Processos que afetam a taxa de gestação pós-inovulação do embrião equino / Processes that affect pregnancy rate after embryo transfer

A transferência de embriões equinos é uma biotecnologia que traz inúmeros benefícios reprodutivos para um haras. Entretanto, os índices reprodutivos obtidos numa estação de monta podem ser afetados por diversos fatores que interferem tanto na recuperação embrionária que normalmente são relacionados à doadora de embriões, quanto na taxa de gestação na receptora de embriões. O objetivo do presente artigo foi revisar os fatores relacionados à receptora de embriões em programas de transferência de embriões equinos.(AU)

Equine embryo transfer is a biotechnology that brings reproductive benefits to a stud farm. However, the reproductive rates obtained in a breeding season can be affected by several factors that interfere both in the embryonic recovery that are normally related to the embryo donor, and in the pregnancy rate in the embryo recipient. The aim of this article was to review the factors related to the recipient of embryos in equine embryo transfer programs.(AU)

Taxa de recuperação embrionária em éguas Mangalarga Marchador inseminadas com sêmen refrigerado / Embryonic recovery rate in Mangalarga Marchador mares inseminated with refrigerated semen

O acompanhamento reprodutivo da espécie equina tem sido cada vez mais aplicado na aplicade de diversos países, resultando em melhores índices reprodutivos para a espécie e em animais de linhagens selecionadas. Nos programas de transferência de embrião, a taxa de recuperação embrionária consiste em um parâmetro essencial a fim de verificar o sucesso da técnica. Por conseguinte, este trabalho propõe-se a avaliar as taxas de recuperação embrionária de éguas doadoras submetidas à inseminação artificial com sêmen refrigerado de maneira a complementar os dados relacionados ao assunto. Conforme os dados coletados durante a estação de monta de agosto de 2018 a fevereiro de 2019, obteve-se 129 lavados uterinos provenientes de 20 éguas e 83 embriões recuperados. Desse modo, a taxa de recuperação embrionária obtida foi de 64,34%. Diante dos dados apresentados neste estudo, conclui-se que a aplicabilidade da técnica de recuperação embrionária visando o uso do sêmen refrigerado na inseminação artificial de éguas se mostra promissora, pois permite o transporte de material genético de alto valor entre propriedades sem interferir drasticamente nos índices dos programas de reprodução.

The reproductive monitoring of the equine species has been increasingly applied in several countries, resulting in better reproductive rates for the species and in animals from selected strains. In embryo transfer programs, the embryo recovery rate is an essential parameter to verify the technique success. Therefore, the present work proposes to evaluate the embryo recovery rates of donor mares submitted to artificial insemination with refrigerated semen to complement the data related to the subject. According to the data collected during the breeding season for the period from August 2018 to February 2019, 129 uterine washes were obtained from 20 mares and 83 recovered embryos. Thus, the embryonic recovery rate obtained was 64.34%. Given the data presented in this study, it is concluded that the applicability of the embryonic recovery technique aiming at the use of refrigerated semen in artificial insemination of mares is promising, as it allows the transport of high-value genetic material between properties without interfering dramatically in breeding program indexes.

Pontos críticos na produção de embriões equinos com enfoque na doadora / Critical points in the production of equine embryos with a donor approach

Inúmeras são as vantagens da utilização da técnica de transferência de embriões (TE) em equinos. No entanto, alguns fatores podem afetar a taxa de recuperação embrionária: dia da colheita do embrião; condição uterina e idade da doadora; manejos reprodutivo, sanitário e nutricional; garanhão/qualidade do sêmen; habilidade do técnico; condições climáticas, número de ovulações e adaptação da doadora. O objetivo deste artigo é revisar os fatores que podem exercer influência sobre a taxa de recuperação embrionária tendo impacto direto nos índices reprodutivos de um programa de TE.(AU)

There are countless advantages of using the embryo transfer (ET) technique in horses. However, some factors may affect the embryonic recovery rate: day of embryo collection; uterine condition and donor age; reproductive, health and nutritional management; stallion/semen quality; skill of the technician; climatic conditions, number of ovulations and adaptation of the donor. The objective of this article is to review those factors that can influence the embryonic recovery rate, having a direct impact on the reproductive rates of an ET program.(AU)

