Abordagem terapêutica hormonal para cistos foliculares ovarianos em vacas leiteiras - relato de casos / Hormonal therapeutic approach for ovarian follicular cysts in dairy cattle - case reports / Enfoque terapéutico hormonal para quistes foliculares ováricos en vacas lecheras - informe de casos

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.

Effect of GnRH administration on pregnancy-associated glycoproteins in dairy sheep with different reproductive status

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.

Use of new recombinant proteins for ovarian stimulation in ruminants

Currently, gonadotropin products (follicle stimulating hormone, FSH, and luteinizing hormone, LH) used in animal reproduction are produced by extraction and purification from abattoir-derived pituitary glands. This method, relying on animal-derived materials, carries the potential risk of hormone contamination and pathogen transmission. Additionally, chorionic gonadotropins are extracted from the blood of pregnant mares (equine chorionic gonadotropin; eCG) or the urine of pregnant women (human chorionic gonadotropin; hCG). However, recent advancements have introduced recombinant gonadotropins for assisted animal reproduction therapies. The traditional use of FSH for superovulation has limitations, including labor requirements and variability in superovulation response, affecting the success of in vivo (SOV) and in vitro (OPU/IVEP) embryo production. FSH treatment for superstimulation before OPU can promote the growth of a homogenous follicular population and the recovery of competent oocytes suitable for IVEP procedures. At present, a single injection of a preparation of long-acting bovine recombinant FSH (rFSH) produced similar superovulation responses resulting in the production of good-quality in vivo and in vitro embryos. Furthermore, the treatment with eCG at FTAI protocol has demonstrated its efficacy in promoting follicular growth, ovulation, and P/AI, mainly in heifers and anestrous cows. Currently, treatment with recombinant glycoproteins with eCG-like activity (r-eCG) have shown promising results in increasing follicular growth, ovulation, and P/AI in cows submitted to P4/E2 -based protocols. Bovine somatotropin (bST) is a naturally occurring hormone found in cows. Recombinant bovine somatotropin (rbST), produced through genetic engineering techniques, has shown potential in enhancing reproductive outcomes in ruminants. Treatment with rbST has been found to improve P/IA, increase donor embryo production, and enhance P/ET in recipients. The use of recombinant hormones allows to produce non-animal-derived products, offering several advantages in assisted reproductive technologies for ruminants. This advancement opens up new possibilities for improving reproductive efficiency and success rates in the field of animal reproduction.(AU)

Effect of castration and vasectomy on some oxidative stress parameters and blood hormone levels in rats / Efeito da castração e da vasectomia em alguns parâmetros de estresse oxidativo e níveis de hormônios no sangue

Vasectomy and castration are the most preferred surgical methods to control reproduction in males. While sexual functions are terminated reversibly in vasectomy, they are removed irreversibly in castration. After these processes, changes are observed in hormones and oxidative stress parameters. In this study, we investigated the effects of vasectomy and castration operations on blood follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, nitric oxide (NO) and malondialdehyde (MDA) levels in rats. As a result of the analysis, it was determined that FSH, LH, NO, and MDA levels increased (p<0.05) and testosterone levels decreased (p<0.05) in the castration group compared to the sham and vasectomy groups. Considering the data obtained from the present study, when the two operations (vasectomy and castration) are compared in rats, which are preferred for the control of reproduction, it is thought that vasectomy is a healthier method because it is reversible, does not affect hormone levels, and does not increase oxidative stress.

A vasectomia e a castração são os métodos cirúrgicos preferidos para controlar a reprodução no sexo masculino. Enquanto as funções sexuais terminam reversivelmente na vasectomia, elas são removidas irreversivelmente na castração. Após esses processos, são observadas alterações nos hormônios e nos parâmetros de estresse oxidativo. Neste estudo, foram investigados os efeitos das operações de vasectomia e castração nos níveis sanguíneos de hormônio folículo estimulante (FSH), hormônio luteinizante (LH), testosterona, óxido nítrico (NO) e malondialdeído (MDA) em ratos. Como resultado da análise, foi determinado que os níveis de FSH, LH, NO e MDA aumentaram (P<0,05) e os níveis de testosterona diminuíram (P<0,05) no grupo de castração em comparação com os grupos sham e vasectomia. Considerando os dados obtidos no presente estudo, quando comparadas as duas operações (vasectomia e castração) em ratos, preferidas para o controle da reprodução, acredita-se que a vasectomia é um método mais saudável por ser reversível, não afetar os níveis hormonais e não aumentar o estresse oxidativo.

