SEARCH · PubMed Health

Results for “Embryo Transfer”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources

PubMed1989

Early pregnancy wastage following late implantation of embryos after in-vitro fertilization and embryo transfer.

Serial plasma concentrations of human chorionic gonadotrophin (HCG), progesterone and oestradiol were measured in pregnancies after in-vitro fertilization and embryo transfer. The first detection day of HCG after embryo transfer (8.4 +/- 1.1) and the HCG doubling time (DT) of 64 normal singleton pregnancies were compared to those of 14 first-trimester miscarriages. The same parameters were evaluated in nine late-implanted conceptions, seven of which resulted in early pregnancy wastage. The HCG DT of late-implanted pregnancies was consistent with that of singleton term pregnancies in the first 12 days, while first-trimester miscarriages which had implanted at the usual time had a significantly longer DT from implantation onwards. The reduced trophoblastic secretory rate suggests poor embryo quality in these cases. A decreased progesterone/oestradiol ratio was observed in late-implanted pregnancies but because of the small number of individuals, no definite conclusion can be drawn. More patients with delayed implantation should be tested to justify this observation.

Adult↗

PubMed1982

[In-vitro fertilization of human eggs and embryo transfer].

This is a first report on experience with in-vitro fertilization of human eggs and embryo transfer. The follicle was aspirated to obtain eggs in 24 patients. A successful fertilization of the oocytes with obvious formation of a pronucleus was observed in 3 cases. In 9 more cases cell divisions were obtained and the embryos were transferred at the 4-cell stage. In spite of the unfavourable female patient population a good fertilisation and embryo transfer rate was achieved.

Adult↗

PubMedDate not supplied

Endometrial secretion aspiration prior to embryo transfer does not reduce implantation rates.

Analysis of protein patterns in endometrial secretion fluid may offer a relatively non-invasive means of assessing endometrial receptivity during fertility treatment cycles. In order to study the impact of the removal of endometrial secretions on embryo implantation, a prospective matched controlled study was performed. In 66 women undergoing IVF, endometrial fluid was obtained transcervically by aspiration just prior to embryo transfer (study group). Biochemical and ongoing pregnancy rates were compared with 66 control patients matched for stimulation treatment protocol, age, number of collected oocytes and number of high quality embryos. The protein content and uterine fluid protein profile in each sample was determined. Respective biochemical and ongoing pregnancy rates per embryo transfer were 36 and 33% in patients who underwent aspiration of endometrial secretion, compared with 33 and 30% respectively in matched control patients (P = 0.84 and P = 0.85). The protein content in endometrial fluid was sufficient for protein pattern analysis. Uterine fluid aspiration prior to IVF embryo transfer is a safe method for obtaining sufficient material for uterine secretion electrophoresis, thus allowing analysis of protein patterns serving as receptivity markers during treatment cycles. This technique may offer a novel tool for assessing endometrial receptivity during treatment cycles without affecting implantation rates.

Adult↗

PubMed2007

Nucleolar remodeling in nuclear transfer embryos.

Transcription of the ribosomal RNA (rRNA) genes occurs in the nucleolus and results in ribosome biogenesis. The rRNA gene activation and the associated nucleolus formation may be used as a marker for the activation of the embryonic genome in mammalian embryos and, thus serve to evaluate the developmental potential of embryos originating from varied nuclear transfer protocols. In bovine in vivo developed embryos, functional ribosome-synthesizing nucleoli become structurally distinct toward the end of the 4th post-fertilization cell cycle. In embryonic cell nuclear transfer embryos, fully developed nucleoli are not apparent until the 5th cell cycle, whereas in somatic cell nuclear transfer embryos the functional nucleoli emerge already during the 3rd cell cycle. Intergeneric reconstructed embryos produced by the fusion of bovine differentiated somatic cell to a nonactivated ovine cytoplast fail to develop fully functional nucleoli. In bovine in vivo developed embryos, a range of important nucleolar proteins (e.g., topoisomerase I, upstream binding factor and RNA polymerase I, fibrillarin, nucleophosmin and nucleolin) become localized to the nucleolar anlage over several cell cycles. This relocation is completed toward the end of the 4th cell cycle. A substantial proportion of bovine embryos produced by nuclear transfer of embryonic or somatic cells to bovine ooplasts display aberrations in protein localization in one or more blastomers. This information is indicative of underlying aberrations in genomic reprogramming and may help to explain the abnormalities observed in a proportion of fetuses and offspring derive from nuclear transfer embryos.

