How does reproduction account for dairy farm sustainability?

Sustainability - the new hype of the 21st century has brought discomfort for the government and society. Sustainable agriculture is essential to face our most concerning challenges: climate change, food security, and the environmental footprint, all of which add to consumers' opinions and choices. Improvements in reproductive indexes can enhance animal production and efficiency, guaranteeing profit and sustainability. Estrus detection, artificial insemination (AI), embryo transfer (ET), estrus synchronization (ES), and multiple ovulations are some strategies used to improve animal reproduction. This review highlights how reproductive strategies and genetic selection can contribute to sustainable ruminant production. Improved reproductive indices can reduce the number of nonproductive cows in the herd, reducing methane emissions and land use for production while preserving natural resources.(AU)

Multiple matings modify the estrous length, the moment of ovulation, and the estradiol and LH patterns in ewes

In several species, mating reduces the estrous length and advances ovulation. The aim of this study was to determine if multiple matings reduces the estrous length and modifies the moment of ovulation, as well as the estradiol and LH patterns in ewes. The estrous cycle of Corriedale ewes was synchronized, and the onset of receptivity was monitored every 3 h with rams, avoiding mating. At the estrous onset, ewes were assigned to two experimental groups (n=10 each): 1) estrous was monitored every 3 h with a ram avoiding mating (group CON), and 2) a ram was allowed to mate and ejaculate once every 3 h (group MAT). The ovaries were scanned with transrectal ultrasonography and blood samples were collected for measuring 17β-estradiol and LH concentrations every 3 h until ovulation. Estrus was shorter in MAT than CON ewes (24.7 ± 1.5 h vs. 30.4 ± 1.5 h, respectively; P=0.02); the proportion of animals that ovulated before the end of estrus was greater in CON ewes: (9/10 vs. 3/10, P=0.009). The area under the LH curve (AUC) was greater in MAT than CON ewes (36.1 ± 3.5 ng.h-1.mL-1 vs 24.9 ± 3.5 ng.h-1.mL-1 P=0.03). However, MAT ewes had a lower 17β-estradiol AUC than CON ewes (41.0 ± 4.9 pg.h-1.mL-1 vs 59.4 ± 4.9 pg.h-1.mL-1 P=0.01). Mating reduced the estrous length, induced a greater secretion of LH but less total 17β-estradiol secreted and, additionally, ovulation occurred more frequently after the end of estrus in mated ewes.(AU)

A rare case of heteropaternal twin calves after natural mating in Brazil

Twin birth is a complex condition observed in most livestock animals, when the female gives birth to two or more offspring, generally out of the same mating. In cattle, it is a rare condition (3 to 5%) and depends on the genetic background and environmental factors. Twin birth is a result of multiple ovulations, being more common in dairy rather than in beef cattle. Calves could be monozygous or dizygous, with the same or of different sexes. When twins are born with different sexes, a sexual condition called Freemartinism occurs in between 90 to 97% of pregnancies, causing infertility in the female calf. Knowing that the twin rate is rare in commercial beef cattle, here we present an even rarer case of twin birth from two different sires after natural mating, also called heteropaternal superfecundation.

A rare case of heteropaternal twin calves after natural mating in Brazil

Twin birth is a complex condition observed in most livestock animals, when the female gives birth to two or more offspring, generally out of the same mating. In cattle, it is a rare condition (3 to 5%) and depends on the genetic background and environmental factors. Twin birth is a result of multiple ovulations, being more common in dairy rather than in beef cattle. Calves could be monozygous or dizygous, with the same or of different sexes. When twins are born with different sexes, a sexual condition called Freemartinism occurs in between 90 to 97% of pregnancies, causing infertility in the female calf. Knowing that the twin rate is rare in commercial beef cattle, here we present an even rarer case of twin birth from two different sires after natural mating, also called heteropaternal superfecundation.(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)

Mechanisms regulating follicle selection in ruminants: lessons learned from multiple ovulation models

Selection of a single dominant follicle from a cohort of growing follicles is a unique biological process, a key step in female reproductive function in monovular species, and lies at the core of reproductive technologies in cattle. Follicle growth and the number of follicles that ovulate are regulated by precise endocrine, paracrine, and autocrine mechanisms. Most of our current understanding about follicle selection focuses on the role of FSH, LH, and the IGF family in follicle growth and selection of the dominant follicle. However, more recently the role of members of the TGF-ß family has been highlighted, particularly in high fecundity genotypes in sheep. Intercellular signaling between the oocyte and granulosa cells (GC) regulates proliferation and differentiation due to actions of bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) within the follicle. Mutations that either knockout or reduce the activity of BMP15 or GDF9 have been found to increase ovulation rate in heterozygotes and generally cause severe follicle abnormalities in homozygotes. A mutation in the intracellular kinase domain of the BMPR1B receptor (Booroola fecundity gene) increases ovulation rate in heterozygotes with further increases in ovulation in homozygotes. The physiological mechanisms linking these mutations to increased ovulation rates are still not well defined. A recently identified high fecundity bovine genotype, Trio, causes increased expression of SMAD6, an intracellular inhibitor of the BMP15/GDF9 signalling pathways. This bovine model has provided insights into the mechanisms associated with selection of multiple dominant follicles and multiple ovulations in carriers of fecundity alleles. The present review focuses on the mechanisms involved in follicle selection in ruminants with a special emphasis on the contribution made by multiple ovulation models in both cattle and sheep. The evaluation of multiple ovulation models in ruminants has allowed us to construct a new physiological model that relates changes in the BMP15/GDF9 signalling pathways to the physiological changes that result in selection of multiple dominant follicles. This model is characterized by acquisition of dominance at a smaller follicle size but at a similar time in the follicular wave with multiple follicles acquiring dominance in a hierarchal sequence, delaying FSH suppression and, thus allowing additional follicles to continue to grow and acquire dominance.(AU)

