受体绵羊人工授精后移植胚胎的试验

试验通过使用人工授精后绵羊作为受体进行胚胎移植,以寻找一种更加有效的方法提高绵羊胚胎移植的经济效益。试验中使用FSH对10只无角道赛特绵羊进行超数排卵处理,同时对60只受体小尾寒羊进行同期发情。供体羊在发情配种后4.5～5.0d从子宫角收集胚胎。同时,将胚胎移植到同期发情并进行人工授精的受体羊子宫内。总共有57枚可用胚移植给44只受体小尾寒羊,32只怀孕到分娩,共产下羔羊51只(无角道赛特羔28只,道赛特与小尾寒羊杂种羔23只)。此外,经人工授精但未进行手术移植的7只小尾寒羊产下15只杂种羔羊。移胚植受体妊娠率72.7%(32/44),移胚受体繁殖率118%(51/44),受体利用率88.3%(53/60)。移胚受体总妊娠率和受体利用率均显著高于常规ET组(P<0.01)。与常规胚胎移植相比,受体羊人工授精后移植胚胎不仅提高了无角道赛特母羊的繁殖率,而且提高了受体羊的利用率。     

不同品种受体对绵羊胚胎移植效果及羔羊早期生长性能的影响

旨在探讨以小尾寒羊和蒙古羊作为受体时,二者的胚胎移植效果及所产羔羊的早期生长性能之间的差异。选用南非肉用美利奴羊(n=11)和澳洲白绵羊(n=110)作为供体,以小尾寒羊(n=196)和蒙古羊(n=504)作为受体;对供体母羊进行超数排卵以及人工授精处理,记录供体母羊的收集胚胎总数和可用胚胎数,计算平均每只羊收集的可用胚胎数以及胚胎合格率;对小尾寒羊和蒙古羊进行同期发情及胚胎移植处理,记录受体母羊的产羔数,计算繁殖率;计算并比较不同受体母羊所产羔羊的平均初生重、成活率以及70日龄断奶羔羊数、70日龄断奶重、平均日增重、平均每只母羊提供的断奶羔羊数。结果表明,从供体母羊中共获得可用胚胎549枚,平均每只羊收集可用胚胎4.54枚,胚胎合格率为82.56%;利用胚胎移植技术,移植受体母羊529只,所产羔羊240只,平均繁殖率为45.37%;小尾寒羊的发情率和繁殖率明显高于蒙古羊;共获得70日龄断奶羔羊211只,羔羊成活率为87.92%,平均日增重为280.00g;小尾寒羊和蒙古羊所产的羔羊初生重没有显著差异(P>0.05),小尾寒羊所产羔羊的70日龄断奶重和平均日增重分别极显著(P<0.01)和显著(P<0.05)高于蒙古羊,而蒙古羊所产羔羊的成活率显著高于小尾寒羊(P<0.05);平均每只小尾寒羊母羊可提供的断奶羔羊数(0.42只)略高于蒙古羊(0.39只),小尾寒羊作为胚胎移植受体略具有优势。综合分析表明,在内蒙古兴安盟地区小尾寒羊和蒙古羊均可以作为胚胎移植的受体来使用。     

