Recent advances in treatments for resynchronization of ovulation in small ruminants: a review

Hormonal methodologies to control small ruminants' estrous cycle are worldwide used and evolved, adjusting the application to the precise female physiological moments to enhance reproductive performance. The estrous cycle can be induced and/or synchronized, aiming for fixed-time artificial insemination, or based on estrus behavior signs for insemination, natural or guided mating. Successive protocols can be performed to resynchronize ovulation and increase reproductive outcomes in females that failed to conceive. These recently developed treatments aim to resynchronize the ovulation as earlier as non-pregnancy is detected. The present review aimed to summarize the recent advances and main findings regarding resynchronization protocols used in small ruminants. Lastly, we present future perspectives and new paths to be studied in the subject. The resynchronization treatment is still a growing field in small ruminant reproduction, nevertheless, some enhancements are found in the reproductive outcome, showing that such protocols can be successfully used in sheep and goat production.(AU)

Atualizações no controle do ciclo estral em ovinos / Updates on the control of the estrous cycle in sheep

Nos últimos anos, observou-se um aumento no tamanho do rebanho ovino no país, indicando uma retomada na ovinocultura. Para melhorar a eficiência reprodutiva desses animais, a utilização de biotécnicas tem se mostrado uma ferramenta importante. Dentre essas biotécnicas, destacam-se os protocolos de sincronização do ciclo estral, os quais frequentemente utilizam progesterona associada a gonadotrofinas ou análogos da prostaglandina em duas aplicações. Este artigo tem como objetivo revisar os protocolos de sincronização utilizados em ovinos e apresentar atualizações relevantes sobre os mesmos.(AU)

In recent years, there has been an increase in the size of the sheep herd in the country, indicating a recovery in sheep farming. To improve the reproductive efficiency of these animals, the use of biotechniques has been shown to be an important tool. Among these biotechniques, estrous cycle synchronization protocols stand out, which frequently use progesterone associated with gonadotropins or prostaglandin analogues in two applications. This article aims to review the synchronization protocols used in sheep and present relevant updates about them.(AU)

Biópsia endometrial na égua: importância no diagnóstico da subfertilidade e principais achados / Endometrial biopsy in the mare: importance in the diagnosis of subfertility and main findings

A biópsia endometrial na égua é uma técnica simples e bastante antiga. É uma importante ferramenta para o diagnóstico de patologia no endométrio nesta espécie utilizada para determinar o estágio do ciclo estral, para detectar a presença de inflamações agudas ou crônicas e para determina a possibilidade do útero levar a gestação a termo. Mais recentemente outras alterações tais como a má-diferenciação e as angiopatias, também estão sendo avaliadas em amostras de biópsia endometrial em éguas, uma vez que também podem interferir no prognóstico reprodutivo destas fêmeas. Esta revisão tem por objetivo descrever a avaliação da biópsia endometrial e as principais alterações que ocorrem no endométrio das éguas.(AU)

Endometrial biopsy in the mare is a simple and quite old technique. It is an important tool for the diagnosis of pathology in the endometrium in this species, used to determine the stage of the estrous cycle, to detect the presence of acute or chronic inflammation and to determine the possibility of the uterus carrying the pregnancy to term. More recently, other alterations, such as poor differentiation and angiopathies, are also being evaluated in endometrial biopsy samples in mares, since they may also interfere with the reproductive prognosis of these females. This review aims to describe the evaluation of the endometrial biopsy and the main changes that occur in the endometrium of mares.(AU)

Estratégias farmacológicas para a manipulação do ciclo estral de fêmeas bovinas de raças de corte taurinas / Pharmacological approaches to manipulate bovine estrous cycle in taurine beef breeds

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)

Reproductive response of synchronized and extensively grazed Blackbelly ewes during the summer in the tropics