Mechanisms regulating follicle selection in ruminants: lessons learned from multiple ovulation models

Selection of a single dominant follicle from a cohort of growing follicles is a unique biological process, a key step in female reproductive function in monovular species, and lies at the core of reproductive technologies in cattle. Follicle growth and the number of follicles that ovulate are regulated by precise endocrine, paracrine, and autocrine mechanisms. Most of our current understanding about follicle selection focuses on the role of FSH, LH, and the IGF family in follicle growth and selection of the dominant follicle. However, more recently the role of members of the TGF-ß family has been highlighted, particularly in high fecundity genotypes in sheep. Intercellular signaling between the oocyte and granulosa cells (GC) regulates proliferation and differentiation due to actions of bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) within the follicle. Mutations that either knockout or reduce the activity of BMP15 or GDF9 have been found to increase ovulation rate in heterozygotes and generally cause severe follicle abnormalities in homozygotes. A mutation in the intracellular kinase domain of the BMPR1B receptor (Booroola fecundity gene) increases ovulation rate in heterozygotes with further increases in ovulation in homozygotes. The physiological mechanisms linking these mutations to increased ovulation rates are still not well defined. A recently identified high fecundity bovine genotype, Trio, causes increased expression of SMAD6, an intracellular inhibitor of the BMP15/GDF9 signalling pathways. This bovine model has provided insights into the mechanisms associated with selection of multiple dominant follicles and multiple ovulations in carriers of fecundity alleles. The present review focuses on the mechanisms involved in follicle selection in ruminants with a special emphasis on the contribution made by multiple ovulation models in both cattle and sheep. The evaluation of multiple ovulation models in ruminants has allowed us to construct a new physiological model that relates changes in the BMP15/GDF9 signalling pathways to the physiological changes that result in selection of multiple dominant follicles. This model is characterized by acquisition of dominance at a smaller follicle size but at a similar time in the follicular wave with multiple follicles acquiring dominance in a hierarchal sequence, delaying FSH suppression and, thus allowing additional follicles to continue to grow and acquire dominance.

Induction of ovulation in Mangalarga Marchador mares by hCG or GnRH

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods & Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P > 0.05) for induction of ovulation and that both agents were effective (P < 0.05) for such purpose, since greater percentages (P < 0.05) of induction on mares treated from those of the control. Moreover, the total number of ovulations in mares treated at the end of the experiment was not different (P > 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment.[...](AU)

Induction of ovulation in Mangalarga Marchador mares by hCG or GnRH

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods & Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P > 0.05) for induction of ovulation and that both agents were effective (P 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment.[...]

INDUÇÃO DE DUPLA OVULAÇÃO EM ÉGUAS MANGALARGA MARCHADOR

Uma das estratégias para aumentar a eficiência dos programas de transferência de embriões em equinos é a indução de múltiplas ovulações. Neste contexto o objetivo do presente estudo foi avaliar a eficiência em de agonistas do GnRH para indução de duplas ovulações, bem como na taxa de ovulação e recuperação embrionária nos grupos estudados. Foram avaliados 41 ciclos estrais de éguas Mangalarga Marchador. Todos os animais foram induzidos ao estro no 8o dia do ciclo estral (D8) com 5 mg de dinoprost trometamina e quando foram observados ao menos dois folículos de tamanho entre 17 e 19 mm, os ciclos foram divididos em três grupos de tratamento: Grupo I (n=13 ciclos) - 100 µg de acetato de deslorelina, a cada 12 horas; Grupo II (n=14 ciclos) - 125 µg de acetato de histrelina, a cada 12 horas e Grupo III (n= 14 ciclos) considerado grupo controle, no qual foi administrado 1,0 ml de solução salina a cada 12 horas. A duração do tratamento com análogos de GnRH não excedeu sete dias, sendo interrompido quando a maioria dos folículos atingissem diâmetro 35 mm e edema uterino ou quando os mesmos cessassem o crescimento. A indução da ovulação foi realizada utilizando 1000 UI de hCG intravenoso quando o folículo atingisse um diâmetro médio entre eles de 35 mm e edema uterino. A partir da indução da ovulação, 24 horas após as éguas foram inseminadas com sêmen a fresco de um garanhão de fertilidade comprovada. A colheita de embriões foi realizada no oitavo dia após a detecção da ovulação. O número médio de ovulações por ciclo de 1,15 (GI), 0,86 (GII) e 1,14 (GIII). Quanto o número de embriões recuperados por ovulação, os grupos I, II e III apresentaram, 0,46, 0,36 e 0,71. Já o número de embriões recuperados por ciclo foi de 0,67 (GI), 0,50 (GII) e 0,71 (GIII). Não foi observada diferença estatística entre os grupos de tratamento (P > 0,05). Conclui-se que os protocolos propostos não foram capazes de aumentar as taxas de duplas ovulações nos grupos avaliados assim como a taxa de recuperação embrionária