A Programme for Oestrus Synchronization and Embryo Transfer in Sheep

Eighty-five animals were used to develop an embryo transfer programme including a study on how oestrus synchronization influenced the ovulation rate. The animals, both ewes and ewe lambs, were divided into three groups: donors, recipients and controls. Oestrus was synchronized in donors and recipients by the use of progesterone-impregnated vaginal pessaries. The donors also received one injection of 600 IU PMSG. Samples for microbiological investigation of the vaginal flora were taken in connection with synchronization. The ovulation rate was determined by laparoscopy in the control animals and by laparotomy in the donors and recipients. The embryos were surgically recovered from the donors by flushing of the uterine horns seven days after pessary removal. The embryos were classified according to developmental stage and quality. At transfer each recipient received 2–4 embryos (moruhs or blastocysts) by a surgical method. A ± 1 day asynchrony in oestrus between donors and recipients was tolerated. All synchronized animals came into oestrus within 2.5 days after pessary removal. The interval was shorter if the animals had been injected with PMSG. The largest number of ovulations occuwed in the synchronized and PMSG-treated animals (mean 4.5 ± 2.1). Synchronized animals that did not receive PMSG had almost the same ovulation rate as the control animals (2.6 ± 0.9 versus 2.5 ± 0.7). The pessary treatment influenced the bacterial flora of the vagina. The number of ewes with bacterial growth in the vagina increased. The number of isolated organisms also increased. The embryo recovery rate was 80.8% and 3.7 ± 2.7 ovas was recovered on average. Eighty-eight percent of all donors yielded transferable embryos. Morulas and blastocysts comprised 84.4% of the recovered oocytes/embryos. Only 5.2% of these were of poor quality. Of the transferred embryos, 65.1% developed into lambs and 91.3% of the recipients lambed. The ewe lambs were as suitable as donors and recipients as the older ewes.     

Congenital arthrogryposis: an inherited limb deformity in pedigree Suffolk lambs

Thirty of 52 pedigree Suffolk lambs (58 per cent) were born with arthrogryposis characterised by bilateral flexion rigidity of the metacarpophalangeal and carpal joints. The recent introduction of a breeding ram was identified as the only significant risk factor in the flock, and embryo transfer was used to test the hypothesis that the arthrogryposis was an inherited disorder associated with the introduction of this ram. Two adult ewes that had previously produced lambs with arthrogryposis by the ram and four of its affected daughters were available as donors, and 20 crossbred ewes were used as recipients. Ten Suffolk-crossed ewes that had no known familial relationship with the ram were also mated by the ram as controls and they produced 10 normal lambs. Following embryo transfer, 19 lambs were born, of which seven were stillborn; arthrogryposis was evident in 10 of the 12 live lambs. Analysis of the data suggested that in the population under study, arthrogryposis was inherited as an autosomal recessive condition.     

季节对杜泊羊体内胚胎生产与移植效果的影响

为了研究季节对杜泊羊体内胚胎生产效率及胚胎移植妊娠率的影响,于2016年选取内蒙古赛诺草原羊业有限公司种羊场经产纯种杜泊母羊作为供体,采用同期发情、超数排卵及腹腔镜人工输精等方法对供体羊进行处理后,利用手术冲胚的方法获得纯种杜泊羊胚胎,同时对受体羊进行同期发情处理和胚胎移植。经统计分析,2016年全年该公司共有放栓供体4 241只,超排处理4 180只,配种供体4 131只,冲胚供体3 987只,供体可用率为94.01%;冲出胚胎总数为23 516枚,可用胚胎18 002枚,胚胎可利用率为76.55%,平均每只供体能获得可用胚胎4.52枚。供体在10月、11月、12月冲胚所获得的平均冲胚数和平均可用胚数明显高于4月、5月、6月(P<0.05),其中10月的平均冲胚数和平均可用胚数最高(P<0.01),分别为7.04枚和5.62枚。将获得的部分胚胎用于胚胎移植,移植单胚怀孕受体数为4 446只,妊娠率为53.67%;移植双胚怀孕受体数805只,妊娠率65.02%。此外,受体在1月、3月、6月、12月受胎率较其他月份高(P<0.05)。该研究可为杜泊种羊超数排卵、胚胎移植和肉羊的产业化生产提供一定的数据参考。     

Production of prolific microsheep by embryo transfer into large non-prolific sheep

The Garole is a prolific breed of microsheep that possesses the FecB gene, which increases ovulation rate. The purpose of this study was to compare embryo production by multiple ovulation in seven Garole ewes with that in seven normal size, non-prolific Malpura ewes, and assess the influence of the large body size of Awassi crossbred recipient ewes on the birth-weight of Garole lambs. Oestrus was synchronised with two intramuscular injections of 7.5 mg prostaglandin F(2alpha) administered 10 days apart. The donor ewes were superovulated by the use of pregnant mare serum gonadotrophin and follicle-stimulating hormone. The onset and duration of oestrus were similar in both breeds. The Garole donors had higher total mean (se) ovarian responses (15.6 [3.6] v 9.1 [2.3]), ovulation rate (13.6 [3.1] v 8.4 [2.2]) and produced more transferable embryos (6.0 [3.5] v 4.0 [0.9]) than the Malpura donors, but the differences were not statistically significant. The Garole lambs produced by embryo transfer were on average 57.8 per cent heavier at birth than contemporary Garole lambs produced by natural mating.     

