Resumo
Background: Measurement of pregnancy-associated glycoproteins (PAGs) by radioimmunoassay or enzyme-linked immunosorbent assay has been commonly used for early pregnancy diagnosis in ruminants. However, an accurately pregnancy detection depends on test antibody, breed and number of embryos. Only few studies have conducted to detect or predict animals at risk of late embrionic mortality (LEM) and to use hormonal interventions for embryo losses reducing, but this area is still open in sheep. The current study aimed to evaluate the effect of gonadotropin releasing hormone (GnRH) administration on Day 4 after artificial insemination on the pregnancy-associated glycoproteins in dairy sheep with different reproductive status in relation to pregnancy and late embrionic mortality detection. Materials, Methods & Results: Sixty-five East Friesian sheep were divided in 2 groups - I (Control group, n = 35) and II (GnRH group, n = 30) and sublected to estrus synchronization and artificial insemination (AI). Group I was not treated and Group II received 50 µg GnRH on Day 4 after AI. PAGs in blood serum were measured by Alertys Ruminant Pregnancy test on Days 4, 12, 20, 25 and 35 after AI and ultrasound pregnancy test was conducted on Days 20, 25, 35 and 60. Reproductive status (non-pregnant, pregnant and animals with LEM) was determined by ultrasound and the results between different groups were compared. The PAGs mean values according to reproductive status and Day after AI were analysed. Accuracy, sensitivity and specificity of the PAGs test for pregnancy diagnosis on Day 35 were calculated. On Day 20 after AI the pregnat sheep (83.3%) in group I tended to be higher than those (77.1%) in group II with decrease of 25.7% and 20% for the same groups on Day 25. On day 25 LEM was recorded in 33.3% and 24% in group I and II, respectively. The ultrasound exams on Day 60 confirmed the results from Day 25 after AI. A total value of non-pegnant, pregnant animals and LEM was 20%, 56.9% and 28.8%, respectively. The mean values of PAGs in animals with the same reproductive status in group I and II no differed statistically between Days 4 and 35 after AI. On Day 25 the PAGs values in LEM groups (0.126 ± 0.072 and 0.179 ± 0.029) were higher than those (0.062 ± 0.038 and 0.083 ± 0.023) in the non-pregnant groups, but no significan difference was deternined. On Day 35 after AI the mean values of PAGs (0.414 ± 0.125 and 0.421 ± 0.121) for the pregnant groups were significantly (P < 0.05) higher than those (0.078 ± 0.053 and 0.093 ± 0.034) for the non-pregnant groups. The values of PAGs in LEM groups on Day 25 (0.099 ± 0.062 and 0.113 ± 0.058) were decreased and close to the mean values in non-pregnant sheep. A significant effect of the day after AI on the PAGs values was evidenced in pregnant animals only (control r = 0.97 and GnRH r = 0.98; P < 0.05). The PAGs started to rise rapidly between Days 25 and 35 after AI. On Day 35 the accuracy (98%), the sensitivity (97.3%) and the specificity (100%) of the PAG test for pregnancy diagnosis were similar to the values (100%) for ultrasound method. Discussion: The gonadotropin treatment on Day 4 after AI tended to improve the reproductive performance in the sheep, but no significant effect of GnRH on the PAGs values in the animals with different reproductive status was found. The PAGs profiles in non-pregnant and LEM sheep were close and distinguishing between non-pregnant and LEM ewes on Day 35 was impossible. The PAGs values in pregnant sheep showed significantly (P < 0.05) increase between Days 25 and 35 after AI with higher mean values in pregnant than non-pregnant groups on Day 35 (P < 0.05). Alertys Ruminant Pregnancy test was a reliable for pregnancy detection in sheep on Day 35 after artificial insemination.
Assuntos
Animais , Feminino , Radioimunoensaio , Ovinos/fisiologia , Glicoproteínas/análise , Hormônio Liberador de Gonadotropina/administração & dosagem , Desenvolvimento EmbrionárioResumo
The follicular growth waves are directly linked to the fluctuations in plasma gonadotrophins, which are controlled by the hypothalamic GnRH release pattern. Therefore, if the actions of the GnRH are inhibited or blocked, the final stages of the antral follicle growth are suppressed, resulting in an induced anestrus (a.k.a. waveless model). In the human medicine, GnRH agonists or antagonists are broadly used in the control of ovarian disfunctions, as well as in the preparation of women for assisted reproductive cycles. In cattle, a similar effect can be obtained by active immunization against GnRH. This was shown to be a viable strategy, for example, for the control of chronic cases of cystic ovarian disease in oocyte donors. However, on shall take into account the substantial individual variation on the immune response and, consequently, the lack of control of the duration of the anestrus induced. The waveless model is also very useful as a research model, once it controls the potential interference of the endogenous FSH and LH, improving the sensitivity of essays with exogenous hormones and consequently reducing the required number of replicas within studies.(AU)
O padrão de crescimento folicular em ondas está diretamente associado às flutuações nas concentrações plasmáticas de gonadotrofinas, controladas por sua vez pelo padrão de liberação de GnRH hipotalâmico. Desta forma, a inibição ou bloqueio da ação do GnRH suprime as etapas finais do crescimento folicular, resultando em anestro induzido (também chamado modelo waveless). Na medicina humana, agonistas ou antagonistas de GnRH são utilizados tanto no controle de disfunções ovarianas quanto na preparação de pacientes para procedimentos de reprodução assistida. Em bovinos, este efeito pode ser obtido pela imunização ativa contra GnRH, e mostrou-se estratégia viável, por exemplo, no controle de casos crônicos de doença ovariana cística em doadoras de oócitos. Contudo, é importante considerar a grande variação individual na resposta à imunização e consequente impossibilidade de controlar a duração do anestro induzido. O modelo waveless também é de grande utilidade na pesquisa, uma vez que elimina a potencial interferência do FSH e LH endógenos, aumentando a sensibilidade nos ensaios com hormônios exógenos e consequentemente reduzindo o número de réplicas necessárias nos estudos.(AU)
Assuntos
Animais , Bovinos/embriologia , Estruturas Embrionárias/crescimento & desenvolvimento , Fase Folicular , Gonadotropinas/análiseResumo
Vacas de alta produção de leite estão mais sujeitas a desequilíbrios metabólicos pós-parto, influenciando na performance reprodutiva subsequente. Alterações relacionadas a funcionalidade do ovário podem desencadear desequilíbrios hormonais e desordens reprodutivas, como a formação de cistos ovarianos, os quais podem interferir no processo de ovulação e impactar substancialmente na eficiência reprodutiva. Neste estudo de caso em específico, sete vacas leiteiras foram diagnosticadas com a presença de cistos foliculares ovarianos. Foram submetidas a terapia hormonal envolvendo o uso de análogos de Hormônio Liberador de Gonadotrofinas (GnRH) e prostaglandina-F2a (PGF-2a), a qual apresentou resultados satisfatórios. A abordagem terapêutica hormonal tem sido amplamente utilizada devido à sua efetividade na resolução dos cistos ováricos e melhoria da função reprodutiva. É fundamental que o médico veterinário tenha conhecimento clínico sobre a abordagem adequada de cistos ovarianos, a fim de proporcionar saúde e bem-estar aos animais, garantindo bons índices em produção de leite e desempenho reprodutivo.