One of the strategies to increase the efficiency of embryo transfer programs in horses is the induction of multiple ovulations. In this context, the objective of the present study was to evaluate the efficiency of GnRH agonists for inducing double ovulations, as well as the rate of ovulation and embryonic recovery in the studied groups. 41 estal cycles of Mangalarga Marchador mares were evaluated. All animals were induced to estrus on the 8th day of the estrous cycle (D8) with 5 mg of dinoprost tromethamine and when at least two follicles between 17 and 19 mm in size were observed, the cycles were divided into three treatment groups: Group I (n = 13 cycles) - 100 µg of deslorelin acetate, every 12 hours; Group II (n = 14 cycles) - 125 µg of histrelin acetate, every 12 hours and Group III (n = 14 cycles) considered a control group, in which 1.0 ml of saline solution was administered every 12 hours. The duration of treatment with GnRH analogs did not exceed seven days, being interrupted when most follicles reached a diameter 35 mm and uterine edema or when they stopped growing. Ovulation induction was performed using 1000 IU intravenous hCG when the follicle reached an average diameter between them of 35 mm and uterine edema. After ovulation induction, 24 hours after the mares were inseminated with fresh semen from a proven fertility stallion. Embryo collection was performed on the eighth day after ovulation was detected. The average number of ovulations per cycle is 1.15 (GI), 0.86 (GII) and 1.14 (GIII). Regarding the number of embryos recovered by ovulation, groups I, II and III showed 0.46, 0.36 and 0.71. The number of embryos recovered per cycle was 0.67 (GI), 0.50 (GII) and 0.71 (GIII). There was no statistical difference between the treatment groups (P> 0.05). It is concluded that the proposed protocols were not able to increase the rates of double ovulations in the evaluated groups as well as the rate of embryo recovery

Produção de embriões em ovinos Morada Nova e Somalis Brasileira / Embryo production in Morada Nova and Somalis Brasileira ewes

Superovulatory response and embryo yield in 19 Morada Nova and 20 Somalis Brasileira ewes was analyzed. All animals were synchronized with the insertion of an intravaginal device (CIDR®) on Day 0, replaced by a new device on Day 7, which remained in place until Day 14 and superovulated with 133mg of porcine FSH (pFSH) in decreasing doses at 12h intervals from Day 12 until Day 15 of the treatment, and a single dose of equine chorionic gonadotropin (eCG, 200UI) on Day 14 (i.e., administered in CIDR removal). Fifty hours after CIDR® removal, females were inseminated by laparoscopy. All embryos were recovered by laparotomy 5 days after insemination. Sheep which responded to the superovulation protocol (P>0.05) included 74% of the Morada Nova ewes and 50% of the Somalis Brasileira ewes. Morada Nova showed better results (P<0.05) than Somalis Brasileira in number of ovulations (15.38 ± 5.24 vs. 10.56 ± 2.83), total structures (11.00 ± 7.55 vs. 3.33 ± 1.94) and embryo yields (6.79 ± 5.35 vs. 2.90 ± 2.18). Despite the high fertilization rate, degenerate embryo rate was high for both breeds, with an overall rate of 39% (57/145). In conclusion, superovulatory response and embryo yields in Morada Nova ewes were considered sufficient to justify the use of this procedure in genetic resources conservation programs. However, improvements to embryo quality and control of precocious regression of corpus luteum are necessary to produce better results in the MOET program, with minimal variations and maximum embryo yield in Morada Nova and Somalis Brasileira ewes.(AU)

Produção de embriões em ovinos Morada Nova e Somalis Brasileira / Embryo production in Morada Nova and Somalis Brasileira ewes

Superovulatory response and embryo yield in 19 Morada Nova and 20 Somalis Brasileira ewes was analyzed. All animals were synchronized with the insertion of an intravaginal device (CIDR®) on Day 0, replaced by a new device on Day 7, which remained in place until Day 14 and superovulated with 133mg of porcine FSH (pFSH) in decreasing doses at 12h intervals from Day 12 until Day 15 of the treatment, and a single dose of equine chorionic gonadotropin (eCG, 200UI) on Day 14 (i.e., administered in CIDR removal). Fifty hours after CIDR® removal, females were inseminated by laparoscopy. All embryos were recovered by laparotomy 5 days after insemination. Sheep which responded to the superovulation protocol (P>0.05) included 74% of the Morada Nova ewes and 50% of the Somalis Brasileira ewes. Morada Nova showed better results (P<0.05) than Somalis Brasileira in number of ovulations (15.38 ± 5.24 vs. 10.56 ± 2.83), total structures (11.00 ± 7.55 vs. 3.33 ± 1.94) and embryo yields (6.79 ± 5.35 vs. 2.90 ± 2.18). Despite the high fertilization rate, degenerate embryo rate was high for both breeds, with an overall rate of 39% (57/145). In conclusion, superovulatory response and embryo yields in Morada Nova ewes were considered sufficient to justify the use of this procedure in genetic resources conservation programs. However, improvements to embryo quality and control of precocious regression of corpus luteum are necessary to produce better results in the MOET program, with minimal variations and maximum embryo yield in Morada Nova and Somalis Brasileira ewes.(AU)