Effect of Inter‐Breed Embryo Transfer on Lamb Growing Performance and Survival

The roles of recipient and embryo genotype in determining the growth performance and survivability of offspring based on specific behavioural differences were investigated using inter‐breed embryo transfer. This study was carried out using three recipient genotypes (Awassi, Redkaraman and Tuj) and two embryo genotypes (Charollais and Romanov) to obtain the six possible combinations of ewe and lamb genotypes. Data were collected from 71 recipient ewes (10 Redkaraman with Charollais and 15 Redkaraman with Romanov embryos; 10 Tuj with Charollais and 12 Tuj with Romanov embryos, and 12 Awassi with Charollais lambs and 12 Awassi with Romanov embryos); all ewes received two frozen‐thawed embryos. Awassi ewes had a significantly longer duration of the licking/grooming event (25.5 min, p < 0.05) than Tuj ewes. Charollais lambs were significantly (p < 0.05) more likely to require birth assistance compared to Romanov lambs. Romanov lambs were significantly more (p < 0.01) active than Charollais lambs in the first 2 h after birth; ewe breed had no effect on lamb behaviour. There was no recipient breed effect on either birth or weaning weights of lambs. Charollais lambs were recorded with higher birth (5.5 ± 0.3 kg vs 3.9 ± 0.2 kg; p < 0.001) and weaning (29.4 ± 1.2 kg vs 22.4 ± 1.9 kg; p < 0.001) weights compared to Romanov lambs. At weaning Romanov lambs had significantly higher (95% vs 75%; p < 0.05) survival rates, however, this was not significantly affected by recipient breed. It was concluded that recipient breed was not an important factor in survival and weaning performance of embryo transferred lambs from a prolific breed (Romanov) while these traits recorded for lambs from meat type (Charollais) embryos were influenced by dam breed.     

高寒牧区陶赛特绵羊鲜胚移植试验

选取兰州信合牧业34只陶赛特绵羊为供体,采用递减法注射FSH进行超排,采用人工授精配种,30只长途运输到青海省海北州西海镇手术法回收胚胎,鉴定后移植。155只藏系绵羊作为受体,采用两次PG注射进行同期发情,119只受体在西海镇移植,32只长途运输到甘肃兰州信合牧业进行移植。结果表明:34只供体获得胚胎共168枚,、每只供体平均获得4.94枚,合格率89.88%,151只受体表现发情,发情率为97.42%。其中,在西海镇移植的119只产羔73只,产羔率为61.34%,在兰州移植的32只产羔21只,产羔率为65.6%。     

胚胎移植试验羊群发情规律的研究

为了有效提高绵羊体细胞克隆和转基因等研究工作的效率,缩短胚胎移植试验羊群中空怀个体的利用周期间隔,试验对采用不同移植方法的胚胎移植受体及供体绵羊进行了移植前后的发情规律研究。结果表明:采用自制孕激素海绵栓和进口阴道孕激素释放装置(CIDR)对绵羊进行同期发情处理时发情率均接近90%,且92%以上的个体发情起始时间均集中在撤栓后24～48 h。在胚胎移植试验结束后,未参加胚胎移植个体和子宫角法未移植受体第2情期发情起始时间主要集中在上次发情后的14～20 d,而输卵管法未移植受体和输卵管法冲卵供体的发情时间则比较分散,呈现明显延后状态。未参加胚胎移植个体和子宫角法未移植受体人工授精后的受胎率接近往年羊场的平均水平,输卵管法未移植受体的受胎率略有下降,且输卵管法冲卵供体的受胎率明显降低。     

