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Direct transfer (DT) of cryopreserved embryos to recipients facilitates on-farm application. We analyzed a new freezing/thawing (F/T) procedure for in vitro produced (IVP) embryos, integrating: 1) an ethylene-glycol based system; 2) a culture step without protein; and 3) a synthetic protein substitute (CRYO3) in cryopreservation medium. IVP embryos from abattoir ovaries were cultured in groups in BSA-containing synthetic oviduct fluid with or without 0.1% fetal calf serum (FCS) until Day-6. Morulae and early blastocysts were subsequently cultured without protein from Day-6 onwards. Day 7 and Day 8 expanded blastocysts (EXB) were subjected to F/T or vitrification/warming (V/W). Thawed and warmed EXB were cultured in vitro , and development rates, cell counts and dead cells were analyzed in surviving embryos. V/W improved survival over F/T (live and hatching rates at 2 h, 24 h and 48 h) (P < 0.0001), and FCS before Day 6 did not affect in vitro survival. After F/T, embryos had lower cell counts in the ICM, TE and total cells than after V/W. Day-7 embryos after F/T showed % apoptotic, % pycnotic and % total dead cells higher (p < 0.05) than their Day-8 counterparts, probably because F/T reduced the numbers of ICM cells within Day-8 embryos. Thereafter, Day-7 blastocysts were transferred to heifers in an experimental herd. There were no differences in birth rates with frozen (-FCS [n = 40]: 45%; +FCS [n = 14]: 28%), vitrified (-FCS [n = 47]: 53%; +FCS [n = 11]: 36%) and fresh (-FCS [n = 30]: 47%; +FCS [n = 17]: 53%) embryos. However, frozen embryos produced with FCS showed 5/9 miscarriages after Day-40. Calves born from frozen (n = 22), vitrified (n = 29) and fresh (n = 22) transfers did not differ in birth weight, gestation length and daily gain weight (P > 0.10). Subsequently, transfer of frozen embryos (n = 29) derived from oocytes collected from live, hormonally stimulated cows in experimental herd, led to pregnancy rates of 57% (heifers) and 40% (dry cows). with EXB on Day-62 Finally, embryos produced with BSA were transferred to cows in an on-field trial (frozen [n = 80]; fresh [n = 58]), with no differences in pregnancy rates (days 30–40). Pregnancy and birth rates could not be predicted from in vitro approaches. The new F/T system yields pregnancy and birth rates comparable to vitrified and fresh embryos without birth overweight. The absence of products of animal origin, defined chemical composition, and direct transfer entail sanitary, manufacturing and application advantages. • Bovine IVP embryos frozen in chemically defined media lead to birth rates comparable to vitrified and fresh embryos. • Pregnancy and birth rates are not predicted from in vitro experiments. • Cryopreservation of embryos developed in a 24h single culture step without protein does not induce birth overweight. [ABSTRACT FROM AUTHOR]

Recipient cow is the key to success in embryo transfer (ET) programs in cattle. Therefore, it is necessary to know the factors that influence on its reproductive potential. It is considered that multiparous cows have a better response to the ET program than nulliparous cows. The objective of this study was to evaluate the effect of parity on the reproductive efficiency of multiparous and nulliparous cows in a fresh ET program. Twenty-six recipient cows of Suizo Americano breed were divided into two experimental groups (n = 13/each) according to their parity (multiparous and nulliparous). Donor cows underwent a synchronization and superovulation program. Subsequently, the recipient cows were treated with fresh ET. The percentage of cows in estrus was higher on day 1 in multiparous cows than in nulliparous cows (P <0.05). On the other hand, gestation percentage, estrus time, embryo stage and pregnancy percentage per uterine horn were not significantly affected among the experimental groups (P> 0.05). In conclusion, parity did not affect the reproductive response of multiparous and nulliparous recipient cows subjected to a fresh ET program under tropical conditions. [ABSTRACT FROM AUTHOR]

The effect of artificial insemination (AI), embryo transfer (ET) to bull dams (BD), and sexed semen (SS) to cow dams (CD) with and without controlling inbreeding were studied using stochastic simulation. Three levels of embryo transfer (no ET, ET on all BD, and ET on 20% of BD), five levels of sexed semen (no SS: control, SS-X on all CD, SS-X on 20% CD, SS-Y on all CD, and SS-Y on 20% CD), three levels of artificial insemination (no AI, AI on 50% cows, and AI on 90% cows), two levels of mating system (random and minimum consistory) were combined together to make 66 scenarios in which the combination of no ET, no SS, and no AI are assigned as a control. The simulated population consisted of 40 herds with 50 cows each was monitored for 30 years. The results showed that the use of AI, ET, and SS techniques increased the annual change of total merit index (TMI), inbreeding, and selection accuracy. Compared to control, the rate of annual change in TMI and inbreeding were increased as 41.95, 36.91 and 83.91%; and 192, 57 and 207%, for using of AI, ET and combination of SS + AI + ET, respectively. The minimum consistory mating decreased inbreeding, but not affected other parameters. The results suggested that using of ET on 20% BD, SS-Y for all CD, and 90% AI alone or in combination with each other along with minimum consistory mating might resulted in high genetic progress and low inbreeding rate. These technologies and inbreeding control strategies may increase the ratio of annual change of TMI to inbreeding. [ABSTRACT FROM AUTHOR]

Objectives were to determine effects of: 1) handling temperament and administration of flunixin meglumine, an inhibitor of prostaglandin F2a (PGF2a) synthesis, given at the time of embryo transfer, on pregnancy rates in beef cattle embryo transfer recipients; 2) handling temperament and flunixin meglumine on peripheral concentrations of progesterone, cortisol, substance-P, prostaglandin F metabolites (PGFM, (13,14-dihydro-15-keto-PGF2a) and isoprostane 8-epi PGF2a; and 3) flunixin meglumine treatment on proportion of non-pregnant recipient cows returning to estrus within an expected interval. Angus cross beef cows (n = 710) at 7 locations were assigned a body condition score (BCS: 1, emaciated; 9, obese) and a temperament score [0, calm, slow chute exit; walk (n = 352), 1, excited, fast chute exit; jump, trot or run (n = 358)] and were synchronized with Select-Synch with a controlled internal drug release (CIDR) protocol. Estrus detection aids were applied at CIDR removal and cows were observed thrice daily for estrus until 72 h. Recipient cows that expressed estrus and had a corpus luteum received a frozen-thawed embryo on Day 7 after estrus. At the time of transfer, recipient cows were randomly allocated to receive 10 mL of flunixin meglumine im, immediately after transfer (n = 365) or served as an untreated control (n = 345). In a subset of cows (n = 80), ovarian ultrasonography was performed on the day of embryo transfer to determine corpus luteum volume and blood samples were collected twice, at the time of embryo transfer and 7 d later. All cows received estrus detection aids again on Day 14 (7 d after embryo transfer) and were observed for estrus twice daily until Day 24. Accounting for treatment (P > 0.1), embryo transfer difficulty score (P < 0.1), temperament by treatment interaction (P < 0.05), recipient cows with calm temperament had a higher pregnancy rate compared to those with an excited temperament [59.4 (209/352) vs 51.7% (185/358)]. The pregnancy rate for excitable cows without flunixin meglumine was lower (46.3% 81/175) compared to excitable cows that did received flunixin meglumine [56.8% (104/183)], and calm cows that did [59.3% (108/182)] or did not [59.4% (104/170)] receive flunixin meglumine. Proportions of non-pregnant recipient cows returning to estrus on Days 18–24 were not different between flunixin meglumine and control groups, 87.6% (134/153) and 84.0% (137/163), respectively (P > 0.1). At the time of embryo transfer and 7 d later, there were moderate to strong correlations among circulating concentrations of progesterone, cortisol, substance-P, PGFM and isoprostane 8-epi PGF2a. Among excitable cows, progesterone concentrations were lower and cortisol, substance-P, PGFM and isoprostane 8-epi PGF2a concentrations were greater for cows in the control group compared to cows that received flunixin meglumine. In conclusion, administration of flunixin meglumine improved pregnancy rates in excitable recipient cows following embryo transfer without affecting the proportion of non-pregnant cows returning to estrus. [ABSTRACT FROM AUTHOR]

Objective: Phellodendron amurense (P. amurense) and Humulus japonicus (H. japonicus) are closely involved in anti-oxidative response and increasing antioxidant enzymes activities. However, the effects of their extracts on development of preimplantation bovine embryos have not been investigated. Therefore, we investigated the effects of P. amurense and H. japonicus extracts on developmental competence and quality of preimplantation bovine embryos. Methods: After in vitro fertilization, bovine embryos were cultured for 7 days in Charles Rosenkrans amino acid medium supplemented with P. amurense (0.01 µg/mL) and H. japonicus (0.01 µg/mL). The effect of this supplementation during in vitro culture on development competence and antioxidant was investigated. Results: We observed that the blastocysts rate was significantly increased (p<0.05) in P. amurense (28.9%±2.9%), H. japonicus (30.9%±1.5%), and a mixture of P. amurense and H. japonicus (34.8%± 2.1%) treated groups compared with the control group (25.4%±1.6%). We next confirmed that the intracellular levels of reactive oxygen species (ROS) were significantly decreased (p<0.01) in P. amurense and/or H. japonicus extract treated groups when compared with the control group. Our results also showed that expression of cleaved caspase-3 and apoptotic cells of blastocysts were significantly decreased (p<0.05) in bovine blastocysts derived from both P. amurense and H. japonicus extract treated embryos. Conclusion: These results suggest that proper treatment with P. amurense and H. japonicus extracts in the development of preimplantation bovine embryos improves the quality of blastocysts, which may be related to the reduction of ROS level and apoptosis. [ABSTRACT FROM AUTHOR]