Estudos para o incremento da produção de embriões in vivo e in vitro em vacas de corte taurinas e sintéticas / Studies to improve in vivo and in vitro embryo production in beef cows from taurine and synthetic breeds

O Brasil destaca-se por ser um dos líderes mundiais na produção in vitro de embriões, o que é decorrente do rebanho nacional ser predominantemente composto por raças zebuínas, que possuem maior número de folículos antrais aspiráveis. Por outro lado, vacas taurinas apresentam menor população folicular antral, o que limita o número de ovócitos obtidos por seção de aspiração folicular (ovum pick-up; OPU). Portanto, na região Sul do Brasil há demanda para produção tanto in vivo como in vitro de embriões de doadoras de raças taurinas e sintéticas. Este texto discute estudos recentes que buscam estratégias para aperfeiçoar as etapas envolvidas na produção de embriões bovinos, bem como para aumentar o aproveitamento de receptoras utilizadas nos programas de transferência de embriões (TE), com foco em vacas taurinas e sintéticas.(AU)

Brazil stands among the leaders on in vitro embryo production, as the Brazilian herd is predominantly composed by Zebu breeds, which have a greater number of antral follicles available to ovum pick-up (OPU). On the other hand, taurine cows have a lower antral follicle population, which limits the number of oocytes obtained by each OPU section. Therefore, in the Brazilian Southern region there is a demand for both in vivo and in vitro production of embryos from donors of taurine and synthetic breeds. This text discusses recent studies that seek strategies to improve the steps involved in the production of bovine embryos, as well as to increase the use of recipients in embryo transfer (ET) programs, focusing on taurine and synthetic cows.(AU)

Prostaglandin F2α treatment concurrent with artificial insemination does not affect bovine embryo production / Administração de prostaglandina F2 alfa no momento da inseminação artificial não afeta a produção de embriões bovinos

Treatment with prostaglandin F2α (PGF) induces ovulation and increases conception rates in cows, while improving embryo production in buffalos. However, its effect on superovulated cows is unknown. This study verified whether single PGF administration concurrent with artificial insemination (AI) improves fertilization and embryo production rates in superovulated cows. In each replicate, embryo donor cows were equally allocated to two groups: the untreated control and PGF groups. The latter of which received 482 µg of cloprostenol concurrent with the first AI. Each cow (n = 35) was subjected to two superovulations (SOV) in a crossover design (total = 70 embryo collections). In the control and PGF groups, respectively, the observed responses were [median (95% CI)]: 12 (10-18) and 15 (12-18) total structures, 9 (7-11) and 7 (6-10) viable embryos, 1 (0-1) and 1 (1-3) degenerated embryos, and 1 (0-3) and 2 (0-5) oocytes (P > 0.05). In conclusion, single PGF treatment concurrent with the first AI did not affect embryo production in superovulated cows.

A prostaglandina F2α (PGF) pode induzir a ovulação e melhorar tanto a concepção em vacas, como a produção de embriões em búfalas, mas o efeito em vacas superovuladas é desconhecido. Esse estudo teve como objetivo verificar se a administração de uma dose de PGF na inseminação artificial (IA) após a superovulação (SOV) melhora as taxas de fecundação e produção embrionária em vacas. Em cada replicação, vacas doadoras de embriões foram equilibradamente alocadas em dois grupos: controle, não tratado, ou PGF, que recebeu 482 µg de cloprostenol no momento da primeira IA. Cada doadora (n = 35) foi submetida a duas SOV em um delineamento crossover (total = 70 coletas de embriões). Nos grupos controle e PGF, respectivamente, foram observados [medianas (IC 95%)]: 12 (10-18) e 15 (12-18) estruturas totais; 9 (7-11) e 7 (6-10) embriões viáveis; 1 (0-1) e 1 (1-3) embriões degenerados; e 1 (0-3) e 2 (0-5) ovócitos (P > 0,05). Conclui-se que uma única administração de PGF no momento da primeira IA não afeta a produção embrionária de vacas superovuladas.