High milk production cows are more likely to postpartum metabolic imbalances, which may influence subsequent reproductive performance. Changes in ovarian functionality can trigger hormonal alterations and reproductive disorders, such as the formation of ovarian cysts, which can interfere with the ovulation process and substantially impact reproductive efficiency. In this specific case study, seven dairy cows were diagnosed with the presence of ovarian follicular cysts. They were submitted to hormonal therapy involving the use of Gonadotropin-Releasing Hormone (GnRH) and prostaglandin F2a (PGF-2a) analogs, which presented satisfactory results. Hormonal therapeutic approaches have been widely employed due to their effectiveness in resolving ovarian cysts and improving reproductive function. It is essential for the veterinarian to have clinical knowledge about the appropriate management of ovarian cysts in order to provide the health and welfare of the animals, ensuring suitable rates in milk production and reproductive performance.
Las vacas de alta producción de leche tienen mayor probabilidad de desequilibrios metabólicos posparto, lo cual puede influir en el rendimiento reproductivo posterior. Los cambios en la funcionalidad ovárica pueden desencadenar alteraciones hormonales y trastornos reproductivos, como la formación de quistes ováricos, que pueden interferir en el proceso de ovulación y afectar sustancialmente la eficiencia reproductiva. En este estudio de caso específico, se diagnosticó la presencia de quistes foliculares ováricos en siete vacas lecheras. Se sometieron a terapia hormonal que incluyó el uso de análogos de Hormona Liberadora de Gonadotropinas (GnRH) y prostaglandina F2α (PGF-2a), lo cual arrojó resultados satisfactorios. Los enfoques terapéuticos hormonales se han utilizado ampliamente debido a su efectividad en la resolución de quistes ováricos y la mejora de la función reproductiva. Es fundamental que el médico veterinario tenga conocimiento clínico sobre el manejo adecuado de los quistes ováricos para garantizar la salud y el bienestar de los animales, asegurando adecuadas tasas de producción de leche y rendimiento reproductivo.
Assuntos
Animais , Feminino , Bovinos , Cisto Folicular/terapia , Cisto Folicular/veterinária , Dinoprosta/administração & dosagem , Hormônio Liberador de Gonadotropina/administração & dosagem , Doenças do Sistema Endócrino/veterináriaResumo
As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. The development of Fixed-Time Artificial Insemination (FTAI) protocols at the end of the 20th century has increased exponentially the number of animals inseminated over the last 20 years. The main reasons for this growth were the possibility of obtaining acceptable pregnancy rates without heat detection and, above all, the induction of cyclicity in suckled cows in postpartum anestrus and prepubertal heifers at the beginning of the breeding season. Most FTAI treatments in South America have been based on the use of progesterone (P4) releasing devices and estradiol to synchronize both follicular wave emergence and ovulation, with pregnancy rates ranging from 40 to 60%. These protocols are implemented on a regular basis, allowing producers access to high-quality genetics, and increasing the overall pregnancy rates during the breeding season. In addition, it provided the professionals involved in these programs with a new source of income and the diversification of their practices into activities other than their usual clinical work. Many of these practices are now apparently at risk from restrictions on the use of estradiol by the European Union (EU) and other countries. However, the development of alternative protocols based on GnRH, with P4 devices and eCG and other new products that are not in the market yet will allow us to adapt to the new times that are coming. Logically, the challenge has already been raised and we must learn to use alternative protocols to try to continue increasing the use of this technology in beef and dairy herds. The objective of the present review is to describe the main aspects of banning estradiol in livestock production, the negative impacts on reproductive efficiency, and to present some alternative FTAI protocols for dairy and beef cattle.(AU)
Assuntos
Animais , Feminino , Bovinos/embriologia , Inseminação Artificial/tendências , Estradiol/fisiologia , Prenhez/fisiologiaResumo
Este texto discute as estratégias farmacológicas para a manipulação do ciclo estral de fêmeas taurinas de corte, com foco na inseminação artificial em tempo fixo (IATF). Os zebuínos, rebanho predominante no Brasil, apresentam características de ciclo estral diferentes das raças taurinas, o que justifica a busca por estratégias hormonais adaptadas para o controle do ciclo estral nas subespécies. O estradiol combinado com a progesterona (P4) e prostaglandina F2 alfa (PGF) é o esquema hormonal mais comumente utilizado para a manipulação do ciclo estral em protocolos de IATF. Porém, o uso de GnRH combinado ou em substituição aos ésteres de estradiol vem sendo considerado. Coletivamente, os dados do nosso grupo reforçam a necessidade de customizar as abordagens para o controle do ciclo estral de acordo com a composição genética das fêmeas bovinas.(AU)