Oocyte development and fecundity type of the Brazilian Snapper Lutjanus alexandrei Moura & Lindeman, 2007 (Perciformes: Lutjanidae)

Abstract Lutjanid species exhibit multiple spawning behaviour during an extended spawning season in warm months, asynchronous oocyte development and indeterminate fecundity. Although early studies have contributed to knowledge of the reproductive cycle of many species within the group, they have not considered aspects about the number of cortical alveoli oocyte stage throughout maturity phases along spawning season. The latter aspect is also considered very important to confirm indeterminate fecundity hypothesis. In the present study, were analyzed 154 Brazilian snapper Lutjanus alexandrei female gonads obtained from artisanal fisheries in Pernambuco State (Brazil) between October 2010 and March 2011. Were measured oocyte size frequency distribution for maturity phases (developing, spawning capable and actively spawning), and oocyte development stage (unyolked oocytes, cortical alveoli, primary, secondary and tertiary vitellogenic oocytes and hydrated oocytes), and also the oocyte stage frequency during spawning season. The frequency of cortical alveoli oocyte stage was constantly found in the spawning period (>37%), showing slight variation throughout maturity phases. The absence of gap in the oocyte size frequency distribution between primary and secondary oocyte growth stages during spawning season is a strong indicator of continuous oocyte recruitment from reserve stocks. In addition, co-occurrence of tertiary vitellogenic oocytes, hydrated oocytes, post-ovulatory follicles and yellow-brown bodies in the histological sections of ovaries reinforce indeterminate fecundity hypothesis.(AU)

Resumo Os lutjanídeos apresentam um comportamento de desovas parceladas ao longo de uma extensa estação reprodutiva nos meses mais quentes do ano, desenvolvimento assincrônico dos ovócitos e padrão de regulação de fecundidade indeterminado. Embora muitos estudos anteriores tenham contribuído no conhecimento do ciclo reprodutivo das espécies do grupo, não foram considerados os aspectos relacionados ao percentual dos ovócitos em estágio de cortical alveoli entre as fases de maturidade sexual durante a estação reprodutiva. Este último aspecto, considerado importante para confirmação da hipótese de fecundidade do tipo indeterminada. Para isso, no presente trabalho foram analisadas 154 gônadas de fêmeas da baúna de fogo Lutjanus alexandrei obtidas da pesca artesanal em Pernambuco entre o período de outubro de 2010 a março de 2011. Foram mensurados os diâmetros dos ovócitos nas fases de maturidade sexual (desenvolvimento, capaz de desovar e ativamente desovando), e para todos os estágios ovocitários (ovócitos pre-vitelogênicos, cortical alveolar, vitelogênese primária, secundária, terciária e ovócitos hidratados), e avaliada a frequência de ocorrência ao longo do período de desova. O percentual de ovócitos em estágio cortical alveoli permaneceu constante durante o período de reprodutivo (> 37%), apresentando pouca variação entre as fases de maturidade sexual. A ausência de um intervalo na frequência de diâmetro dos ovócitos em crescimento primário e secundário entre todas as fases de maturidade sexual é um forte indicador de recrutamento contínuo de ovócitos do estoque de reserva. Além disso, a presença conjunta de ovócitos em vitelogênese terciária, ovócitos hidratados, folículos pós-ovulatórios e corpos amarelados nos cortes histológicos reforçam a hipótese de fecundidade do tipo indeterminada.(AU)

Gestação gemelar em equinos: com ênfase na raça Crioula

Gestações gemelares em equinos frequentemente resultam em aborto ou natimortos, sendo responsáveis por prejuízos na criação. Poucos estudos descrevem a características reprodutivas e gestacionais em éguas Crioulas. O objetivo da presente dissertação é realizar uma revisão bibliográfica a respeito dos principais aspectos da gestação gemelar e apresentar resultados sobre a incidência em éguas Crioulas. Foram realizados dois artigos de revisão bibliográfica, sendo o primeiro a respeito dos fatores que influenciam a ocorrência e o segundo sobre métodos de diagnóstico e manipulação dessas gestações. Já o terceiro artigo traz um estudo retrospectivo composto por 814 éguas gestantes, demonstrando a incidência de gestações gemelares e ovulações múltiplas em éguas Crioulas, relacionando a ocorrência com status reprodutivo, idade da égua, uso de indutores de ovulação e mês da estação reprodutiva. A incidência de gestação gemelar foi de 3,44%, sendo mais frequente em éguas solteiras e primíparas. Mesmo com índices reduzidos quando comparadas a outras raças, é importante conhecer os fatores de risco, métodos de diagnóstico e intervenção da gestação gemelar para abordar aspectos reprodutivos em éguas Crioulas.