Early Pregnancy Diagnosis by Serum Progesterone and Ultrasound in Sheep Carrying Somatic Cell Nuclear Transfer-Derived Pregnancies

Early pregnancy diagnosis and monitoring play an important role following embryo transfer in sheep. The aims of the current study were to investigate (i) the pattern of serum progesterone profiles in sheep carrying somatic cell nuclear transfer (SCNT)‐derived (clone) pregnancies, and (ii) the frequency of pregnancy loss during development following SCNT embryo transfer. Sheep SCNT embryos were made using standard nuclear transfer techniques. Day 7 embryos were surgically transferred to oestrus‐synchronized recipients (n = 27). As a control, normal fertile ewes (n = 12) were bred by natural breeding. Serum was collected from all the ewes on the day of estrus (day 0 sample), 7 days post‐estrus (day 7 sample) and 19 days post‐estrus (day 19 sample) and every 10 days thereafter until lambing or pregnancy loss occurred. Serum progesterone (P4) was assessed using enzyme immunoassay. Pregnancy was confirmed by ultrasound scanning on day 35 of pregnancy followed by subsequent scanning every 10 days. In control ewes, pregnancy rate on day 35 was 83.3% (10/12), whereas in the ewes that received SCNT embryos, it was 22.2% (6/27; p < 0.05). The day 45 pregnancy rate in the control ewes was 83.3%, whereas in the SCNT embryo recipients it was 11.0% (p < 0.05). Hormone analysis revealed that SCNT embryo recipients exhibited a significantly lower P4 profiles at different time points in pregnancy compared to controls (p < 0.05). This study highlights the use of serum progesterone in combination with ultrasound for the investigation of embryo loss and crucial times during development of normal and SCNT embryos in sheep. Further, the serum P4 levels directly reflect the degree of placental development in these two groups.     

高原地区肉羊胚胎移植试验

2003年在青海省东部农业区和环湖牧区开展了以特克赛尔、萨福克和无角陶赛特为主要品种的肉羊胚胎移植试验。对农区55只小尾寒羊受体和牧区76只半细毛羊受体进行了同期发情处理,小尾寒羊同期发情率为81.28%,半细毛羊为63.16%。半细毛羊移植胚胎44枚,产羔13只,流产1只(双羔),移植受胎率为31.82%;每只小尾寒羊移植2枚胚胎,共移植20只受体40枚胚胎,产羔5只,其中1只母羊产双羔,受胎率为12.50%。所产18只羔羊全部成活。     

Nontransmission of bluetongue virus by embryos from bluetongue virus-infected sheep

Donor sheep were infected either by bites of bluetongue virus (BTV)-infected (serotype 11, "Texas Station strain") Culicoides variipennis or by inoculation with 100,000 median chicken embryo intravascular lethal doses of BTV (serotype 11) from a suspension made from infected C variipennis. Fourteen embryos from 4 BTV-infected ewes bred by rams not infected with BTV were transferred to 8 BTV-seronegative recipient ewes, and 35 embryos and 4 unfertilized eggs from 14 BTV-infected ewes bred by BTV-infected rams were transferred to 19 BTV-seronegative recipient ewes. Eleven pregnancies and 12 lambs resulted. None of the recipients or lambs seroconverted, and BTV was not isolated from the pregnant recipient ewes or their lambs at slaughter 30 days after parturition.     

Results of a crossbreeding experiment with sheep for different systems of fat lamb production. I. Reproductive traits