Prostaglandin F2α treatment concurrent with artificial insemination does not affect bovine embryo production / Administração de prostaglandina F2 alfa no momento da inseminação artificial não afeta a produção de embriões bovinos

ABSTRACT: Treatment with prostaglandin F2α (PGF) induces ovulation and increases conception rates in cows, while improving embryo production in buffalos. However, its effect on superovulated cows is unknown. This study verified whether single PGF administration concurrent with artificial insemination (AI) improves fertilization and embryo production rates in superovulated cows. In each replicate, embryo donor cows were equally allocated to two groups: the untreated control and PGF groups. The latter of which received 482 µg of cloprostenol concurrent with the first AI. Each cow (n = 35) was subjected to two superovulations (SOV) in a crossover design (total = 70 embryo collections). In the control and PGF groups, respectively, the observed responses were [median (95% CI)]: 12 (10-18) and 15 (12-18) total structures, 9 (7-11) and 7 (6-10) viable embryos, 1 (0-1) and 1 (1-3) degenerated embryos, and 1 (0-3) and 2 (0-5) oocytes (P > 0.05). In conclusion, single PGF treatment concurrent with the first AI did not affect embryo production in superovulated cows.

RESUMO: A prostaglandina F2α (PGF) pode induzir a ovulação e melhorar tanto a concepção em vacas, como a produção de embriões em búfalas, mas o efeito em vacas superovuladas é desconhecido. Esse estudo teve como objetivo verificar se a administração de uma dose de PGF na inseminação artificial (IA) após a superovulação (SOV) melhora as taxas de fecundação e produção embrionária em vacas. Em cada replicação, vacas doadoras de embriões foram equilibradamente alocadas em dois grupos: controle, não tratado, ou PGF, que recebeu 482 µg de cloprostenol no momento da primeira IA. Cada doadora (n = 35) foi submetida a duas SOV em um delineamento crossover (total = 70 coletas de embriões). Nos grupos controle e PGF, respectivamente, foram observados [medianas (IC 95%)]: 12 (10-18) e 15 (12-18) estruturas totais; 9 (7-11) e 7 (6-10) embriões viáveis; 1 (0-1) e 1 (1-3) embriões degenerados; e 1 (0-3) e 2 (0-5) ovócitos (P > 0,05). Conclui-se que uma única administração de PGF no momento da primeira IA não afeta a produção embrionária de vacas superovuladas.

Uso de éguas receptoras acíclicas em programas de transferência de embrião / Anovulatory recipient mares in embryo transfer programs

O maior entrave para o êxito de um programa de transferência de embrião (TE) está relacionado às receptoras, tanto a qualidade de características reprodutivas, quanto a sincronização entre doadoras e receptoras. Éguas doadoras, geralmente, apresentam melhor escore corporal e disponibilidade alimentar nos períodos de seca, fazendo com que iniciem o seu ciclo estral precocemente enquanto éguas receptoras se encontram ainda em anestro ou período transicional, o que dificulta a TE. Vários estudos foram realizados com o objetivo de utilizar receptoras acíclicas como receptoras de embrião. Assim, podem ser utilizadas nos programas de TE quando submetidas a protocolos hormonais que mimetizam o ciclo estral natural. Uma diversidade de protocolos é encontrada na literatura, usando diferentes doses, posologias e intervalos do uso de estradiol associado a progestágenos. Portanto, objetivou-se analisar resultados de pesquisas com protocolos hormonais que poderiam ajudar a solucionar a escassez de receptoras cíclicas e maximizar os resultados da biotécnica de transferência de embriões.(AU)

There are obstacles to the success of equine embryo transfer programs, concomitantly there has been an increase in the popularity of the technique. One of the most urgent issues to overcome is related to the recipient mare availability and the donor-recipient synchrony. Usually, the donor mares have a higher body condition score and are fed a higher quality diet than recipient mares during the non-breeding season. Therefore, the donor mares start cycling earlier than recipient mares, which makes embryo transfer challenging. Several studies have been carried on finding hormonal protocols that mimic the natural oestrous cycle to allow the use of noncycling recipient mares for embryo transfer programs. Many protocols can be found in the literature, using different doses and intervals. Among the main difference is the use of progestogens, which can be used alone or in combination with oestradiol. The aim of this review was to analyse results that could help solve the lack of recipient mares and improve the results of the embryo transfer technique.(AU)