Twin pregnancies in horses often result in abortion or stillbirths and are responsible for huge losses in the equine industry. Few studies describe reproductive and gestational characteristics in Criollo mares. The aim of this dissertation is to review the main aspects of twin pregnancy in mares and to present scientific results about the incidence of twin pregnancies in Criollo mares. Two articles of bibliographic review were made, the first about the factors that influence the occurrence and the second about diagnostic methods and manipulation of these gestations. The third article presents retrospective study with 814 pregnant mares, demonstrating the incidence of twin pregnancies and multiple ovulations in Criollo mares, correlating the occurrence with reproductive status, age of the mare, use of ovulation inducers and month of breeding season. The incidence of twin pregnancy was 3.44%, being more frequent in single and primiparous mares. Even with low rates when compared to other breeds, it is important to know the risk factors, diagnostic methods and intervention of twin pregnancy to address reproductive aspects in Criollo mares.

Gestação gemelar em éguas (parte 1): Desenvolvimento e Fatores de Risco / Twin pregnancies in mares, part I: Development and risk factors / Embarazos gemelares en yeguas, parte l: desarrollo y factores de riesgo

Gestações gemelares em equinos são responsáveis por abortos no terço final de gestação ou nascimento de potros debilitados. O objetivo desta revisão é discutir os fatores de risco para o de gêmeos, sendo mais frequentes em éguas Puro Sangue Inglês, de Polo Argentino e Brasileiro e de Hipismo quando comparadas a Árabes e Pôneis. Éguas solteiras terão maior incidência do múltiplas ovulações e gestações gemelares e éguas mais velhas possuem maiores taxas de múltiplas ovulações, mas não de gêmeos. O uso de indutores de ovulação pode elevar as taxas de ovulações duplas e à medida que a estação reprodutiva progride, aumenta a incidência de gestações gemelares. O conhecimento desses fatores de risco é importante para a realização do diagnóstico e intervenção adequada para evitar prejuízos causados por essas gestações.

Twin pregnancies in horses are responsible for abortion in the late gestation or birth of debilitated foals. The aim of this review is to discuss the risk factors for the development of twin pregnancies. The multiple ovulations are responsible for the occurrence of twins, being more frequent in Thoroughbred, Polo Argentino and Brazilian Sport Horse when compared to Arabs and Ponies. Single mares will have a higher incidence of multiple ovulations and twin pregnancies and older mares have higher rates of multiple ovulations but not twins. The use of ovulation inducers may increase double ovulation rates and as the reproductive season progresses, the incidence of twin pregnancies increases. Knowledge of these risk factors is important for proper diagnosis and intervention to avoid loses caused by this pregnancies.

Los embarazos gemelares en yeguas son pueden causar abortos en la gestación tardía o el nacimiento de potros debilitados. El objetivo de esta revisión es analizar los factores de riesgo para el desarrollo de embarazos gemelares. Las ovulaciones múltiples son responsables por la ocurrencia de gemelos, siendo más frecuentes en yeguas Pura Sangre Inglés, de Polo Argentino y Brasileiro de Hipismo en comparación con las Árabes y Ponis. Las yeguas solteras tendrán una mayor incidencia de ovulaciones múltiples y embarazos gemeiares, y las yeguas mayores tienen tasas más altas de ovulaciones múltiples pero no gemelos. El uso de inductores de la ovulación puede aumentar las tasas de ovulación doble y a medida que avanza la temporada reproductiva aumenta la incidencia de embarazos gemelares. El conocimiento de estos factores de riesgo es importante para un diagnóstico e intervención adecuados para eviar daños causados por estos embarazos.

Gestação gemelar em éguas (parte 1): Desenvolvimento e Fatores de Risco / Twin pregnancies in mares, part I: Development and risk factors / Embarazos gemelares en yeguas, parte l: desarrollo y factores de riesgo

Gestações gemelares em equinos são responsáveis por abortos no terço final de gestação ou nascimento de potros debilitados. O objetivo desta revisão é discutir os fatores de risco para o de gêmeos, sendo mais frequentes em éguas Puro Sangue Inglês, de Polo Argentino e Brasileiro e de Hipismo quando comparadas a Árabes e Pôneis. Éguas solteiras terão maior incidência do múltiplas ovulações e gestações gemelares e éguas mais velhas possuem maiores taxas de múltiplas ovulações, mas não de gêmeos. O uso de indutores de ovulação pode elevar as taxas de ovulações duplas e à medida que a estação reprodutiva progride, aumenta a incidência de gestações gemelares. O conhecimento desses fatores de risco é importante para a realização do diagnóstico e intervenção adequada para evitar prejuízos causados por essas gestações.(AU)

Twin pregnancies in horses are responsible for abortion in the late gestation or birth of debilitated foals. The aim of this review is to discuss the risk factors for the development of twin pregnancies. The multiple ovulations are responsible for the occurrence of twins, being more frequent in Thoroughbred, Polo Argentino and Brazilian Sport Horse when compared to Arabs and Ponies. Single mares will have a higher incidence of multiple ovulations and twin pregnancies and older mares have higher rates of multiple ovulations but not twins. The use of ovulation inducers may increase double ovulation rates and as the reproductive season progresses, the incidence of twin pregnancies increases. Knowledge of these risk factors is important for proper diagnosis and intervention to avoid loses caused by this pregnancies.(AU)

