果优于颗粒冻精。     

影响曲靖肉牛冻精冷配受胎率的因素

本研究围绕解冻后精液保存温度、母牛发情规律、输精部位和情期输精次数等影响牛冻精冷配受胎率的因素进行分析。结果表明，冻精解冻后，在低温（4℃）下保存6h、在常温（10-15℃）下保存4h和在高温（28℃）下保存2h输精对受胎率没有显著影响；曲靖母牛发情表现明显，在发情母牛卵泡发育至成熟期时冷配受胎率最高（84．40％）;母牛发情配种所占比重依次为秋季〉夏季〉春季〉冬季;母牛2-4胎时冷配受胎率最高，达72．03％，5胎以上的冷配受胎率则有所下降；母牛冷配最佳输精部位是卵泡发育好的一侧子宫角和子宫体内，同时输精可得到较高冷配受胎率（80．38％）。在同一个情期，输精1次与2次对受胎率的影响差异不显著。     

我国猪精液冷冻技术研究现状

我国于1974年开始研究猪精液冷冻保存技术,内容主要有:冷冻精液稀释液、平衡时间、冷冻时间、冻后精子活率及输入有效精子数等项目。结果解冻后活率在30～60％之间。1975～1983年共输精21859头母猪,情期受胎率达56.25％(33.30～74.78),窝产仔为8.18头。试验证明我国猪冷冻精液的保存技术有所进展。     

提高颗粒冻精受胎率五法

提高颗粒冻精受胎率五法一、维生素Ｂ＿（１２），解冻法取维生素Ｂ＿（１２）注射液（１毫升／支），在４０℃温度下，常规解冻颗粒冻精，解冻后给奶牛人工授精。输精奶牛４１头，受胎２７头，情期受胎率为６５．９％比用２．９％柠檬酸钠解冻液组提高２１．５％。大群使...     

波尔山羊冻精解冻方法效果的分析

采用不同解冻方法对波尔山羊冻精精子活力、存活时间、顶体完整率、死活染色率以及受胎率几方面的影响进行试验分析。结果表明：８０℃高温干解冻最理想，活力０．３￣０．４，存活时间１２￣１８ｈ，优于４０℃低温湿解冻（Ｐ＜０．０５）；干解冻效果与温度呈正相关关系，以８０℃为量好，湿解冻与温度呈负相关关系，以４０℃为最好；精子存活时间与受胎率呈正相关关系；一次性解冻一粒冻精活力最好，两项指标均超过一次解冻多粒冻     

猪冷冻精液新技术研究试验报告

本研究筛选出的猪精液冷冻稀释液配方，主要成分为葡萄糖，卵黄，甘油和蒸馏水等，按一定比例配制而成，稀释液与精液按１：１稀释；用改进后的制冻方法平衡降温和滴冻；冻精活力达０．５２，顶体完整率４５％－５２％；试验点授配母猪４５２头，情期受胎率８４．５９％，总受胎率８６．２８％，平均窝产仔８．５８头；大面积授配母猪７２８０头，受率７５．３％。     

咖啡因提高山羊精液冷冻效果试验

试验将５ｍｍｏｌ／Ｌ的咖啡因添加于冷冻前的山羊稀释精液中，测定咖啡因对冷冻后山羊精液品质的影响。结果表明，咖啡因可使山羊冻精的解冻活率达０．５０，显著高于对照组，并能提高解冻后３小时活率，延长精子在３７℃条件下的总存活时间，对顶体形态无显著影响。用含咖啡因的冻精给发情母羊输配，情期受胎率７１．９６％，比对照组提高９．５８％。     

Synchronisation of oestrus and fertility in buffaloes using a prostaglandin analogue

Cloprostenol, a prostaglandin analogue, was administered intramuscularly to a total of 35 cycling buffalo cows and heifers in two doses, each of 0.5 mg, given 11 days apart. Out of five cows and 12 heifers subjected to observations after the second injection of cloprostenol (day 0), all except one heifer responded. Signs of oestrus were most marked on days 3 or 4. Eighteen treated heifers were kept with buffalo bulls for four days after the second injection while a control group of nine heifers was kept with bulls for 21 days. The first-service conception rate, diagnosed by rectal palpation at 60 days, was 33 1/3 per cent in both groups. Twelve treated heifers were artificially inseminated at 72 and 96 hours after the second injection of cloprostenol, using fresh semen diluted in egg yolk--citrate extender. The first service conception rate at 60 days was 30 per cent.     