The present experiment aimed to evaluate the reproductive response of Blackbelly ewes synchronized with low doses of eCG during the summer in a tropical climate. Sixty multiparous hair ewes were divided into three groups (20 ewes/group): control group (CG; 0 IU of eCG), treated group 1 (TG-1; 140 IU of eCG) and treated group 2 (TG-2; 300 IU of eCG). The study found that the three groups of ewes showed differences in their reproductive behavior (P < 0.01). Indeed, all the ewes in the TG-1 and TG-2 groups presented a higher response to estrus than the CG (P < 0.01). In the same way, TG1 and TG-2 had an onset to estrus in less time (P < 0.01). On the other hand, prolificacy was also higher in TG-1 and TG-2 (P < 0.05). Likewise, ewes from TG-1 and TG-2 had more lambs than those from CG (P < 0.05). On the other hand, the variables of fertility and gestation length were similar regardless of the group of ewes (P > 0.05). It´s concluded that the ewes treated with eCG presented good reproductive behavior, and the majority did so in the first 24 to 36 h after removing the intravaginal device.

Interação reprodução x produção na ovinocultura: Aspectos reprodutivos relacionados com produtividade / Reproduction x production interaction in sheep farming: Reproductive aspects related to productivity

A importância dos manejos reprodutivos, que contribui para o avanço da ovinocultura e rentabilidade dos sistemas, revela oportunidades para trabalho com a interação reprodução x produção. Estratégias para incremento produtivo no setor, através de biotécnicas reprodutivas, que permitem redução da idade a puberdade, diminuição da estacionalidade reprodutiva e aumento da taxa ovulatória. Além das possibilidades hormonais, métodos alternativos que consideram efeito macho e nutrição, são considerados eficiente para controle do ciclo. Este artigo tem como objetivo revisar os protocolos de controle do ciclo estral e incremento produtivo na ovinocultura.(AU)

The importance of reproductive management, which contributes to the advancement of sheep farming and the profitability of the systems, reveals opportunities for work with the reproduction x production interaction. Strategies to increase production in the sector, through reproductive biotechniques, which allow reducing the age at puberty, reducing reproductive seasonality and increasing the ovulatory rate. In addition to hormonal possibilities, alternative methods that consider male effect and nutrition are considered efficient for cycle control. This article aims to review the estrous cycle control protocols and productive increase in sheep farming.(AU)

Reproductive and economic evaluation of sexual stimulation during the anestrous period in a commercial farm with neonatal lamb losses / Avaliação reprodutiva e econômica da estimulação sexual durante o período antrópico em uma fazenda comercial com perdas neonatais de cordeiros

This study was performed during the anestrous, involving 140 Akkaraman Kangal ewes whose lambs had died in the neonatal stage due to pneumonia and enteritis. Intravaginal sponge containing progesterone was placed to the animals (Group 1, n = 70) on day 0 and removed after 7 days, following which 263 µg PGF2α and 500 IU eCG were administered to the sheep. Ram introduction was performed for 7 days (days 8-14), starting from the day after the removal of the intravaginal sponge (day 8). The animals in Group 2 (n = 70) were not exposed to any treatment. Ram introduction was performed simultaneously in both the groups. To determine the reproductive response, reproductive parameters such as estrous, pregnancy, multiple pregnancy, and embryonic mortality rates, number of births, number of offspring, and fertility, as well as their economic implications, were compared between groups. Each reproductive parameter exhibited a statistical difference between groups. An economically positive trend was observed in the study group compared with the control group. It was concluded that in case of lamb losses in commercial farms that derive profit from lambing, pregnancy of ewes can be achieved via sexual stimulation without waiting for the next breeding season.

Este estudo foi realizado durante o anestrous, envolvendo 140 ovelhas Akkaraman Kangal cujos cordeiros haviam morrido no estágio neonatal devido a pneumonia e enterite. A esponja intragaginal contendo progesterona foi colocada aos animais (Grupo 1, n = 70) no dia 0 e removida após 7 dias, após os quais 263 µg PGF2α e 500 UI eCG foram administrados às ovelhas. A introdução do carneiro foi realizada por 7 dias (dias 8-14), a partir do dia seguinte à remoção da esponja intravaginal (dia 8). Os animais do Grupo 2 (n = 70) não foram expostos a nenhum tratamento. A introdução do carneiro foi realizada simultaneamente em ambos os grupos. Para determinar a resposta reprodutiva, foram comparados entre os grupos parâmetros reprodutivos, tais como estrogênio, gravidez, gravidez múltipla e taxas de mortalidade embrionária, número de nascimentos, número de descendentes e fertilidade, bem como suas implicações econômicas. Cada parâmetro reprodutivo exibia uma diferença estatística entre os grupos. Uma tendência economicamente positiva foi observada no grupo de estudo em comparação com o grupo de controle. Concluiu-se que no caso de perdas de cordeiros em fazendas comerciais que obtêm lucros com a parição, a gravidez de ovelhas pode ser obtida através de estimulação sexual sem esperar pela próxima estação de reprodução.