Colheita de sêmen e inseminação artificial em onças-pintadas (Panthera onca) / Semen collection and artificial insemination in jaguars (Panthera onca)

A onça-pintada encontra-se classificada como "quase ameaçada" na lista vermelha de animais ameaçados da União Internacional para Conservação da Natureza (IUCN), com tendência ao declínio na América Latina, o que pode afetar o fluxo gênico elevando o risco de endogamia. Técnicas de reprodução assistida (TRAs) como colheita de sêmen e inseminação artificial (IA), são ferramentas que podem se tornar essenciais a manutenção da diversidade genética desses animais. A colheita de sêmen pode ser realizada por eletroejaculação (EEJ) ou colheita farmacológica (CF), sendo que podem ser aplicadas individualmente ou associadas, embora EEJ tenha se mostrado mais eficiente em inseminação artificial (IA) com sêmen a fresco. Para realização de IA a utilização de progestina oral (altrenogest), seguida da aplicação de gonadotropinas exógenas (Gonadotropina Coriônica equina-eCG e Hormônio Luteinizante suíno-pLH), tem se mostrado eficiente, promovendo ovulações consistentes. IA intratubárica (IA-IT) mostrou-se eficiente, tendo a vantagem de utilizar sêmen com baixo número de espermatozoides. O sucesso alcançado com o nascimento do primeiro filhote de Panthera onca utilizando TRAs se deve a vários fatores, dentre eles, a utilização de um novo protocolo hormonal ajustado à espécie; e a utilização da IA-IT, que possibilitou a utilização de sêmen com reduzido número de espermatozoides viáveis por inseminação.(AU)

The jaguar is classified as "near threatened" according International Union for Conservation of Nature red list, with a decreasing trend in the population of Latin America, increasing the risk of inbreeding. Assisted reproduction techniques (ARTs), such as semen collection and artificial insemination (AI), are tools that can become essential to maintain the genetic diversity of jaguars. Semen collection can be performed by electroejaculation (EEJ) or pharmacological collection (PC); and can be applied individually or associated, however EEJ was more efficient for artificial insemination (AI) with fresh semen. To perform Artificial Insemination (AI), oral progestin (altrenogest) followed exogenous gonadotropins (Gonadotropin Chorionic equine-eCG e Hormone Luteinizing porcine-pLH) application was efficient, promoting consistent ovulations. Similarly, laparoscopic oviductal insemination (IA-IT) was efficient, with the advantage to use low viable spermatozoa number by insemination. The success of jaguar cub birth using ARTs is due to several factors, among than, a new hormonal protocol adjusted to the species; and the use of IA-IT, which allowed the reduction in the number of sperm by insemination.(AU)

Regulation of progesterone during follicular development by FSH and LH in sheep

Progesterone (P4) can participate in the development of female mammalian antral follicles through nuclear receptor (PGR). In this experiment, the differences of P4 synthesis and PGR expression in different developmental stages of sheep antral follicles (large > 5mm, medium 2-5mm, small < 2mm) were detected by enzyme-linked immunosorbent assay, immunohistochemistry, qRT-PCR and Western blotting. Secondly, sheep follicular granulosa cells were cultured in vitro. The effects of different concentrations of FSH and LH on P4 synthesis and PGR expression were studied. The results showed that acute steroid regulatory protein (StAR), cholesterol side chain lyase (P450scc) and 3β Hydroxysteroid dehydrogenase (3β-HSD) and PGR were expressed in antral follicles, and with the development of antral follicles in sheep, StAR, P450scc and the expression of 3β-HSD and PGR increased significantly. In vitro experiments showed that FSH and LH alone or together treatment could regulate P4 secretion and PGR expression in sheep follicular granulosa cells to varying degrees, hint P4 and PGR by FSH and LH, and LH was the main factor. Our results supplement the effects of FSH and LH on the regulation of P4 synthesis during follicular development, which provides new data for further study of steroid synthesis and function in follicular development.(AU)

Deslorelina como contraceptivo em cães e gatos / Deslorelin as a contraceptive in dogs and cats / Deslorelina como contraceptivo en perros y gatos

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)

Seminal plasma nerve growth factor signaling on the reproductive physiology of female llamas

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)

Three superovulation protocols for in vivo embryo production in Santa Inês sheep / Três protocolos para produção in vivo de embriões em ovelhas Santa Inês

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.