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

Estradiol cypionate (EC) or GnRH have been widely used for ovulation induction in timed embryo transfer (TET). EC administration increases the proportion of cows that show estrus, whereas GnRH promotes more synchronized ovulations. The aim of the present study was to evaluate the potential beneficial effects of combining EC and GnRH in TET. In experiment 1, no difference was observed on serum progesterone concentrations on Day 6 and 13 after GnRH treatment between GnRH and EC+GnRH groups. In experiment 2, pregnancy per embryo transfer (P/ET) did not differ (p = 0.69) between GnRH (62.8%) and EC+GnRH (58.7%) groups. In conclusion, combining EC and GnRH for ovulation induction does not increase progesterone secretion and pregnancy rate after TET in cattle.(AU)

Evaluation of corpus luteum vascularization in recipient mares by using color Doppler ultrasound

Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryotransfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Dopplerimaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in severalorgans, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound,the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were givenad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterineconsistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a lineartransducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 andsubjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated bycolor Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentrationon the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM).Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and...

Evaluation of corpus luteum vascularization in recipient mares by using color Doppler ultrasound

Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryotransfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Dopplerimaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in severalorgans, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound,the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were givenad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterineconsistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a lineartransducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 andsubjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated bycolor Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentrationon the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM).Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and...(AU)

Lentivirus vectors fail to deliver transgenes into bovine zygotes after co-incubation with sperm during in vitro fertilization / [Lentivírus falham na entrega de transgenes em zigotos bovinos após coincubação com espermatozoide, durante fertilização in vitro]

As vantagens dos animais transgênicos têm sido demonstradas em diferentes aplicações, entretanto muitas metodologias usadas para gerar animais geneticamente modificados (GM) apresentam baixas taxas de eficiência. O objetivo deste estudo foi avaliar a entrega dos vetores lentivirais (VLs) em zigotos durante a fertilização in vitro (FIV), para gerar embriões GM, com o gene da proteína verde fluorescente (GFP) ou do fator IX de coagulação humana (FIX). Vetores lentivirais com os genes GFP (pLGW-GFP-LV) ou FIX (pLWE2-FIX-LV) foram utilizados na FIV ou na cultura de embriões in vitro (CIV). A coincubação de pLWE2-FIX-LV com espermatozoides e complexos oócitos-células do cumulus (COCs) durante a FIV diminuiu (P<0,05) as taxas de clivagem e de blastocistos, enquanto com pLGW-GFP-LV diminuiu (P<0,05) a taxa de blastocisto quando se comparou ao controle sem VL. A coincubação de pLWE2-FIX-LV e pLGW-GFP-LV com presumíveis zigotos durante a CIV não afetou (P>0,05) o desenvolvimento embrionário. A expressão da proteína GFP não foi detectada em embriões após a coincubação de FIV ou CIV, embora as células do cumulus expressassem a proteína até o dia oito de cultivo in vitro. Reações em cadeia da polimerase (PCR) não detectaram os genes GFP ou FIX em embriões, mas ambos foram detectados em células do cumulus. Assim, a coincubação de VL com espermatozoide bovino e COCs não é eficaz para produzir embriões geneticamente modificados por meio de FIV.(AU)

Ovarian responses and FSH profiles at superovulation with a single epidural administration of gonadotropin in the Thai-Holstein crossbreed

The conventional method of ovarian superstimulation requires multiple injections of gonadotropins which is time-consuming and may be stressful for the cows. This study was designed to determine whether a single epidural injection of FSH (EI group) would induce the superovulatory response in the Thai-Holstein crossbreed and evaluate FSH plasma hormone concentrations. Eight cows (replication = 3; n=24) were assigned to one of 2 treatments in switch back design. Control group (n=12): cows were received 400 mg FSH twice daily by intramuscularly for 4 days (80, 80, 60, 60, 40, 40, 20 and 20 mg), EI group (n=12): cows were received 400 mg FSH by single epidural injection. Data were collected in term of ovarian follicle responses, superovulatory responses, ova/embryo collection. FSH concentrations were examined using ELISA. The total follicular responses during oestrus were not different between treatments; however, the large follicles were less frequent (P < 0.01) while the medium follicle sizes were higher (P < 0.05) in the EI group. The plasma concentration of FSH in EI was dramatically increased within 2 hours before decreasing sharply thereafter (P < 0.01) and did not remain above baseline after 10 hours of administration. The embryo quality was better in the control than the EI groups (P < 0.05). Interestingly, the number of ovulation cysts in the EI group was 50%. The ovarian responses and embryo quality in the cows with cysts were worse compared with the non-cyst groups (P < 0.05). In conclusion, alternative protocols decreased the superovulatory response and increased poor embryo quality in Thai-Holstein crossbred. Also, the incidence of ovarian follicular cysts is higher in the EI group.(AU)