Changes in expression levels of Nod-like receptors in the spleen of ewes

Nucleotide-binding oligomerization domain receptors (NOD-like receptors, NLRs) have critical effects on interfaces of the immune and reproductive systems, and the spleen plays a key role in both innate and adaptive immune functions. It is hypothesized that NLR family participates in maternal splenic immune regulation during early pregnancy in sheep. In this study, maternal spleens were collected on day 16 of the estrous cycle, and days 13, 16 and 25 of gestation (n = 6 for each group) in ewes. Expression of NLR family, including NOD1, NOD2, class II transactivator (CIITA), NLR family apoptosis inhibitory protein (NAIP), nucleotide-binding oligomerization domain, Leucine rich repeat and Pyrin domain containing 1 (NLRP1), NLRP3 and NLRP7, was analyzed using quantitative real-time PCR, Western blot and immunohistochemistry analysis. The results revealed that expression levels of NOD1, NOD2, CIITA and NLRP3 were downregulated at days 13 and 16 of pregnancy, but expression of NLRP3 was increased at day 25 of pregnancy. In addition, expression values of NAIP and NLRP7 mRNA and proteins were improved at days 16 and 25 of pregnancy, and NLRP1 was peaked at days 13 and 16 of pregnancy in the maternal spleen. Furthermore, NOD2 and NLRP7 proteins were limited to the capsule, trabeculae and splenic cords. In summary, early pregnancy changes expression of NLR family in the maternal spleen, which may be related with the maternal splenic immunomodulation during early pregnancy in sheep.(AU)

Thecoma in an elderly crioulo mare

Background: Ovarian enlargement in mares can either be a physiological or pathological condition associated with neoplastic or non-neoplastic causes. Neoplasia is more prominent in elderly than young horses. Granulosa cell tumors are the most common neoplastic cause of ovarian enlargement, and thecoma is the rarest. Thecoma is a benign ovarian stromal neoplasia originating from the sexual cords of the embryonic gonad and can affect the production of steroid hormones, leading to changes in behavior and the estrous cycle. If only one ovary is affected, after unilateral ovariectomy, usually the mare can still be used for reproductive purposes. Herein, we report a case of ovarian thecoma in an elderly Crioulo mare. Case: A 15-year-old Crioulo mare was evaluated due to progressive weight loss. The mare presented a low body score, and on physical examination, all parameters were within reference limits. Hematological examination revealed anemia, hyperfibrinogenemia, and neutrophilia. Serum biochemistry examination were within the physiological limits. Rectal palpation revealed an increase in volume in the left ovary (4.3 × 2.9 × 3 cm), smooth consistency and no associated pain in either of the ovaries. Rectal ultrasonography revealed a heterogeneous pattern, suggesting a neoplasm. As a treatment modality and for definitive diagnosis, the mare underwent a unilateral flank ovariectomy laparoscopically in the quadrupedal position. On histopathological evaluation of the left ovary, the sample showed cysts associated with proliferating spindle cells arranged in a solid arrangement, occasionally forming eddies, in addition to hemosiderosis, with clear cytoplasm and lipid vacuoles. Macroscopically, the ovary presented with a regular surface, smooth to firm consistency, a homogeneous brownish appearance with blackened foci, and brownish fluid-filled cysts. These findings confirmed thecoma of the left ovary in the mare. Discussion: Ovarian enlargement in mares can be associated to the presence of neoplasia. Clinical signs of ovarian neoplasms can be nonspecific; therefore, to achieve a definitive diagnosis, it is imperative to evaluate and compare the patient's history, physical examination, and results of complementary examinations. Excessive production of hormones lead to behavioral changes in mares with ovarian tumors, such as masculinized or aggressive behavior, and anestrus persistence. Thecomas may or may not interfere with steroid production and levels. On ultrasound examination, ovarian neoplasms may present similar echogenicity patterns. Histopathological evaluation is the best diagnostic approach after an ovariectomy. The prognosis of ovariectomy is considerably successful with the mare regaining reproductive health, although some mares may become infertile, with a small, inactive contralateral ovary. Thecoma is a rare neoplasm in horses; however, owing to its potential to cause altered reproductive functions, it should be considered as a differential diagnosis in mares with increased ovarian volume.

