Pregnancy Monitoring of In Vitro Produced Embryos in Buffaloes

In the present study, pregnancies obtained from 115 in vitro produced embryos were monitored by ultrasonography on days 30 and 60 after embryo transfer (ET), and at calving. Additionally, the health of newborns and recipients were also evaluated. On day 30 after ET, positive pregnancy was diagnosed in 50 animals (43.5%). A total of 8 fetal mortalities (16.0%) were verified from 30 days until calving, in which 2 occurred from 30 to 60 days after ET (4.0%), and 6 occurred from 60 days until calving (12.0%). In this last period of pregnancy, 3 pregnancy losses were due to abortion, and the other 3 were stillbirth. One additional animal was eliminated from the study, remaining 41 pregnancies. From these 41 pregnancies, a total of 20 female calves (48.8%) and 21 male calves (51.2%) were born. Pregnancies from female and male calves had a mean length of 309.8 and 310.9 days, respectively (range 300 to 328 days, and 297 to 320 days, respectively). Weight at calving was a mean of 31.4 and 33.8 kg for female and male calves, respectively. All calving occurred without intervention and dystocia was not observed in any case. No large offspring syndrome, hydramnios, hydroallantois, or umbilical cord anomalies were observed in calves. Delivery was normal in all recipients, and no puerperal infections, or retained placenta occurred. Suckling assistance was not necessary in any newborn. All genetic pedigree was confirmed later by DNA tests.

Efeito da administração da sulpirida no desenvolvimento folicular em éguas

Pós-graduação em Biotecnologia Animal - FMVZ

The role of proestrus on fertility and postovulatory uterine function in the cow

Modern protocols to synchronize ovulations for timed artificial insemination and timed embryo transfer that include manipulations in the proestrus period (i.e., between luteolysis and estrus) affect fertility in cattle. Specifically, stimulating pre-ovulatory follicle growth and exposure to estrogens after CL regression increase the proportion of cows pregnant and decrease late embryo mortality. Such effects may be due to both preovulatory actions of estrogens and post-ovulatory actions of progesterone, as concentrations of the later hormone may be changed in response to manipulations conducted during proestrus. In the first portion of this paper we describe strategies used recently to manipulate the proestrus period in protocols for synchronization of ovulation, and to present evidence of their effects on fertility. Manipulations of timing and prominence of sex steroids during the proestrus and early diestrus that affect fertility may act on targets such as the endometrium. This tissue expresses receptors for both estrogens and progesterone and these hormones change endometrial function to support conceptus growth and pregnancy maintenance. However, specific cellular and molecular mechanisms through which fertility is affected via manipulations of the proestrus are poorly understood. In the second portion of this paper we describe a well-defined animal model to study changes in endometrial function induced by manipulations conducted during the proestrus. Such manipulations induced endometrial changes on sex steroid receptors expression, cell proliferation, oxidative metabolism and eicosanoid synthesis in the uterus, but not on glucose transport to uterine lumen. In summary, evidence is accumulating to support a positive role of increasing duration and estrogen availability during the proestrus on fertility to synchronization protocols. Such positive effects may be through changes in endometrial function to stimulate conceptus growth and survival.

Lethal effect of high concentrations of Parecoxib and Flunixin meglumine on the in vitro culture of bovine embryos

Since cyclooxygenase (COX) inhibitors have been pointed out as potential treatments to increase pregnancy rates after embryo transfer, the present experiment aimed to evaluate the effects of flunixin meglumine (FM) and parecoxib (P), a COX-1 and 2 or COX-2 specific inhibitor, respectively, on the development of bovine embryos until the hatched blastocyst stage. In vitro produced bovine embryos were cultured in media with different concentrations of FM (0.14; 1.4; 14; 140 or 1400 mu g/ml) or P (0.09; 0.9; 9; 90 or 900 mu g/ml) and the production rates were evaluated. Concentrations of FM <= 14 mu g/ml and P <= 90 mu g/ml did not impair embryo development, although compiled data from non-lethal FM concentrations (<= 14 mu g/ml) indicated a toxic effect enough to decrease the hatching rate of blastocysts. Concentrations of FM at 140 and 1400 mu g/ml and P at 900 mu g/ml were lethal as no cleavage was detected on presumptive zygotes.