Two commercial FSH products were compared in a retrospective study on 3990 commercial superovulations and embryo recoveries in dairy heifers and cows. In addition, the 56-day nonreturn rate of 19,400 embryos produced with these two preparations was analyzed. Embryo collections were performed during a 16-year period from donors of Holstein and Ayrshire breeds. Folltropin (Vetoquinol S.A., Lure cedex, France) group (Group F) consisted of 2592 superovulations, of which 80% were performed on heifers and 20% on cows, and Pluset (Laboratorios Calier, S.A., Barcelona, Spain) group (Group P) of 1398 treatments, of which 66% and 34% were on heifers and cows, respectively. Total number of recovered structures, number of transferable embryos, and the proportion of unfertilized ova (UFO) and degenerated embryos were analyzed. Distribution of embryos into quality grades (1–3) and developmental stages (4–9) according to the IETS classification guidelines and means for each collection were evaluated. The proportion of low-responders having fewer than five corpora lutea and yielding fewer than five embryos or ova was investigated for each treatment. Group P yielded 1.1 recovered structures more than Group F (P < 0.001). Consequently, however, the number of transferable embryos did not differ among the groups, being 7.0 and 7.1 in Groups F and P, respectively. Instead, there was an increase in the number of UFO from 2.0 in Group F to 3.0 in Group P (P < 0.001). The quality of embryos and the developmental stages were similar between the groups and there was no difference in the proportion of low-responding donors in Group F and Group P. Also, there was no difference in the nonreturn rate after transfer of embryos originating from donors superovulated with Folltropin or Pluset. It was concluded that equal numbers of transferable embryos and pregnancies can be achieved with Folltropin and Pluset. [ABSTRACT FROM AUTHOR]

The aim of this study is designed to evaluate the best methods for cow oocytes collection from abattoir specimens which is the cheapest, easily obtained and bulky number. Forty five fresh cow genitalia specimens and testicle were collected directly after slaughter from Al-Shoáalla abattoir north-west of Baghdad the capital early morning, transported in cool box under (4-8) °C to the laboratory of theriogenology in the College of Veterinary Medicine/Baghdad University during the period from November 2016 to February 2017. Ovaries were separated from the surrounding tissues, washed thoroughly with dis. water repeatedly, then with normal saline and finally with MEM medium containing Antibiotics and Nystatin for contaminant elimination. Oocytes were collected with four methods aspiration, slashing, slicing after aspiration and slicing. The result showed that; the collected oocytes were 55, 68, 87 and 106 oocytes respectively; slicing methods yield more oocytes count. Period of time between slaughtering and samples processing significantly affect oocytes collected percentage and quality, periods as 2, 6, 12 and 24 hours yield 75%, 68%, 61% and 55% oocytes counts of good, fair, poor to aged and bad quality oocytes respectively. Two hours period yield an elevated oocytes count with good quality. Maturation index of oocytes according to the type of collected methods showed 44, 37, 39 and 42 with 12, 8, 6 and 6 good oocyte quality for the four methods respectively. In conclusion slicing methods yield more oocytes count with a moderate quality and embryos production while aspiration methods yield a moderate oocytes count with an elevated quality and good embryos production. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine (i) whether Chlamydia abortus would adhere to or penetrate the intact zona pellucida (ZP-intact) of early in vivo -derived caprine embryos, after in vitro infection; and (ii) the efficacy of the International Embryo Transfer Society (IETS) washing protocol for bovine embryos. Fifty-two ZP-intact embryos (8–16 cells), obtained from 14 donors were used in this experiment. The embryos were randomly divided into 12 batches. Nine batches (ZP-intact) of five embryos were incubated in a medium containing 4 × 10 7 Chlamydia /mL of AB7 strain. After incubation for 18 hours at 37 °C in an atmosphere of 5% CO 2 , the embryos were washed in batches in 10 successive baths of a phosphate buffer saline and 5% fetal calf serum solution in accordance with IETS guidelines. In parallel, three batches of ZP-intact embryos were used as controls by being subjected to similar procedures but without exposure to C. abortus . The 10 wash baths were collected separately and centrifuged for 1 hour at 13,000 × g. The washed embryos and the pellets of the 10 centrifuged wash baths were frozen at −20 °C before examination for evidence of C. abortus using polymerase chain reaction. C. abortus DNA was found in all of the infected batches of ZP-intact embryos (9/9) after 10 successive washes. It was also detected in the 10th wash fluid for seven batches of embryos, whereas for the two other batches, the last positive wash bath was the eighth and the ninth, respectively. In contrast, none of the embryos or their washing fluids in the control batches were DNA positive. These results report that C. abortus adheres to and/or penetrates the ZP of in vivo caprine embryos after in vitro infection, and that the standard washing protocol recommended by the IETS for bovine embryos, failed to remove it. The persistence of these bacteria after washing makes the embryo a potential means of transmission of the bacterium during embryo transfer from infected donor goats to healthy recipients and/or their offspring. Nevertheless, the detection of C. abortus DNA by polymerase chain reaction does not prove that the bacteria found was infectious. Further studies are required to investigate whether enzymatic and/or antibiotic treatment of caprine embryos infected by C. abortus would eliminate the bacteria from the ZP. [ABSTRACT FROM AUTHOR]

This study aimed to assess the suitability of luteal blood flow analyses measured by color Doppler ultrasonography (CDUS), to predict pregnancy at pre- and post-embryo transfer (ET) in dairy cows, and to compare with the established criterion like luteal size and plasma progesterone (P 4 ) concentrations. Lactating Holstein cows (n = 65) with spontaneous (n = 34) or synchronized estrus (n = 31) were examined. Cows with a CL greater than or equal to 20 mm in diameter (n = 58) received embryo transfer on Day 7 (Day 0 = estrus). Brightness mode images were captured for calculation of the CL area, luteal cavity area, and dominant follicle area on Days 3, 5, 7, and 14. Color Doppler ultrasonography examinations were conducted to determine the blood flow area (BFA) within the CL at the maximum diameter and the time-averaged maximum velocity (TAMV) of the base of the spiral artery on the same days. Plasma P 4 concentrations were determined from blood samples collected at each ultrasound examination. Pregnancy was diagnosed by an ultrasound on Day 30. There was no significant difference in the proportion of cows received embryo (91.2% vs. 87.1%, P = 0.70) and pregnancy rate (58.1% vs. 59.3%, P = 1.00) between the spontaneous estrus and synchronized groups. The BFA values of the pregnant group (n = 34) were approximately 1.42 and 1.54 times higher than those of the nonpregnant group (n = 24) on Days 7 (0.54 ± 0.04 cm 2 vs. 0.38 ± 0.02 cm 2 ; P < 0.01) and 14 (0.80 ± 0.23 cm 2 vs. 0.52 ± 0.22 cm 2 ; P < 0.01), respectively. The TAMV of the pregnant group was approximately 1.45 times higher than that of the nonpregnant group on Day 14 (57.8 ± 3.5 cm/s vs. 40.0 ± 3.3 cm/s; P < 0.01). However, no differences were found in the CL area, CL tissue area, dominant follicle area, and plasma P 4 concentrations among these groups. In addition, the best logistic regression model to predict pregnancy included scores for BFA on Day 7, BFA and TAMV on Day 14. Setting the cutoff value of BFA at 0.43 cm 2 yielded the highest sensitivity (79.4%) and specificity (75.0%) on Day 7, indicating the effectiveness of using BFA data for predicting pregnancy on Day 7. Furthermore, setting the cutoff value at one obtained from a sample with BFA 0.63 cm 2 and TAMV 50.60 cm/s yielded the highest sensitivity (85.3%) and specificity (91.7%) on Day 14. In conclusion, the evaluations of BFA on Day 7, and paired BFA and TAMV on Day 14 represent reliable predictors of pregnancy in the cow. [ABSTRACT FROM AUTHOR]

Artificial insemination and in vitro embryo production are powerful tools for disseminating superior genetic qualities and improving the reproductive performance of dairy and beef cattle. In conjunction with these biotechnologies, sexed-sorted semen has been used to obtain offspring of a predetermined sex. This study compared the pregnancy rates obtained using in vitro fertilization/timed embryo transfer (IVF/TET) and timed artificial insemination (TAI), both performed using sexed-sorted (Y-chromosome-bearing) semen obtained from the same bull. For the in vitro embryo production, the ovaries of 250 Nelore cows with known histories were collected in the slaughterhouse and used for IVF. After evaluation of the recipients (IVF/TET group; n = 974), the resultant embryos were transferred to the females with corpus luteum (n = 822). The pregnancy-related data for this group were compared with those for the TAI group (n = 974). Ultrasonography was performed at 60 days to determine the pregnancy status and confirm the sex of the fetus. A total of 2008 oocytes produced 1050 embryos, with 52% of them reaching the blastocyst stage. The pregnancy rate and the accuracy in determining the fetal sex were 35.4% (345/974) and 95.07% (328/345), respectively, for the IVF/TET group and 30% (293/974; P < 0.05) and 94.88% (278/293), respectively, for the TAI group. In the present study, we concluded that male calves could be better obtained using IVF/TET rather than TAI; therefore, this strategy can be considered to increase the pregnancy rate of beef cattle. [ABSTRACT FROM AUTHOR]

The gross anatomic features (cotyledonary type) and histologic classification (synepitheliochorial) of the bovine placenta have been known for many years. Thorough ultrastructural analysis as well as a variety of descriptive studies dealing with the localization of cytoskeletal filaments, extracellular matrix, growth factor systems, steroid hormone receptors, and major histocompatibility complex have contributed further significant knowledge. However, this knowledge was not sufficient to solve clinical placenta-based problems, such as retained fetal membranes. Owing to the complexity of the fetomaternal interface in vitro , culture systems have been developed. As trophoblast giant cells (TGC) are thought to be key players in the cattle placenta, most cell culture models attempt to overcome the pitfall of losing the entire TGC population in vitro . Nevertheless, distinct cell line–based in vitro systems such as cell monolayers or 3-dimensional (co-culture) spheroids were generated for the fetal (trophoblast) and maternal (uterine epithelium) placental compartments. Monolayers have been used to study for example, growth factor or hormonal signaling and TGC formation, whereas spheroids served as models for, for example, trophoblast attachment, uterine epithelium depolarization, and also TGC formation. In the future, the use of more improved culture models might lead to better treatments of retained fetal membranes and increased prevention of embryonic loss. In addition, the in vitro models could shed more light on the mechanisms of the differentiation of uninucleate trophoblast into TGC. [ABSTRACT FROM AUTHOR]