Transgênese e clonagem adotadas como biotécnicas reprodutivas em pequenos ruminantes / Transgenesis and cloning as reproductive biotechniques in small ruminants

Ovinos e caprinos são espécies que devido ao seu tamanho adequado, curto período gestacional e produção leiteira, tornaram-se importantes modelos na pesquisa pecuária, farmacêutica e biomédica. Assim, a engenharia genética tem sido amplamente aplicada à pesquisa com pequenos ruminantes. Caprinos e ovinos modificados geneticamente fornecem modelos valiosos para pesquisa sobre as funções dos genes, melhorando a exploração, obtendo produtos farmacêuticos no leite e aumentando a resistência às doenças. Além disso, o uso conjunto da clonagem e transgênese já foi responsável por marcos importantes na biotecnologia animal. Esta revisão destaca os avanços da clonagem e da engenharia genética nessas espécies obtidos nas últimas quatro décadas, com ênfase nas pesquisas realizadas no Brasil.

Sheep and goats are valuable species that due to their suitable size, short pregnancy period, and secretion of milk, have become important model in agricultural, pharmaceutical, and biomedical research. Thus, genome engineering has been widely applied to sheep and goat research. Gene-edited sheep and goats provide valuable models for investigations on gene functions, improving animal breeding, producing pharmaceuticals in milk and improving disease resistance. Additionally, the joint use of cloning and transgenesis has already been responsible for major milestones in animal biotechnology. This review highlights the advances of cloning and genome engineering in these species over the past four decades with particular emphasis on research in Brazil.

A review of simulation analyses of economics and genetics for the use of in-vitro produced embryos and artificial insemination in dairy herds

The use of in-vitro produced (IVP) embryo transfer (ET) in dairy herds is growing fast. Much of this growth is on dairy farms where the focus is on milk production and not on selling breeding stock. The value of implementing IVP-ET in a dairy herd arises from a higher genetic merit of the IVP-embryo, but the cost to produce a pregnancy with an IVP embryo is greater than the cost of artificial insemination (AI). The first objective of this study was to review estimates of the net benefit of using IVP-ET over AI in dairy herds using existing literature. Another objective was to show how much IVP-ET use in a herd is optimal. Most of the literature is based on simulation modeling, including our own work that focuses on the dairy industry in the USA. We found that the most profitable use of AI and IVP-ET is often a combination of the two. More IVP-ET should be used when the value of surplus calves is greater and the cost of IVP-ET is lower, among many other factors. In the future, use of IVP-ET will be further improved by more accurately identifying superior donors and recipients, reducing the generation interval, and achieving greater efficiency in embryo production.(AU)

Influência da progesterona injetável na taxa de prenhez de novilhas receptoras de embriões bovinos / Influence of injectable progesterone on the pregnancy rate of heifers receiving bovine embryos

Background: In vitro embryo production (IVEP) allows the spread of superior animal genetics, but pregnancy rates show a high variability with this biotechnique. In the initial stage of pregnancy, progesterone plays a fundamental role in uterine preparation, acting on embryonic growth, implantation, and development. However, on the day of the IVEP transfer to the recipients, progesterone levels may be lower than that expected, influencing the uterine environment and, consequently, the pregnancy rate. Therefore, the objective of this study was to evaluate the pregnancy rate in heifers after the administration of injectable progesterone (P4) in the fixed-time embryo transfer (FTET) protocol. Materials, Methods & Results: The experiment was conducted inside a rural property near the city of Rio Branco, Acre, Brazil. The experimental group consisted of 232 animals, including 78 zebuine (Bos indicus) and 154 mixed (½ blood B. indicus and ½ blood B. taurus) animals, aged between 16 and 24 months, with a mean weight of 300 and 330 kg for zebuine and mixed animals, respectively. The selected animals were previously synchronized using the progesteroneestrogen-prostaglandin-estrogen protocol. Embryo transfer was performed on day 18 of the protocol, which was 9 days after the removal of intravaginal progesterone implant. On day 15 of the protocol, that is, 144 h (6 days) after the device removal, the animals were randomly distributed into two experimental groups: Control Group (CG; 0.5 mL of 0.9% saline solution, intramuscular) and Treated Group (P4G; 0.5 mL of injectable P4, 150 mg, intramuscular). Chi-square test was used for the statistical analysis of the pregnancy rate at a 5% probability. After 23 days of embryo transfer, pregnancy was diagnosed by ultrasonography. The general pregnancy rate, considering all groups (CG and P4G) and breeds included, was 55.17% (128/232). The pregnancy rates of the P4G and CG groups, regardless of breeds, were...