This text discusses pharmacological strategies to manipulate the estrous cycle of taurine and synthetic females, with a focus on timed artificial insemination (TAI). Zebu cattle, the predominant herd in Brazil, have different estrous cycle characteristics than taurine breeds, requiring different synchronization hormonal strategies for each subspecies. Estradiol combined with progesterone (P4) and prostaglandin F2 alpha (PGF) is the most used hormonal scheme for estrous cycle manipulation in TAI protocols. But the use of GnRH instead of estradiol esters is being considered. Collectively, our group's data reinforce the need to customize approaches to estrous cycle control according to the genetic composition of bovine females.(AU)
Assuntos
Animais , Feminino , Ovulação/fisiologia , Ações Farmacológicas , Ciclo Estral/efeitos dos fármacos , Progesterona , Inseminação Artificial/métodosResumo
Animals that exhibited estrus had greater pregnancy success compared to animals that did not exhibit estrus before fixed-time AI (FTAI). Estradiol is synthesized in bovine ovarian follicles under gonadotropin regulation and can directly and indirectly regulate the uterine receptivity and luteal function. Estradiol concentrations at FTAI impacted oviductal gene expression and has been reported to play an important role in establishing the timing of uterine receptivity. These changes have been reported to impact uterine pH and sperm transport to the site of fertilization. After fertilization, preovulatory estradiol has been reported to improve embryo survival likely by mediating changes in uterine blood flow, endometrial thickness and changes in histotroph. Cows with greater estradiol concentrations at the time of GnRH-induced ovulation also had a larger dominant follicle size and greater circulating progesterone concentrations on day 7. Therefore, it is impossible to accurately determine the individual benefit of greater estradiol concentrations prior to ovulation and greater progesterone concentrations following ovulation to pregnancy establishment, as these two measurements are confounded. Research has indicated an importance in the occurrence and timing of increasing preovulatory concentrations of estradiol, but increasing estradiol concentrations by supplementation may not be sufficient to increase fertility. Increased production of estradiol by the preovulatory follicle may be required to enhance fertility through the regulation of sperm transport, fertilization, oviductal secretions, the uterine environment, and embryo survival.(AU)
Assuntos
Animais , Feminino , Gravidez , Bovinos/embriologia , Estradiol/efeitos adversos , Folículo Ovariano/química , Útero/química , Corpo Lúteo/química , Fase FolicularResumo
There is still no consensus regarding the best protocol for in vivo embryo production in sheep despite increasing studies in this area. Moreover, there is variability in the response of ewes to superovulation (SOV). An approach to mitigate this inconsistency is to initiate gonadotropin administration under favorable ovarian conditions. The present study compared three treatments in a crossover design: a traditional SOV protocol (TRAD) and "Day 0" D0 SOV protocol with (D0+GnRH), or without Lecilerin (D0-GnRH). Fifteen Santa Inês ewes received 200 mg of FSH at six decreasing doses and PGF2α with the fifth dose of FSH. They were naturally mated with fertile rams and subjected to surgical embryo collection. The number of viable embryos was similar among the different treatments (TRAD = 6.0 ± 4.7; D0-GnRH = 3.8 ± 6.4; D0+GnRH = 7.5 ± 6.5). Regardless of the treatment method, ewes with follicles ≤ 4 mm, at the first FSH dose, produced more viable embryos (9.6 ± 6.0, P < 0.05) compared to ewes that had follicles > 4 mm at the beginning of the SOV (2.9 ± 3.1, viable embryos). Both the TRAD and D0+GnRH groups had fewer animals with large follicles (> 4 mm) at the first FSH dose than the D0-GnRH group (P < 0.05). In conclusion, both the TRAD and D0+GnRH treatments induced a more favorable ovarian condition (follicles ≤ 4 mm) for adequate SOV; although, all three treatments exhibited similar efficacies in Santa Inês sheep.
Ainda não há consenso sobre qual é o protocolo mais apropriado para a produção in vivo de embriões em ovinos, apesar do crescente conhecimento. Uma abordagem para mitigar a variabilidade de resposta de ovelhas à superovulação (SOV) é iniciar a aplicação de gonadotrofinas em uma condição ovariana favorável. O presente estudo comparou três tratamentos em delineamento do tipo crossover: protocolo de SOV tradicional (TRAD) e "Dia 0" D0 SOV sem (D0-GnRH) ou com GnRH (D0+GnRH). Quinze ovelhas Santa Inês foram superovuladas com 200 mg de FSH em seis doses decrescentes e receberam PGF2α na quinta dose de FSH. As ovelhas foram submetidas a monta natural com carneiros férteis e os embriões colhidos por via cirúrgica. O número de embriões viáveis não diferiu entre os tratamentos (TRAD = 6,0 ± 4,7; D0-GnRH = 3,8 ± 6,4; D0+GnRH = 7,5 ± 6,5). Independentemente do tratamento, ovelhas com folículos ≤ 4 mm na primeira dose de FSH produziram mais embriões viáveis (9,6 ± 6,0; P < 0.05) quando comparadas aos animais que apresentavam folículos > 4 mm no início da SOV (2,9 ± 3,1 embriões viáveis). Os grupos TRAD e D0+GnRH apresentaram menor número de animais com folículos grandes (> 4 mm), no momento da primeira dose de FSH, quando comparados ao grupo D0-GnRH (P < 0,05). Em conclusão, os protocolos TRAD e D0+GnRH induziram uma condição ovariana mais favorável (folículos ≤ 4 mm) para a SOV. No entanto, os três tratamentos apresentaram eficiência semelhante em ovelhas Santa Inês.