The embryo transfer techniques used in small ruminants worldwide are based in surgical procedures. These actions are performed under general anesthesia which needs a combination of animal fasting and drugs for secure animal handling and surgery manipulations. Therefore, it involves risks to animal health and life. The major limiting sequels are adhesions formed by the abdominal surgery, in the ovaries, uterus, or between them. These occurrences can both compromise uterus accessing and oocyte capture and are responsible for decreasing success and limiting successive embryo collections. In contrast, nonsurgical embryo procedures can be performed in a relatively simplified way. Nonsurgical embryo recovery does not need animal prolonged starvation, drug retention is minimized, and donors can stay in a standing position. After the end of embryo recovery, donors are promptly restored to their routine housing and feeding. Furthermore, this technique does not need incisions and, therefore, can be used repetitively in superovulated or nonsuperovulated goats and sheep for embryo recovery—a similar procedure done in cattle. In Brazil, promising results are reported using nonsurgical embryo transfer in recipient goats, and studies are currently evaluating similar procedures in sheep. Therefore, this review aimed to present the current panorama of nonsurgical embryo transfer in sheep and goats. [ABSTRACT FROM AUTHOR]

Contents The current study investigated the possibility of using the AMH concentration as a predictor of the ability of Korean Hanwoo cows to produce cumulus-oocyte complexes, embryos that survive after transfer as well as the pregnancy outcome of surrogates. Eight sessions of ovum pick-up ( OPU) were performed with 19 donor cows at an interval of 3-4 days. Antral follicle count ( AFC), oocyte quality and in vitro embryo development were recorded for each cow. Embryos produced from cows with different AMH profiles were transferred into recipients (n = 96). Cows in the high (≥0.25 ng/ml) and intermediate (0.1≥ to <0.25 ng/ml) AMH groups had a significantly higher AFC per OPU session (20.40 ± 1.36 and 16.91 ± 1.52, respectively; mean ± standard deviation) than cows in the low AMH group (<0.1 ng/ml; 12.19 ± 2.14). In addition, more cumulus-oocyte complexes per donor were recovered in the high (11.46 ± 1.22) and intermediate (7.38 ± 0.83) AMH groups than in the low AMH group (4.77 ± 0.44). The percentage of oocytes reached blastocyst stage was significantly higher in the intermediate (47.0%) and high (38.5%) AMH groups than in the low AMH group (32.3%). The number of embryos produced per cow was higher in the high (3.9 ± 0.2) and intermediate (6.9 ± 0.6) AMH groups than in the low AMH group (2.2 ± 0.3). The percentage of embryos that gave birth to viable calves when transferred into recipients was higher for those derived from cows in the intermediate AMH group (50.7%) than for those derived from cows in the low (35.7%) and high (36.4%) AMH groups. In conclusion, a single measurement of AMH concentration predicted the in vitro embryo production potential of donor Korean native cows before OPU and is linked with embryo viability after transfer into recipients. [ABSTRACT FROM AUTHOR]

Content The aim of this study was to determine whether vitrification is an effective method when used for Japanese Black Cattle (Wagyu) in vivo-derived embryos, collected following a superovulation treatment and embryo transfer ( MOET) programme. In vivo-derived morula and blastocysts collected on day 7 after artificial insemination, were vitrified using a modified droplet vitrification ( MDV) procedure and subsequently warmed for transfer ( ET) into synchronized recipients. Fresh embryos, and embryos cryopreserved using a standardized slow freezing procedure (direct thaw/direct transfer, DT) served as ET controls. Two different follicle-stimulating hormone ( FSH) sources, Folltropin® Canada ( FSH BAH, 24 donors) and a brand prepared by the Chinese Academy of Science ( FSH CAS, 16 donors), were compared in a series of superovulation outcomes following well-established FSH administration protocols. Following data analysis, the total number of ovulations recorded at the time of embryo flushing (10.5 vs 8.5; p = 0.28) and the total number of transferable embryos (6.2 vs 5.1; p = 0.52) were similar between the two FSH sources. ET for MDV (39.7%, n = 78), DT (35.2%, n = 71) and fresh controls (47.1%, n = 34) resulted in similar pregnancy rates (p > 0.05). When MDV was used, a higher pregnancy rate (42.6%) resulted from the transfer of vitrified morulae, when compared to the DT counterparts (24.3%), (p = 0.05). Transfer of vitrified morulae resulted also in higher pregnancy rate, when compared to the transfer of vitrified blastocysts (42.6% vs. 29.4%; p < 0.05). Transfer of DT blastocysts resulted in higher pregnancy rate than morulae, similarly cryopreserved (47.1% vs. 24.3%, p < 0.05). In conclusion, MDV is an effective alternative methodology for cryopreservation of in vivo-derived embryos. This study gives also indication that, compared to vitrified blastocysts, MDV of morula stage embryos results in higher pregnancy rates following warming and transfer into synchronized recipients. [ABSTRACT FROM AUTHOR]

The objective of the present study was to examine whether genomic selection of females interacts with the use of reproductive technologies (RT) to increase annual monetary genetic gain (AMGG). This was tested using a factorial design with 3 factors: genomic selection of females (0 or 2,000 genotyped heifers per year), RT (0 or 50 donors selected at 14 mo of age for producing 10 offspring), and 2 reliabilities of genomic prediction. In addition, different strategies for use of RT and how strategies interact with the reliability of genomic prediction were investigated using stochastic simulation by varying (1) number of donors (25, 50, 100, 200), (2) number of calves born per donor (10 or 20), (3) age of donor (2 or 14 mo), and (4) number of sires (25, 50, 100, 200). In total, 72 different breeding schemes were investigated. The profitability of the different breeding strategies was evaluated by deterministic simulation by varying the costs of a born calf with reproductive technologies at levels of €500, €1,000, and €1,500. The results confirm our hypothesis that combining genomic selection of females with use of RT increases AMGG more than in a reference scheme without genomic selection in females. When the reliability of genomic prediction is high, the effect on rate of inbreeding (ΔF) is small. The study also demonstrates favorable interaction effects between the components of the breeder's equation (selection intensity, selection accuracy, generation interval) for the bull dam donor path, leading to higher AMGG. Increasing the donor program and number of born calves to achieve higher AMGG is associated with the undesirable effect of increased ΔF. This can be alleviated, however, by increasing the numbers of sires without compromising AMGG remarkably. For the major part of the investigated donor schemes, the investment in RT is profitable in dairy cattle populations, even at high levels of costs for RT. [ABSTRACT FROM AUTHOR]

This study investigated the pregnancy rate and calf mortality after transfer of embryos produced using sex-sorted semen. Data for 12,438 embryo transfers performed on dairy farms were analyzed. Of these, 10,697 embryos were produced using conventional semen (CONV embryos) and 1741 using sex-sorted semen from 97 bulls (SEX embryos), predominantly of Ayrshire and Holstein breeds. Of the CONV embryos, 27.4% were transferred fresh, whereas of the SEX embryos, 55.7% were fresh. Recipient attributes (breed, parity, number of previous breeding attempts, and interval from calving to transfer) were comparable for both embryo types, heifers representing 57.8% of recipients in the CONV group and 54.8% in the SEX group. Recipients that were not artificially inseminated or did not undergo a new embryo transfer after the initial embryo transfer and had registered calving in fewer than 290 days after the transfer were considered pregnant. Pregnancy rate for recipients receiving CONV embryos was 44.1%, and for those receiving SEX embryos, it was 38.8%. The odds ratio for pregnancy in recipients receiving CONV embryos was 1.34 compared with SEX embryos (P < 0.001). The proportion of female calves was 49.6% and 92.3% in CONV and SEX groups, respectively. Overall, calf mortality was comparable in both groups. Mortality was similar in CONV and SEX groups (6.6% and 7.7%, respectively) for female calves. For male calves, mortality was 9.2% in the CONV group but significantly higher, 16.0% (P < 0.05), in the SEX group. This study showed that transfer of embryos produced with sex-sorted semen decreased the pregnancy rate by about 12% compared with embryos produced using conventional semen. Mortality of male calves born from SEX embryos was higher than for those born from CONV embryos. [ABSTRACT FROM AUTHOR]

In the present paper, we highlight the need to study very early maternal-embryo interactions and discuss how these interactions can be addressed. Bovine species normally carry one or, less frequently, two embryos to term; there are very rare cases of triplets or higher-order multiple pregnancies in which all the offspring are born alive. Multiple-embryo transfer (MET) in cattle allows for the detection of endometrial responses in scenarios where single-embryo transfer would not. Although MET is non-physiological, the present study shows that at the very early embryonic stages, a uterus carrying zona-enclosed embryos does not exhibit non-physiological reactions. On the contrary, MET should be considered the sum of multiple individual effects triggered by developing embryos. We provide arguments to support our hypothesis that describe a rationale for current work with MET, and we discuss alternative hypotheses. Using cattle as a model, we describe how technical approaches to analyzing zona-enclosed early embryo-maternal interactions (i.e., transcriptomics, proteomics, and endometrial cell culture) can help identify molecular changes that may be difficult to observe when only a single embryo is present. We conclude that MET can be used for studying very early maternal-embryo interactions in vivo in monotocous species. [ABSTRACT FROM AUTHOR]