A crossbreeding experiment with sheep was carried out at two of the University's experimental stations between 1969 and 1973. On farm I ewes of five groups of different first crosses were tested against the indigenous purebred Merinoland sheep for five lambing periods. The ewes were kept under an accelerated lambing programme, the lambs were reared artificially. On farm II the same domestic breed was tested against three first cross lines with spring lambing and ewes suckling their lambs for 5 to 8 weeks. Each test group consisted of at least 50 ewes made up of 10 halfsib groups. 10 rams of each of four exotic fat lamb sire lines were hand-mated to the ewes. In addition, purebred and special control matings were carried out. All ewes in the experiment were of the same age.The data were analyzed by least squares procedures for different reproductive traits (gestation length, litter size for lambs born and reared, litter weight, score for lambing difficulties) and by simple one-way classifications for various others (lambs born and reared per ewe and year, lambing frequency, body weight, fleece weight, wool income).Since no significant interactions among main effects were detected for any trait, the presentation of the results emphasizes the general combining ability of the sire and dam lines. No significant differences were found between sire lines on both farms in all traits except gestation length. For the most important reproductive traits the differences between the dam lines were highly significant, the Finnish Landrace crosses being the best in both lambing frequency and number of lambs per litter. The superiority of these crosses cannot be maintained for the number of lambs reared and slaughtered, if, like in farm II, facilities are not available to rear lambs of large litters without high losses.     

Ultrasonographic monitoring of 103 recipient mares of different reproductive status during the first 30 days after embryo transfers

Ten pluriparous mares were used as donors to supply embryos which were transferred into 103 recipients, 31 of which were nulliparous, 34 were pluriparous and lactating, and 38 were pluriparous and non-lactating. The embryos were recovered eight days after ovulation and pregnancy was confirmed by ultrasound six days after the transfer; the length of the embryos was measured ultrasonographically on days 12, 14, 16, 18, 20, 25 and 30 after the embryo transfer. One hundred and fifteen of 200 flushes provided embryos, 12 being degenerate and 103 being viable embryos. From the 103 embryo transfers carried out, 51 pregnancies were confirmed by ultrasound within 30 days; 16 of the 31 nulliparous recipients became pregnant, 16 of the 34 pluriparous lactating recipients and 19 of the 38 pluriparous non-lactating recipients. There were no significant differences between the groups of mares in the mean (sd) rate of growth of their embryos between 12 and 30 days of gestation.     

Multiple Factors Affecting Superovulation in Poll Dorset in China

To expand the breeding flock of Poll Dorset sheep in China, multiple ovulation and embryo transfer breeding program was applied to the limited number of imported Australian Poll Dorset sheep. This study investigated the effects of FSH from three different manufacturers, parity (nulliparous vs multiparous), repeated superovulation, oestrus induction, corpus luteum regression and oestrus delay on Poll Dorset superovulation. The results showed that gonadotropin FSH from Canada Folltropin‐V (Ca‐FSH) was successfully used for superovulatory treatment with 160 mg–200 mg dosage per ewe and recovered 12.91 ± 7.80 embryos. Multiparous ewes for superovulation treatment were significantly better nulliparous ewes (p < 0.05). The successive superovalution treatment reduced significantly embryo collection but did not affect transferable embryo number. Ewes with natural oestrus resulted in significantly higher number of embryos (13.83 ± 4.64) and of transferable embryos (12.00 ± 5.76) than ewes with induced oestrus (7.00 ± 4.92; 4.22 ± 3.42) and unknown oestrus cycle (5.94 ± 3.38; 3.19 ± 2.56, p < 0.05). The delayed oestrus ewes at 24 h after superovulatory treatment produced significantly fewer embryos and transferable embryos (0.92 ± 1.51 vs 0.42 ± 0.90) than those with normal oestrus (p < 0.01). Furthermore, the more transferable embryos were recovered from ewes with normal corpus luteum than those with corpus luteum regression (5.88 ± 5.09 vs 3.59 ± 4.30 and 8.83 ± 5.75 vs. 6.66 ± 5.41, p < 0.01). These results suggest that in our farm practice, a comprehensive treatment method by using the Canadian FSH (Folltropin‐V), plus choosing multiparous and natural oestrus ewes with normal corpus luteum might obtain an optimum embryo collection and embryos transfer in sheep.     

