Induction of short-term pseudopregnancy in gilts by the administration of estradiol benzoate or estradiol dipropionate to achieve ovulatory synchronization for embryo collection

A study was conducted to investigate whether ovulation in gilts could be synchronized for embryo collection by the administration of estradiol benzoate (EB) or estradiol dipropionate (EDP) to induce pseudopregnancy, followed by the treatment with prostaglandin F_2α (PGF_2α) on 10 days after. Ten gilts each received a total of 20 mg of EB or EDP on Day 10 or EB on Day 10 and 14 to induce pseudopregnancy (Day 0 = onset of estrus). Donors received PGF_2α 10 or 15 days (as a control) after the first administration of estrogens and subsequently eCG and hCG, and were then inseminated artificially. The embryos were collected 7 days after the administration of hCG, and assessed for embryo yield and their developmental stages. All protocols resulted in good embryo yield (9.8–13.2 embryos in average), and the embryos showed average ability to develop to the expanded blastocyst stage (3.29–4.03 as developmental scores) without any significant differences among the protocols. These results suggest that the administration of PGF_2α 10 days after the treatment of gilts with EB or EDP would allow synchronization of ovulation and embryo collection, as well as shortening the period from estrus detection to embryo collection, thus improving embryo collection efficiency.     

德系乳肉兼用型西门塔尔牛胚胎移植效果研究

[目的]建立德系乳肉兼用型西门塔尔牛群体,探索文山牛快速扩繁和生产性能提升技术。[方法]在马关县从600头文山黄牛、西本杂、安本杂和短本杂牛母牛中选择270头,用CIDR+PG法进行同期发情处理,选择黄体合格的受体,采用非手术法移植德系乳肉兼用型西门塔尔牛胚胎,在移植后60~90 d通过直肠检查法进行妊娠诊断,确定妊娠率,跟踪调查产犊情况,并测定胚胎移植所产犊牛的初生体重和主要体尺指标。[结果]受体牛同期发情处理270头,胚胎移植87头,妊娠28头,移植妊娠率32.18%;妊娠母牛中产犊17头,产犊率60.71%,产犊19头,成活16头,产犊成活率84.21%。公母犊牛平均的初生重33.00 kg,体高69.50 cm,体斜长62.19 cm,胸围72.69 cm,管围13.50 cm。[结论]首次在文山州开展了牛胚胎移植获得成功,杂交牛受体的移植妊娠率极显著或显著高于文山牛受体,秋季移植的妊娠率极显著高于春季和冬季的。提示以杂交牛为受体在秋季进行胚胎移植可有效提高移植成功率。     

不同同期发情处理方法对威宁黄牛胚胎移植效果的影响研究

[目的]研究不同同期发情处理方法对威宁黄牛胚胎移植效果的影响。[方法]采用CUE-MATE孕酮栓＋PG法和PG注射法进行对比试验,并分析结果。[结果]PG注射法的可移植率、产犊率均优于CUE-MATE孕酮栓＋PG法。[结论]采用PG注射法和CUE-MATE孕酮栓＋PG法对威宁黄牛进行同期发情处理后,PG注射法的胚胎移植...     

波尔山羊胚胎移植技术的研究与应用

对 75只波尔山羊超排处理 ,共获 A、B级胚胎 776枚 ,平均 (10 .35± 6 .4 5 )枚 /只 ,鲜胚移植受体 36 7只 ,移植产羔率达 5 5 .6 %。应用 CIDR和 PMSG同期发情处理受体山羊 5 6 0只 ,5 4 9只达到同期发情 ,32 h内同期率为 98.0 4 %。囊胚和扩张囊胚在发情后 7d的移植产羔率分别为 6 2 .2 2 % (84 /135 )和 5 8.2 6 % (6 7/115 ) ,显著高于桑椹胚 (43.18% )和孵化囊胚 (5 1.72 % ) (P<0 .0 1) ,而囊胚和扩张囊胚间、桑椹胚和孵化囊胚间差异不显著 (P>0 .0 5 )。受体山羊的黄体数量直接影响到移植产羔结果 ,黄体数≥ 2的受体山羊移植产羔率显著高于黄体数为 1的受体山羊移植产羔率 (P<0 .0 1) ,分别为 6 4 .83% (94 /14 5 )和 4 9.5 5 % (110 /2 2 2 )。PMSG注射时间 (在取 CIDR前 2 d或当天注射 )和剂量对受体羊的黄体数和移植产羔率均无显著影响 (P>0 .0 5 )     