Animals↗

PubMed2002

Plasma progesterone profiles and factors affecting embryo-fetal mortality following embryo transfer in dairy cattle.

The relationship between plasma progesterone (P4) levels and embryo survival, and the value of P4 profiles for the selection of cattle embryo transfer recipients is still a matter of controversy. This study reports a comparison between lactating cows and heifers (n = 407) from a single dairy herd, after transfer of either fresh or frozen-thawed good quality embryos, of their ability to sustain embryo-fetal development to term. Plasma P4 concentrations on the day of estrus (Day 0 = D0), Day 4, Day 7 and on Day 21 were measured and related to embryo survival. Plasma P4 levels on Days 0, 4 and 7 were similar in recipients later found pregnant or open. Plasma P4 levels on Day 7 were significantly higher (P < 0.01) in heifers than in cows, but they were similar in pregnant and nonpregnant heifers and in pregnant and nonpregnant cows. Pregnancy rates for fresh and frozen-thawed embryos were higher in heifers than in cows, but the differences did not reach significance. However, the overall late embryonic mortality was significantly higher (P < 0.01) and the calving rate for frozen-thawed embryos was significantly lower (P < 0.05) in cows than in heifers. As expected, plasma P4 on Day 21 was significantly higher (P < 0.001) in pregnant than in nonpregnant recipients, but there was no difference between pregnant cows and pregnant heifers. Plasma P4 levels on Day 7 of recipients presumed pregnant on Day 21 and later found pregnant or nonpregnant were similar, but plasma P4 levels on Day 21 were significantly higher (P < 0.001) in pregnant than in nonpregnant recipients. The results of this study suggest that plasma P4 levels until the day of transfer, except for the rejection of recipients with abnormal luteal function, are of limited practical use for embryo transfer recipient selection. However, in lactating cows low plasma P4 values on Day 7 might negatively affect embryo survival, while in heifers this effect is not noticeable. Lactating cows are more prone to embryo loss than heifers, especially in the case of frozen-thawed embryos; this is associated with a lower competence of the corpus luteum at Day 7.

Animals↗

PubMed1995

Risk factors for ectopic pregnancy after in vitro fertilization and embryo transfer.

PURPOSE: To find the incidence of ectopic pregnancy (EP) in patients who conceived in the IVF-ET program, and risk factors affecting the occurrence of EP. METHODS: We analyzed the effects of the indication for IVF, type of ovarian stimulation (hMG + hCG vs. GnRH + hMG + hCG), type of embryo transfer (transcervical intratubal, intrauterine in chest-knee position and intrauterine in lithotomy position) and number of embryos transferred on the occurrence of EP. EP was treated by laparotomy, prostaglandin E2 or laparoscopic surgery. RESULTS: In 7991 stimulated and 92 natural cycles treated in the Ljubljana IVF-ET program between May 1983 and June 1994 we achieved 1059 pregnancies, of which 44 were ectopic (incidence 4.1%), the main risk being tubal factor infertility. There were 38 (86.3%) tubal, 3 (6.8%) heterotopic, 1 (2.4%) ovarian, and 2 (4.5%) cornual EP. In two patients multiple tubal EP occurred (1 twin, 1 triplet). Forty-two patients (95.4%) had tubal factor infertility, 1 (2.3%) unexplained, and 1 (2.3%) patient had male factor. The incidence of EP in patients with tubal infertility was 5.4%, in patients with unexplained infertility 2.0% and in those with male factor 0.9%. There appeared to be no correlation between the two superovulatory methods. With transcervical intrauterine ET the incidence of EP was 0 of 5 clinical pregnancies (CP); with intrauterine in chest-knee position it was 26 (3.5%) of 738 CP; with intrauterine in lithotomy position it was 17 (5.4%) of 316 CP. The difference between the two types of intrauterine ET is not statistically significant. The incidence of EP did not correlate with the number of embryos transferred. The average initial values of beta hCG performed 17 days after ET were significantly lower in patients with EP than in those with normal singleton pregnancy (157 +/- 143 mIU/ml vs. 408 +/- 148 mIU/ml). CONCLUSIONS: EP can complicate the IVF procedure. The main risk factor is tubal infertility with or without previous tubal surgery. The low initial value of beta hCG has a strong predictive value in the diagnosis of EP.