Produção in vitro de embriões de mini vacas / In vitro embryo production of miniature cattle

With a focus on productivity, Brazil has advanced research and application of reproductive biotechnologies. However, much remains to be explored, such as in vitro embryo production and transfer in miniature breeds. Thus, the objective of the present work is to report the in vitro production of miniature bovine embryos and transfer to conventional sized cows located in Palmas/To. Nine miniature Jersey-Holstein cross breed donors were aspirated to obtain approximately 13 viable oocytes per female. The oocytes were matured, fertilized and cultured the in vitro, where the production of viable embryos was 23.2%. On day 7 of development (D7) the embryos were transferred to 17 crossbred dairy recipients and after 30 days of innovulation by ultrasound examination a conception rate of 76.4% was found. Thus, the technique of in vitro production and embryo transfer is viable for the reproduction of mini dairy cows, despite the lack of data regarding the work performed on small animals that serve as comparative parameters for the results achieved in the study.

Produção in vitro de embriões de mini vacas / In vitro embryo production of miniature cattle

With a focus on productivity, Brazil has advanced research and application of reproductive biotechnologies. However, much remains to be explored, such as in vitro embryo production and transfer in miniature breeds. Thus, the objective of the present work is to report the in vitro production of miniature bovine embryos and transfer to conventional sized cows located in Palmas/To. Nine miniature Jersey-Holstein cross breed donors were aspirated to obtain approximately 13 viable oocytes per female. The oocytes were matured, fertilized and cultured the in vitro, where the production of viable embryos was 23.2%. On day 7 of development (D7) the embryos were transferred to 17 crossbred dairy recipients and after 30 days of innovulation by ultrasound examination a conception rate of 76.4% was found. Thus, the technique of in vitro production and embryo transfer is viable for the reproduction of mini dairy cows, despite the lack of data regarding the work performed on small animals that serve as comparative parameters for the results achieved in the study.(AU)

Efeito de protocolo hormonal e programa de luz artificial na gestação de éguas receptoras de embrião durante o período de transição de primavera / Effect of hormonal protocol and artificial light program on the pregnancy of embryo recipient mares during spring transition period

O objetivo do estudo foi comparar o efeito das técnicas hormonais e de luz artificial nas éguas receptoras de embrião acíclicas avaliando as taxas de gestação aos 14 e 28 dias durante a fase de transição de primavera. Os 48 animais foram distribuídos aleatoriamente nos grupos: controle (CONT, n=16), éguas cíclicas na fase ovulatória; luz artificial (LUZ, n=16), éguas acíclicas submetidas ao tratamento de luz artificial; e hormônio (HORM, n= 16), éguas acíclicas submetidas ao protocolo hormonal na fase de transição. As éguas do grupo LUZ foram estimuladas por 60 dias com luz artificial durante cinco horas por dia. Nos grupos CONT e LUZ, quando observada a presença de folículo ≥ 35 mm de diâmetro e edema uterino ≥ grau II, foram administrados 1,5 mg de acetato de deslorelina e 1500 UI de hCG para induzir a ovulação. As éguas do grupo HORM foram tratadas com três doses de 1,5 mg de benzoato de estradiol e seguiram os mesmos protocolos dos Grupos CONT e LUZ. Foi avaliada a taxa de gestação por ultrassonografia aos 14 dias e confirmação aos 28 em todos os grupos experimentais. Foi realizada análise descritiva e teste Qui-quadrado (significância de 5%). Taxas de gestação aos 14 e 28 dias foram semelhantes (p>0,05) entre todos os grupos. Os tratamentos HORM e LUZ durante o período de transição inverno-primavera mostraram-se eficazes para atender ao programa de transferência de embrião. Por ser um método mais natural, o protocolo LUZ tem potencial como mais uma ferramenta biotecnológica na reprodução de equinos.