胚胎移植供受体山羊发情控制及配比问题的研究

用含１８甲基炔诺酮６０ ｍ ｇ 的阴道海绵栓预处理１１３ 只供体羊 １４～１５ ｄ后注射 Ｆ Ｓ Ｈ 进行超排,３６ ｈ 或４８ ｈ 后撤栓。１９９ 只受体羊用含炔诺酮５０ ｍ ｇ 的阴道栓处理,撤栓时注射或不注射 Ｆ Ｓ Ｈ 进行同期发情。结果表明,供、受体羊发情开始距撤栓的平均间隔时间分别为（３３．９±９９） ｈ 和（４４．３±１６．１） ｈ（ Ｐ＜ ０．０５）,供、受体羊发情持续期长短相似（ Ｐ＞ ０．０５）。撤栓时注射 Ｆ Ｓ Ｈ ２５ Ｉ Ｕ 或 ３３ Ｉ Ｕ 的受体羊,卵巢上形成功能黄体的比率分别为６４．０％ 和 ６０．７％ ,显著高于不注射 Ｆ Ｓ Ｈ的受体羊（４２．２％ , Ｐ＜ ０．０５）。结论认为,用本研究采用的超排及同期发情程序,受体撤栓时间应与供体相同或早于供体羊１２ ｈ;受体羊撤栓时应注射 Ｆ Ｓ Ｈ ２５ Ｉ Ｕ;根据供体羊回收可用胚胎数及同期发情后可用受体数量,供、受体羊的适宜比例为１∶６～１∶８。     

绵羊胚胎移植受体同期发情方法的比较

为了比较CIDR＋PG与CIDR＋PG＋PMSG两种激素处理方法对于受体同期发情以及胚胎移植的效果,将103只小尾寒羊作为胚胎移植受体分为两组,分别使用上述两种方法进行同期发情处理。其中,CIDR＋PG组83只,CIDR＋PG＋PMSG组20只。在对供体羊人工输精后第6．5天获取移植囊胚,分别移植到两组受体子宫内。统计受体的发情率、黄体生成情况,以及移植后的妊娠情况。CIDR＋PG组与CIDR＋PG＋PMSG组受体羊发情率分别为87．95％、90．00％;有黄体羊的比例分别为37．35％和75．00％,平均黄体数为1．81和1．93个;两组受体胚胎移植后妊娠率分别为77．41％和86．67％。结果表明,使用CIDR＋PG＋PMSG进行同期发情效果较好,且胚胎移植后妊娠效果较好。     

Effects of the estrous cycle on the efficacy of oocyte collection and in vitro embryo production in Duroc‐breed

Collection efficacy and in vitro embryo developmental ability of oocytes obtained from Duroc‐breed ovary donors at different stages of the estrous cycle (days 6, 12 and 16 after estrus) were performed. The numbers of collected oocytes did not differ significantly among the different estrous cycle groups (total 72–90 oocytes per gilt). However, the blastocyst rates of oocytes collected on days 12 and 16 (9.2% and 19.4%, respectively) were significantly higher than those on day 6 (1.1%). More oocytes were obtained on day 16 from small follicles (<2 mm in diameter; 85.3 oocytes per gilt) than from medium‐sized (≥2–<6 mm) and large (≥6 mm) follicles (17.5 and 12.8 oocytes, respectively). The blastocyst rates in both the medium‐sized and large follicle groups (20.0% and 19.2%, respectively) were significantly higher than that in the small follicle group (6.3%). The blastocyst cell numbers in both the medium‐sized and large follicle groups (39.4 and 43.3 cells, respectively) were significantly higher than that in the small follicle group (30.6 cells). The results suggest that oocyte collection from cycling Duroc pigs can be carried out efficiently from the late luteal to follicular stage. Those oocytes collected from medium‐sized and large follicles show better embryo development.     