Chorionic Gonadotropin↗

PubMed1994

Sharing of human leukocyte antigens in couples with unexplained infertility affects the success of in vitro fertilization and tubal embryo transfer.

OBJECTIVE: The purpose was to test further our hypothesis that genes, or genetic defects, linked to the major histocompatibility complex affect reproduction by correlating human leukocyte antigen sharing with the success or failure of in vitro fertilization and tubal embryo transfer in couples having unexplained infertility. STUDY DESIGN: Seventy-six couples with unexplained infertility who failed superovulation and intrauterine insemination at least three times were typed for human leukocyte antigens and treated by in vitro fertilization and tubal embryo transfer. The results were correlated with the sharing of human leukocyte antigens in the couples. RESULTS: Thirty-four of the women had successful pregnancies, 36 did not become pregnant, and six became pregnant but aborted shortly thereafter. There was a highly significant excess of human leukocyte antigen sharing in the couples who failed treatment: three of the A, B, DR, and DQ antigens (p = 0.015) or two of the B, DR, and DQ antigens (p = 0.015). No specific human leukocyte antigen alleles were present in excess. CONCLUSIONS: Genes, or genetic defects, linked to the major histocompatibility complex significantly affect the success of in vitro fertilization and tubal embryo transfer just as they affect the prevalence of recurrent spontaneous abortion, cancer, and congenital anomalies. It appears as if the critical genes, or genetic defects, are located in the B-DR-DQ region of the major histocompatibility complex.

Abortion, Spontaneous↗

PubMed1978

Embryo transfer for cows with reproductive problems.

Surgical embryo recovery and transfer methods were applied to 25 cows and heifers with chronic reproductive problems. In 16 of the 25 animals, abnormalities could not be detected by palpation per rectum and, at laparotomy, the probable cause of low fertility was found to be oviductal obstructions or periovarian adhesions in 6 of them. Four pregnancies were obtained from 3 of these 6 animals. A definitive diagnosis was not obtained through laparotomy in the other 10 animals in this group; however, an abnormal uterine environment associated with senescence may have been responsible for low fertility in the older cows. Eighteen calves were obtained by embryo transfer from 8 of these 10 donor animals. The remaining 9 heifers and cows had lesions detectable by palpation per rectum. Chronic, purulent metritis was found in 2 cows, one of which produced 7 calves by embryo transfer. The other 7 had periovarian adhesions, and 8 calves were obtained from 2 of them. The adhesions in 6 of these 7 cows were attributable to cesarean section. Laparotomy was valuable for defining the extent of the adhesions and establishing a reliable prognosis in some cases.

Animals↗

PubMed1994

[Effect of different follicle puncture methods on hormone homeostasis in the woman. Studies within the scope of an in vitro fertilization-embryo transfer program].

Different methods for follicular puncture which were used in an in vitro fertilization-embryo transfer program have been analyzed in order to determine their influence on plasma levels of estradiol, progesterone, prolactin and beta-endorphins. Thirty-eight patients awaiting oocyte aspiration were randomized into a laparoscopic (n = 20) and an ultrasound-guided oocyte aspiration group (n = 18). No differences were observed as far as estradiol and progesterone levels and embryo transfer rates were concerned. When using the laparoscopic technique, prolactin levels were found to be elevated 1.5 times in comparison with the ultrasound-guided aspiration procedure, which is highly significant (p < 0.001). Also, beta-endorphins peaked at a significantly higher level during laparoscopy (27.8 vs. 20.7 mol/l, p < 0.001). The enhanced prolactin and beta-endorphin levels reflect an increased stress response during laparoscopy. With respect to less trauma and shorter duration of the procedure, we now perform the sonographically guided transvaginal aspiration technique in our program almost exclusively.

Adult↗

PubMed1996

Microsurgery and in-vitro fertilization and embryo transfer for infertility resulting from pathological proximal tubal blockage.

