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.

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

Abstract 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.

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)

Colony aging affects the reproductive performance of Swiss Webster females used as recipients for embryo transfer

The objective was to evaluate the influence of colony aging in a Swiss Webster (SW) outbred stock used as recipients for embryo transfer. In the first study, a retrospective analysis was performed throughout several generations during a 38-month period in 2,398 embryos transferred to 108 SW recipients. A decrease in the percentage of live pups from transferred embryos was found at the end of the period. Impairment occurred due to the incidence of maternal cannibalism that increased from 0% to 67-100% (P 0.05), while pregnancy rate (pregnant/transferred recipients) and number of pups per delivered female were not affected throughout the period (P=NS). A following study was carried out to compare the reproductive performance of SW stock vs. B6D2F1 hybrid females in a 5-year interval. The study was conducted on a total of 893 embryos transferred to 40 females (20 SW and 20 B6D2F1) in Year /1, and 514 embryos transferred to 30 females (15 SW and 15 B6D2F1) in Year /5. No cases of maternal cannibalism were found on Year /1 in any of the strains (0/10 and 0/10). However, an incidence of 44,4% (4/9) was seen on Year /5 for SW, while for B6D2F1 the incidence was 0% (0/12) (P 0.05). Further examination of the uterus showed endometrial cysts and abnormal implantation sites in SW on Year /5 but not in B6D2F1 females. In conclusion, this study reports an impairment of the reproductive performance of an early aged SW outbred stock colony mainly due to the occurrence of maternal cannibalism. This finding has important implications for embryo transfer programs conducted in mouse facilities.

Colony aging affects the reproductive performance of Swiss Webster females used as recipients for embryo transfer

The objective was to evaluate the influence of colony aging in a Swiss Webster (SW) outbred stock used as recipients for embryo transfer. In the first study, a retrospective analysis was performed throughout several generations during a 38-month period in 2,398 embryos transferred to 108 SW recipients. A decrease in the percentage of live pups from transferred embryos was found at the end of the period. Impairment occurred due to the incidence of maternal cannibalism that increased from 0% to 67-100% (P 0.05), while pregnancy rate (pregnant/transferred recipients) and number of pups per delivered female were not affected throughout the period (P=NS). A following study was carried out to compare the reproductive performance of SW stock vs. B6D2F1 hybrid females in a 5-year interval. The study was conducted on a total of 893 embryos transferred to 40 females (20 SW and 20 B6D2F1) in Year /1, and 514 embryos transferred to 30 females (15 SW and 15 B6D2F1) in Year /5. No cases of maternal cannibalism were found on Year /1 in any of the strains (0/10 and 0/10). However, an incidence of 44,4% (4/9) was seen on Year /5 for SW, while for B6D2F1 the incidence was 0% (0/12) (P 0.05). Further examination of the uterus showed endometrial cysts and abnormal implantation sites in SW on Year /5 but not in B6D2F1 females. In conclusion, this study reports an impairment of the reproductive performance of an early aged SW outbred stock colony mainly due to the occurrence of maternal cannibalism. This finding has important implications for embryo transfer programs conducted in mouse facilities.(AU)

Challenges to increase the AI and ET markets in Brazil

Artificial insemination (AI) and embryo transfer (ET) are the most widely used biotechnologies in the world with the goal of increasing genetic gain and improving reproductive efficiency of beef and dairy herds. The protocols for ovulation synchronization for timed AI (TAI) or ET (TET) are tools that allow artificial insemination or transfer of a high number of embryos in a pre-established moment and without the necessity of estrous detection. Currently, 86% of inseminations in Brazil are performed using TAI (13.6 million TAI out of a total of 15.4 million doses of semen marketed in 2018). With the use of TAI, it was possible to verify that the percentage of artificially inseminated females in Brazil went from 5.8% in 2002 to 13.1% in 2018. The ET market also presented considerable growth in the last 20 years. There was an increase of approximately 8 fold in the number of produced embryos, escalating from 50,000 in 1999 to 375,000 in 2017. In this period, there was a significant increase on the in vitro embryo production, which represented 92.1% of embryos produced in Brazil in 2017. Also, in this period, there was an increase on the embryo production of dairy breeds and reduction on the embryo production of zebu breeds in comparison to data from the early 2000’s. TET increases significantly the number of recipients suitable to receive an embryo. After synchronization, 75 to 85% of recipients present a suitable CL for ET without estrous detection. Currently, many synchronization and resynchronization protocols for TAI/TET have been studied to attend different managements, breeds and animal categories, with predictable and satisfactory results. With the intensification of the use of these biotechnologies, it is possible to obtain elevated reproductive efficiency with increase on the genetic gain, which determines greater productivity and economic return for dairy and beef farms. However, the challenge to keep the market growing in the next decade could depend on some factors, such as: increase of the extension services for producers and of the extension training for specialists, improvement of the technological advances to develop more efficient and cost-effective products and practical protocols, increase the integration between universities, research institutes, veterinarians and industries and also, asses market demand for production of animal protein with higher quality, efficiency and environmental and economic sustainability.