O uso da somatotropina bovina recombinante em reprodução bovina

The recombinant bovine somatotropin (rbST) at first, had its widespread use in dairy cows in order to increase milk production. Currently, it has been studied frequently and use their influence both in bovine milk, such as cutting. Its production has been an evolution to the science, using bacteria to produce recombinant DNA. Most authors that have studied and obtained positive results, such as increasing the number of ovarian follicles larger than five millimeters, among others. Its action takes place directly on the ovary, follicles, corpus luteum, the granulosa cells, oviduct, myometrium, endometrium and placenta, where they were found receptors, or indirectly through the release of insuline like growth factor-1 (IGF-1). Therefore, the objective of this work is to explain the importance of bST in bovine as well as the usefulness of this, its mechanism of action and the benefits it can bring when combined with other biotechnology, such as superovulation, embryo transfer, synchronization of estrus, and others

Técnicas associadas à biotecnologia da reprodução para minimizar os efeitos do estresse térmico e aumentar a fertilidade em vacas leiteiras de alta produção

The dairy sector has undergone considerable economic losses due to low fertility rates due to adverse effects of heat stress on reproduction of cows. Genetic selection for increased production, coupled with the expanding dairy to tropical areas of the planet, and global warming has further aggravated the problem of heat stress. The effects of heat stress are multifactorial and act directly or indirectly at various levels of reproductive tissues, resulting in low fertility of cows, which in practice, results in reduced reproductive efficiency in the property, reducing the producers’ profit. Some strategies related to breeding biotechnology such as fixed-time artificial insemination, embryo transfer and use of BST, can minimize these effects and improve the reproductive efficiency of the herd

Dinâmica folicular ovariana e bases para a aplicação das biotécnicas da reprodução em bovinos

In the last years Brazil has achieved a leading position in worldwide cattle breeding. This country is consolidating the practice of an intensive and technical level cattle breeding, due to greater emphasis on reproductive efficiency and genetic improvement. The attention given to reproductive efficiency became to enhance the genetic improvement process, by exploiting the full reproductive potential of the animals. The biotechniques applied to reproduction arised to expand the reproductive potential for greater economic return. Are the most important reproductive biotechniques the FTAI and in vivo and in vitro embryo production for embryo transfer. Different hormonal treatments are consolidating to interfere with normal physiology in order to achieve the desired goals. The FTAI works to increase the reproductive rates of cattle through pre-booked artificial insemination in all the females in reproduction, without the need for estrous detection. The in vivo and in vitro embryo production aims to distribute the genetics of males and females genetically improved by transferring their embryos to genetically inferior females. Superovulation treatments designed to prevent the mechanism of dominance, which results in many follicles ovulating simultaneously for in vivo embryo production. To the in vitro embryo production, the technique of ovarian puncture guided by transvaginal ultrasound allows to aspirate a number of quality oocytes. The application of biotech is based on knowledge of the female and ovarian reproductive physiology and knowledge of their acting in different breeds and environments.

Indução de parto em bovinos: Princípios e aplicações

Currently, Brazil has one of the largest cattle herds worldwide. In order to keep that milk and meat were introduced reproductive biotechnologies such as artificial insemination, embryo transfer and in vitro fertilization. In certain situations the technique may have undesired effect, for example, the production of calve calves due to the very large increase in the gestation period when performed in vitro fertilization. To avoid this problem we perform the induction of labor in order to prevent the product is longer the womb. This induction can also be made in case of diseases that compromise the life of the mother, twin pregnancy an abnormal size calf. The administration of short acting steroids, prostaglandins, association of short acting steroids and prostaglandins and association of short acting steroids, prostaglandins and long-acting corticosteroids are some of the possibilities of induction