Assuntos
Animais , Feminino , Superovulação , Ovinos/embriologia , Hormônio Liberador de GonadotropinaResumo
A superpopulação de felinos e caninos é um problema global que ainda não encontrou uma solução definitiva. Existem várias estratégias que procuram encontrar uma resposta para este problema. Atualmente, a castração cirúrgica é o único método de controle permanente da reprodução. No entanto, existem vários relatos sobre o uso de anticoncepcionais não cirúrgicos para cães e gatos para controle da reprodução a longo prazo. Os análogos de GnRH suprimem a reprodução por muito tempo e seu efeito é reversível, podendo ser usados nos casos em que a castração cirúrgica não pode ser realizada ou até que possa ser realizada. A deslorelina é um agonista de GnRH desenvolvido como implante subcutâneo para uso em cães, embora também tenha sido usado em gatos e espécies não domésticas. O objetivo deste relato foi resumir o conhecimento atual sobre o agonista de GnRH deslorelina como um contraceptivo não cirúrgico para cães e gatos.(AU)
La sobrepoblación felina y canina es un problema mundial que aún no ha encontrado una solución definitiva. Existen diversas estrategias, que buscan encontrar una respuesta a esta problemática. Actualmente, la castración quirúrgica es el único método de control permanente de la reproducción. Sin embargo, existen múltiples reportes sobre la utilización de contraceptivos no quirúrgicos para perros y gatos para el control a largo plazo de la reproducción. Los análogos de GnRH, suprimen la reproducción en forma prolongada y su efecto es reversible, por lo que pueden ser utilizados en casos donde la castración quirúrgica no pueda ser realizada o hasta que la misma pueda llevarse a cabo. La deslorelina, es un agonista de GnRH desarrollado en forma de implante subcutáneo para su utilización en perros, aunque ha sido utilizada también en gatos y en especies no domésticas. El objetivo de este reporte fue resumir el conocimiento actual acerca del agonista de GnRH deslorelina como contraceptivo no quirúrgico para perros y gatos.(AU)
Assuntos
Animais , Gatos , Cães , Hormônio Liberador de Gonadotropina/administração & dosagem , Hormônio Liberador de Gonadotropina/análogos & derivados , Controle da População , Anticoncepcionais/efeitos adversosResumo
The ovulation mechanism is one of the fascinating physiological processes in reproductive biology in mammals. From the reproductive point of view, the species have been classified as spontaneous or induced ovulators. Although the release of GnRH followed by the preovulatory LH surge is shared between both types of ovulation, the stimulus to initiate GnRH release varies between both categories. In spontaneous ovulators, ovulation depends on the systemic concentration of ovarian steroids, however, in induced ovulators, different stimuli such as copulation, environmental, and social cues can facilitate or induce ovulation regardless of the increases in systemic estradiol concentration. In this review, we document evidence that a male-derived protein is the main factor responsible for inducing ovulation and also modulating the ovarian function in the domestic South American camelid, the llama. The neurotrophin beta-Nerve Growth Factor (β-NGF) is the principal factor present in the semen of llamas responsible for inducing ovulation in this species. After the intrauterine deposit of semen during mating, β-NGF is absorbed through the endometrium to reach the circulatory system, where it reaches the hypothalamus and stimulates GnRH release. The potential site of action of this neurotrophin at the brain has not been elucidated, however, hypotheses are raised that the factor may cross the blood-brain barrier and stimulate upstream neuronal networks that lead to the stimulation of GnRH-secreting neurons. It is possible that β-NGF could be sensed at the median eminence without crossing the blood-brain barrier. Finally, it has been observed that this factor is not only a powerful stimulator of ovulation but also has a luteotrophic effect, resulting in the development of a corpus luteum capable of secreting more progesterone when compared to other ovulation-stimulating analogues.(AU)
Assuntos
Animais , Feminino , Ovulação/fisiologia , Camelídeos Americanos/fisiologia , Fenômenos Reprodutivos Fisiológicos , Hormônio Liberador de Gonadotropina/análiseResumo
Estradiol cypionate (EC) or GnRH have been widely used for ovulation induction in timed embryo transfer (TET). EC administration increases the proportion of cows that show estrus, whereas GnRH promotes more synchronized ovulations. The aim of the present study was to evaluate the potential beneficial effects of combining EC and GnRH in TET. In experiment 1, no difference was observed on serum progesterone concentrations on Day 6 and 13 after GnRH treatment between GnRH and EC+GnRH groups. In experiment 2, pregnancy per embryo transfer (P/ET) did not differ (p = 0.69) between GnRH (62.8%) and EC+GnRH (58.7%) groups. In conclusion, combining EC and GnRH for ovulation induction does not increase progesterone secretion and pregnancy rate after TET in cattle.(AU)
Assuntos
Animais , Feminino , Gravidez , Indução da Ovulação/veterinária , Hormônio Liberador de Gonadotropina/análogos & derivados , Estradiol/análogos & derivados , Transferência Embrionária/instrumentaçãoResumo