The hormone progesterone is essential for proper embryonic development. The objective of this study was to examine the relationship between recipient serum concentrations of progesterone, at the time of embryo transfer and at conceptus recovery, on conceptus development from in vivo- or in vitro-produced embryos. Embryos were produced in vivo by superovulation of Holstein cows (IVO; n = 17) or in vitro with either serum-containing (IVPS; n = 27) or serum-restricted medium (IVPSR; n = 34). Single grade I blastocysts from each embryo production system were transferred into heifers on day 7 of development. Conceptuses were recovered on day 17 of gestation and classified as complete, degenerated, or no conceptus. Compared with the IVO group, in vitro-produced embryos had more ( P = 0.055) degenerated conceptuses (IVO, 0%; IVPS, 18.5%; and IVPSR, 20.6%). There were no differences in progesterone concentrations at the time of transfer when recipients received either male or female embryos ( P > 0.05). Progesterone concentrations in recipients receiving in vivo-produced embryos were higher ( P < 0.05; 3.74 ± 0.4 ng/mL; least-squares mean ± standard error of the mean) on day 7 compared with those receiving in vitro-produced embryos (IVPS, 2.4 ± 0.2; IVPSR, 2.58 ± 0.3 ng/mL). However, there was no difference in progesterone concentration on day 7 between treatment groups for heifers from which short conceptuses (≤194 mm) were recovered on day 17. In contrast, when longer (>194 mm) conceptuses were recovered on day 17, heifers receiving in vitro-produced embryos had lower ( P = 0.05) serum concentrations of progesterone on day 7 compared with those receiving in vivo-produced embryos (IVPS, 2.2 ± 0.5; IVPSR, 2.3 ± 0.5; IVO, 3.9 ± 0.5 ng/mL). In conclusion, differences in autonomy may exist between in vitro- and in vivo-produced embryos during the period of conceptus elongation with in vitro-produced embryos relying more on intrinsic factors to influence elongation. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the impact of varying features of an open multiple ovulation and embryo transfer (MOET) nucleus used in a genomic dairy cattle breeding scheme on both genetic gain and inbreeding rates. The Viking Red breeding scheme served as a case study to design scenarios that were stochastically simulated. We analyzed the number of AI sires used in the breeding population, the number of flushed heifers, the number of flushings per heifer and the genotyping capacity allocated to young females. The results supported that setting up a MOET program in a genomic dairy cattle scheme increases genetic gain without increasing inbreeding rates when the MOET nucleus size and the number of AI sires in service are large enough. Secondly, it was shown that increasing the number of genotyped heifers could not compensate the loss in genetic gain caused by closing the MOET nucleus. On the contrary, when extending the flushing capacity of the MOET program, increasing the number of flushings per heifer had a greater impact on genetic gain, but also on inbreeding rates, than increasing the number of flushed females. So, when a constraint applies on the flushing capacity in an open MOET scheme and the achieved inbreeding rate permits it, it seems more relevant to increase the number of flushings per heifer than the number of flushed heifers. Results also indicated that the number of genotypings allocated to females had to be sufficient to get maximal returns from the MOET scheme. In this case study, little extra genetic gain could be obtained by extending the MOET scheme size with the initial genotyping strategy (800 genotyped females). Indeed, the genotyping capacity should permit to genotype all heifers produced in the MOET scheme to discriminate the best heifers within families, and should be also sufficient to identify the best heifers outside the MOET nucleus. [ABSTRACT FROM AUTHOR]

Cloned bovine preimplantation embryos were generated by somatic cell nuclear transfer (SCNT) of bovine fetal fibroblasts with a silent copy of the pluripotency reporter gene GOF, integrated at a single site of a chromosome 13. GOF combines the regulatory Oct4/Pou5f1 sequence with the coding sequence for EGFP. EGFP expression served as a marker for pluripotency gene activation and was consistently detected in preimplantation embryos with 9 and more cells. Three-dimensional radial nuclear positions of GOF, its carrier chromosome territory and non-carrier homolog were measured in nuclei of fibroblasts, and of day 2 and day 4 embryos, carrying 2 to 9 and 15 to 22 cells, respectively. We tested, whether transcriptional activation was correlated with repositioning of GOF toward the nuclear interior either with a corresponding movement of its carrier chromosome territory 13 or via the formation of a giant chromatin loop. A significant shift of GOF away from the nuclear periphery was observed in day 2 embryos together with both carrier and non-carrier chromosome territories. At day 4, GOF, its carrier chromosome territory 13 and the non-carrier homolog had moved back toward the nuclear periphery. Similar movements of both chromosome territories ruled out a specific GOF effect. Pluripotency gene activation was preceded by a transient, radial shift of GOF toward the nuclear interior. The persistent co-localization of GOF with its carrier chromosome territory rules out the formation of a giant chromatin loop during GOF activation. [ABSTRACT FROM AUTHOR]

Nuclear landscapes were studied during preimplantation development of bovine embryos, generated either by in vitro fertilization (IVF), or generated as cloned embryos by somatic cell nuclear transfer (SCNT) of bovine fetal fibroblasts, using 3-dimensional confocal laser scanning microscopy (3D-CLSM) and structured illumination microscopy (3D-SIM). Nuclear landscapes of IVF and SCNT embryonic nuclei were compared with each other and with fibroblast nuclei. We demonstrate that reprogramming of fibroblast nuclei in cloned embryos requires changes of their landscapes similar to nuclei of IVF embryos. On the way toward the 8-cell stage, where major genome activation occurs, a major lacuna, enriched with splicing factors, was formed in the nuclear interior and chromosome territories (CTs) were shifted toward the nuclear periphery. During further development the major lacuna disappeared and CTs were redistributed throughout the nuclear interior forming a contiguous higher order chromatin network. At all stages of development CTs of IVF and SCNT embryonic nuclei were built up from chromatin domain clusters (CDCs) pervaded by interchromatin compartment (IC) channels. Quantitative analyses revealed a highly significant enrichment of RNA polymerase II and H3K4me3, a marker for transcriptionally competent chromatin, at the periphery of CDCs. In contrast, H3K9me3, a marker for silent chromatin, was enriched in the more compacted interior of CDCs. Despite these striking similarities, we also detected major differences between nuclear landscapes of IVF and cloned embryos. Possible implications of these differences for the developmental potential of cloned animals remain to be investigated. We present a model, which integrates generally applicable structural and functional features of the nuclear landscape. [ABSTRACT FROM AUTHOR]

Abstract: After the first successful transfer of mammalian embryos in 1890, it was approximately 60 years before significant progress was reported in the basic technology of embryo transfer (ET) in cattle. Starting in the early 1970s, technology had progressed sufficiently to support the founding of commercial ET programs in several countries. Today, well-established and reliable techniques involving superovulation, embryo recovery and transfer, cryopreservation, and IVF are utilized worldwide in hundreds, if not thousands, of commercial businesses located in many countries. The mean number of embryos produced via superovulation has changed little in 40 years, but there have been improvements in synchrony and hormonal protocols. Cryopreservation of in vivo-derived embryos is a reliable procedure, but improvements are needed for biopsied and in vitro-derived embryos. High pregnancy rates are achieved when good quality embryos are transferred into suitable recipients and low pregnancy rates are often owing to problems in recipient management and not technology per se. In the future, unanticipated disease outbreaks and the ever-changing economics of cattle and milk prices will continue to influence the ET industry. The issue of abnormal pregnancies involving in vitro embryos has not been satisfactorily resolved and the involvement of abnormal epigenetics associate with this technology merits continued research. Last, genomic testing of bovine embryos is likely to be available in the foreseeable future. This may markedly decrease the number of embryos that are actually transferred and stimulate the evolution of more sophisticated ET businesses. [Copyright &y& Elsevier]

Abstract: The insulin-like growth factor 1 receptor (IGF1R) is a membrane glycoprotein mediating most biological actions of IGF1 and IGF2, and has an important effect on ovulation, pre-implantation embryo development and pregnancy rate. The objectives of this study were to detect IGF1R gene polymorphisms of cattle and analyze the relationship with superovulation performance and pregnancy rates after embryo transfer (ET), as well as the hormone concentrations at the day of ET. One reported SNP of IGF1R G404T and a novel SNP of IGF1R G399A were analyzed in 170 Chinese Holstein donor cows and 118 Luxi recipients cattle. Statistical analysis revealed that the G404T mutation was associated (p =0.019) with increased ovulation rate and females with this mutation had enhanced performance in producing transferable embryos. For the polymorphic locus G399A, recipients with g.399 GG and g.399 GA genotypes had greater pregnancy rates after ET than that of g.399 AA genotype. Furthermore, the same tendency was observed that the genotype groups with greater pregnancy rates had greater progesterone and lesser estrogen concentrations, but these did not reach statistical significance. Results of the present study showed, for the first time, that the polymorphism in IGF1R is associated with superovulation traits, and indicated that the IGFIR gene can be used as a potential marker for donor selection. [Copyright &y& Elsevier]

Abstract: It has been reported that buffalo (Bubalus bubalis) embryos reconstructed by somatic cell nucleus transfer (SCNT) can develop to the full term of gestation and result in newborn calves. However, the developmental competence of reconstructed embryos is still low. Recently, it has been reported that treating donor cells or embryos with trichostatin A (TSA) can increase the cloning efficiency in some species. Thus, the present study was undertaken to improve the development of buffalo SCNT embryos by treatment of donor cells (buffalo fetal fibroblasts) with TSA and explore the relation between histone acetylation status of donor cells and developmental competence of SCNT embryos. Treatment of donor cells with either 0.15 or 0.3 μM TSA for 48 hours resulted in a significant increase in the cleavage rate and blastocyst yield of SCNT embryos (P < 0.05). Meanwhile, the expression level of HDAC1 in donor cells was also decreased (0.4–0.6 fold, P < 0.05) by TSA treatment, although the expression level of HAT1 was not affected. Further measurement of the epigenetic maker AcH4K8 in buffalo IVF and SCNT embryos at the eight-cell stage revealed that the spatial distribution of acH4K8 staining in SCNT embryos was different from the IVF embryos. Treatment of donor cells with TSA resulted in an increase in the AcH4K8 level of SCNT embryos and similar to fertilized counterparts. These results suggest that treatment of donor cells with TSA can facilitate their nucleus reprogramming by affecting the acetylated status of H4K8 and improving the in vitro development of buffalo SCNT embryos. The AcH4K8 status at the eight-cell stage can be used as an epigenetic marker for predicting the SCNT efficiency in buffalos. [Copyright &y& Elsevier]