Fertility in buffaloes after oestrus synchronisation with cloprostenol and fixed time insemination.

Fifty-seven cycling buffalo cows of the river type were treated with two doses of 0.5 mg cloprostenol intramuscularly given 11 days apart. Each animal was inseminated twice at 72 and 96 hours after the second injection of cloprostenol. The first service conception rate diagnosed by rectal palpation at 90 days was 38.6 per cent. At the time of insemination the cervix was easily penetrable on both days in only 39 (68.4 per cent) of the animals. They were inseminated at or beyond the internal cervical os, while the others were inseminated in the cervical canal. There was a marked difference in conception rate between those receiving deep inseminations (48.7 per cent) and the others (16.7 per cent). In relation to the interval from calving to insemination the conception rates for those which had calved 60 to 90, 90 to 120 and 120 to 150 days earlier were 16.6, 36.4 and 55.5 per cent respectively. The use of cloprostenol treatment and fixed-time insemination is a useful method of overcoming the problem of oestrus detection in buffaloes. Acceptable levels of fertility can be obtained in those animals which have a sufficiently relaxed cervix to permit semen deposition at the internal os, provided the interval from calving to insemination is more than 90 days.     

Bitch fertility after natural mating and after artificial insemination with fresh or frozen semen

The birth rate and fecundity of 92 bitches of 32 different breeds mated naturally or following artificial insemination of fresh or frozen semen were compared. The birth rate after natural service was 92 per cent compared with 84 per cent when fresh semen was deposited in the uterine body. When frozen semen was inseminated intra-uterine a birth rate of 67 per cent was obtained whilst a figure of 25 per cent was obtained following intra-vaginal insemination of fresh semen. There were no differences in litter size.     

Laparoscopic intra-uterine insemination of fallow deer with frozen-thawed or fresh semen after synchronisation with CIDR devices

This study investigated the efficacy of fixed-time laparoscopic intra-uterine insemination of farmed fallow deer (Dama dama) with frozen-thawed or fresh semen. In the trials with frozen-thawed semen, a total of 547 mature non-lactating does across five New Zealand farms were used. For oestrous synchronisation and artificial insemination, a standard control regimen was applied to at least 30% of the does on each farm, involving the insertion of single CIDR type-G devices intravaginally for 14 days, deposition of 50 x 10(6) frozen-thawed spermatozoa at 65 hours after withdrawal of the CIDR device and the continuous presence of vasectomised bucks from the insertion of the CIDR device until 10 days after insemination. Various aspects of this protocol were changed for the remaining does on each farm, including inseminations at 60 or 70 hours, the absence of vasectomised bucks, insemination with 25 x 10(6) or 10 x 10(6) spermatozoa, synchronisation with CIDR type-S devices and synchronisation with prostaglandin. The conception rate, based on rectal ultrasonography at 45 days after insemination, was 67% across all treatments (n=547). Corrected conception rates (+/-s.e.), calculated following between-farm adjustments, were 67+/- 3% for the control regimen, 67+/- 9% and 73 +/- 8% for inseminations at 60 and 70 hours respectively, 61 +/- 9% for absence of bucks, 80 +/- 8% and 74 +/- 9% for inseminations with 25 x 10(6) and 10 x 10(6) spermatozoa respectively, 62 +/- 10% for CIDR type-S device synchronisation, and 49 +/- 10% for prostaglandin synchronisation. Despite apparent differences, none of the treatments resulted in adjusted conception rates that were significantly different from the control regimen (P>0.01). In the trials with fresh semen, 216 does in the USA were inseminated at 69-71 hours after withdrawal of the CIDR device using either cryopreserved semen from New Zealand (n=158; 25 x 10(6) spermatozoa per inseminate) or fresh semen (n=58; 7.5 x10(6) to 20 x 10(6) spermatozoa per inseminate) collected less than 10 hours earlier. The overall conception rates were 77% and 81% respectively, with no significant differences between semen type (frozen v. fresh) or fresh spermatozoa number per inseminate (P>0.01). A further 102 does in New Zealand similarly received fresh semen from 3/4 Mesopotamian buck. Doses of 10 x 10(6) (n=35), 5 x 10(6) (n=32) or 2.5 x 10(6) (n=35) spermatozoa per inseminate were delivered at 69-71 hours after withdrawal of the CIDR device. The conception rates were 77%, 66% and 51% respectively, reflecting a dose effect (P<0.05). However, 1/4 Mesopotamian does in the group (n=19) exhibited higher conception rates (95% overall) irrespective of semen dose, possibly indicating a semen/recipient genotype interaction. It is concluded that laparoscopic intra-uterine insemination of fallow deer with frozen-thawed or fresh semen at fixed intervals after removal of a CIDR device can give acceptable conception rates under a range of on-farm management options and semen doses.     