Challenges to increase the AI and ET markets in Brazil

Artificial insemination (AI) and embryo transfer (ET) are the most widely used biotechnologies in the world with the goal of increasing genetic gain and improving reproductive efficiency of beef and dairy herds. The protocols for ovulation synchronization for timed AI (TAI) or ET (TET) are tools that allow artificial insemination or transfer of a high number of embryos in a pre-established moment and without the necessity of estrous detection. Currently, 86% of inseminations in Brazil are performed using TAI (13.6 million TAI out of a total of 15.4 million doses of semen marketed in 2018). With the use of TAI, it was possible to verify that the percentage of artificially inseminated females in Brazil went from 5.8% in 2002 to 13.1% in 2018. The ET market also presented considerable growth in the last 20 years. There was an increase of approximately 8 fold in the number of produced embryos, escalating from 50,000 in 1999 to 375,000 in 2017. In this period, there was a significant increase on the in vitro embryo production, which represented 92.1% of embryos produced in Brazil in 2017. Also, in this period, there was an increase on the embryo production of dairy breeds and reduction on the embryo production of zebu breeds in comparison to data from the early 2000s. TET increases significantly the number of recipients suitable to receive an embryo. After synchronization, 75 to 85% of recipients present a suitable CL for ET without estrous detection. Currently, many synchronization and resynchronization protocols for TAI/TET have been studied to attend different managements, breeds and animal categories, with predictable and satisfactory results. With the intensification of the use of these biotechnologies, it is possible to obtain elevated reproductive efficiency with increase on the genetic gain, which determines greater productivity and economic return for dairy and beef farms. However, the challenge to keep the market growing in the next decade could depend on some factors, such as: increase of the extension services for producers and of the extension training for specialists, improvement of the technological advances to develop more efficient and cost-effective products and practical protocols, increase the integration between universities, research institutes, veterinarians and industries and also, asses market demand for production of animal protein with higher quality, efficiency and environmental and economic sustainability.(AU)

Superovulação em éguas da raça Crioula e Quarto de Milha com extrato de pituitária equina (EPE) / Superovulatory protocol with equine pituitary extract (EPE) in mares Crioula and the Quarter Horse

Este trabalho compara a resposta superovulatória de éguas doadoras de embriões das raças Quarto de Milha (QM) e Crioula, utilizando um protocolo com baixa dose de extrato de pituitária equina (EPE). Oito éguas QM e seis éguas Crioulas foram acompanhadas durante 3 ciclos estrais consecutivos, sendo que cada ciclo corresponde a um grupo. Grupo Controle – monitoramento do crescimento folicular até a ovulação; Grupo EPE – monitoramento ultrassonográfico até que os folículos atingissem cerca de 20 mm de diâmetro e, posteriormente, administração de 7 mg de EPE, duas vezes ao dia, até a indução da ovulação com 2500UI de hCG; Grupo Pós-EPE – idem ao grupo controle. Os dados foram submetidos à análise de variância, utilizando o procedimento GLM do pacote estatístico SAS, sendo previamente testadas para normalidade dos resíduos, e as médias comparadas pelo teste de Tukey ao nível de 5%. Nas éguas Crioulas tratadas com EPE houve um aumento no número de ovulações (p=0,0534), com média de 3,33±2,06 quando comparadas aos grupos controle e pós-EPE e às éguas da raça QM (2,00±0,53). O tratamento com EPE na dose preconizada permitiu uma melhor resposta superovulatória e produção embrionária nas éguas Crioulas, quando comparadas com as éguas Quarto de Milha.

This study compared the superovulatory response of embryos donor mares of Quarter Horse (QH) and Crioula using a protocol with low dose of equine pituitary extract (EPE). Eight QH mares and six Crioula mares were monitored during 3 consecutive estrous cycles, with each cycle corresponds to a group. Control Group - monitoring of follicle growth up to the ovulation; EPE group - when the follicles reached 20 mm in diameter were administered 7 mg EPE twice daily. When the follicles achieved a diameter 35 mm, the ovulation was induced with 2500UI hCG; Post-EPE Group - idem to the control group. Data were analyzed using GLM procedure of the SAS statistical package. The variables were submitted to the Tukey’s test and least square means adjusted for multiple comparisons using the Tukey-Kramer’s test, with significance level of 5%. Values are presented as mean ± SD. In the Crioula mares treated with EPE, there was an increase in the number of ovulations (p =0.0534) with a mean of 3.33 ± 2.06 ovulations when compared to the control and post-EPE groups, and mares QM. (2.00±0.53). Treatment with EPE in the recommended dose allowed better superovulatory response and rate of embryo recovery in Crioula mares when compared to the QM mares.