In this study, we compared the developmental ability of somatic cell nuclear transfer ( SCNT) embryos reconstructed with three bovine somatic cells that had been synchronized in G0-phase ( G0- SCNT group) or early G1-phase (e G1- SCNT group). Furthermore, we investigated the production efficiency of cloned offspring for NT embryos derived from these donor cells. The G0-phase and e G1-phase cells were synchronized, respectively, using serum starvation and antimitotic reagent treatment combined with shaking of the plate containing the cells (shake-off method). The fusion rate in the G0- SCNT groups (64.2 ± 1.8%) was significantly higher than that of e G1- SCNT groups (39.2 ± 1.9%) ( P < 0.05), but the developmental rates to the blastocyst stage of SCNT embryos per fused oocytes were similar for all groups. The overall production efficiency of the clone offspring in e G1- SCNT groups (12.7%) per recipient cow was higher than that in G0- SCNT groups (3%) ( P < 0.05). The mean birth weight of cloned calves and the average calving score in the G0- SCNT groups (48.1 ± 3.4 kg and 3.3 ± 0.3, respectively) was significantly higher ( P < 0.05) than those of e G1- SCNT groups (37.2 ± 2.1 kg and 2.3 ± 0.2, respectively). Results of this study indicate that synchronization of donor cells in e G1-phase using the shake-off method improved the overall production efficiency of the clone offspring per transferred embryo. [ABSTRACT FROM AUTHOR]

Contents Total five ear skin fibroblast lines (named F1, F2, F3, F4 and F5) from different newborn Holstein cows have been used as nuclear donor cells for producing cloned cows by somatic cell nuclear transfer ( SCNT). The effects of these cell lines on both in vitro and in vivo developmental rates of cloned embryos, post-natal survivability and incidence of large offspring syndrome ( LOS) were examined in this study. We found that the different cell lines possessed the same capacity to support pre-implantation development of cloned embryos, the cleavage and blastocyst formation rates ranged from 80.2 ± 0.9 to 84.5 ± 2.5% and 28.5 ± 0.9 to 33.3 ± 1.4%, respectively. However, their capacities to support the in vivo development of SCNT embryos showed significant differences (p < 0.05). The pregnancy rates at 90 and 240 day were significantly lower in groups F2 (4.9% and 3.3%) and F3 (5.4% and 5.4%) compared to groups F1 (23.3% and 16.3%), F4 (25.7% and 18.6%) and F5 (25.9% and 19.8%) (p < 0.05). The cloning efficiency was significantly higher in group F5 than those in group F1, F2, F3 and F4 (9.3% vs 4.1%, 1.2%, 2.0% and 5.0%, respectively, p < 0.05). Moreover, large offspring syndrome ( LOS) incidence in group F5 was significantly lower than those in other groups (p < 0.05). All cloned offspring from cell line F1, F2, F3 and F4 showed LOS and gestation length delay, while all cloned offspring from F5 showed normal birthweight and gestation length. We concluded that the nuclear donor cell lines have significant impact on the in vivo development of cloned embryos and the incidence of LOS in cloned calves. [ABSTRACT FROM AUTHOR]

Contents Using a novel in vivo model considering a low developmental competence embryo (demi-embryo) and a subnormal fertility recipient (lactating high-yielding dairy cow), this experiment evaluated the effect of human chorionic gonadotrophin ( hCG) treatment at embryo transfer ( ET) on embryonic size at implantation, embryonic survival and recipient plasma progesterone ( P4) and bovine pregnancy-specific protein B ( PSPB) concentrations until day 63 of pregnancy. Embryos were bisected and each pair of demi-embryos was bilaterally transferred to recipients (n = 61) on day 7 of the oestrous cycle. At ET recipients were randomly assigned to treatment with 1500 IU h CG or to untreated controls. Higher (p < 0.01) pregnancy rates on days 25, 42 and 63, and embryo survival rate on day 63 were observed in h CG-treated cows with secondary CL than in h CG-treated cows without secondary CL and in untreated cows. Pregnancy rates and embryo survival rate were similar in h CG-treated cows without secondary CL and untreated cows. Embryonic size on day 42 was not affected by treatment with h CG, presence of secondary CL and type of pregnancy (single vs twin). Presence of secondary CL increased (p < 0.05) plasma P4 concentrations of pregnant cows on days 14, 19 and 25 but not thereafter and of non-pregnant cows on days 14-21. Treatment with hCG and presence of secondary CL had no effect on plasma PSPB concentrations, which were higher (p < 0.05) in twin than in single pregnancies. In conclusion, secondary CL induced by h CG treatment at ET significantly increased plasma P4 concentrations, the survival rate of demi-embryos and the pregnancy rate of high-yielding lactating dairy cows. Embryos were rescued beyond maternal recognition of pregnancy, but later embryonic survival, growth until implantation and placental PSPB secretion until day 63 of pregnancy were not affected by treatment or presence of secondary CL. [ABSTRACT FROM AUTHOR]

Abstract: The first successful equine embryo transfer was reported in 1972, 21 years after the first reported embryo transfer in cattle. Adaptations of embryo transfer and the various related technologies have generally been more rapid in the equine than in cattle, with the exceptions of superovulation, in vitro fertilization and cryopreservation. Recent progress has been achieved in all three of these areas. This paper presents a time line of various events in the history of equine embryo transfer and related technologies. Approximately 25,000 equine embryo transfers are being conducted per year, worldwide. [Copyright &y& Elsevier]

Abstract: The main objective was to determine the efficacy of using X-sorted sperm to produce embryos in vitro for transfer into lactating dairy cows. Cows were bred by timed artificial insemination (TAI) using nonsorted semen or X-sorted sperm, or they received a fresh embryo produced in vitro by fertilization with X-sorted or nonsorted sperm using timed embryo transfer (TET). Pregnancy rates at approximately Day 32 averaged over all dairies were 39.3 ± 3.2% (least-squares mean ± SEM) for TAI nonsorted, 27.3 ± 3.4% for TET nonsorted fresh embryos, and 30.2 ± 3.3% for TET X-sorted fresh embryos (TAI vs. both TET groups, P < 0.05; 206 to 233 cows per group). Pregnancy losses between approximately Day 32 and term ranged from 16% to 37%, the latter from TET with X-sorted sperm. Pregnancy losses to term were higher for cows receiving embryos produced in vitro than for cows bred by TAI. Calves produced via TET were not substantively different from AI controls in physical measurements or standard blood chemistry profiles. [Copyright &y& Elsevier]

Abstract: Objectives were to determine progesterone concentration (P4) from days 4 to 28 relative to presumptive estrus necessary for maintenance of pregnancy in lactating Holstein cows. Cows were assigned to the low P4 (LowP4, n =28) or control (n =153) treatments. All cows were presynchronized with two injections of PGF2α (14d apart) and an ovulation synchronization protocol (11d later; GnRH on day −10, PGF2α on day −3; and GnRH on day 0=presumptive estrus). Cows in the Low P4 treatment received 2 injections of prostaglandin F2α on days 4 and 5 (day 0=presumptive estrus) and a new CIDR insert on day 5 that was replaced every 7d until day 28. Blood was sampled on days −9, −2, 0, 4, 7,14, 21, and 28. Ovaries were examined with ultrasound on days −9, −3, and 7 and cows bearing a corpus luteum ≥20mm on day 7 received an embryo. On days 0, 4 and 7 P4 did not differ (P ≥0.27) but control cows had greater (P <0.01) P4 on days 14, 21, and 28. Progesterone concentration fold change from day 0 to 7 was not (P =0.14) affected by treatment, but P4 concentration fold change from day 7 to 14 was (P <0.01) greater for control cows compared with LowP4 cows. No LowP4 cows became pregnant after embryo transfer, whereas 35.7, 25.5, and 21.4% of control cows were pregnant on day 28, 42, and 63, respectively. Progesterone concentration fold changes from day 0 to 7 (P =0.03) and from day 7 to 14 (P =0.05) were associated with pregnancy outcomes on day 63. Among cows that were pregnant on day 63, the minimum P4 concentration fold changes from day 0 to 7 and from day 7 to 14 were 2.71 and 1.48, respectively. Interestingly, cows with P4 concentration <5ng/mL on day 14 were (P =0.01) and tended to be (P =0.07) more likely to lose pregnancy from day 28 to 42 and from day 28 and 63, respectively. Faster rise in P4 concentration during the metestrus and early diestrus are associated with pregnancy establishment following embryo transfer, which suggests that early rise in P4 concentration has an indirect effect on embryo development through modulation of uterine environment and secretion of histotroph. Furthermore, the positive effects of early rise in P4 concentration appear to go beyond the phase of maternal recognition of pregnancy through adhesion and placentation stages. [Copyright &y& Elsevier]