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.

     

A retrospective study of artificial insemination of 251 mares using chilled and fixed time frozen-thawed semen

REASONS FOR PERFORMING STUDY: Historically, artificial insemination (AI) using frozen semen has been perceived to have poorer success rates and be more labour intensive than using chilled semen. A retrospective study was therefore conducted to compare the conception rate achieved by AI between chilled and frozen semen, using fixed time insemination protocols over 2 breeding seasons. HYPOTHESIS: Artificial insemination using chilled semen produces a higher conception rate than that achieved with frozen semen. METHOD: Mares (n = 251) were inseminated with either chilled (n = 112) or frozen (n = 139) semen in the 2006 and 2007 northern hemisphere breeding season. Per rectum ultrasonography of the mare's reproductive tract determined the timing of insemination, and deslorelin acetate was used to induce ovulation. Chilled semen insemination was performed using a single preovulatory dose delivered into the uterine body. Frozen semen was administered as 2 doses (pre- and post ovulation) using a deep uterine insemination technique. Pregnancy was detected ultrasonographically at 15 days post insemination. Conception rates were compared using a Chi-squared test. RESULTS: Insemination with frozen semen produced a significantly (P = 0.022) higher seasonal conception rate (82.0%) than that achieved with chilled semen (69.6%). CONCLUSIONS AND POTENTIAL RELEVANCE: Insemination with frozen semen can achieve conception rates equal to those with chilled semen, enabling the mare owner a greater selection of stallions.     

Evaluation of glucose as a cryoprotectant for boar semen

Fertility parameters of boar spermatozoa were evaluated in vitro, after freeze-thawing the semen in three different extenders containing permeable and non-permeable cryoprotectants: A (111.0 mM Tris, 31.4 mM citric acid, 185.0 mM glucose, 20 per cent egg yolk, 3 per cent glycerol and 100 iu/ml penicillin G); B (200 mM Tris; 70.8 mM citric acid, 55.5 mM glucose, 20 per cent egg yolk, three per cent glycerol and 100 iu/ml penicillin G); C (200 mM Tris, 70.8 mM citric acid, 55.5 mM fructose, 20 per cent egg yolk, 3 per cent glycerol and 100 iu/ml penicillin G). The freeze-thawing techniques were the same for each extender. Eight ejaculates from four boars were obtained; the sperm-rich fraction of each ejaculate was extended in each of the three media at a final concentration of 400 x 106 sperm/ml, loaded into 0.5 ml straws and frozen at a rate of 30 degrees C/minute to -196 degrees C. The straws were thawed at 60 degrees C for eight seconds. Sperm motility, acrosomal integrity and in vitro sperm penetration through the zona pellucida of gilt oocytes matured in vitro were evaluated. The motility of unfrozen spermatozoa was 93.1 per cent compared with 60.7 per cent, 48.2 per cent and 35 per cent for sperm frozen in extenders A, B and C respectively; these values were all significantly different (P<0.05). There was no significant decline in sperm motility after incubation for 30 minutes in extender A, but there were significant decreases in sperm motility after 30 minutes of incubation in B and C. The percentage acrosomal integrities were 97.2 per cent for the control and 45.5 per cent, 30.3 per cent and 16.8 per cent for the frozen-thawed spermatozoa in extenders A, B and C respectively. The results of the in vitro penetration assay were 80.7 per cent when using control spermatozoa, and 42.2 per cent, 18.4 per cent and 3.3 per cent when using frozen-thawed spermatozoa in extenders A, B and C respectively     