超排过程中不同发情时间对胚胎生产效果的影响

在牛胚胎生产过程中,由于不同牛只存在个体差异（如超排月龄、体重、营养状况、卵巢发育情况及初情期月龄等）,其对外界环境的适应能力存在不同的差异;目的：如何有效的控制好供体母牛同期发情的发情时间,提升超排后胚胎的质量与数量。方法：笔者选用10-16月龄的纯种肉用型西门塔尔牛进行胚胎生产,通过对112头次10-16月龄牛只超排进行胚胎生产并对相关数据进行统计分析;结果：根据认真观察记录供体牛只拆栓后的发情期表现,出现部分牛只提前发情或延迟发情现象,其中大部分牛只处于拆栓后24h前后两h集中发情情况;结论：供体母牛在拆栓后24h前后两h集中发情的牛只,其头均生产胚胎的数量与质量均优于延迟发情和提前发情的牛只。     

高产奶牛性控雌性冻胚规模化移植试验

从美国引进高产奶牛性控雌性胚胎，在农村条件下，选择自然发情的黄牛作受体，移植合格受体牛648头。结果显示，自然发情黄牛924头中，经直肠检查合格受体牛648头，使用合格率为70．13％（648／924）；氯前列烯醇同期处理476头，使用合格率为36．13％（172／476），差异极显著（P〈0．01）。80～100d怀孕检查，自然发情移植成功率41．98％（272／648），同期发情移植成功率40．12％（69／172），差异不显著（P〉0．05）。自然发情黄牛不同黄体级别的移植成功率分别为：A级44．09％（41／93），B级42．43％（199／469），C级37．21％（32／86），差异不显著（P〉0．05）。单胚移植580头，移植成功率42．41％（242／580），双胚移植68头，移植成功率44．12％（30／68），差异不显著（P〉0．05）。正常胚胎单枚移植541头，移植成功率42．51％（230／541），裸胚单枚移植39头，移植成功率30．77％（12／39），裸胚比正常胚移植成功率低11．74％。怀孕牛已出生犊牛83头。其中母犊79头．公犊4头，母犊占95．18％，与自然发情的性比例（50％）相比较，差异极显著（P〈0．01）。     

Effects of milk replacer and starter diet provided as creep feed for suckling pigs on pre‐ and post‐weaning growth

This study was aimed at investigating the long‐term effects of provision of liquid milk replacer (MR) and solid starter diet (SD) during lactation on post‐weaning (PW) growth of pigs. In experiment 1, 33 cross‐bred litters were allotted to four treatments: no supplement (CON), MR ad libitum, SD ad libitum and 100 g SD/litter/day from lactation day 4 through weaning at day 21 during late fall. In experiment 2, 40 litters received MR or none in July. PW pigs received commercial diets to marketing. In experiment 1, weaning weight (WW), pre‐weaning average daily gain (ADG) and mortality (2.4%) were not influenced by creep‐feeding MR or SD. ADG was greater (P < 0.05) in the MR group versus CON during days 21–54, but did not differ across the treatments during days 54–162. In experiment 2, ADG during lactation and WW were greater in the MR group versus CON, with mortality lower in the former (5.6 vs. 10.3%). However, PW ADG to day 175 did not differ between the two groups. Results suggest that creep‐feeding MR or SD has no effect on PW growth. However, it remains possible that MR reduces PW mortality during the hot season.     

Bisphenol A attenuates thyroxine‐induced apoptosis in ovarian granulosa cells of pigs