In the present study, we investigated the influence of exogenous estrogen on embryo survival after transfer into prepubertal gilts in which estrus had been induced. In the first experiment, estrus was induced in prepubertal gilts by the administration of 1,000 IU of eCG and 750 IU of hCG every 72 h. Several blastocysts were recovered on d 6 (d 0 is the day of hCG administra-tion), and 1 embryo was transferred to the tip of 1 side of the uterine horn on d 6 (Control). In treated groups, after embryo transfer, 5 mg of estradiol benzoate (EB) was administered on d 11 (EB5mg-1) or d 11, d 13, and d 15 (EB5mg-3) or d 11, 12, 13, 14, and 15 (EB5mg-5) or 20 mg of estradiol dipropionate (EDP) was administered on d 11 (EDP20mg-1) or d 11 and d 14 (EDP20mg-2). Autopsy examinations were perfonned on d 53 to 60. Although nontreated gilts did not become pregnant, gilts in each of the estradiol-treated groups became pregnant. The greatest pregnancy rate (77.8%, 7/9) was obtained with EDP20mg-2 (EDP20mg-2 > control: P < 0.05). In a second experiment, 1 blastocyst was transferred to prepubertal gilts and treated with EDP20mg-2. Pregnan-cy in recipient pigs was confirmed by ultrasonography, and pigs were allowed to farrow. Embryo survival rate was high on d 30 of pregnancy (75%, 9/12) but had a tendency (P = 0.0995) to decline from d 30 to delivery (33.3%, 4/12). In a third experiment, prepubertal gilts were administered 5 mg of EDP on d 11 (EDB5mg-l) and d 11 and d 14 (EDP5mg-2). Autopsy examinations were perfonned on d 53 to 58. Pseudopregnancy rate was high for EDP5mg-2 (63.6%, 7/11) compared with EDP5mg-1 (0%, 0/11; P < 0.05). In a fourth experiment, prepuber-tal gilts were transferred 1 blastocyst and treated with EDP5mg-2. Pregnancy was confirmed in recipient pigs by ultrasonography, and pigs were subsequently allowed to farrow. Embryo survival rate remained unchanged from d 30 of pregnancy to delivery (66.7%; 8/12). One piglet died from dystocia, and 1 suffered from deformity involving double-breasted hooves and died 6 d after birth. There was no difference (P > 0.05) in survival rate on d 30 of pregnancy and weaning (50%, 6/12). Body weight at birth and at weaning did not differ from that reported in previous studies. In conclusion, this study showed that EDP5mg-2 treatment during early pregnancy leads to full-term development of a single embryo. [ABSTRACT FROM AUTHOR]

The objective of the current study was to investigate the effects of the addition of oviduct co-culture to synthetic oviduct fluid (SOF) and M´n´zo B2 media used in an in vitro study of cows, and the effects of different gas atmospheres (5% CO2 or 5% CO2, 5% O2, and 90% N2) on in vitro cultures. Oocytes obtained through aspiration from the ovaries of slaughtered Holstein cows were washed and cultured within a TCM-199 maturation medium at 38.8 °C for 23 h. Then the matured oocytes and thawed semen, prepared in accordance with the swim-up method, were incubated for fertilization within in vitro fertilization (IVF)-Tyrode's albumin lactate pyruvate (TALP) medium with an atmosphere including the combination of 5% CO2, 5% O2, and 90% N2 gas, at 38.8 °C for 18-24 h. Fertilized oocytes were distributed into 3 main groups: Group I: B2 (5% CO2), Group II: B2 medium (5% CO2, 5% O2, and 90% N2), and Group III: SOF (5% CO2, 5% O2, and 90% N2), and each group was divided into 2 subgroups, with and without oviduct co-culture cells, and were cultured for 9 days. The percentage of embryos that reached the blastocyst stage was 34.0%, 20.0%, and 32.3% in the co-culture group and 26.7% and 23.3% in the without co-culture group, respectively. Group III showed the highest development of expanded blastocyst stage (P < 0.01). In conclusion, the addition of co-culture to B2 (5% CO2 atmosphere) and SOF (5% CO2, 5% O2, and 90% N2 atmosphere) media increased the rate of transferable embryos. [ABSTRACT FROM AUTHOR]

ABSTRACT This study was designed to evaluate the effect of estrus synchronization treatments on recipient heifers for embryo transfer (ET). Holstein heifers were separated into the following three groups: (i) an administration of 50 µg GnRH (gonadotropin-releasing hormone) analog was given to heifers at a random stage of the estrus cycle, followed 7 days later by two administrations of 7.5 mg prostaglandin F2 alfa analog (PG) as control; (ii) another administration of 100 µg GnRH was given to the control group at 48 h after the administration of PG as the second GnRH group; and (iii) an administration of 0.75 mg estradiol benzoate (E2) was given to the control group at 24 h after the administration of PG as the E2 group. Each method caused estrus synchronization. Fresh embryos were nonsurgically transferred into the suitable recipients that had a functional corpora lutea (CL) 7 days after estrus. The E2 group showed a significantly higher ( P < 0.01) rate of estrus synchronization (98.9%) at 1-3 days after PG administration and the final pregnancy rate of the E2 group (50.6%) was also significantly higher than the other groups (37.1%, P < 0.05 and 30.9%, P < 0.01, respectively). These findings demonstrate that E2 administration 24 h after PG protocol is effective for estrus synchronization of Holstein heifers, thus improving the productivity of ET. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, 809 uterine flushes and 454 embryo transfers performed in mares over a 4-yr interval were examined to evaluate the effects of: (1) the day of embryo collection on recovery rates; (2) the degree of synchrony between donor and recipient mares on pregnancy rates; (3) the recipient day post ovulation on pregnancy rates; and (4) the age of the embryo at recovery on pregnancy rates at 60 days. Uterine flushes were performed on Days 6, 7, 8, 9, and 10 (Day 0 = ovulation) and embryos were transferred to recipients with degrees of synchrony varying between +1 to −6 (recipient ovulated 1 day before through 6 days after the donor). Recipient mares ranged from 2 to 8 days post ovulation. Embryo recovery rates were similar for flushes performed on Day 7 (61%), Day 8 (66%), Day 9 (59%), and Day 10 (56%), but the embryo recovery rate was lower (P < 0.03) for flushes performed on Day 6 (42%) compared with all other days. Pregnancy rates for various degrees of synchrony were as follows: +1 (71%), 0 (77%), −1 (68%), −2 (63%), −3 (66%), −4 (76%), −5 (61%), and −6 (27%). The −6 day of degree of synchrony had the lowest (P < 0.05) pregnancy rate compared with all other days, but there was no significant difference among +1 to −5 days. There was a lower (P < 0.05) pregnancy rate for embryos transferred to recipient mares on Day 2 (33%) compared with mares on Day 3 (66%), Day 4 (66%), Day 5 (62%), Day 6 (55%), Day 7 (58%), and Day 8 (56%). Pregnancy rate was higher (P < 0.05) for Day 7 (76%) embryos compared with Day 6 (50%), Day 8 (64%), and Day 9 (44%) embryos; Day 9 embryos resulted in lower (P < 0.05) pregnancy rates than Days 7 or 8 embryos. In conclusion, this study demonstrated that: (1) embryo recovery rates between Days 7 and 10 were similar and acceptable (e.g., 63% 488/771); (2) the degree of synchrony between donor and recipient mares does not need to be as restricted as previously reported in horses. Acceptable pregnancy rates (e.g., 70%, 99/142) were obtained even when recipient mares ovulated 4 to 5 days after the donors; (3) similar pregnancy rates were obtained when recipient mares received embryos within a large range of days post ovulation (Days 3 to 8); and (4) Day 7 embryos produced higher pregnancy rates when compared with Days 8 and 9 embryos. In clinical terms, the application of these new findings will be beneficial to large equine embryo transfer operations in producing more pregnancies per season. [Copyright &y& Elsevier]

A receptive uterine environment is a key component in determining a successful reproductive outcome. We tested the hypothesis that endometrial gene expression patterns differ in fertile and subfertile dairy cow strains. Twelve lactating dairy cattle of strains characterized as having fertile (n = 6) and subfertile (n = 6) phenotypes underwent embryo transfer on day 7 of the reproductive cycle. Caruncular and intercaruncular endometrial tissue was obtained at day 17 of pregnancy, and microarrays used to characterize transcriptional profiles. Statistical analysis of microarray data at day 17 of pregnancy revealed 482 and 1,021 differentially expressed transcripts (P value < 0.05) between fertile and subfertile dairy cow strains in intercaruncular and caruncular tissue, respectively. Functional analysis revealed enrichment for several pathways involved in key reproductive processes, including the immune response to pregnancy, luteolysis, and support of embryo growth and development, and in particular, regulation of histotroph composition. Genes implicated in the process of immune tolerance to the embryo were downregulated in subfertile cows, as were genes involved in preventing luteolysis and genes that promote embryo growth and development. This study provides strong evidence that the endometrial gene expression profile may contribute to the inferior reproductive performance of the subfertile dairy cow strain. [ABSTRACT FROM AUTHOR]

Abstract: Currently, timed ovulation induction and fixed-time artificial insemination (FTAI) in superstimulated donors and synchronization protocols for fixed-time embryo transfer (FTET) in recipients can be performed using GnRH or estradiol plus progesterone/progestin (P4)-releasing devices and prostaglandin F2α (PGF2α). The control of follicular wave emergence and ovulation at predetermined times, without estrus detection, has facilitated donor and recipient management. However, because Bos taurus cows have subtle differences in their reproductive physiology compared with Bos indicus cattle, one cannot assume that similar responses will be achieved. The present review will focus on the importance of orchestrating donor and recipient management to assure better logistics of procedures to achieve more desirable results with embryo collection and transfer. In addition, this will provide clear evidence that the use of FTAI in superstimulated donors and FTET in embryo recipients eliminates the need to detect estrus with satisfactory results. These self-appointed programs reduce labor and animal handling, facilitating the use of embryo transfer in beef and dairy cattle. [Copyright &y& Elsevier]

Abstract: Technologies for in vitro embryo production have the potential to enhance the efficiency of cattle production systems. However, utilization of in vitro-produced embryos for transfer remains limited throughout much of the world. Despite improvements over the past two decades, problems associated with the production of bovine embryos in vitro still exist which limit the widespread commercial application of this technology. In particular, bovine embryos produced in vitro have a reduced capacity to establish and maintain pregnancy as compared with their in vivo-derived counterparts. Embryo competence for survival following transfer is improved by in vivo culture in the sheep oviduct, thus indicating that standard embryo culture conditions are sub-optimal. Therefore, one strategy to improve post-transfer survival is to modify embryo culture media to more closely mimic the in vivo microenvironment. The maternal environment in which the bovine embryo develops in vivo contains various growth factors, cytokines, hormones, and other regulatory molecules. In addition to affecting bovine embryo development in vitro, recent research indicates that embryo competence for survival following transfer can also be improved when such molecules are added to embryo culture medium. Among the specific molecules that can increase post-transfer embryo survival are insulin-like growth factor-1 (IGF-1), colony stimulating factor-2 (CSF-2) and hyaluronan. This paper will review the effects IGF-1, CSF-2 and hyaluronan on post-culture embryo viability and discuss the potential mechanisms through which each of these molecules improves post-transfer survival. [Copyright &y& Elsevier]