Fatores que interferem nas taxas de recuperação embrionária em éguas

The success in implementing an embryo transfer program derives from many factors. The embryo recovery rate is one of the most important factors, and allows the transfer to the recipient mare. This rate comes from a group of elements such as donor´s characteristics, collection date, reproductive management, semen quality, technician skill. Mainly because of the great importance of this direct interference on the results of an embryo recovery program, this study aimed to review the factors involved in embryo recovery rates in donor mares during an embryo transfer, suggesting some ways of improving these results

Utiização de altrenogest injetável par o estabelecimento e manutençao da gestação em éguas receptoras de embriões acíclicas

Pós-graduação em Medicina Veterinária - FMVZ

Avaliação do pico pré-ovulatório de LH em ovelhas da raça Santa Inês superestimuladas nos períodos de ciclicidade, transição e anestro

Pós-graduação em Medicina Veterinária - FCAV

Uso de LH ou eCG no último dia do protocolo superovulatório em bovinos

In the last decades several hormonal treatments to induce multiple ovulation and embryo transfer (MOET) have been developed. Tight control of the time of ovulation allowed the use of fixed-time artificial insemination (FTAI) in bovine embryos donors, facilitating animal management. Although, protocols that allow FTAI have evolved and yield as much embryo as conventional protocols that requires estrus detection, substantial increase in viable embryo production has not been observed in superestimulated bovine cattle. The present review put emphasis on superestimulatory protocols in wich the last two doses of pFSH are replaced by eCG or LH. Recent results indicate that an extra LH stimulus (using eCG or LH), on the last day of P-36 superestimulatory treatment, seems to improve transferable embryo yield in both Bos taurus and Bos indicus cattle.

Induction of multiple ovulations in mares using low doses of GnRH agonist Deslorelin Acetate at 48 hours after luteolysis

This study was aimed to test low doses of a GnRH agonist, deslorelin acetate (DA), for induction of multiple ovulations in mares and to determine its impact upon their reproductive efficiency. Seven mares aging from 8-20 years were used in three consecutive reproductive cycles. Mares were initially monitored by ultrasound irrespectively of cycle stage, inseminated and submitted to embryo collection (EC) (T1). Immediately after, mares received 7.5 mg dinoprost tromothamine (DT) and were monitored by ultrasound twice a day until larger follicle reached 23-25mm and the second >18mm (T2). At this time point, mares received 100 mu g DA and ovulation was induced with 1000 mu g DA and 1000IU hCG when largest follicle reached 33-35mm in diameter, followed by EC. Mares were further allocated to T3 when received 7.5 mg DT after EC on 12 and 100 mu g DA 48 h later. DA treatment was performed until dominant follicle reached 34 +/- 1 mm or 6 days of application. All EC were performed 8 days after ovulation. Mares with multiple ovulations in T1, T2 and T3 were 14.28% (1/7), 100.00% (7/7) and 0.00% (0/7), respectively, and averaged 0.43 +/- 0.53 in T1, 0.86 +/- 0.38 in T2 and 0.00 in T3 embryos per donor, respectively. Embryo recovery rate was 43.00% in T1, 85.71% in T2 and 0.00% T3. In conclusion, use of DA in mares with follicles larger than 25mm enhanced dominant and co-dominant follicle growth, that ultimately increased the incidence of multiple ovulations and embryo recovery rate.

Supplementation with sunflower seed increases circulating cholesterol concentrations and potentially impacts on the pregnancy rates in Bos indicus beef cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Laparoscopy of the genitourinary tract of small ruminants

Laparoscopic endosurgery is an important tool for small ruminant breeding especially due to its wide versatility, both in reproductive biotechnologies and therapeutic approach. The purpose of this review is to present the applicability and advantages of endosurgery for routine use in small ruminants. Several endosurgical techniques of the genitourinary tract of small ruminants, including artificial insemination, embryo transfer, and oocyte retrieval for IVF, ovariectomy, cystotomy and renal biopsy are approached. The endoscopic techniques can improve the development of potential zootechnical indexes on the short-term period in comparison to traditional approaches.