O procedimento de imunocastração vem sendo utilizado como técnica alternativa amplamente favorável ao bem-estar animal, por ser indolor, pouco invasiva e com eficácia semelhante à da castração cirúrgica, que causa maior estresse aos animais, principalmente quando realizada de forma inadequada. A imunocastração estimula a produção de anticorpos contra o Hormônio Liberador de Gonadotrofina (GnRH), bloqueando temporariamente a produção da testosterona pelas gônadas masculinas. Face a escassez de informações sobre este procedimento em touros bubalinos, o estudo teve como objetivo analisar os possíveis efeitos da imunocastração no parênquima testicular de búfalos. Vinte touros bubalinos, com idade entre 2 a 3 anos, oriundos da ilha do Marajó PA, foram avaliados e divididos aleatoriamente em dois grupos composto por dez animais no grupo controle (GC) e dez do grupo imunocastrado (GIM). O produto utilizado foi a vacina anti-GnRH Bopriva ® (Zoetis, SP, Brasil). O GIM recebeu duas doses de 1,0ml contendo 400µg da vacina Bopriva ® com intervalo de 8 semanas entre as aplicações e o grupo controle recebeu 1,0 ml de solução fisiológica. Após 14 dias da última dose, os animais foram abatidos e coletado os 20 pares de testículos para analises de parâmetros macroscópicos como: comprimento, largura, circunferência e peso. Além disso, foi realizada a retirada de fragmentos do parênquima testicular para confecção de lâminas histológicas. Para comparação dos dados foi aplicado o teste t de Student (Nonparametric Test) considerando a significância com p<0,05 e intervalo de confiança de 95%. Foi observado diferença significativa entre os dois grupos para grupos para peso (direto p<0001; esquerdo p≤ 0,0001), circunferência (direita p< <0,0001), 1; esquerda p<0,0001), ), largura (somente lado direito p<0,0372) e comprimento (direita p≤ 0,0013; esquerda p<0,0437). Na avaliação microscópica, os animais do GC não apresenteram alterações. Nos animais do GIM houve degeneração em todas as amostras, sendo visualizado descamação, tortuosidade e espessamento da membrana basal do túbulo seminífero, assim como vacuolização e atrofia das células de Sertoli. Foi observado também uma redução do número de células de Leydig, fibrose intertubular pronunciada, núcleos picnóticos, azoospermia e células multinucleadas no interior dos túbulos. Conclui-se a vacina anti-GnRH mostrou-se eficaz em provocar lesões no parênquima testicular, comprometendo significativamente a espermatogênese a partir da possível supressão de testosterona.(AU)
The immunocastration procedure has been used as an alternative technique widely favorable to animal welfare, as it is painless, minimally invasive and with similar efficacy to surgical castration, which causes greater stress to animals, especially when performed improperly. Immunocastration stimulates the production of antibodies against Gonadotropin Releasing Hormone (GnRH), temporarily blocking the production of testosterone by the male gonads. Due to the scarcity of information about this procedure in buffalo bulls, the study aimed to analyze the possible effects of immunocastration on the testicular parenchyma of buffaloes. Twenty buffalo bulls, aged between 2 and 3 years, from the island of Marajó - PA, were evaluated and randomly divided into two groups consisting of ten animals in the control group (CG) and ten from the immunocastrated group (GIM). The product used was the anti-GnRH vaccine Bopriva ® (Zoetis, SP, Brazil). The GIM received two doses of 1.0ml containing 400µg of Bopriva ® vaccine with an interval of 8 weeks between applications and the control group received 1.0 ml of saline solution. After 14 days of the last dose, the animals were slaughtered and the 20 pairs of testes were collected for analysis of macroscopic parameters such as: length, width, circumference and weight. In addition, fragments of the testicular parenchyma were removed for the preparation of histological slides. To compare the data, Student's t test (Nonparametric Test) was applied, considering the significance with p< 0.0372) and length (right p≤ 0.0013; left p<0.0437). In the microscopic evaluation, the animals of the CG showed no alterations. In the GIM animals there was degeneration in all samples, with desquamation, tortuosity and thickening of the seminiferous tubule basement membrane, as well as vacuolization and atrophy of Sertoli cells. A reduction in the number of Leydig cells, pronounced intertubular fibrosis, pyknotic nuclei, azoospermia and multinucleated cells within the tubules were also observed. In conclusion, the anti-GnRH vaccine proved to be effective in causing lesions in the testicular parenchyma, significantly compromising spermatogenesis from the possible suppression of testosterone.(AU)
Assuntos
Animais , Masculino , Búfalos/fisiologia , Castração/veterinária , Receptores LHRH/imunologia , Epitélio Seminífero/imunologia , Bem-Estar do AnimalResumo
This study evaluated (a) the efficacy of an association between injectable antibiotic therapy and sealant (ATBS) on milk yield (MY), somatic cell count (SCC), and prevalence of intramammary infections (IMI); and (b) the efficacy of gonadotropin-releasing hormone (GnRH) on follicular cyst (FCs) resolution (cyclicity at the 45th day in milk; DIM) and cumulative pregnancy rate (CPR) in heifers submitted to a lactation induction protocol (LIP). A total of 114 crossbred (Holstein × Jersey) heifers, with 34.7 ± 4.8 months and 439 ± 56.35 kg were submitted to LIP. On the 5th day of the LIP, the heifers were assigned to (i) ATBS (n = 57) with 7 mg/kg of norfloxacin associated with sealant and (ii) Control 1 (n = 57; CONT1) with no treatments. Lactation began on the 21st day of LIP and the 15th DIM, FCs were diagnosed and 106 heifers were randomized into two treatment groups with 53 heifers each: (i) GnRH (5 mL injectable GnRH) and (ii) Control 2 (CONT2; no treatment). Of the 114 heifers initially induced, 83.33% (n = 95) responded to LIP with an average MY of 15.19 kg/milk/day during 22 weeks of lactation. In the first 14 DIM, the IMI prevalence was 18% and 28% for heifers ATBS and CONT1 treated, respectively. Additionally, coagulase-negative Staphylococcus was the most frequently isolated group of pathogens. Mammary quarters that received ATBS treatment had a lower risk of IMI and SCC than CONT1. The cyclicity at 45 DIM was 68% (ATBS) and 35% (CONT1), and 57% and 46% for animals in the GnRH and CONT2. CPR was 60% in the ATBS group and 89% in CONT1, but GnRH treatment did not affect the CPR. In conclusion, LIP was effective in stimulating MY in heifers, and the IMI prevalence decreased with ATBS treatment. Also, the use of GnRH did not affect the FC regression, cyclicity at 45 DIM, and CPR.(AU)