Abstract: The objective was to investigate the effect of recipient oocyte age and the interval from activation to fusion on developmental competence of buffalo nuclear transfer (NT) embryos. Buffalo oocytes matured in vitro for 22 h were enucleated by micromanipulation under the spindle view system, and a fetal fibroblast (pretreated with 0.1 μg/mL aphidicolin for 24 h, followed by culture for 48 h in 0.5% fetal bovine serum) was introduced into the enucleated oocyte, followed by electrofusion. Both oocytes and NT embryos were activated by exposure to 5 μM ionomycin for 5 min, followed by culture in 2 mM 6-dimethyl-aminopurine for 3 h. When oocytes matured in vitro for 28, 29, 30, 31, or 32 h were activated, more oocytes matured in vitro for 30 h developed into blastocysts in comparison with oocytes matured in vitro for 32 h (31.3 vs 19.9%, P < 0.05). When electrofusion was induced 27 h after the onset of oocyte maturation, the cleavage rate (78.0%) was higher than that of electrofusion induced at 28 h (67.2%, P < 0.05), and the blastocyst yield (18.1%) was higher (P < 0.05) than that of electrofusion induced at 25 or 26 h (7.4 and 8.5%, respectively). A higher proportion of NT embryos activated at 3 h after electrofusion developed to the blastocyst stage (18.6%) in comparison with NT embryos activated at 1 h (6.0%), 2 h (8.3%), or 4 h (10.6%) after fusion (P < 0.05). No recipient was pregnant 60 d after transfer of blastocysts developed from NT embryos activated at 1 h (0/8), 2 h (0/10), or 4 h (0/9) after fusion. However, 3 of 16 recipients were pregnant following transfer of blastocysts developed from the NT embryos activated at 3 h after fusion, and two of these recipients maintained pregnancy to term. We concluded that the developmental potential of buffalo NT embryos was related to recipient oocyte age and the interval from fusion to activation. [Copyright &y& Elsevier]

Since the first successful somatic cell nuclear transfer (SCNT) experiments were carried out, a number of domestic and agriculture species have been cloned using donor cells derived from different sources and origin. However, differences in nuclear transfer efficiency both in vitro and in vivo have been generally observed. These differences may be accentuated when transgenic cell lines are used as nuclear donors in an attempt to generate transgenic cloned offspring. The present study examined the suitability of cell lines derived from 3 different fetal sources and the effects of genetic manipulation of donor fetal fibroblasts with a red fluorescent plasmid, on the in vitro developmental potential and quality of nuclear transfer derived bovine embryos. We observed no differences in the cleavage rate of nuclear transfer embryos generated with any of the cell lines evaluated. However, the blastocyst rate was significantly affected when cell lines were derived from the 3 different fetal sources (21, 18 and 11%, respectively) or from 2 transgenic clonal cell lines that had originated from the same primary fetal cell (18 and 10%, respectively). Despite this difference, quality of embryos as measured by the total number of cells and by assessing some morphology aspects of their appearance was not different. Together these results indicate that fetal fibroblast cell lines derived from different fetal sources and transgenic clonal cell lines that had originated from the same fetus results in different in vitro developmental potential when used as donors for nuclear transfer experiments. Further studies, including evaluation of pregnancy rates, development to term, and epigenetic modifications of these cell lines will be necessary to better understand the differences observed in nuclear transfer efficiency. [ABSTRACT FROM AUTHOR]

Abstract: We hypothesized that administration of hCG to recipients at embryo transfer (ET) would induce accessory CL, increase serum progesterone concentrations, and reduce early embryonic loss (as measured by increased transfer pregnancy rates). At three locations, purebred and crossbred Angus, Simmental, and Hereford recipients (n = 719) were assigned alternately to receive i.m. 1,000 IU hCG or 1 mL saline (control) at ET. Fresh or frozen-thawed embryos were transferred to recipients with a palpable CL on Days 5.5 to 8.5 (median = Day 7) of the cycle (Locations 1 and 2), or on Day 7 after timed ovulation (Location 3). Pregnancy diagnoses (transrectal ultrasonography) were done 28 to 39 d (median = 35 d) and reconfirmed 58 to 77 d (median = 67 d) post-estrus. At Location 1 (n = 108), ovaries were examined at pregnancy diagnosis to enumerate CL. More (P < 0.001) pregnant hCG-treated cows (69.0%) had multiple CL than pregnant controls (0%). Serum progesterone (ng/mL) determined at Locations 1 and 2 (n = 471) at both pregnancy diagnoses in pregnant cows was greater (P ≤ 0.05) after hCG treatment than in controls (first: 8.1 ± 0.9 vs 6.1 ± 0.8; second: 8.8 ± 0.9 vs 6.6 ± 0.7), respectively. Unadjusted pregnancy rates at the first diagnosis were 61.8 and 53.9% for hCG and controls. At the second diagnosis, pregnancy rates were 58.6 and 51.3%, respectively. Treatment (P = 0.026), embryo type (P = 0.016), and BCS (P = 0.074) affected transfer pregnancy rates. Based on odds ratios, greater pregnancy rates occurred in recipients receiving hCG, a fresh embryo (66.3 vs 55.5%), and having BCS >5 (62.3 vs 55.3%). We concluded that giving hCG at ET increased incidence of accessory CL, serum progesterone in pregnant recipients, and transfer pregnancy rates. Furthermore, we inferred that increased progesterone resulting from hCG-induced ovulation reduced early embryonic losses after transfer of embryos to recipients. [Copyright &y& Elsevier]

The objective of experiment 1 was to evaluate the effects of treatments with human chorionic gonadotropin (hCG) or GnRH 7 d after induced ovulation on reproductive performance of lactating dairy cows submitted to timed artificial insemination (TAI) or timed embryo transfer (TET). A total of 834 potential breedings were used from 661 lactating Holstein cows (37.3 ± 0.3 kg of milk/d). Cows had ovulation synchronized and were assigned randomly to receive TAI on d 0 or TET on d 7. Within each group, cows were assigned randomly to receive on d 7 no additional treatment (control; nTAI = 156; nTET = 126), a 100 μg i.m. injection of GnRH (nTAI = 155; nTET = 124), or a 2,500 IU i.m. injection of hCG (nTAI = 151; nTET = 122). Postbreeding treatment affected the percentages of pregnant cows at TET on d 28 (control: 38.1%; GnRH: 52.4%; hCG: 45.1%) and on d 60 (control: 32.5%; GnRH: 41.1%; hCG: 38.5%), but postbreeding treatment did not affect percentages of pregnant cows at TAI on d 28 (control: 30.1%; GnRH: 32.2%; hCG: 32.4%) or on d 60 (control: 25.6%; GnRH: 27.1%; hCG: 29.8%). The objective of experiment 2 was to evaluate the effect of a treatment with GnRH 7 d after TET on reproductive performance of lactating dairy cows that received a previous GnRH treatment at TET. A total of 285 potential breedings were used from 257 lactating Holstein cows (35.1 ± 0.8 kg of milk/d). Cows had ovulation synchronized and were assigned for TET on d 7. Immediately after TET, all cows were treated with a 100 μg i.m. injection of GnRH. On d 14, cows were assigned randomly to receive (G7–14; n = 147) or not (G7; n = 138) an additional injection of GnRH. Pregnancy diagnosis were performed on d 28 and 60. The additional treatment with GnRH on d 14 did not affect the percentages of pregnant cows on d 28 (G7: 48.5%; G7–14: 42.9%) or on d 60 (G7: 39.8%; G7–14: 37.4%). In conclusion, treatment with GnRH or hCG 7 d after induced ovulation increased conception rates in lactating dairy cows submitted to TET, but not in cows submitted to TAI. Moreover, treatment with GnRH 7 d after TET did not enhance reproductive performance of lactating dairy cows that received a previous GnRH treatment at TET. [ABSTRACT FROM AUTHOR]

Abstract: Neosporosis is considered to be one of the main causes of abortions in bovines. In this study we evaluated the congenital transmission and occurrence of abortions by Neospora caninum in an embryo transfer center in Neropolis, Goiás. Serological samples from 101 recipients, 61 donors, and 90 calves were analyzed. Among these animals, 32.67% of the recipients, 22.22% of the donors, and 6.66% of the calves were positive for N. caninum. The rate of vertical transmission was 24%. There was a statistically significant difference between antibody titer of the recipient cows and the serological status of the calves. There was no statistically significant relationship between N. caninum serological status and reproductive rates such as estrum repetition and embryo production. Eight abortions occurred, six (75%) in positive females and two (25%) in negative females. These results indicate that neosporosis may be an important cause of failing reproduction and that in embryo transfer centers recipients should be previously examined, and those that are seronegative for Neospora should be chosen to reduce abortion and the birth of seropositive calves. [ABSTRACT FROM AUTHOR]