Superovulação em éguas da raça Crioula e Quarto de Milha com extrato de pituitária equina (EPE) / Superovulatory protocol with equine pituitary extract (EPE) in mares Crioula and the Quarter Horse

Este trabalho compara a resposta superovulatória de éguas doadoras de embriões das raças Quarto de Milha (QM) e Crioula, utilizando um protocolo com baixa dose de extrato de pituitária equina (EPE). Oito éguas QM e seis éguas Crioulas foram acompanhadas durante 3 ciclos estrais consecutivos, sendo que cada ciclo corresponde a um grupo. Grupo Controle monitoramento do crescimento folicular até a ovulação; Grupo EPE monitoramento ultrassonográfico até que os folículos atingissem cerca de 20 mm de diâmetro e, posteriormente, administração de 7 mg de EPE, duas vezes ao dia, até a indução da ovulação com 2500UI de hCG; Grupo Pós-EPE idem ao grupo controle. Os dados foram submetidos à análise de variância, utilizando o procedimento GLM do pacote estatístico SAS, sendo previamente testadas para normalidade dos resíduos, e as médias comparadas pelo teste de Tukey ao nível de 5%. Nas éguas Crioulas tratadas com EPE houve um aumento no número de ovulações (p=0,0534), com média de 3,33±2,06 quando comparadas aos grupos controle e pós-EPE e às éguas da raça QM (2,00±0,53). O tratamento com EPE na dose preconizada permitiu uma melhor resposta superovulatória e produção embrionária nas éguas Crioulas, quando comparadas com as éguas Quarto de Milha.(AU)

This study compared the superovulatory response of embryos donor mares of Quarter Horse (QH) and Crioula using a protocol with low dose of equine pituitary extract (EPE). Eight QH mares and six Crioula mares were monitored during 3 consecutive estrous cycles, with each cycle corresponds to a group. Control Group - monitoring of follicle growth up to the ovulation; EPE group - when the follicles reached 20 mm in diameter were administered 7 mg EPE twice daily. When the follicles achieved a diameter 35 mm, the ovulation was induced with 2500UI hCG; Post-EPE Group - idem to the control group. Data were analyzed using GLM procedure of the SAS statistical package. The variables were submitted to the Tukeys test and least square means adjusted for multiple comparisons using the Tukey-Kramers test, with significance level of 5%. Values are presented as mean ± SD. In the Crioula mares treated with EPE, there was an increase in the number of ovulations (p =0.0534) with a mean of 3.33 ± 2.06 ovulations when compared to the control and post-EPE groups, and mares QM. (2.00±0.53). Treatment with EPE in the recommended dose allowed better superovulatory response and rate of embryo recovery in Crioula mares when compared to the QM mares.(AU)

Efficacy and limitations of different approaches to anticipate the diagnosis of pregnancy in cattle / Eficácia e limitações de diferentes abordagens para antecipar o diagnóstico de gestação em bovinos

The study evaluated sonographic and serologic exams performed for early (20 to 30d) diagnosis of pregnancy. One hundred-twenty (n= 120) bovine recipients were synchronized (estrous=D0) and timed embryo transferred (TET, D7) with fresh in vitro produced embryos. In the first trial (n= 46), diagnosis of pregnancy was performed on day 20 (D20) by detecting CL blood flow (BF) and by Pregnancy-Associated Glycoproteins (PAGs) serology. In the second trial (n= 30), pregnancy diagnosis was performed on D25 by ultrasound visualization of uterine contents and by PAGs serology. In the last trial, PAG's serology was performed on D30. Ultrasonographic detection of the uterine contents and embryo viability performed on D30 (DG30) was considered the gold standard. The PROC FREQ procedure was used to test the agreement between diagnostic methods. On D20, the Doppler ultrasonography of the CL had showed high sensitivity (100%), but only moderate specificity (53.3%). On the same day, serologic diagnostic had no agreement (k= -0.08, P< 0.46) with the gold standard, with very low sensitivity (6.3%). However, the sensitivity of the serologic exam increased dramatically (from 6.3 to 100%) from D20 to D25, and it contributed to detect false negatives from the ultrasound diagnosis, improving the overall accuracy from 90% to 96.7%.(AU)