Bisphenol A (BPA) is a chemical of high production volume that is used widely in many industries and is known as a xenooestrogen and anti‐thyroid hormone endocrine disrupter. There is little information regarding the effects of BPA in the presence of thyroid hormone on porcine granulosa cell development. Thus, the primary granulosa cells were treated with thyroxine (T4, 10 nM), BPA (10 µM) or T4 plus BPA; we subsequently evaluated the effects of T4 or BPA on 17β‐estradiol synthesis, cellular proliferation and apoptosis. Our data showed that BPA significantly increased the accumulation of 17β‐estradiol and promoted granulosa cell proliferation, whereas T4 significantly decreased 17β‐estradiol and had no effect on cellular proliferation. In addition, it was noteworthy that T4 treatment induced apoptosis in porcine granulosa cells and BPA co‐incubation attenuated T4‐induced apoptosis as shown from flow cytometric assay analysis. We hypothesized that BPA attenuates T4‐induced apoptosis by regulating 17β‐estradiol accumulation and oestrogen receptor‐mediated signalling pathways. In conclusion, our results demonstrated that T4 affected 17β‐estradiol accumulation and induced cellular apoptosis, but did not affect granulosa cell proliferation. Exposure to BPA increased 17β‐estradiol accumulation, promoted granulosa cell proliferation and attenuated T4‐induced apoptosis in porcine granulosa cells in vitro.     

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non‐surgical embryo recovery in oestrous‐induced Santa Inês ewes

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.     

Development of large and small blastomeres from 2‐cell embryos produced in vitro in pigs

In the present study, we examined the development to blastocysts of large and small blastomeres from unevenly cleaved 2‐cell embryos (uneven 2‐cell embryos) in pigs. Proportion of blastocysts derived from large blastomeres (52.8 ± 6.4%) was significantly higher (P < 0.05) compared with small ones (32.1 ± 4.6%). However, there were no differences in total cell number, inner cell mass (ICM) cell number and ICM/total cells ratio between them. Of 53 sister blastomere pairs in the same embryos examined there were 12 pairs (22.6%) in which both blastomeres developed to blastocysts, 16 pairs (30.2%) in which only large blastomeres developed to blastocysts, and five pairs (9.4%) in which only small blastomeres developed to blastocysts. Relative total amount of active mitochondria in small blastomeres were lower (P < 0.05) than that of large blastomeres and blastomeres from evenly cleaved 2‐cell embryos. However, there was no difference in relative density of active mitochondria in these three types of blastomeres. In conclusion, blastocysts derived from small and large blastomeres in uneven 2‐cell embryos had comparable quality in terms of cell number, ICM number, ICM/total cell ratio and distribution of active mitochondria. The results suggest that these blastomeres may contribute multiple offspring production in pigs.     

Duration of estrus induced after GnRH‐PGF2α protocol in dairy heifer

Estrous expressions in dairy cows have been shortened and weakened. Dairy heifers, on the other hand, may not have had such changes in estrous signs as observed in cows, since they have less stresses than cows. The aim of this study was to describe the duration of estrus in a herd of dairy heifers. A total of 56 Holstein Friesian heifers estrus was synchronized using two different hormonal protocols. They were checked for primary and secondary estrous signs with the help of heat detection devices for 48 h at an interval of 4 h starting at 16.00 hour, one day after PGF_2α treatment. Onset and end of standing estrus during 48 h observation period was recorded in 35 of the 44 heifers coming into estrus within 5 days after PGF_2α treatment during the observation period. The duration of standing estrus on the average (±SD) was 9.7 ± 5.3 h. Percentage of heifers with standing estrus longer than 12 h was 40%, and 53% showed standing estrus only for 4–8 h. It is indicated that duration of estrus in dairy heifers has been shortened recently.     

Utilization of porcine in vitro‐produced parthenogenetic embryos for co‐transfer with vitrified and warmed embryos

The present study was conducted to evaluate the possibility of using in vitro‐produced parthenogenetic (PA) embryos for co‐transfer with morulae that had been collected in vivo and cryopreserved. The proportion of PA blastocysts (20.5%) was higher than that of their in vitro fertilization (IVF) counterparts (16.6%). Although there were no differences in morphology or diameter between the two groups, the number of cells in early PA blastocysts after in vitro culture for 6 days was lower than for IVF blastocysts (25.7 and 30.4 cells, respectively), and the number in recovered PA blastocysts was also smaller than that in recovered IVF blastocysts (37.4 and 50.2 cells, respectively). When 10 morulae warmed after vitrification were co‐transferred with 10 PA blastocysts (total 20 embryos) to the uterus of five recipients, the rates of pregnancy and farrowing did not differ, but the average period until spontaneous abortion tended to be longer relative to the control (when 20 morulae were transferred). These data suggest that in vitro‐produced PA embryos offer the possibility of assisted pregnancy for cryopreserved embryos; further experiments will be needed to confirm the beneficial effect of this approach on piglet production.     