Studies on factors affecting superovulation and embryo transfer in Hungarian merino ewes

The objectives of this study were (a) to assess the ovulatory response and embryo production of Hungarian Merino ewes after superovulation, (b) to investigate the factors influencing the efficiency of embryo transfer (ET) in Hungarian Merino ewes, (c) to compare the results of two ovarian stimulation protocols (PMSG and PMSG + FSH treatment) in Hungarian Merino ewes, and (d) to study how superovulation, laparoscopic insemination and surgical embryo retrieval (ER) affect the subsequent reproduction of Hungarian Merino donor females after an ET programme. There was no significant difference between the ovarian stimulation protocols in the ratio of donor ewes responding to superovulation nor in the average number of corpora lutea. However, the number of transferable embryos recovered per donor ewe was higher in the PMSG + FSH group. The proportion of transferable embryos, unfertilized oocytes and degenerated embryos did not differ between the treatment protocols. The total pregnancy rate was 53.4% (179/335). Neither the developmental stage of the embryo nor the number of transferred embryos affect the implantation of embryos. However, the increased number of transferred embryos positively influenced the pregnancy rate. No difference was found in the pregnancy rate between synchronised and non-synchronised groups of recipients. Thirty-six out of 45 donor ewes (80%) became pregnant within one year after the ET programme, indicating that ovarian stimulation and surgical ER did not affect adversely their reproduction.     

Use of embryo transfer to induce twinning in beef cattle: embryo survival rate, gestation length, birth weight and weaning weight of calves

Experiments were conducted in 1985 and 1986 at the Eastern Ohio Resource Development Center, Belle Valley, to examine the feasibility of using embryo transfer to induce twinning and to examine the influence of twinning on traits of the cow and calf. Embryos were collected from a total of 14 superovulated Angus donors on two dates each in 1985 and 1986 and were transferred to Angus recipients. A total of 124 embryos were transferred to 79 recipients, with 43 (34.7%) calves born alive. Seven of 45 (15.6%) recipients implanted with two embryos produced twins. In no case did both halves of the 15 embryos that were split to produce identical twins and implanted in the same recipient survive to birth. Proportion of calves born alive did not differ among transfer codes 3 (nonsplit embryos from two different donors implanted in separate uterine horns of the same recipient), 6 (nonsplit embryos from one embryo flush implanted in separate uterine horns of the same recipient) and 7 (nonsplit embryos from two different donors implanted in the same uterine horn of one recipient). Surgical transfers tended to result in a higher proportion of embryos surviving to birth (.43 vs .21; P = .16) and a higher twinning rate (.29 vs .04; P = .36) than did nonsurgical transfers. Age of recipient did not influence embryo survival (P = .98) or twinning rate (P = .99). Gestation length was 5 d shorter (P less than .01) for twin calves than for singles. Singles were 9 kg heavier (P less than .01) at birth and 32 kg heavier (P less than .01) at weaning than twins. However, cows raising twins produced 108 kg (51%) more total weaning weight than did cows raising singles.     

Efficient production of pronuclear embryos in breeding and nonbreeding season for generating transgenic sheep overexpressing TLR4

Background: Brucella is a zoonotic Gram-negative pathogen that causes abortion and infertility in ruminants and humans. TLR4 is the receptor for LPS which can recognize Brucella and initiate antigen-presenting cell activities that affect both innate and adaptive immunity. Consequently, transgenic sheep over-expressing TLR4 are an suitable model to investigate the effects of TLR4 on preventing Brucellosis. In this study, we generated transgenic sheep overexpressing TLR4 and aimed to evaluate the effects of different seasons(breeding and non-breeding season) on superovulation and the imported exogenous gene on growth.Results: In total of 43 donor ewes and 166 recipient ewes in breeding season, 37 donor ewes and 144 recipient ewes in non-breeding season were selected for super-ovulation and injected embryo transfer to generate transgenic sheep.Our results indicated the no. of embryos recovered of donors and the rate of pronuclear embryos did not show any significant difference between breeding and non-breeding seasons(P 0.05). The positive rate of exogenous TLR4 tested were 21.21 % and 22.58 % in breeding and non-breeding season by Southern blot. The expression level of TLR4 in the transgenic sheep was 1.5 times higher than in the non-transgenic group(P 0.05). The lambs overexpressing TLR4 had similar growth performance with non-transgenic lambs, and the blood physiological parameters of transgenic and non-transgenic were both in the normal range and did not show any difference.Conclusions: Here we establish an efficient platform for the production of transgenic sheep by the microinjection of pronuclear embryos during the whole year. The over-expression of TLR4 had no adverse effect on the growth of the sheep.     