Los embarazos gemelares en yeguas son pueden causar abortos en la gestación tardía o el nacimiento de potros debilitados. El objetivo de esta revisión es analizar los factores de riesgo para el desarrollo de embarazos gemelares. Las ovulaciones múltiples son responsables por la ocurrencia de gemelos, siendo más frecuentes en yeguas Pura Sangre Inglés, de Polo Argentino y Brasileiro de Hipismo en comparación con las Árabes y Ponis. Las yeguas solteras tendrán una mayor incidencia de ovulaciones múltiples y embarazos gemeiares, y las yeguas mayores tienen tasas más altas de ovulaciones múltiples pero no gemelos. El uso de inductores de la ovulación puede aumentar las tasas de ovulación doble y a medida que avanza la temporada reproductiva aumenta la incidencia de embarazos gemelares. El conocimiento de estos factores de riesgo es importante para un diagnóstico e intervención adecuados para eviar daños causados por estos embarazos.(AU)

Múltipla ovulação e transferência de embriões em ovinos / Multiple ovulation an embryo transfer in sheep

A Múltipla Ovulação e Transferência de Embriões (MOTE) é uma biotécnica da reprodução de aplicação imediata em animais de fazenda e é uma importante ferramenta de melhoramento genético. Este trabalho foi elaborado para abordar alguns aspectos significativos para o sucesso da MOTE na espécie ovina.

The Multiple Ovulation and Embryo Transfer (MOET) is a reproductive biotechnique that it is immediately applied in farm animals and it is an important tool of genetic improvement. This paper was prepared in order to comment some significant aspects that lead to success of MOET in ovine species.

EFEITO DA ADMINISTRAÇÃO DE ANTICOAGULANTES SOBRE A RECUPERAÇÃO EMBRIONÁRIA DE ÉGUAS SUPEROVULADAS

A superovulação é uma biotécnica utilizada nos programas de transferência de embrião e proporciona diversos benefícios devido ao maior número de ovulações por ciclo. Entretanto, os protocolos superovulatórios na espécie equina ainda não são utilizados rotineiramente, pois apresentam resultados inconsistentes relacionados a baixa taxa de recuperação embrionária frente ao número de ovulações, estando muito aquém do esperado quando comparado a espécie bovina. Atualmente, sabe-se que uma das possíveis causas responsáveis por este fato pode estar relacionada pela formação de grandes coágulos de sangue obstruindo a fossa da ovulação, dificultando assim a captação do oócito para o interior da tuba uterina. Desta forma, o objetivo desse estudo foi avaliar o efeito da utilização de dois tipos de anticoagulantes parenterais (heparina não fracionada - HNF e heparina de baixo peso molecular - HBPM) em éguas superovuladas com extrato de pituitária equina (EPE), sobre a posterior taxa de recuperação embrionária. Foram utilizados quatro ciclos estrais de 11 éguas, sendo subdivididos em quatro grupos: Grupo 1 (G1) utilizado como controle; Grupo 2 (G2) receberam 25 mg de EPE intramuscular (IM) a cada 12 horas sendo a primeira e a terceira administração associada a 5 mg de dinoprost-trometamina (IM) e solução fisiológica 0,9% única aplicação 35 horas após indução da ovulação; Grupo 3 (G3) foi utilizado mesmo protocolo superovulatório, sendo substituído a solução fisiológica por um dos anticoagulantes, Heparina Sódica 450 UI/Kg/IV, e Grupo 4 (G4) onde as éguas foram superovuladas pelo mesmo protocolo mencionada acima e receberam 1 mg/Kg/IV de Enoxaparina Sódica. Os animais foram aleatoriamente designados aos quatros grupos em cross-over design, nos quais todos foram submetidos a todos os tratamentos. O intervalo de um ciclo estral para cada égua foi utilizado entre os tratamentos. Os tratamentos foram iniciados no sétimo dia pós-ovulação. A duração do tratamento com EPE não excedeu oito dias, sendo interrompido quando a maioria dos folículos atingissem diâmetro adequado para indução da ovulação. A indução da ovulação foi realizada utilizando 1 ml (250µg) de GnRH (Histrelina Acetato) intramuscular e 2500 UI de hCG (Gonadotrofina Coriônica Humana) intravenoso quando o(s) folículo(s) atingisse um diâmetro médio entre eles de 35 mm em ambos os grupos. A partir da indução da ovulação, 24 horas após as éguas foram inseminadas com sêmen a fresco de um garanhão de fertilidade comprovada. A colheita de embriões foi realizada no nono dia após a primeira ovulação detectada. Para cada animal submetido ao tratamento com anticoagulante foram realizadas avaliações laboratoriais (hemograma e coagulograma). Para isso foram padronizados os seguintes momentos de avaliação; para hemograma as amostras de sangue foram coletadas nos momentos prévio a administração do anticoagulante (T0 hora) servindo como controle, e três horas após a aplicação do anticoagulante (T3 horas), já para o coagulograma as amostras foram coletadas nos momentos T0, T1, T2, T3, T6, T9 e T12 horas após aplicação do anticoagulante. Os resultados demostraram maior (p<0,05) número de ovulações nos grupos de éguas superovuladas (G2 4,6±0,4; G3 5,2±0,5; G4 4,9±0,6) em relação ao G1 (1±0). Já o número de embriões recuperados por égua não diferiu (p>0,05) entre o G1 (0,6±0,2) e G2 (1,6±0,5), no entanto, foi maior para os grupos que receberam anticoagulantes G3 (2,5±0,3) e G4 (2,6±0,6) em relação ao G1. Quando a taxa de recuperação embrionária por folículo ovulado foi avaliado, os resultados demostraram que os grupos tratados com anticoagulantes apresentaram taxas similares (G3 50%; G4 52%) em comparação ao grupo controle (G1 64%), já o grupo superovulado controle (G2 36%) apresentou tendência de redução (P = 0,8) em relação ao G1. Em relação a avaliação laboratorial, os valores hematológicos dos animais em ambos os grupos que receberam anticoagulante (G3 e G4) no momento T3 horas não diferiu (p>0,05) em relação ao momento T0 hora, mantendo-se dentro dos valores de referência. Quanto ao coagulograma, para o G3 os valores de tempo de tromboplastina parcial ativado (TTPA) a partir de uma hora após aplicação (T1 hora) apresentou aumento significativo se manteve até doze horas após aplicação (T12 horas), onde todos os momentos diferiram-se (p<0,05) em relação ao momento (T0 hora), já para o tempo de protrombina (TP) houve um aumento (p<0,05) após aplicação do anticoagulante (T1-T2 horas) em relação ao tempo de avaliação pré aplicação (T0 hora), reduzindo-se gradativamente a partir de três horas até doze horas após aplicação (T3-T12 horas), não diferindo (p>0,05) em relação do T0 hora. Para o G4, uma hora após a aplicação (T1 hora) houve um aumento (p<0,05) da atividade plasmática fator anti-Xa, apresentando um constante declínio até doze horas (T12), não apresentando diferença (p>0,05) apenas neste momento em relação ao T9 horas e T0 hora. Desta forma, pode-se concluir que o protocolo proposto no presente estudo é uma alternativa para melhoria das taxas de recuperação embrionária em éguas superovuladas com EPE, mostrando-se seguro para o uso de ambos os tipos de anticoagulantes sem apresentar alterações hematológicas ou efeitos adversos que possam comprometer ou colocar em risco a condição clínica do animal.