Abstract: The objective was to use the bovine viral diarrhea virus (BVDV) as a model to assess the risk of infectious disease transmission in the system of in vitro embryo production and transfer via somatic cell nuclear transfer (SCNT) technology. The risks of BVDV transmission in the SCNT embryo production were previously evaluated . In that in vitro study, following standard operating procedures (SOP), including pre-nuclear transfer donor cell testing, oocyte decontamination and virus-free cell and embryo culture conditions, SCNT embryos produced were free of detectable viral RNA. The current study focused on the evaluation of the potential risk of disease transmission from SCNT embryos to recipients, and the risk of producing persistently infected animals via SCNT embryo transfer. Blood samples were collected from 553 recipients of SCNT embryos and 438 cloned calves and tested for the presence of BVDV viral RNA via a sensitive real time PCR method. All samples tested were negative. These results, in conjunction with the previous in vitro study, confirmed that the established SCNT embryo production and transfer system is safe and presents no detectable risk of disease transmission. [Copyright &y& Elsevier]

Abstract: Stochastic modeling of dairy cattle populations using multiple ovulation and embryo transfer (MOET) was used to compare 15-year genetic responses with an artificial insemination (AI) program. MOET and AI techniques were simulated in four populations, two with 100 breeding females each and two with 400 breeding females. The selection goal was to maximize genetic progress in milk yield. The reduction in genetic variation due to inbreeding and linkage disequilibrium was accounted for in the simulation process. All four MOET breeding schemes studied achieved larger genetic responses than the realized and theoretical genetic gains from the current AI progeny testing populations. Strict restriction against inbred matings slowed genetic progress significantly in the small population but would not be consequential in the larger population. However, allowing inbred matings in the smaller population caused a rapid accumulation of inbreeding. Linkage disequilibrium was as important as inbreeding in reducing genetic variation. Genetic drift variance was much smaller in the larger population. [Copyright &y& Elsevier]

The persistence of A-type nuclear lamin in somatic cell nuclear transfer (SCNT) embryos has been proposed as a marker for incomplete nuclear reprogramming. Using monoclonal antibodies to A/C- (A/C-346 and A/C-131C3) and B-type lamin, we compared distribution during early development of bovine IVF, parthenogenetic and SCNT embryos. A/C-346 staining was observed in the pronuclei of IVF embryos and in nuclei at the two-cell stage, but was not detected in subsequent cleavage stages up to and including hatched blastocysts. In contrast, A/C-131C3 and anti-lamin B2 stained all preimplantation stage embryos. Parthenogenetic and SCNT embryos had similar staining patterns to IVF embryos for all three antibodies, demonstrating correct nuclear architecture reprogramming. Inhibiting protein synthesis with cycloheximide (CHX) in parthenogenetic and SCNT embryos did not affect lamin A/C localisation, suggesting that lamin A/C is maternal in origin. However, activation with CHX delayed lamin A/C incorporation compared with 6-dimethylaminopurine activation. In SCNT embryos, staining for both A/C- and B-type lamin was delayed compared with parthenotes, although lamin B2 incorporation preceded lamin A/C in both. In conclusion, the lamin A/C distribution in SCNT bovine embryos paralleled that of IVF and parthenogenetic controls and therefore is not a marker of incomplete reprogramming. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present study was to compare a synchronization of time of ovulation protocol for fixed-timed embryo transfer (FTET) with the usual administration of a single dose of prostaglandin associated with detection of estrus. Also, the effect of the presence of CL at the beginning of FTET protocol was evaluated. Lactating Holstein cows (n =651) with three previous artificial inseminations were classified according to presence or absence of a corpus luteum (CL). Cows with a CL were randomly assigned to two additional treatments and submitted to embryo transfer after detection of estrus (PGF-Estrus) or FTET (FTET-CL). Cows without CL were allocated to the FTET-NoCL treatment. On a random day of the estrous cycle (Day 0), cows in the PGF-Estrus treatment (n =229) were treated with 150μg d-cloprostenol (PGF) i.m. followed by detection of estrus from Day 1 through Day 5 after PGF. Embryos were transferred 6–8 days after estrus detection. Cows in the FTET-CL (n =208; presence of CL) and FTET-NoCL (n =214; absence of CL) treatments received a norgestomet ear implant plus 2mg estradiol benzoate (EB) and 50mg progesterone i.m. on Day 0. On Day 8, the implant was removed and 400IUeCG, 150μg d-cloprostenol and 1mg estradiol cypionate i.m. were administered. No detection of estrus was performed and Day 10 was arbitrarily considered as the estrus day. Ultrasonographic exams were performed in all recipients and only cows with a single CL≥15mm or multiple CL received a fresh or frozen–thawed embryo on Day 17. Pregnancy was diagnosed by ultrasonography at 30 and 60 days of pregnancy. When FTET and PGF-Estrus were compared, the proportion of cows receiving an embryo (recipients transferred-to-treated rate) was greater in the FTET-CL (75.0% (156/208) than in PGF-Estrus (34.5%, 79/229; P <0.0001) treatment. Pregnancy rate (60 days) was also greater in FTET-CL (29.3%, 61/208) when compared to PGF-Estrus (16.2%, 37/229; P =0.001). However, no differences were found in pregnancy loss [PGF-Estrus=11.9% (5/42), FTET-CL=9.0% (6/67); P =0.62] and circulating progesterone concentration at embryo transfer [PGF-Estrus=4.02±0.52ng/mL (n =25), FTET-CL=3.33±0.32ng/mL (n =27); P =0.25] among these treatments. The presence of CL at the beginning of FTET protocol resulted greater transferred-to-treated rate [FTET-CL=75.0% (156/208) vs. FTET-NoCL=61.2% (131/214); P =0.003], but showed no effect on pregnancy rate at 60 days [FTET-CL=29.3% (61/208) vs. FTET-NoCL=22.9% (49/214); P =0.13], pregnancy loss [FTET-CL=9.0% (6/67) vs. FTET-NoCL=2.0% (1/50); P =0.15] and circulating progesterone concentration at ET [FTET-CL=3.33±0.32ng/mL (n =27) compared to FTET-NoCL=3.44±0.40ng/mL (n =2 9); P =0.82]. In conclusion, the protocol for synchronization of time of ovulation using norgestomet ear implant, EB and eCG increased recipients transferred-to-treated and pregnancy rates in high-producing repeat-breeder Holstein cows. Also, recipients without CL at the beginning of the time of ovulation synchronization treatment resulted in similar pregnancy rate as recipients with CL submitted to FTET protocol. Thus, the suggested protocol allowed the performance of FTET, without the need for detection of estrus, simplifying the reproductive management and increasing the reproductive efficiency in repeat-breeder Holstein recipients. [Copyright &y& Elsevier]

Lactating buffaloes are sensitive to heat stress and are not able to maintain their core temperature within the thermo neutral zone because of their particular specie characteristics e.g. black body color and more affiliation to water for their production and reproduction. The high ambient temperature is conducive to reproductive failures and embryonic mortality, especially in buffaloes. Feed intake is reduced and milk yield is alarmingly decreased. The prominent signs of heat stress in buffalo include decreased feed intake, increased reddening of hide, protruded tongue, panting, obvious blood shot eyes, very hot to touch and increased rectal temperature. Increased incidence of certain health problems during the summer months may be manifested as increased occurrences of mastitis, retained placentas, metritis, and ketosis. It can also elevate cortisol levels. There is general agreement throughout the literature that buffalo are in sufficiently heat tolerant and reports indicate that milk yield, growth and fertility are all reduced during periods of high ambient temperature. Each of these variables shows a direct relationship with rectal temperature and will consequently increase with improvements in heat tolerance. Heat stress represents one of the major factors for impairment of infertility in tropical and subtropical countries and need effective applicable strategy to overcome the harmful effects of heat stress on health condition and breeding efficiency of buffalo. Investigation revealed that showering of buffaloes twice a day, wallowing and cooled drinking water can increase conception rate from 21 to 30 percent and there is a definite increase in yield of about 20 to 25%. The feeding of antioxidants during summer can also improve health and fertility rate. This heat load can be reduced by the provision of wallows or showers, feeding manipulations and improvements in the housing infrastructures, but the long term solution is to improve heat dissipation of the animal itself. This paper reviews the effects of heat stress in buffalo at different physiological states, hormonal and behavioral changes associated with heat stress, effects on production and reproduction and suitable remedy measures to combat this problem. [ABSTRACT FROM AUTHOR]

In order to analyse anatomic particularities between buffalo and bovine females, the genital systems from 31 cyclic buffalo and 21 cyclic bovine were morphometrycally evaluated. The genital systems were dissected and the organs were separated and measured. The ovaries weight, the right ovary length and wideness, the number of cervix rings, the vagina and cervix length were higher in bovine than buffalo. Otherwise, the ovaries thickness, the left oviduct length, the uterine body, the left horn length and wideness were higher in buffalo than bovine. The left ovary length and wideness, the right oviduct length, the right uterine horn length and wideness did not differ between species. The knowledge of the anatomic particularities is important to the employment of reproductive techniques like artificial insemination and embryo transfer on these species. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of the biopsy of 8-cell to 16-cell bovine embryos on their subsequent development and the effect of whole genome amplification (WGA) on removed blastomeres. Design: Randomized study. Setting: Molecular genetics and animal reproduction laboratories. Patient(s): Cow ovaries obtained from slaughterhouses. Intervention(s): The ovaries were punctured, and the oocytes were matured and fertilized in vitro. On the fourth day after fertilization, 8-cell to 16-cell bovine embryos were biopsied, one quarter of each embryo being removed. The blastomeres were submitted to WGA followed by polymerase chain reaction (PCR). The embryos were returned to culture for evaluation of their development. Main Outcome Measure(s): Subsequent rate of blastocyst development, embryo cell number, WGA efficiency, and sex determination. Result(s): A total of 92 embryos were submitted to biopsy. The blastocyst production was 53.3%, with 44.9% of hatching rate. These results were similar to those of the control group (66.0% and 42.6%) of 103 embryos. Overall, no impact was detected on embryo quality in blastocyst cell number between the two groups. Removed blastomeres were submitted to WGA, resulting in 98.2% of efficiency. However, only 59% of the samples were sexed by PCR. Conclusion(s): Biopsy of 8-cell to 16-cell bovine embryos did not affect their subsequent development. WGA was successful in removed blastomeres. [Copyright &y& Elsevier]