The aim of this study was to evaluate the prognosis for the patients after the treatment of infertility resulting from proximal tubal blockage using microsurgical tubocornual anastomosis and in-vitro fertilization (IVF) and embryo transfer complementarily. A total of 59 microsurgical operations (1986-1992) for infertility resulting from pathological proximal tubal lesions were analysed. The cumulative live birth rate was 52% for tubocornual anastomosis, 58% for bilateral operations and 28% for two-site operations. In all, 35 singleton babies were born. Of the 32 operated patients who did not deliver within 2 years of surgery, 21 were treated by 66 IVF cycles; 12 babies were born. The live birth rate was 18% per cycle and 57% per patient. Combining both treatment methods the cumulative live birth rate was improved up to 69% in the group of tubocornual anastomoses, up to 75% in the group of bilateral operations, and up to 57% in the group of two-site operations. Complementary use of microsurgery and IVF and embryo transfer improves the prognosis for selected infertile patients with pathological proximal tubal blockage. In the absence of pregnancy, IVF and embryo transfer should be commenced 1 year after surgery.

Adult↗

PubMed1987

Follicular factors, serum estradiol, and outcome of pregnancy following in vitro fertilization and embryo transfer.

Success rate of in vitro fertilization and embryo transfer (IVF-ET) depends upon clinical and laboratory variables. This study compared follicular measurements and serum estradiol (E2) between 23 delivered and 23 nonpregnant controls following IVF-ET. E2, number of large follicles (no.), E2/no. ratio, total diameter of large follicle (TD), and the E2/TD ratio were compared between the two groups and between 23 women who delivered and 10 who aborted. E2 (P = 0.03), E2/no. (P = 0.006), and E2/TD (P = 0.005) were found to differ significantly between delivered and controls and between delivered and those who aborted.

Embryo Transfer↗

PubMed2004

Prediction of ovarian reserve based on day-3 serum follicle stimulating hormone concentrations during the pituitary suppression cycle using a gonadotropin releasing hormone agonist in patients undergoing in vitro fertilization-embryo transfer.

Satisfactory results following in vitro fertilization-embryo transfer (IVF-ET) treatments depend on retrieving an appropriate number of mature oocytes without causing the development of ovarian hyperstimulation syndrome (OHSS). The present study was carried out to investigate whether the ovarian reserve is predictable based on the day-3 serum concentration of follicle stimulating hormone (FSH) during the pituitary suppression cycle using a gonadotropin releasing hormone (GnRH) agonist (defined as day-3 FSH) in patients undergoing IVF-ET treatment. Day-3 FSH before the administration of gonadotropin was assessed in 72 IVF-ET cycles from 59 infertile women. The mean+/-SD of day-3 FSH, the total amount of FSH plus human menopausal gonadotropin (hMG) administered, and the total number of oocytes retrieved was 5.5+/-2.6 mIU/ml, 2834.2+/-1236.5 IU and 7.7+/-5.8, respectively. There were significant correlations between day-3 FSH and the total amount of FSH-hMG administered (p < 0.001), and day-3 FSH and total number of oocytes retrieved (p < 0.001). There was a significant difference of day-3 FSH between patients who subsequently conceived (4.4+/-1.3 mIU/ml) and those who did not conceive (6.1+/-2.9 mIU/ml) (p = 0.001). There was also a significant difference of day-3 FSH between patients who developed moderate or severe OHSS (4.5+/-1.2 mIU/ml) and those who did not (5.9+/-2.8 mIU/ml) (p = 0.003). Receiver-operator characteristic curve analysis showed that the significant cut-off point for day-3 FSH for predicting ovarian reserve was 5.25 mIU/ml. These findings indicate that day 3-FSH is usefulfor predicting ovarian reserve during the pituitary suppression cycle using a GnRH agonist in patients undergoing IVF-ET.

Adult↗

PubMed2004

A glance into the uterus during in vitro simulation of embryo transfer.

BACKGROUND: The currently low implantation rate after embryo transfer (ET) is partially attributed to technical aspects, such as catheter type, catheter load, placement of catheter tip and physician skills. METHODS: Mock ET simulations were conducted with a transparent laboratory model of the uterine cavity. The catheter was loaded with alternating air and coloured liquid media. The transfer procedure was recorded by a digital video camcorder for later analysis. Different sequences of air and liquid volumes, as well as liquids of different viscosity were simulated. RESULTS: Injection of liquid with air into the uterus formed an air bubble which blocked the transport of the transferred liquid towards the fundus. The distribution of the transferred matter within the uterine cavity was determined by the composition of the liquid-air sequence and the viscosity ratio between the transferred liquid and the uterine fluid. CONCLUSIONS: It is suggested that the catheter load should contain minimal volumes of air in order to enhance the embryos' chances of reaching the site of implantation. The viscosity of the transferred liquid should be as close as possible to that of the uterine fluid in order to avoid transport of embryos towards the cervix.