Superovulation is a biotechnic from embryo transfer programs providing several benefits due to the higher number of ovulations per cycle. However, superovulation protocols in the equine species are not yet routinely used, as they present inconsistent results related to the low embryonic recovery rate concerning the number of ovulations, being far below expectations when compared to the bovine species. Currently, one of the possible causes responsible for this fact may be related to the development of large blood clots obstructing the ovulation fossa, making it difficult to capture the oocyte into the fallopian tube. Therefore, this study aimed to evaluate the effect of two types of parenteral anticoagulants (unfractionated heparin - HNF and low molecular weight heparin - LMWH) on equine pituitary extract (EPE) superovulated mares of embryonic recovery. Four estrous cycles of 11 mares were used and subdivided into four groups: Group 1 (G1) as a control; Group 2 (G2) received 25 mg intramuscular EPE (MI) every 12 hours being the first and third administration associated with 5 mg dinoprost-tromethamine (IM) and 0.9% saline only application 35 hours after ovulation induction; Group 3 (G3) in the same superovulation protocol, replacing the physiological solution with one of the anticoagulants, Sodium Heparin 450 IU / kg / IV, and Group 4 (G4) where the mares were superovulated by the same protocol mentioned above and received 1 mg. / Kg / IV of Enoxaparin Sodium. All animals were randomly assigned to the four cross-over design groups, in which all underwent all treatments. The interval of one estrous cycle for each mare was used between treatments. Treatments started on the seventh day after ovulation. EPE treatment did not exceed eight days being interrupted when most follicles reached the appropriate diameter for ovulation induction. Ovulation induction was performed using 1 ml (250µg) of intramuscular GnRH (Histrelin Acetate) and 2500 IU of intravenous hCG (Human Chorionic Gonadotropin) when the follicle (s) reached a mean diameter of 35 mm in both groups. Twenty-four hours afterward ovulation induction the mares were inseminated with fresh semen from a proven fertility stallion. Embryo collection was performed on the ninth day after the first ovulation detected. Each animal at anticoagulant treatment was submitted to laboratory evaluations (blood count and coagulogram). For blood count blood samples were collected before anticoagulant administration (T0 hour) serving as a control, and three hours after applying anticoagulant (T3 hours), while for the coagulogram the samples were collected at T0, T1, T2, T3, T6, T9 and T12 hours after anticoagulant application. Groups of superovulated mares showed higher (p <0.05) number of ovulations (G2 - 4.6 ± 0.4; G3 - 5.2 ± 0.5; G4 - 4.9 ± 0.6) in relation to G1 (1 ± 0). The number of embryos recovered by mare did not differ (p> 0.05) between G1 (0.6 ± 0.2) and G2 (1.6 ± 0.5), however, it was higher for the groups that received anticoagulants G3 (2.5 ± 0.3) and G4 (2.6 ± 0.6) concerning G1. Evaluating the embryo recovery rate by ovulated follicle, anticoagulant-treated groups had similar rates (G3 - 50%; G4 - 52%) compared to the control group (G1 - 64%). Superovulated control (G2 - 36%) showed a tendency to decrease (P = 0.8) concerning G1. Hematological values in both groups receiving anticoagulant (G3 and G4) at T3 hours did not differ (p> 0.05) from T0 hour, remaining the reference values. As for the coagulogram, for G3 the activated partial thromboplastin time (TTPA) values from one hour after application (T1 hour) showed a significant increase until twelve hours after application (T12 hours), where all moments differed (p <0.05) to (T0 hour). Prothrombin time (PT) had an increase (p <0.05) after anticoagulant application (T1-T2 hours) about pre-application evaluation (T0 hour), gradually decreasing from three hours to twelve hours after application (T3-T12 hours), not differing (p> 0.05) from T0 hour. For G4, one hour after application (T1 hour) there was an increase (p <0.05) of anti-Xa factor plasma activity, showing a constant decline up to twelve hours (T12), with no difference (p> 0, 05) only at this moment in relation to T9 hours and T0 hour. The protocol proposed in this study is an alternative for improving embryo recovery rates in EPE superovulated mares, proving safe use of both types of anticoagulants without presenting hematological alterations or adverse effects compromising or endangering the clinical condition of the animal.