湖羊胚胎和精液超低温保存效果的评价

【目的】 检验长期保存在国家家畜基因库的湖羊冷冻胚胎和冷冻精液的质量,评价超低温冷冻保存技术保种的效果。【方法】 对保存于国家家畜基因库的冷冻胚胎（保存20年）和冷冻精液（保存20和30年）进行复苏,进行相应鉴定后分别进行胚胎移植和人工授精,同时以0年冷冻精液和新鲜精液为对照,测定其受胎率和后代的羔皮性能、生长性能及繁殖性能,检验保存效果。【结果】 本试验共解冻胚胎36枚,其中,A级胚胎22枚,B级胚胎7枚,C级胚胎5枚,D级胚胎2枚,冷冻胚胎复苏利用率达到94.44%（34/36）,A级胚胎率达到61.11%（22/36）,移植34枚,产羔17只,冷冻胚胎复苏移植产羔率达50.00%;保存30年的冷冻精液复苏后平均精子活力达35%,受胎率为58.57%,平均产羔1.90只;保存20年冷冻精液复苏后平均精子活力达31%,受胎率为53.66%,平均产羔1.95只;胚胎复苏移植羊、30和20年冷冻精液后代体型外貌鉴定均符合纯种湖羊特征,没有畸形个体;羔羊一级羔皮率分别是31.25%、42.03%和23.81%,保持了当年湖羊的羔皮特性;生长发育及繁殖性能与现有湖羊群体性能基本保持一致。【结论】 利用超低温冷冻技术长期保存湖羊冷冻胚胎和冷冻精液的方法是可行的,对地方品种保种具有重要意义。     

Frozen Turkey Semen

Semen samples from Bronze turkeys, extended with Brown's buffer and antibiotics, and protected with combinations of ethylene glycol-glycerol and N,N-dimethylacetamide-glycerol were frozen at the rate of 8°C per minute down to -196°C. Similar treatments were used as controls. Five White virgin hens were inseminated with semen from each group before and after dialysis. The per cent fertility of the frozen semen samples after dialysis was lower than the corresponding control groups.     

Use of Cholesterol‐Loaded Cyclodextrin in Donkey Semen Cryopreservation Improves Sperm Viability but Results in Low Fertility in Mares

The use of cholesterol‐loaded cyclodextrin (CLC) on semen cryopreservation has been related with better sperm viability in several species; however, the effect on fertility is not known in donkey semen. Ejaculates (n = 25) from five donkeys were diluted in S‐MEDIUM with 0, 1, 2 or 3 mg of CLC/120 × 10⁶ spermatozoa. Semen was frozen, and thawed samples were evaluated by computer‐assisted sperm analyser system (CASA), supravital test, hyposmotic swelling test and fluorescent dyes to assess the integrity of sperm membranes. Mares (n = 60) were inseminated with frozen‐thawed semen treated with the doses of 0 or 1 mg CLC. Percentages of sperm with progressive motility and with functional plasma membrane were greater (p < 0.05) in the CLC‐treated groups than in the control. Percentages of intact plasma membrane and intact plasma membrane and acrosome detected by fluorescent dyes were also greater (p < 0.05) in CLC‐treated groups. Although no difference (p > 0.05) in conception rates was detected between groups (control, 3/30, 10%; CLC‐treated, 1/30, 3.3%), fertility was low for artificial insemination programs in mares. Therefore, we firstly demonstrated that frozen semen treated with CLC in S‐MEDIA extender before freezing improves the in vitro sperm viability, but semen treated or not with CLC in S‐MEDIUM extender results in a very low conception rate in mares inseminated with thawed donkey semen.