Air↗

PubMed1990

Levels of steroid-binding proteins and steroids in human preovulatory follicle fluid and serum as predictors of success in in vitro fertilization-embryo transfer treatment.

In an attempt to identify the embryos and cycles that have the best chances of resulting in establishment of pregnancies, after in vitro fertilization-embryo transfer (IVF-ET) treatment, the concentrations of sex hormone-binding globulin (SHBG) and cortisol-binding protein (CBP) were measured, using two new enzyme-linked immunosorbent assays in serum and follicle fluid (FF) from 30 women (125 FF) undergoing IVF-ET. The concentrations were compared to those of total estradiol and total progesterone, and correlated to oocyte cleavage and the establishment of pregnancies. Serum concentrations of CBP were significantly higher in women who became pregnant (1469 +/- 108) nM (+/- SEM] than in those who did not (CBP, 1200 +/- 58 nM; P less than or equal to 0.05). The concentrations of SHBG were not significant different in these two groups of women (72.4 +/- 9.3 and 60.8 +/- 4.2 nM, respectively; P greater than or equal to 0.10). By contrast, in FF significantly higher concentrations of both SHBG and CBP were found in women achieving pregnancy (SHBG, 56.1 +/- 2.8 nM; CBP, 1198 +/- 37 nM) than in those who did not (SHBG, 45.5 +/- 1.4 nM; P less than or equal to 0.001; CBP, 1079 +/- 29 nM; P less than or equal to 0.01). A positive correlation was found between serum and FF levels of both SHBG (r = 0.85; P less than or equal to 0.001) and CBP (r = 0.70; P less than or equal to 0.001). FF levels of estradiol and progesterone did not differ regardless of whether the oocyte cleaved. However, a significant reduction of estradiol was found in fluid from follicles in which the oocyte cleaved and resulted in pregnancy (3046 +/- 180 nM) than in fluid from follicles in which the oocyte cleaved but without establishment of pregnancy (4162 +/- 282 nM; P less than or equal to 0.001). There was no correlation between estradiol and SHBG and between progesterone and CBP. However, levels of FF progesterone above 15,000 nM combined with CBP concentrations above the mean concentration found in FF (1,127 nM) were related with oocyte cleavage in 87% of the cases. The overall cleavage rate is 56%. The higher levels of SHBG and CBP in serum compared to those in FF, and the positive relationship between serum and FF levels suggest that both proteins arise from the circulation. The similar levels in serum and FF indicate that neither SHBG nor CBP is responsible for maintaining the concentration gradient of estradiol and progesterone from follicle to plasma.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed2004

[Prophylactic antibiotic therapy (amoxicillin + clavulanic acid) before embryo transfer for IVF is useless. Results of a randomized study].

OBJECTIVES: We studied the implantation rate during IVF cycles according to the prescription or not of antibiotics. MATERIALS AND METHODS: During a 5-month period all the patients aged less than 38 years were randomized into two groups according to an independent personal variable. In group 1 amoxicilline + clavulanic acid 1g/125 mg were administrated from the ovum pick-up day for 6 days. In the group 2 no antibiotic treatment was administered. RESULTS: The two groups were identical for all the criteria (type of stimulation, IVF/ICSI report, indications, average age). The average number of collected oocytes, obtained embryos and transferred embryos was similar in the two groups. The implantation rate per transfer was similar in the two groups (36.9% versus 36.5%; p>0.95). The pregnancy loss rate (biological pregnancy, early and late miscarriages or extra uterine pregnancy) was increased in a non significant manner (p=0.15) in the group with antibiotic: 33.3% (16/48) versus 20.8% (11/53) in the group without antibiotic. CONCLUSION: This prospective randomised study leads us not to recommend this antibiotic prescription at the time of the embryo transfer during in vitro fertilisation attempt.

Adult↗

PubMed2004

Elective single embryo transfer (eSET) policy in the first three IVF/ICSI treatment cycles.