Uso da deslorrelina para controle da população folicular durante tratamento superovulatório em ovinos (Ovis aries)

O presente estudo teve por objetivo a utilização do hormônio agonista de GnRH, Deslorelina, para controle da população folicular, com intuito de homogeneizar a onda folicular ao início do tratamento de múltiplas ovulações e transferência de embriões (MOET), reduzindo os efeitos deletérios do folículo dominante no tratamento superovulatório com hormônio folículo estimulante, foltropina de pituitária suína. Foram utilizadas 24 ovelhas deslanadas mestiças da raça santa inês, com idades entre 2 e 4 anos, divididas em dois grupos, Controle (Contr), e Deslorelina (Des). Os experimentos foram conduzidos na propriedade rural denominada Sítio Panorama, no município de Porangaba-SP, situado na latitude -23.15050993 e longitude -48.09904348, estando a uma altitude de 583m. As ovelhas foram monitoradas ultrassonograficamente por um período de sete dias quanto ao dinâmica de crescimento folicular e presença de corpo lúteo. Após determinação da ciclicidade ovariana todas as ovelhas receberam dispositivo intravaginal com 60mg de medroxiprogesterona no dia 0, que foi substituído por um novo dispositivo no dia 7 e que foi mantido até o dia 14, as fêmeas receberam única dose de 125 µg de clopostenol no dia 7. O tratamento superovulatório foi realizado com aplicação de Hormônio Folículo Estimulante Suíno- pFSH, na dose total de 200mg (10 mL), divididas em oito aplicações decrescentes com intervalo de 12h iniciando no decimo segundo dia (40 e 40; 30 e 30; 20 e 20; 10 e 10 mg, respectivamente). No dia 14 foi aplicada 300 UI de eCG. No grupo deslorrelina além do tratamento descrito acima, foram administradas três doses de 100µg deslorrelina, iniciando no dia 3 após inserção do dispositivo vaginal, repetindo a cada 72 horas. Após 36 horas da retirada do implante de progesterona foi realizada a cobertura natural das fêmeas, utilizando machos com fertilidade comprovada por participação em estação de cobertura obtendo 82% de prenhez, além de atestados aptos à reprodução através de exame andrológico prévio. A coleta de embriões realizou-se no sexto dia após as coberturas, e imediatamente antes à coleta de embriões, foi realizada a laparoscopia para avaliação dos ovários e contagem da quantidade de corpos lúteos formados. Após a coleta os embriões foram quantificados e avaliados quanto à qualidade e estádio de desenvolvimento. Imediatamente antes da primeira aplicação de FSH, antes das coberturas, e antes da coleta de embriões foi realizada ultrassonografia por via transretal para avaliação dos ovários, a fim de determinar a população folicular ovariana e a presença de corpos lúteos.

The present study main objective was to use the GnRH agonist hormone deslorelin to control ovarian follicular population, achieving this way a more homogenous follicular wave at the beginning of multiple ovulations and embryo transfer (MOET) program, reducing deleterious effects from dominant follicles over the superovulatory protocol with porcine Follicle Stimulating Hormone (pFSH). Twenty four Santa Inês breed sheep were used, aging from 2 to 4 years, and divided into two groups: control (Contr), and Deslorelin (DES). The experiment was conducted in a private property, located in Brazil, São Paulo, City of Porangaba, latitude -23.15050993 and longitude -48.09904348. All sheep were monitored ultrassonographicaly for seven days, until the presence of a corpus luteum was detected. All sheep received intravaginal sponges containing 60mg of medroxiprogesteron on day 0, and new sponges on day 7 maintained until day 14, among side a single cloprostenol 125 µg dose. Superovulatory treatment was achieved using porcine Follicular Stimulating Hormone -FSH, with the total dose of 200mg (10ml), spread in eight decreasing administrations with 12 hours interval between them, starting on the twelve day. On day 14, 300 UI of equine chorionic gonadotrophin eCG was administrated. On the treated group, in addition to the treatment described above, 3 doses of 100µg of GnRH agonist Deslorelin were administrated with 72 hours intervals, starting at day 4 after sponge insertion (day 3, day 6 and day 9). 36 hours after sponge removal, all sheep were naturally bred with rams of known fertility. Embryo recovery was realized 6 days after sheeps breeding. Immediately before the first FSH administration, before breeding, and before embryo recovery, ovarian ultrasonography was realized to determine population and presence of corpus luteum.