A between‐experiment analysis of relationships linking dietary protein intake and post‐weaning diarrhea in weanling pigs under conditions of experimental infection with an enterotoxigenic strain of Escherichia coli

Numerous experiments have demonstrated that feeding a lower protein diet decreases protein fermentation in the gastrointestinal tract (GIT) and reduces the incidence of post‐weaning diarrhea (PWD). However, there is a lack of holistic evidence underpinning the relationship between feeding a lower protein diet and PWD in relation to physiological responses and protein fermentation in the GIT. The scope of this article, therefore, will: (i) focus on the impact of dietary protein levels on selected indices of GIT health in weaned pigs without and with experimental infection with an enterotoxigenic strain of Escherichia coli; and (ii) attempt to conduct regression analysis to examine the relationships between dietary‐origin protein intake, nitrogen fermentation indices, fecal consistency and the incidence of PWD. We used datasets generated from a series of four intensive experiments in weaned pigs. The collective results derived from these datasets indicate that restriction of daily protein intake to less than 60 g through feeding a lower protein diet for as little as 7 days after weaning reduced the incidence of PWD commensurate with a reduction in protein fermentation indices.     

Description of post‐implantation embryonic stages in European roe deer (Capreolus capreolus) after embryonic diapause

The embryonic stage of development is defined as the period between fertilization and the establishment of most of the organ systems by the end of this period. Development in this stage is rapid. In many mammalian species, particularly in humans, the interval between fertilization and implantation is exactly determined and continuous without intermission. However, European roe deer (Capreolus capreolus) embryos undergo a reversible retardation of development. This interesting reproduction strategy is called embryonic diapause (delayed implantation). After this period of embryonic arrest, development continues without further interruption. The aim of this study was to investigate embryonic development after diapause in European roe deer. Because of the embryonic diapause and the unknown date of fertilization, it was impossible to assign the embryos to a certain gestational age (days). This study describes normal stages of embryonic development mainly based on the external morphological traits of 56 well‐preserved post‐implantation roe deer embryos and attempts to assign the embryos to certain development stages. Carnegie stages of human embryos were used as an orientation for staging roe deer embryos. We observed a considerable range of variation of embryonic stages investigated until the end of January. We found post‐implantation stages of embryonic development already at the end of December and foetuses at the end of January. Moreover, assigning the embryos to a particular stage of development allows the comparison between pairs of twins and triplets. We showed that twins and triplets were always at the same development level, despite the discrepancy in inter‐twin and inter‐triplet size.     

Sucrose assists selection of high‐quality oocytes in pigs

We investigated whether high‐quality in vitro matured (IVM) oocytes can be distinguished from poor ones based on the morphological changes after treatment with hyperosmotic medium containing 0.2 mol/L sucrose in pigs. We hypothesize that IVM oocytes maintaining round shape have higher quality than mis‐shapened oocytes following dehydration. Oocyte quality was verified by determining embryonic developmental competence using in vitro fertilization, nuclear transfer and parthenogenetic activation. In all cases, the round oocytes had greater (p < .05) developmental competence than that of mis‐shapened oocytes in terms of blastocyst rate and total cell number in blastocysts obtained after 6 days of in vitro culture. We also confirm that round aged oocytes are higher in quality than mis‐shapened aged oocytes. In an attempt to find out why high‐quality oocytes maintain a round shape whereas poorer oocytes become mis‐shapened following sucrose treatment, we examined the arrangement of actin microfilaments and microtubules. Abnormal organization of these cytoskeletal components was higher (p < .05) in mis‐shapened oocytes compared to round oocytes after 52 hr of IVM. In conclusion, sucrose treatment helps selection of high‐quality oocytes, including aged oocytes, in pigs. Abnormal cytoskeleton arrangements partly explain for low developmental competence of mis‐shapened oocytes.