BACKGROUND: Elective single embryo transfer (eSET), applied in the first or second IVF cycle in young patients with good quality embryos, has been demonstrated to lower the twin pregnancy rate, while the overall pregnancy rate is not compromised. It is as yet unclear whether eSET could be the preferred transfer policy in all treatment cycles, or that it should be restricted to the first or first two cycles. METHODS: eSET policy (when two or more embryos were available, at least one of them being of good quality) was offered to patients younger than 38 years in the first three treatment cycles. Retrospectively, treatment cycle outcome was studied. RESULTS: In 326 patients, 586 treatment cycles were performed (326 first, 168 second and 92 third treatment cycles). In 65 cycles (11%), eSET could not be applied because there was either no fertilization, or only one embryo available. In the remaining 521 cycles, eSET was performed in 111 cycles (19%), while in 410 cycles, no good quality embryo was available resulting in the transfer of two embryos (double embryo transfer, DET). No significant differences in ongoing pregnancy rates after transfer of fresh embryos were observed between eSET and DET in the first (both 33%), second (36 and 23%, respectively) and third treatment cycles (20 and 24%, respectively). In significantly more eSET cycles compared to DET cycles, could embryos be frozen. This resulted in a significantly higher cumulative pregnancy rate after eSET compared to DET. CONCLUSIONS: In patients younger than 38 years with at least one top quality embryo, eSET can be the transfer policy of choice in at least the first three treatment cycles, since the pregnancy rates obtained in each treatment cycle are comparable to those after DET.

Adult↗

PubMed2000

Selection of patients suitable for one-embryo transfer may reduce the rate of multiple births by half without impairment of overall birth rates.

The aim of the present study was to identify a subset of patients at high risk of multiple birth after IVF and hence suitable for one-embryo transfer, which undoubtedly would reduce the multiple birth rate. This retrospective study included 2107 IVF cycles in which two embryos were transferred. Factors with possible correlation to multiple birth were studied in a multivariate analysis. The factors included background data (female age, previous pregnancies and births, previous IVF cycles, indication for IVF) and IVF cycle characteristics. The following factors were independently predictive of multiple birth: female age expressed a negative correlation while number of good quality embryos transferred was positively correlated. A subset of patients was identified as being at high risk of multiple birth by including age, cycle number and presence of tubal infertility in a model derived from a logistic regression analysis. The rate of multiple births can be reduced from 26% to 13% of all births if one-embryo transfer is performed in selected cases. The total birth rate will decrease from 29% to 25% but may be completely restored by performing one additional one-embryo freeze transfer in high risk patients who do not achieve a term pregnancy.

Adult↗

PubMedDate not supplied

The dangers of disease transmission by artificial insemination and embryo transfer.

This review summarizes the major infectious diseases of the three major agricultural species (cattle, sheep and pigs) and horses, and presents the evidence for and against the possibility of infectious agents being transmitted between animals via the venereal route or by the use of semen or early embryos in commercial artificial insemination (AI) or embryo transfer (ET). Cattle feature most prominently in the widespread distribution of frozen semen, and national and international organizations have set out guidelines to work towards disease-free bull studs with semen free from potential pathogens. With the control of major epizootic diseases, attention has been focused on such diseases as IBR, BVD and blue tongue, where clinical signs are rarely evident but the detection of virus in semen is of great importance. New information on the relevance of bacterial disease such as Mycobacterium paratuberculosis, campylobacteriosis and leptospirosis is reviewed, along with details of the mycoplasma and ureaplasma species of the bull's genital tract. Bovine spongiform encephalopathy (BSE) has attracted much research and semen is not regarded as a source of infection. New work on the pathogenesis of a number of diseases and the use of new biotechnology in diagnosis is included. The International Embryo Transfer Society (IETS) has encouraged a great deal of experimental work--much originating in Canada--on the risk of transmission of disease from donors to recipients via a 7-day-old blastocyst. There has been much success in demonstrating that with an approved protocol of handling the embryos, to date there is very little danger in disease transmission with both viruses and bacteria. The mycoplasma group appear more intractable and the role of BSE is still being evaluated. In sheep, scrapie, Brucella ovis infection and blue tongue feature in current work. In the pig there is a surge in international movement of pig semen, and Aujeszky's disease and the new so-called Blue Ear disease feature prominently. Much work is in progress on infectious agents likely to be found in the semen of stallions, with an expanding trade in the international movement of chilled and frozen semen. Equine embryo transfer experiments are hampered by the very limited number of embryos available. Reference is also made to the further risk of disease transmission by in vitro manipulated embryos.

Animal Diseases↗