Efeitos da castração imunológica no epitélio seminífero de machos bubalinos / Effects of immunological castration on the seminipheral epithelium of buffaloes males

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)

Influence of exogenous corticosterone on testicular function and mating behavior of Nigerian indigenous cocks

In bridging the knowledge gap on stress physiology of Nigerian indigenous chickens, this study investigated the effect of exogenous corticosterone (eCORT) as stress inducing agent on the testicular function and mating behavior of Nigerian indigenous cocks. Twenty-four (24) cocks and one hundred and forty four (144) hens (mating ratio of 1 cock: 6 hens) were grouped into four and assigned to each of the four eCORT treatments (0, 2, 4 and 6 mgeCORT/KgBW) daily for 14 days. Semen samples were collected on days 0, 7 and 14 and analyzed for semen volume (SV), progressive sperm motility (PSM), membrane integrity (MI) and sperm abnormality (SA). Mating behaviors were monitored on days 3, 5 and 8. Blood samples, for hormonal (Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH) Testosterone (TEST) and stress analysis (heterophil/lymphocyte ratio, H/L) were collected from brachial vein on days 7 and 14. On day 15, cocks were euthanized and testes harvested for histomorphometry. Data were analyzed using multivariate analysis, one­way ANOVA and Kruskal-Wallis tests all in SPSS 23. Administration of 4 mgeCORT/KgBW declined (P0.05) influence on the mating behaviors, H/L ratio, FSH and TEST. However, 2 mgeCORT/KgBW enhanced LH levels. Administration of eCORT did not affect the testicular epithelial height and seminiferous tubular diameter. In conclusion, optimal stress induced by eCORT impaired semen quality but with less impact on reproductive hormones, H/L and mating behaviors of intensively raised Nigerian indigenous cocks.(AU)

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

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

Effects of melatonin on testicular function in adult male mice under different photoperiods

Photoperiod is an important environmental factor affecting animal physiological function. Melatonin is an endogenous hormone that plays an important role in circadian and seasonal (or cyclical) rhythms and seasonal reproduction in mammals. To investigate the effects of melatonin on the reproductive performance of adult male mice under different photoperiods, sixty mice were randomly allotted to six groups: control (Light Dark, 12 L:12 D), control plus melatonin (MLD, 12 L:12 D), 24-hour continuous light (LL, 24 L:0 D), 24-hour continuous light plus melatonin (MLL 24 L:0 D), constant darkness (DD, 0 L:24 D), and constant darkness plus melatonin (MDD, 0 L:24 D). Normal saline (100 µL) was injected into the LD, LL, and DD groups at noon each day; the MLD, MLL, and MDD groups were injected with melatonin (1 mg/mL; 2 mg/kg·body weigh). After 24 hours of prolonged light exposure, testis morphology decreased, convoluted seminiferous tubules became sparse, the diameter of convoluted seminiferous tubules decreased, and the level of sex hormones decreased. After the administration of exogenous melatonin, testicular morphology and sex hormone levels decreased in the MLD group under normal light conditions. In the MLL group, the testicular tissue morphology returned to normal, the diameter of convoluted tubules increased, the hormone levels of LH (Luteinizing hormone) and MTL (melatonin) significantly increased (P<0.05), and th0e gene expressions of LHß and Mtnr1A (Melatonin receptors 1A) increased. There was almost no difference in the MDD group under continuous darkness. In conclusion, melatonin can damage the reproductive performance of male mice under normal light conditions, while exogenous melatonin can alleviate and protect the testicular injury of male mice under continuous light conditions.(AU)