O estudo foi planejado para correlacionar exames ultrassonográficos e sorológicos realizados para o diagnóstico precoce (20 a 30d) de gestação. Cento e vinte (n= 120) receptoras bovinas foram sincronizadas (estro=D0), e embriões frescos produzidos in vitro foram transferidos em tempo fixo (TETF, D7). No experimento 1 (n= 46), o diagnóstico de gestação foi realizado no D20, pela detecção do fluxo sanguíneo do CL e pela sorologia de glicoproteínas associadas à gestação (PAGs). No experimento 2 (n= 30), a detecção da gestação foi realizada por meio da visualização do conteúdo do útero e também pela sorologia para PAGs. No experimento 3, a sorologia para PAGs foi realizada no D30. Em todos os experimentos, a visualização ultrassonográfica da vesícula e da viabilidade embrionária, realizada no D30, foi considerada padrão-ouro. O procedimento PROC FREQ testou o nível de concordância dos métodos diagnósticos. No D20, o diagnóstico baseado na vascularização do CL mostrou alta sensibilidade (100%) e apenas moderada especificidade (53,3%). Nesse mesmo dia, o diagnóstico sorológico não apresentou concordância (k=-0,08, P<0,46) com o padrão-ouro, além de baixa sensibilidade (6,3%). No entanto, a sensibilidade do exame sorológico aumentou drasticamente (6,3 para 100%) do D20 para o D25, contribuindo para detectar falsos negativos diagnosticados pela ultrassonografia, melhorando a acurácia (90 para 96,7%).(AU)

Efficacy and limitations of different approaches to anticipate the diagnosis of pregnancy in cattle / Eficácia e limitações de diferentes abordagens para antecipar o diagnóstico de gestação em bovinos

The study evaluated sonographic and serologic exams performed for early (20 to 30d) diagnosis of pregnancy. One hundred-twenty (n= 120) bovine recipients were synchronized (estrous=D0) and timed embryo transferred (TET, D7) with fresh in vitro produced embryos. In the first trial (n= 46), diagnosis of pregnancy was performed on day 20 (D20) by detecting CL blood flow (BF) and by Pregnancy-Associated Glycoproteins (PAGs) serology. In the second trial (n= 30), pregnancy diagnosis was performed on D25 by ultrasound visualization of uterine contents and by PAGs serology. In the last trial, PAG's serology was performed on D30. Ultrasonographic detection of the uterine contents and embryo viability performed on D30 (DG30) was considered the gold standard. The PROC FREQ procedure was used to test the agreement between diagnostic methods. On D20, the Doppler ultrasonography of the CL had showed high sensitivity (100%), but only moderate specificity (53.3%). On the same day, serologic diagnostic had no agreement (k= -0.08, P< 0.46) with the gold standard, with very low sensitivity (6.3%). However, the sensitivity of the serologic exam increased dramatically (from 6.3 to 100%) from D20 to D25, and it contributed to detect false negatives from the ultrasound diagnosis, improving the overall accuracy from 90% to 96.7%.(AU)

O estudo foi planejado para correlacionar exames ultrassonográficos e sorológicos realizados para o diagnóstico precoce (20 a 30d) de gestação. Cento e vinte (n= 120) receptoras bovinas foram sincronizadas (estro=D0), e embriões frescos produzidos in vitro foram transferidos em tempo fixo (TETF, D7). No experimento 1 (n= 46), o diagnóstico de gestação foi realizado no D20, pela detecção do fluxo sanguíneo do CL e pela sorologia de glicoproteínas associadas à gestação (PAGs). No experimento 2 (n= 30), a detecção da gestação foi realizada por meio da visualização do conteúdo do útero e também pela sorologia para PAGs. No experimento 3, a sorologia para PAGs foi realizada no D30. Em todos os experimentos, a visualização ultrassonográfica da vesícula e da viabilidade embrionária, realizada no D30, foi considerada padrão-ouro. O procedimento PROC FREQ testou o nível de concordância dos métodos diagnósticos. No D20, o diagnóstico baseado na vascularização do CL mostrou alta sensibilidade (100%) e apenas moderada especificidade (53,3%). Nesse mesmo dia, o diagnóstico sorológico não apresentou concordância (k=-0,08, P<0,46) com o padrão-ouro, além de baixa sensibilidade (6,3%). No entanto, a sensibilidade do exame sorológico aumentou drasticamente (6,3 para 100%) do D20 para o D25, contribuindo para detectar falsos negativos diagnosticados pela ultrassonografia, melhorando a acurácia (90 para 96,7%).(AU)

Evaluation of follicular growth and progesterone production in Bos taurus cows strategically treated with insulin / Avaliação do crescimento folicular e da produção de progesterona em vacas Bos taurus tratadas estrategicamente com insulina