In vivo embryo development in bitches inseminated laparoscopically after ovulation time estimated based on a single progesterone determination

Logistic and economical limitations are often the causes of dog owners not accurately monitoring the estrous cycle and the optimal insemination time. The aim of this study was to evaluate in vivo early embryonic development in bitches, after the analysis of sequential vaginal cytologies associated to single progesterone measurement and single laparoscopic insemination with high quality semen (fresh and with high spermatozoa concentration) or low-quality semen (frozen/thawed and with low spermatozoa concentration) at 48 h post- ovulation time predicted on a single progesterone measurement. Ten bitches were inseminated with 250 x 106 fresh spermatozoa (80% motility), and ten with 80 x 106 frozen/thawed spermatozoa (60% motility) in the cranial part of each uterine horn. Seven days later, ovariohysterectomy was performed and the oviducts and uterine horns and body were flushed to recover embryos and unfertilized oocytes. In 80% of the bitches inseminated with fresh and 50% of bitches inseminated with frozen/thawed semen, embryos at 2 to 8 cells stage were recovered mostly from the, oviducts. This study indicates that pregnancies can be obtained with a single laparoscopic intrauterine insemination after single serum progesterone measurement, although with a low number of embryos. This result should be taken into account in case economic or logistic restrictions that affect the possibility of owners to plan an accurate monitoring of the optimal breeding time using fresh and frozen semen.(AU)

Maternal and fetal ultrasonography, vulvar temperature and vaginal mucous impedance for the prediction of parturition in Saanen does

The aim of this study was to evaluate and correlate modifications of vaginal mucous impedance, vulvar temperature and ultrasonographic measurements (echobiometric parameters) to parturition in pregnant Saanen does. 30 does were selected for the study and submitted to an estrus synchronization protocol and natural mating. The females were evaluated daily from Day 143 of pregnancy to parturition. For the sonographic evaluations, the following structures were measured: biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length, kidney height, cardiac area, placentome length, cervical measurement and fetal heart rate; by means of two different approaches: transrectal and transabdominal, using a 7.5 MHz linear transducer. The vaginal mucous impedance was assessed using an electric estrous detector and vulvar temperature was measured using a non-contact infrared thermometer. Statistical analysis was performed using the R-project software and the significance level was set at 5% for all tests. 25 Saanen does became pregnant, resulting in 80.33% pregnancy rate. Fetal heart rate was negatively correlated to the hours to parturition (p<0,001; r-Pearson= -0,451), as well as vaginal temperature (p= 0,001; r-Pearson= -0,275), while cervical thickness was positively correlated to hours to parturition (p<0,001; r-Pearson= 0,490). The echobiometric parameters (biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length and height, cardiac area, placentome length), as well as vaginal mucous impedance did not vary throughout the timepoints of evaluation and did not correlate to the moment of parturition. It was concluded that the parameters of fetal heartbeat, vaginal temperature and cervical effacement in the last week of pregnancy provide valuable information regarding the proximity of parturition.(AU)

Interação da sazonalidade e nutrição na viabilidade embrionária ovina / Interaction between seasonality and nutrition on embrio viability of ovines