The aim of this study was to compare the effect of hormonal and artificial light techniques on acyclic embryo recipient mares by assessing pregnancy rates at 14 and 28 days during the spring transition period. The 48 animals were randomly assigned to the groups: control (CONT, n = 16), cyclic mares in the ovulatory phase; artificial light (LIGHT, n = 16), acyclic mares subjected to artificial light treatment; and hormone (HORM, n = 16), acyclic mares submitted to hormonal protocol in transition phase. In the LIGHT group, mares were stimulated with artificial light for five hours a day, for 60 days. In CONT and LIGHT groups, when a follicle ≥ 35 mm in diameter and uterine edema ≥ grade II were observed, 1.5 mg of deslorelin acetate and 1500 IU hCG were administered to induce ovulation. In the HORM group, mares were treated with three doses of 1.5 mg of estradiol benzoate and followed the same protocols as the CONT and LIGHT groups. Pregnancy rate was assessed by ultrasound at 14 days and confirmation at 28 days in all experimental groups. Descriptive analysis and chi-square test (5% significance) were performed. Pregnancy rates at 14 and 28 days were similar (p> 0.05) among all groups. The HORM and LIGHT treatments during the winter-spring transition period proved to be effective during the embryo transfer programs. As it is a more natural method, the LIGHT protocol has the potential to be one more biotechnological tool in equine reproduction.

Transferência Nuclear de Células Somáticas interespecífica (TNCSi) na conservação de cervídeos em risco de extinção / Interspecific Somatic Cell Nuclear Transfer (TNCSi) in the conservation of endangered species of deer

A Transferência Nuclear de Células Somáticas interespecífica (TNCSi) envolve a transferência de um núcleo ou célula de uma espécie para o citoplasma de um oócito enucleado de outra espécie. Após ativação, os complexos carioplasto-citoplasto reconstruídos podem ser cultivados in vitro até o blastocisto, o estádio final de desenvolvimento pré-implantação. Esta pode ser uma estratégia interessante na tentativa de conservação de espécies em risco de extinção. Esta revisão tem por objetivo apresentar alguns detalhes da técnica e relatar a experiência de nosso grupo usando como modelo o veado-catingueiro.(AU)

Interspecies Somatic Cell Nuclear Transfer (iSCNT) involves the transfer of a nucleus or cell from one species into the cytoplasm of an enucleated oocyte from another. Once activated, reconstructed caryoplast-cytoplast complexes can be cultured in vitro to blastocyst, the final stage of preimplantation development. This may be an interesting strategy in attempting to conserve endangered species. The objective of this review is to present some details of the technique and to report the experience of our group using as model the brown brocket deer.(AU)

Transferência Nuclear de Células Somáticas interespecífica (TNCSi) na conservação de cervídeos em risco de extinção / Interspecific Somatic Cell Nuclear Transfer (TNCSi) in the conservation of endangered species of deer

A Transferência Nuclear de Células Somáticas interespecífica (TNCSi) envolve a transferência de um núcleo ou célula de uma espécie para o citoplasma de um oócito enucleado de outra espécie. Após ativação, os complexos carioplasto-citoplasto reconstruídos podem ser cultivados in vitro até o blastocisto, o estádio final de desenvolvimento pré-implantação. Esta pode ser uma estratégia interessante na tentativa de conservação de espécies em risco de extinção. Esta revisão tem por objetivo apresentar alguns detalhes da técnica e relatar a experiência de nosso grupo usando como modelo o veado-catingueiro.

Interspecies Somatic Cell Nuclear Transfer (iSCNT) involves the transfer of a nucleus or cell from one species into the cytoplasm of an enucleated oocyte from another. Once activated, reconstructed caryoplast-cytoplast complexes can be cultured in vitro to blastocyst, the final stage of preimplantation development. This may be an interesting strategy in attempting to conserve endangered species. The objective of this review is to present some details of the technique and to report the experience of our group using as model the brown brocket deer.