Este estudo avaliou a (i) eficácia da associação entre antibioticoterapia injetável e selante interno de tetos (ATBS) na produção de leite (PL), contagem de células somáticas (CCS), e prevalência de infecções intramamárias (IIM); e (ii) eficácia do hormônio liberador de gonadotrofina (GnRH) na resolução de cistos foliculares (CFs), ciclicidade ao 45º dia em lactação (DEL) e taxa de prenhez cumulativa (TPC) em novilhas submetidas a um protocolo de indução de lactação (PIL). Um total de 114 novilhas mestiças (Holandês × Jersey), com 34,7 ± 4,8 meses e 439 ± 56,35 kg foram submetidas ao PIL. No 5º dia do PIL, as novilhas receberam: (i) ATBS (n = 57) com 7 mg/kg de norfloxacina associada ao selante interno de tetos e (ii) Controle 1 (n = 57; CONT1) sem tratamento. A lactação teve início no 21º dia do PIL e no 15º DEL, foram diagnosticados CFs e 106 novilhas foram agrupadas em dois grupos de tratamento com 53 novilhas em cada: (i) GnRH (5 mL de GnRH injetável) e (ii) Controle 2 (CONT2; sem tratamento). Das 114 novilhas inicialmente induzidas, 83,33% (n = 95) responderam ao PIL com PL média de 15,19 kg/leite/d durante 22 semanas de lactação. Nos primeiros 14 DEL a prevalência de IIM foi de 18% e 28% para as novilhas tratadas com ATBS e CONT1, respectivamente. Além disso, estafilococos coagulase negativa foram o grupo de patógenos mais frequentemente isolados. Quartos mamários tratados com ATBS tiveram menor risco (0,56) de IIM e menor CCS do que CONT1. A ciclicidade a 45 DEL foi de 68% (ATBS) e 35% (CONT1), e 57% e 46% para os animais no GnRH e CONT2. A TPC foi de 60% no grupo ATBS e 89% no CONT1, porém o tratamento com GnRH não afetou a TPC. Em conclusão, o PIL foi eficaz em estimular a PL em novilhas tardias e a prevalência de IIM diminiuiu com o tratamento ATBS. Além disso, o uso de GnRH não afetou a regressão de CF, ciclicidade em 45 DEL e a TPC.(AU)
Assuntos
Animais , Masculino , Gravidez , Lactação/fisiologia , Hormônio Liberador de Gonadotropina/farmacologia , Mastite Bovina/epidemiologia , Anti-Infecciosos/uso terapêutico , Cisto Folicular/diagnóstico , Bovinos/fisiologia , Norfloxacino/administração & dosagem , Contagem de Células/veterinária , Leite/fisiologiaResumo
- This study compared the social and feeding behaviour of immunocastrated female pigs using different immunocastration protocols. We used seventy-two gilts from industrial crossbreeding (Agroceres × Topigs) at 15 weeks of age. The pigs were distributed in a randomised design with three treatments. The second dose of the immunocastration vaccine was applied in two groups, six weeks before slaughter (I6) and four weeks before slaughter (I4). A non-immunised group (NI) was used for comparison. Due to the divergence in the time of immunisation between the two groups, an individual comparison of each immunocastrated group with the control group (NI vs. I6 and NI vs. I4) was performed. Social behaviour was analysed through the collection of images by a monitoring camera, and the analysis period was from 6:00 to 18:00 h, with behaviour observed every ten minutes. Feeding behaviour data were collected by the automated FIRE® system. Anti-GnRH immunisation and the different protocols of application did not influence most social and feeding behaviours.(AU)
Assuntos
Animais , Feminino , Suínos/fisiologia , Comportamento Animal/fisiologia , Comportamento Alimentar/fisiologiaResumo
This study aimed to evaluate the efficiency of immunocastration in lambs using testicular morphometry. Thirty lambs were randomly divided into two treatments (subcutaneous administration of 1.0 mL and 0.5 mL of an anti-GnRH vaccine) and a control group (1.0 mL saline solution). The animals were vaccinated at four months of age, received a second dose 30 days later, and were slaughtered 90 days after the first vaccine dose. After slaughter, testicles were collected, and samples were removed for histological processing and evaluation of testicular morphometric parameters. Analysis of variance, Tukey's test, and Kruskal-Wallis test were performed, with a 5% level of significance. There was a reduction in testicular weight, gonadosomatic index, seminiferous tubule diameter, germinal epithelium height, leydigosomatic index, and total tubule length. The total length per testicular gram increased in the immunocastrated group. Intrinsic spermatogenesis yield, Sertoli cell indices, and estimates of sperm and Sertoli cell production were reduced in the immunized groups (P < 0.05). The anti-GnRH vaccine in lambs at doses of 1.0 mL and 0.5 mL is sufficient to promote immunocastration, verified through severe changes in testicular morphometry from animals.(AU)
Assuntos
Testículo/cirurgia , Ovinos , Orquiectomia/instrumentação , Análise do Sêmen/veterinária , Gonadotropinas/imunologia , Análise Multivariada , Análise de Variância , Estatísticas não ParamétricasResumo