The goal of this study was to evaluate the effects of strategic insulin administration on follicular growth, progesterone production, and pregnancy rate in beef cattle. Two experiments were conducted, in experiment 1, 215 cows crossbreed cows (Bos indicus × Bos taurus) (Control Group, n = 109; Insulin Group, n = 106) were submitted to fixed-time artificial insemination (TAI) with application of 2 mg of estradiol benzoate and a vaginal device containing progesterone on day 0. On day 9, the device was removed and 0.5 mg of estradiol cypionate was administered with 12.5 mg of dinoprost and 0.25 UI kg-1 of insulin for the treated animals. On day 11, artificial insemination (AI) was performed on all animals. On days 9 and 11 according to the protocol, was evaluated follicular growth and estrus manifestation, and 30 days after AI the pregnancy rate. In experiment 2, 85 cows were utilized, including Aberdeen Angus, Hereford, and crossbreeds (Control Group, n = 49 and Insulin Group, n = 36), and were submitted to the protocol for fixed-time embryo transfer (FTET), and progesterone concentrations were evaluated. On day 0, the cows received 2 mg of estradiol benzoate and a vaginal device containing progesterone. On day 5 of the protocol, 0.150 mg of cloprostenol was administered. On day 8, the vaginal device was removed and 20 mg of purified porcine pituitary extract and 0.25 UI kg-1 of insulin was given to the animals in the treatment group, and on day 9, 1 mg of estradiol benzoate was administered. On day 17, an embryo transfer was performed and blood collection for evaluation of progesterone levels in animals submitted to FTET were collected. In experiment 1, the follicular growth rate and the pregnancy rate were similar between groups (P > 0.05) and in experiment 2, the production of P4 was not different between the animals that received the insulin application and the control group...

O objetivo deste estudo foi avaliar o efeito da aplicação estratégica de insulina sobre o crescimento folicular, produção de progesterona e taxa de prenhez em bovinos de corte. Foram realizados 2 experimentos, no experimento 1, 215 vacas cruzas (Bos indicus x Bos taurus) (Grupo Controle = 109; Grupo Insulina = 106) foram submetidas a um protocolo que consistiu na aplicação de 2 mg de benzoato de estradiol e inserção de um dispositivo intravaginal de liberação lenta de progesterona (P4) sendo este o dia zero do protocolo. No dia 9, foi realizada a remoção do dispositivo de P4, a aplicação de 0,5 mg de cipionato de estradiol, e 12,5 mg de dinoprost. Os animais do grupo insulina receberam ainda a aplicação de 0,25 UI kg-1 de insulina. No dia 11 foi realizada a inseminação artificial de todos os animais. Nos dias 9 e 11 de acordo com o protocolo, foi avaliado crescimento folicular e manifestação de estro, e 30 dias após IA foi avaliado a taxa de prenhez. O experimento 2 foi realizado com 85 vacas da raça Aberdeen Angus, Hereford e cruzas (Grupo Controle = 49; Grupo Insulina = 36) submetidas a um protocolo de Transferência de Embrião em Tempo Fixo (TETF). No dia 0 fez-se aplicação de 2 mg de benzoato de estradiol e a inserção de um dispositivo intravaginal de liberação lenta de progesterona. No 5º dia do protocolo foi aplicado 0,150 mg de d- Cloprostenol. No dia 8 fez-se a remoção do dispositivo de P4 e aplicação de 20 mg de foltropina de pituitária suína e de 0,25 UI kg-1 de insulina nos animais tratados e no dia 9 foi aplicado 1 mg de benzoato de estradiol. No dia 17 procedeu-se com a transferência dos embriões e coleta de sangue para avaliação dos níveis de progesterona nos animais submetidos a TETF. No experimento 1 a taxa de crescimento folicular e a taxa de prenhez foram semelhantes entre os grupos (P > 0,05) e no experimento 2 a produção de P4 não foi diferente entre os animais que receberam a aplicação de insulina e o grupo controle...

Evaluation of follicular growth and progesterone production in Bos taurus cows strategically treated with insulin / Avaliação do crescimento folicular e da produção de progesterona em vacas Bos taurus tratadas estrategicamente com insulina

The goal of this study was to evaluate the effects of strategic insulin administration on follicular growth, progesterone production, and pregnancy rate in beef cattle. Two experiments were conducted, in experiment 1, 215 cows crossbreed cows (Bos indicus × Bos taurus) (Control Group, n = 109; Insulin Group, n = 106) were submitted to fixed-time artificial insemination (TAI) with application of 2 mg of estradiol benzoate and a vaginal device containing progesterone on day 0. On day 9, the device was removed and 0.5 mg of estradiol cypionate was administered with 12.5 mg of dinoprost and 0.25 UI kg-1 of insulin for the treated animals. On day 11, artificial insemination (AI) was performed on all animals. On days 9 and 11 according to the protocol, was evaluated follicular growth and estrus manifestation, and 30 days after AI the pregnancy rate. In experiment 2, 85 cows were utilized, including Aberdeen Angus, Hereford, and crossbreeds (Control Group, n = 49 and Insulin Group, n = 36), and were submitted to the protocol for fixed-time embryo transfer (FTET), and progesterone concentrations were evaluated. On day 0, the cows received 2 mg of estradiol benzoate and a vaginal device containing progesterone. On day 5 of the protocol, 0.150 mg of cloprostenol was administered. On day 8, the vaginal device was removed and 20 mg of purified porcine pituitary extract and 0.25 UI kg-1 of insulin was given to the animals in the treatment group, and on day 9, 1 mg of estradiol benzoate was administered. On day 17, an embryo transfer was performed and blood collection for evaluation of progesterone levels in animals submitted to FTET were collected. In experiment 1, the follicular growth rate and the pregnancy rate were similar between groups (P > 0.05) and in experiment 2, the production of P4 was not different between the animals that received the insulin application and the control group...(AU)