转基因奶牛胚胎移植技术的试验研究

2006年6月至2010年3月以来,北京奶牛中心与中国农业大学合作,在北京奶牛中心良种场开展了转基因牛胚胎移植试验研究。本试验利用中国农业大学培育的转基因母牛作为供体,进行超数排卵生产体内胚胎,将获得的胚胎移植给15～15.5月龄荷斯坦母牛受体。截止2010年3月21日,累计移植转基因奶牛胚胎87枚,移植受体牛87头,妊娠48头,移植妊娠率为55.17%;产犊43头,成活34头,犊牛成活率为79%;经中国农业大学研究人员检测,有14头公牛携带转入目的基因,这14头公牛已全部进入北京市种公牛站饲养。目前,有10头公牛到了试采精月龄,精液经农业部牛冷冻精液质量监督检验测试中心(北京)检测,质量符合国家标准。     

Strategies for Increasing Reproductive Efficiency in a Commercial Embryo Transfer Program With High Performance Donor Mares Under Training

Exercise stress has a negative impact on embryo transfer efficiency (ET). For example, a 34% embryo recovery rate, 43% incidence of poor quality embryos, and a 29% pregnancy rate after transfer have been reported. Administration of nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the inflammatory response produced after nonsurgical embryo transfer. In addition, progesterone supplementation is commonly administered to some recipient mares to improve uterine conditions before the transfer and to ensure adequate progestational support compatible with pregnancy. The aim of the study was to evaluate embryo recovery rates using BioRelease deslorelin versus hCG and to increase posttransfer pregnancy rates by jointly administering BioRelease progesterone and a NSAID (flunixin or meloxicam) to recipient mares. Seventeen upper-level showjumping mares stabled and in daily training were used as embryo donors. To induce ovulation, 1-mg IM BioRelease deslorelin (BioRelease Technologies, Lexington, KY) was injected in treated cycles (n = 66), or 2500-IU hCG IV (Ovusyn, Syntex, Buenos Aires, Argentina) was given in control cycles (n = 79) when a ≥35 mm follicle was present. Artificial insemination with extended fresh semen (at least 500 × 10⁶ progressively motile sperm) was carried out in both groups immediately after injecting the ovulation induction agent. Day 8 embryos were recovered and nonsurgically transferred using a speculum and a cervical traction forceps. Recipient mares (n = 73) were randomly assigned to one of three groups: Group A received a single injection of 1.5-g IM BioRelease progesterone (Progesterone LA 300, BioRelease Technologies) and 3 IV injections of 0.5 g of flunixin meglumine (Flunix Deltavet, Argentina), one injection administered the day of the transfer and one on each of the next two successive days. Group B received 1.5-g IM BioRelease progesterone and a single dose of 1.5-g IM BioRelease meloxicam (Meloxicam LA, BioRelease Technologies) at the moment of embryo transfer. Group C did not receive any treatment. Pregnancy diagnosis was carried out 7 days after transfer. Results were analyzed using comparisons of proportions. More embryos were recovered per cycle (13% increase) when donor mares in training were induced to ovulate with BioRelease deslorelin (60.6%; 40/66) than with hCG (46.8%; 37 of 79; P < .05). Although both recipient groups given NSAIDs in combination with BioRelease progesterone numerically had higher pregnancy rates (A: 70.8%; 17/24 and B: 75%; 15/20) compared with nontreated control recipients (47.1%; 33/70), pregnancy rates were significantly higher only in recipients given LA meloxicam treatment at the time of transfer (P < .05). The LA meloxicam is released over a 72-hour period making it more practical to use as it requires a single IM injection versus the 3 IV flunixin meglumine injections. Thus, to minimize the effects of exercise stress on ET efficiency, a combination of BioRelease deslorelin to induce ovulation in donors and BioRelease progesterone and LA meloxicam in recipients at the time of transfer may offer an interesting alternative for improving results in commercial ET programs.