Background: The intensive reproductive management in the dairy farms requires inclusion of a large group of replacement heifers in the breeding program for a shorter period. In this aspect, a creation of effective estrus synchronization protocols with timed artificial insemination (TAI) by sexed semen and optimization of the current ones have a crucial role for obtaining high pregnancy rate. These protocols are beneficial, because they led to reduced interval to first AI, lack of need for estrus detection, and allow obtaining a large group of female calves for on time. Because of limited fertilizing potential of sexed spermatozoa this type of semen is applied mainly for heifers, as fertility is higher compared to lactating cows. The main objective of the present study was to investigate the effect of ovarian status on the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Materials, Methods & Results: Forty-eight Holstein healthy heifers separated in 2 groups were subjected to PGF2α-GnRH pre-treatment and Ovsynch or PRID-5-day estrus synchronization protocol and timed artificial insemination (TAI) with sex-sorted semen, staring 6 days after end of the hormonal pre-treatment. The ovarian status (presence of follicles with or not a corpus luteum) of the heifers at the begin of the treatment, on day of TAI and pregnancy rate in different groups were determined and compared. Additionally, the ovarian status at the begin of the treatment, ovarian status and size of preovulatory follicle (PF) on day of TAI and total values for both groups according to reproductive performance (pregnant or non-pregnant) were also analyzed. On day of TAI the animals with PF and a lack of corpus luteum (CL) in both groups were more that those with PF and CL (39.3% and 30% vs. 60.7 % and 70%), with significant (P < 0.05) difference in PRID-5-day group. The pregnancy rate tended to be higher in PRID-5 day than Ovsynch treatment (65% vs. 35.7%). A higher percentage (100% and 67.9%) of the pregnant animals in both treatments had not CL on day of TAI, and the size of the PF (1.58 ± 0.12 cm and 1.64 ± 0.13 cm) was increased (P < 0.05). Similar effects of the ovarian status on reproductive performance were obtained after a comparison of the total values between pregnant and non-pregnant animals. The percentage of heifers with observed PF without CL on day of TAI was significantly greater (P < 0.05) in pregnant compared to non-pregnant group (91.3% vs. 40%). The opposite dependence was determined for the parameter presence of follicles and corpus luteum (8.7% vs. 60%; P < 0.05). Furthermore, the size of the PF measured immediately before TAI was increased in animals became pregnant (1.60 ± 0.12 cm vs. 1.34 ± 0.17 cm; P < 0.05). Discussion: The analysis of the obtained results showed that the ovarian status on day of TAI affects the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Hormonal pre-treatment with onset of PRID-5-day protocol 6 days later and TAI with sex-sorted semen ensure acceptable pregnancy rate. The greater preovulatory follicle and a lack of corpus luteum before insemination provide significantly (P < 0.05) more pregnant animals, compared to the cases when CL is presented. Ultrasound determination of the ovarian function before insemination can be used in selection of heifers for TAI with sex-sorted semen.
Assuntos
Animais , Feminino , Gravidez , Bovinos , Sêmen , Corpo Lúteo , Sincronização do Estro/métodos , Folículo Ovariano , Inseminação Artificial/veterináriaResumo
Although studies have shown positive effects of gonadotropin releasing hormone (GnRH) or prostaglandin F2α (PGF2α) at the moment of fixed-time artificial insemination (FTAI) in the conception rate (CR) of cattle, its effects on treatments based on progesterone (P4) and estradiol benzoate (EB) is still not conclusive. The objective of this study was (1) to evaluate the effect of a PGF2α analogue at FTAI in the CR of crossbred beef cows submitted to a 11d FTAI protocol based on P4 and EB; and (2) to describe the CR between PGF2α-treated and control cows in different body condition scores (BCS) and parity categories. Crossbred (½ Nellore and ½ Angus) beef cows were submitted to a synchronization protocol and randomly assigned into 2 groups: Control (n = 163), at FTAI cows received 2 mL of saline solution as a placebo, and PGF2α (n = 163), at FTAI cows were treated with PGF2α analogue (10 mg of dinoprost tromethamine). Pregnancy diagnosis was performed 33d post-FTAI. Binary logistic regression model was used to analyze the effect of PGF2α treatment on CR. There was no difference in CR between PGF2α and control groups (P > 0.05; odds ratio (OR) = 0.92; confidence interval (CI) = 0.59-1.4). A greater CR was found in heifers (P = 0.0006, OR = 2.65, CI = 1.61 - 4.38) and multiparous (P = 0.0006, OR = 2.12, CI = 1.04 - 4.3) when compared to primiparous cows. Cows with low BCS (4; 9-point scale) showed lower CR when compared with moderate BCS (5-6; 9-point scale) (P < 0.05; OR = 0.10; CI = 0.06 - 0.18). There was no numerical difference on CR between PGF2α-treated and control cows in different BCS and parity categories. The results suggested that the CR in this study was not influenced by 10 mg PGF2α analogue at FTAI.(AU)
Assuntos
Animais , Feminino , Bovinos/fisiologia , Inseminação Artificial/veterinária , Dinoprosta/uso terapêutico , Modelos LogísticosResumo
Abstract The aim of this study was to use estrus synchronization protocols to favor fixed-time artificial insemination and consequently fixed-time embryo collection, and increase embryo production using eCG, in gits. In a cross over design, nine Piau breed gilts were subjected to 18 days of oral progesterone; P4 group did not receive any further; GnRH group received 25µg of GnRH 104 hours after the final application of P4; and eCG+GnRH group received 1000IU of eCG 24 hours after the final P4 in addition to GnRH for subsequent embryo collection, that was performed six days after first AI, by laparotomy. Artificial insemination was performed after 12 and 24 hours of estrus in P4 group, and 128 and 144 hours in GnRH and eCG+GnRH groups. The number of CL (8.6±3.9; 8.3±2.1; 26.7±15.0) and anovulatory follicles (4.3±3.7; 3.9±3.9; 17.2±9.5) was higher in the eCG+GnRH gilts (P<0.05). However, the use of 1000 IU of eCG reduced (P<0.05) the number of total structures (5.2±3.6; 5.1±3.1; 1.7±2.7), viable embryos (5.0±3.5; 4.8±3.3; 0.4±0.7), freezable embryos (3.6±3.4; 3.3±3.8; 0.1±0.3) and recovery rate (63.7±38.9; 58.6±24.7; 5.38±9.5). P4 and GnRH protocols were effective in the production and recovery of embryos. However, the use of 1000 IU of eCG, 24 hours after P4, was not effective in promoting the production of embryos, although the animals had superovulated.