O objetivo deste estudo foi avaliar o efeito da aplicação estratégica de insulina sobre o crescimento folicular, produção de progesterona e taxa de prenhez em bovinos de corte. Foram realizados 2 experimentos, no experimento 1, 215 vacas cruzas (Bos indicus x Bos taurus) (Grupo Controle = 109; Grupo Insulina = 106) foram submetidas a um protocolo que consistiu na aplicação de 2 mg de benzoato de estradiol e inserção de um dispositivo intravaginal de liberação lenta de progesterona (P4) sendo este o dia zero do protocolo. No dia 9, foi realizada a remoção do dispositivo de P4, a aplicação de 0,5 mg de cipionato de estradiol, e 12,5 mg de dinoprost. Os animais do grupo insulina receberam ainda a aplicação de 0,25 UI kg-1 de insulina. No dia 11 foi realizada a inseminação artificial de todos os animais. Nos dias 9 e 11 de acordo com o protocolo, foi avaliado crescimento folicular e manifestação de estro, e 30 dias após IA foi avaliado a taxa de prenhez. O experimento 2 foi realizado com 85 vacas da raça Aberdeen Angus, Hereford e cruzas (Grupo Controle = 49; Grupo Insulina = 36) submetidas a um protocolo de Transferência de Embrião em Tempo Fixo (TETF). No dia 0 fez-se aplicação de 2 mg de benzoato de estradiol e a inserção de um dispositivo intravaginal de liberação lenta de progesterona. No 5º dia do protocolo foi aplicado 0,150 mg de d- Cloprostenol. No dia 8 fez-se a remoção do dispositivo de P4 e aplicação de 20 mg de foltropina de pituitária suína e de 0,25 UI kg-1 de insulina nos animais tratados e no dia 9 foi aplicado 1 mg de benzoato de estradiol. No dia 17 procedeu-se com a transferência dos embriões e coleta de sangue para avaliação dos níveis de progesterona nos animais submetidos a TETF. No experimento 1 a taxa de crescimento folicular e a taxa de prenhez foram semelhantes entre os grupos (P > 0,05) e no experimento 2 a produção de P4 não foi diferente entre os animais que receberam a aplicação de insulina e o grupo controle...(AU)

Use of Doppler ultrasonography in embryo transfer programs: feasibility and field results

The intensive use of Doppler ultrasonography in several studies in the last decade allowed the characterization of vascular perfusion and the estimation of function of the reproductive organs and tissues along the estrous cycle and pregnancy in cattle. We aim to discuss the possibility of using Doppler imaging and to explore the potential of its inclusion in reproductive programs in cattle industry. Recent studies in dairy and beef cows indicated a high accuracy and sensitivity when Doppler ultrasonography is used to evaluate corpus luteum function and to diagnosis pregnancy between days 20 and 22. Moreover, resynchronization programs starting 5 to 7 days after timed embryo transfer (FTET) coupled with early pregnancy diagnosis were developed for beef cattle, and have been implemented in commercial embryo transfer programs. These strategies allow a reduction in the interval between two FTET from 40 to 24 days and may improve the gains in reproductive efficiency when compared to traditional programs than begin resynchronization after the pregnancy diagnosis at 30 days. A second alternative to use Doppler imaging is the evaluation of luteal blood perfusion at the time of embryo transfer for selection of recipients with greater receptivity potential. This may increases fertility in FTET, as embryos would not be transferred to females with non-functional CL, and in cases with recipients surplus, females with higher receptivity would be prioritized.

Use of Doppler ultrasonography in embryo transfer programs: feasibility and field results

The intensive use of Doppler ultrasonography in several studies in the last decade allowed the characterization of vascular perfusion and the estimation of function of the reproductive organs and tissues along the estrous cycle and pregnancy in cattle. We aim to discuss the possibility of using Doppler imaging and to explore the potential of its inclusion in reproductive programs in cattle industry. Recent studies in dairy and beef cows indicated a high accuracy and sensitivity when Doppler ultrasonography is used to evaluate corpus luteum function and to diagnosis pregnancy between days 20 and 22. Moreover, resynchronization programs starting 5 to 7 days after timed embryo transfer (FTET) coupled with early pregnancy diagnosis were developed for beef cattle, and have been implemented in commercial embryo transfer programs. These strategies allow a reduction in the interval between two FTET from 40 to 24 days and may improve the gains in reproductive efficiency when compared to traditional programs than begin resynchronization after the pregnancy diagnosis at 30 days. A second alternative to use Doppler imaging is the evaluation of luteal blood perfusion at the time of embryo transfer for selection of recipients with greater receptivity potential. This may increases fertility in FTET, as embryos would not be transferred to females with non-functional CL, and in cases with recipients surplus, females with higher receptivity would be prioritized.(AU)