Productive and reproductive performance of crossbred dairy heifers with induced lactation and efficacy of antimicrobial therapy associated with internal teat sealants / Desempenho produtivo e reprodutivo de novilhas com lactação induzida e eficácia da terapia antimicrobiana associada com selante interno de tetos

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)

Las interacciones socio-sexuales, alternativa para manipular la reproducción de los pequeños rumiantes / Socio-sexual interactions, an alternative to manipulate the reproduction of small ruminants

La estacionalidad de la reproducción es una característica de la mayoría de las razas caprinas y ovinas de latitudes subtropicales. Las hembras presentan anovulación y disminución de las concentraciones plasmáticas de LH en primavera y verano, mientras que los machos disminuyen drásticamente los niveles plasmáticos de testosterona, la producción espermática y el comportamiento sexual en invierno y primavera. Esta estacionalidad es sincronizada principalmente por las variaciones naturales del fotoperiodo. Sin embargo, las interacciones socio-sexuales entre machos y hembras permiten modificar esta estacionalidad. Así, la introducción de machos en grupos de hembras en anestro estacional estimulan las actividades endocrina y reproductiva de las hembras, através del fonómeno conocido como "efecto macho". La respuesta de las hembras al efecto macho varía con la intensidad del comportamiento sexual desplegado por los machos. Por ello, los machos sexualmente activos son más eficaces que los machos en reposo sexual para estimula la ovulación de las hembras. Además, la presencia continua de los machos sexualmente activos evita la anovulación estacional, así como la disminución estacional de las concentraciones plasmáticas de LH en hembras ovariectomizadas portadoras de implantes subcutáneos que liberan estradiol. En conjunto, estos hallazgos indican que los machos cabríos y carneros sexualmente activos son una alternativa para manipular la estacionalidad reproductiva de las hembras durante el anestro estacional, y/o evitar la anovulación estacional. Además, considerando las demandas sociales para reducir o eliminar los tratamientos hormonales en la producción animal, la asociación del fotoperiodo y las interacciones socio-sexuales entre machos y hembras constituye una alternativa sustentable para la manipulación de la actividad reproductiva de los pequeños rumiantes.

Reproductive parameters of lambs immunocastrated with anti-GnRH vaccine

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.(AU)

Estrus expression and pregnancy rates in heifers primiparous and multiparous Nelore cows subjected to timed artificial insemination with strategic use of gonadotropin-releasing hormone / Expressão de estro e taxas de prenhez em novilhas, primíparas e multíparas Nelore submetidas à inseminação artificial em tempo fixo com uso estratégico de hormônio liberador de gonadotrofina

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)

Fixed-time artificial insemination protocols on brazilian locally adapted breed gilts on ovulatory response and embryo production

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.(AU)

Effect of Heat Stress on Expression of Main Reproductive Hormone in Hypothalamic-Pituitary-Gonadal Axis of Wenchang Chicks

ABSTRACT The hypothalamic-pituitary-gonadal (HPG) axis is a key neuroen-docrine regulation system involved in the growth and reproduction of poultry. High-temperature conditions lead to the physiological dysfunction of target organs of the HPG axis of poultry, ultimately affecting the animals growth and development. In this study, we evaluated the effect of heat stress (HS) on the development of cells secreting major reproductive hormones of the HPG axis (i.e., hypothalamus, pituitary gland, ovary, and testis) of Wenchang chicks. Seventy-two one-day-old healthy Wenchang chicks were randomly divided into control (CK) and HS groups. The HS group was placed in a 40 ± 0.5°C artificial climate chamber for heat-stress treatment from 13:00 to 15:00 daily for six consecutive weeks. As development progressed, compared with the CK group, the gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels in the hypothalamus and testosterone (T) levers in the testes of male chicks in the HS group were significantly decreased at three weeks of age (p 0.05). However, GnRH levels in the hypothalamus and estradiol (E2) levels in the ovaries of female chicks in the HS group were variable and significantly lower than those of the CK group at four and five weeks of age (p 0.05). In addition, the LH and FSH levels in the pituitary gland were significantly lower than those in the CK group at two and four weeks of age and at four and six weeks of age, respectively (p 0.05). In brief, HS caused dysfunction of the corresponding target organs of the HPG axis in Wenchang chicks, and this affected the normal growth and development of the cells HPG axis.

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)