Resumo
Abstract Within the hypothalamic-pituitary-gonad (HPG) axis, the major hierarchical component is gonadotropin-releasing hormone (GnRH) neurons, which directly or indirectly receive regulatory inputs from a wide array of regulatory signals and pathways, involving numerous circulating hormones, neuropeptides, and neurotransmitters, and which operate as a final output for the brain control of reproduction. In recent years, there has been an increasing interest in neuropeptides that have the potential to stimulate or inhibit GnRH in the hypothalamus of pigs. Among them, Kisspeptin is a key component in the precise regulation of GnRH neuron secretion activity. Besides, other neuropeptides, including neurokinin B (NKB), neuromedin B (NMB), neuromedin S (NMS), α-melanocyte-stimulating hormone (α-MSH), Phoenixin (PNX), show potential for having a stimulating effect on GnRH neurons. On the contrary, RFamide-related peptide-3 (RFRP-3), endogenous opioid peptides (EOP), neuropeptide Y (NPY), and Galanin (GAL) may play an inhibitory role in the regulation of porcine reproductive nerves and may directly or indirectly regulate GnRH neurons. By combining data from suitable model species and pigs, we aim to provide a comprehensive summary of our current understanding of the neuropeptides acting on GnRH neurons, with a particular focus on their central regulatory pathways and underlying molecular basis.
Resumo
Abstract The objective of this study was to evaluate the testicular biometric, seminal, and plasma testosterone levels in lambs subjected to an anti-GnRH vaccine as a method of castration. Thirty entire, crossbred Santa Inês male lambs were randomly distributed into three treatment (T): T1 was the control group, with the administration of 1 mL of saline solution subcutaneously (SC); 1.0 and 0.5 mL of an anti-GnRH vaccine were administered SC in T2 and T3, respectively. Testicular biometric variables, physical and morphological variables of semen, and plasma testosterone concentrations were evaluated. At D60, there was a reduction in testicular length, width, thickness, and scrotal circumference of the immunocastrated animals regardless of the vaccine dose used (P < 0.05). A reduction in semen physical variables at both dosages (P < 0.05) was observed, with azoospermia, in 80% and 70% of animals in the T2 and T3 groups, respectively. At D60, the immunocastrated animals also showed an increase in spermatozoa defects (P < 0.05), whereas plasma testosterone concentration decreased (P < 0.05). Immunocastration of lambs using the Bopriva vaccine at doses of 1.0 and 0.5 mL is efficient in inducing azoospermia in up to 80% of animals, although two doses in a 30-day interval are necessary for it to be an effective and safe method. Efficacy was demonstrated through a reduction in serum testosterone levels, testicular biometry, and seminal fluid analysis. Considering the efficacy of both doses in this study, we recommend using the lower dose (0.5 mL), which will allow for a 50% reduction in vaccine costs.
Resumo
We evaluated the effects of nulliparous, primiparous, and multiparous conditions on the estrus and pregnancy rates in females that did not show estrus but were treated with gonadotropin-releasing hormone (GnRH) at the time of timed artificial insemination (TAI). Nelore females (n = 531) were allocated according to the following categories: nulliparous (n = 144), primiparous (n = 132), and multiparous (n = 255). The animals received a conventional TAI protocol, and estrus expression was identified by the absence of paint in the sacrococcygeal region on the day of TAI. Females that did not show estrus were treated with 10 µg of GnRH together with insemination. The rates of estrus and pregnancy were analyzed using a logistic regression model (P < 0.05). The estrus expression was lower (P = 0.006) in the primiparous (61.36%) group than in the nulliparous (76.39%) and multiparous (75.69%) groups. Similar pregnancy rates were observed in females that showed estrus (nulliparous 84.54%, primiparous 86.42%, and multiparous 80.31%; P = 0.39) and in females that did not show estrus and received GnRH (nulliparous 41.18%, primiparous 56.86%, and multiparous 58.06%; P = 0.24). The total pregnancy rates were also similar (P = 0.98) among the categories (nulliparous 74.3%, primiparous 75.0%, and multiparous 74.9%). The primiparous females had a lower rate of estrus, and the pregnancy rates were similar among the categories that received GnRH.(AU)
O objetivo do trabalho foi avaliar o efeito das categorias nulíparas, primíparas e multíparas sobre a taxa de manifestação de estro e a taxa de prenhez de fêmeas que não manifestaram estro, mas foram tratadas com GnRH no momento da inseminação artificial em tempo-fixo (IATF). Foram utilizadas 531 matrizes, todas da raça Nelore, alocadas de acordo com a categoria: nulíparas (n = 144), primíparas (n = 132) e multíparas (n = 255). As matrizes foram submetidas a um protocolo reprodutivo para inseminação artificial em tempofixo (IATF) e tiveram a expressão do estro identificada pela ausência de tinta na região sacrococcígea no dia da inseminação. As fêmeas que não apresentaram estro receberam 10 µg de GnRH no momento que foram inseminadas. As taxas de estro e prenhez foram analisadas por meio de um modelo de regressão logística (P < 0,05). A expressão do estro foi menor (P = 0,006) no grupo de primíparas (61,36%) do que nos grupos de nulíparas (76,39%) e multíparas (75,69%). Taxas de prenhez semelhantes foram observadas em fêmeas que apresentaram estro (nulíparas 84,54%, primíparas 86,42% e multíparas 80,31%; P = 0,39) e em fêmeas que não apresentaram estro e receberam GnRH (nulíparas 41,18%, primíparas 56,86% e multíparas 58,06%; P = 0,24). As taxas de prenhez total também foram semelhantes (P = 0,98) entre as categorias (nulíparas 74,3%, primíparas 75,0% e multíparas 74,9%). As fêmeas primíparas apresentaram menor taxa de estro e as taxas de prenhez foram semelhantes entre as categorias que receberam GnRH.(AU)