Freezing goat embryos at different developmental stages and quality using ethylene glycol and a slow cooling rate / Congelação de embriões caprinos em diferentes estádios de desenvolvimento e qualidade utilizando etileno glicol e taxa de resfriamento lenta

The efficiency of an alternative freezing protocol for goat embryos of different morphology and quality was tested. Fifty-eight embryos on Day 6-7 stage were transferred as fresh or after freeze-thawing (n=29/group). For freezing, embryos were placed into 1.5M ethylene-glycol solution for 10min. During this time, they were loaded in the central part of 0.25mL straw, separated by air bubble from columns containing PBS/BSA 0.4% plus 20% BFS. Straws were then frozen using a freezing machine from 20ºC to -6ºC at a cooling rate of 3ºC/min, stabilization for 15min (seeding after 5min), from -6 C to -32ºC at 0.6 C/min,and plunged into liquid nitrogen. Frozen embryos were thawed for 30s at 37ºC in a water bath. Embryos subjected to fresh transfer were maintained in holding medium (37ºC). Fresh and frozen-thawed embryos were transferred at day 7 post-estrus to 30 recipients. Kidding and kid born rates were similar (P> 0.05), respectively, for recipients receiving fresh (66.7% or 10/15; 55.2% or 16/29) or frozen-thawed (60% or 9/15; 51.7% or 15/29) embryos. The cryopreservation of goat embryos using slow-freezing protocol and 1.5MEG resulted in similar efficiency rates of fresh embryos.(AU)

Este estudo testou a eficiência de protocolo alternativo de criopreservação de embriões caprinos de diferentes qualidades morfológicas. Foram utilizados 58 embriões, coletados entre o sexto e o sétimo dia do ciclo estral (n=29/grupo). Embriões congelados passaram por solução 1,5M etilenoglicol por 10min e foram aspirados durante esse tempo para parte central de palheta 0,25mL, separada por bolhas de ar de colunas contendo PBS 0,4% BSA e 20% SFB. As palhetas foram congeladas em máquina de congelação de 20ºC a -6ºC, com taxa de resfriamento de 3ºC/min, estabilização por 15min (seeding após 5min), -6ºC a -32ºC a 0,6ºC/min, e imersas em nitrogênio líquido. Os embriões foram descongelados por 30s a 37ºC, em água. Embriões frescos foram mantidos em solução de manutenção (37ºC). Embriões frescos e congelados/descongelados foram transferidos para 30 receptoras no sétimo dia do ciclo estral. A taxa de partos e a de crias nascidas (respectivamente) foram similares (P>0,05) para receptoras recebendo embriões frescos (66,7% ou 10/15; 55,2% ou 16/29) ou congelados/descongelados (60,0% ou 9/15; 51,7% ou 15/29). O protocolo de criopreservação de embriões utilizado no presente estudo resultou em índices de eficiência semelhantes aos de embriões frescos.(AU)

Freezing goat embryos at different developmental stages and quality using ethylene glycol and a slow cooling rate / Congelação de embriões caprinos em diferentes estádios de desenvolvimento e qualidade utilizando etileno glicol e taxa de resfriamento lenta

The efficiency of an alternative freezing protocol for goat embryos of different morphology and quality was tested. Fifty-eight embryos on Day 6-7 stage were transferred as fresh or after freeze-thawing (n=29/group). For freezing, embryos were placed into 1.5M ethylene-glycol solution for 10min. During this time, they were loaded in the central part of 0.25mL straw, separated by air bubble from columns containing PBS/BSA 0.4% plus 20% BFS. Straws were then frozen using a freezing machine from 20ºC to -6ºC at a cooling rate of 3ºC/min, stabilization for 15min (seeding after 5min), from -6 C to -32ºC at 0.6 C/min,and plunged into liquid nitrogen. Frozen embryos were thawed for 30s at 37ºC in a water bath. Embryos subjected to fresh transfer were maintained in holding medium (37ºC). Fresh and frozen-thawed embryos were transferred at day 7 post-estrus to 30 recipients. Kidding and kid born rates were similar (P> 0.05), respectively, for recipients receiving fresh (66.7% or 10/15; 55.2% or 16/29) or frozen-thawed (60% or 9/15; 51.7% or 15/29) embryos. The cryopreservation of goat embryos using slow-freezing protocol and 1.5MEG resulted in similar efficiency rates of fresh embryos.(AU)

Este estudo testou a eficiência de protocolo alternativo de criopreservação de embriões caprinos de diferentes qualidades morfológicas. Foram utilizados 58 embriões, coletados entre o sexto e o sétimo dia do ciclo estral (n=29/grupo). Embriões congelados passaram por solução 1,5M etilenoglicol por 10min e foram aspirados durante esse tempo para parte central de palheta 0,25mL, separada por bolhas de ar de colunas contendo PBS 0,4% BSA e 20% SFB. As palhetas foram congeladas em máquina de congelação de 20ºC a -6ºC, com taxa de resfriamento de 3ºC/min, estabilização por 15min (seeding após 5min), -6ºC a -32ºC a 0,6ºC/min, e imersas em nitrogênio líquido. Os embriões foram descongelados por 30s a 37ºC, em água. Embriões frescos foram mantidos em solução de manutenção (37ºC). Embriões frescos e congelados/descongelados foram transferidos para 30 receptoras no sétimo dia do ciclo estral. A taxa de partos e a de crias nascidas (respectivamente) foram similares (P>0,05) para receptoras recebendo embriões frescos (66,7% ou 10/15; 55,2% ou 16/29) ou congelados/descongelados (60,0% ou 9/15; 51,7% ou 15/29). O protocolo de criopreservação de embriões utilizado no presente estudo resultou em índices de eficiência semelhantes aos de embriões frescos.(AU)

Expression of estrus as a relevant factor in fixed-time embryo transfer programs using estradiol/progesterone-based protocols in cattle

The main objective of implementing embryo transfer in beef operations is to accelerate the rate of genetic progress in the herd. Among the main factors that affect the use of these technologies are related to nutrition, management and estrus synchronization. As a result of research conducted over the last 20 years, recipient utilization has increased by applying protocols that synchronize ovulation and allow for embryo transfer without the need for estrus detection, usually referred to as fixed-time embryo transfer (FTET). Although these protocols have performed adequately for several years, recent attention has been directed to the effect of estrus expression and estradiol concentrations during growth of the preovulatory follicle on embryo growth and pregnancy. The experiments reviewed herein demonstrate that estrus expression is associated positively with high pregnancy rates and reduced pregnancy losses in recipients receiving in vitro-produced and in vivo-derived frozen/thawed bovine embryos.

Expression of estrus as a relevant factor in fixed-time embryo transfer programs using estradiol/progesterone-based protocols in cattle

The main objective of implementing embryo transfer in beef operations is to accelerate the rate of genetic progress in the herd. Among the main factors that affect the use of these technologies are related to nutrition, management and estrus synchronization. As a result of research conducted over the last 20 years, recipient utilization has increased by applying protocols that synchronize ovulation and allow for embryo transfer without the need for estrus detection, usually referred to as fixed-time embryo transfer (FTET). Although these protocols have performed adequately for several years, recent attention has been directed to the effect of estrus expression and estradiol concentrations during growth of the preovulatory follicle on embryo growth and pregnancy. The experiments reviewed herein demonstrate that estrus expression is associated positively with high pregnancy rates and reduced pregnancy losses in recipients receiving in vitro-produced and in vivo-derived frozen/thawed bovine embryos.(AU)

Evolution of knowledge on ovarian physiology and its contribution to the widespread application of reproductive biotechnologies in South American cattle

As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. Luteal function in cattle has been studied in detail, and prostaglandin F2α has been used for several years for the elective induction of luteal regression. More recently, follicle wave dynamics has been studied and protocols designed to induce follicular wave emergence and ovulation have reduced, and even eliminated, the need for estrus detection. The addition of progestin-releasing devices, estradiol, GnRH and equine chorionic gonadotropin (eCG) have provided opportunities for fixed-time AI (FTAI) and possibilities for increased pregnancy rates. In embryo transfer programs, these same treatments have eliminated the need for estrus detection, permitting fixed-time embryo transfer and the initiation of superstimulatory treatments without regard to day of the estrous cycle. Collectively, new treatment protocols have facilitated the application of assisted reproductive technologies, and this is especially true in South America. Over the last 20 years, the use of AI in South America has increased, due largely to the use of FTAI. There has been more than a 10-fold increase in the use of FTAI in Brazil with more than 11 million treatments in 2016, representing 85% of all AI. Similar trends are occurring in Argentina and Uruguay. Production of in vivo-derived (IVD) embryos has remained relatively stable over the years, but in vitro embryo production (IVP) has increased dramatically over the past 10 to 15 years, especially in Brazil where more than 300,000 IVP embryos were produced in 2010. World-wide, more than 666,000 bovine IVP embryos were produced in 2016, of which more than 57% were produced in South America. The use of assisted reproductive technologies has facilitated the dissemination of improved genetics and increased reproductive performance; other South American countries are now following suit.(AU)