A sazonalidade reprodutiva e a condição nutricional são os principais fatores que influenciam o desempenho reprodutivo em ovinos, principalmente em áreas onde a disponibilidade de alimentos é altamente sazonal. A desnutrição pode comprometer a competência folículo-oocitária, a função lútea e o desenvolvimento embrionário. Por outro lado, o tratamento com melatonina é um método eficaz para induzir ciclicidade, aumentando a ovulação e melhorando a viabilidade do embrião durante o anestro. Portanto, levantamos a hipótese de que a melatonina pode substituir os efeitos prejudiciais da desnutrição para melhorar o desempenho reprodutivo em ovelhas. A este respeito, esta revisão enfoca os efeitos da interação entre melatonina e nutrição na viabilidade do embrião e resume a informação disponível sobre o efeito da melatonina exógena na viabilidade do embrião em ovelhas desnutridas.(AU)

Reproductive seasonality and nutritional condition are the main factors that influence reproductive performance in sheep, particularly in the areas where the availability of food is highly seasonal. Undernutrition can compromise follicle-oocyte competence, luteal function and embryo development. On the other hand, melatonin treatment is an effective method for inducing estrous cycles, increasing ovulation and improving embryo viability during anestrus. Therefore, we hypothesized that melatonin can override the detrimental effects of undernutrition to improve reproductive performance in ewes. In this regard, this review focuses on the effects of the interaction between melatonin and nutrition on embryo viability and summarizes the available information about the effect of exogenous melatonin on embryo viability in undernourished ewes.(au)

Farmacopuntura em protocolos de sincronização de estro em pequenos ruminantes / Pharmacopuncture in estrus synchronization protocols in small ruminants

O objetivo com essa revisão foi realizar o levantamento da produção científica disponível e articular saberes a respeito do uso da farmacopuntura associada à protocolos de sincronização de estro principalmente em caprinos e ovinos, como também, em outras espécies de interesse. Ao analisar as pesquisas realizadas nos últimos 10 anos com a utilização de subdoses hormonais associada à farmacopuntura em programas de inseminação artificial em tempo fixo (IATF), nota-se que a farmacopuntura vem se tornando uma ferramenta promissora para viabilizar a redução das doses hormonais administradas e potencializar o efeito do fármaco aplicado, o que eleva a eficiência dos programas de sincronização de estro/ovulação ao reduzir os custos desses protocolos. Além de diminuir o custo desses protocolos para os produtores, nosso grupo de pesquisa realizou uma série de estudos nessa área, visando a busca por protocolos com menores doses hormonais, o que consequentemente reduz a quantidade de resíduos produzidos e promove manejos mais sustentáveis. Baseado nas publicações, pode-se afirmar que a farmacopuntura apresenta resultados satisfatórios e coloca-se como uma via de aplicação de sub-doses ou micro-doses hormonais em protocolos de controle do ciclo estral em caprinos e ovinos, como também, para outras espécies domésticas.(AU)

The objective of this review was to compile information regarding the use of pharmacopuncture associated with estrus synchronization protocols, mainly in goats and sheep, as well as in other species of interest, with the aim of updating and providing information on the subject. When analyzing the research carried out in the last 10 years with the use of hormonal underdoses associated with pharmacopuncture in fixed-time AI programs, these have become a promising tool to enable the reduction of administered hormonal doses and to potentiate the effect of the applied drug, the that increases the efficiency of estrus/ovulation synchronization programs by reducing the costs of these protocols. In addition to reducing the cost of these protocols for producers, our research group carried out a series of studies in this area, aiming at the search for protocols with lower hormonal doses, less waste produced and more sustainable management. Based on the publications, it can be stated that pharmacopuncture presents satisfactory results and is a way of applying sub-doses or micro-doses of hormones in protocols for controlling the estrous cycle in goats and sheep, as well as for other domestic species.(AU)

Sexual motivation and performance in sexual naïve and experienced rats treated with ivermectin: an ultrasonic vocalization study / Motivação e desempenho sexual em ratos com e sem experiência sexual tratados com ivermectina: um estudo da vocalização ultrassônica

In mammals, ivermectin acts as a GABAA receptor agonist and stimulates GABA release. Previous studies showed that ivermectin (IVM) reduces sexual performance, impairing the latency to the first mount and intromission. These parameters are usually considered motivational parameters of sexual behavior. However, IVM increases GABAergic activity leading to motor incoordination. Thus, it is reasonable to propose that IVM affects sexual performance via motor incoordination pathways. The present study analyzed ultrasonic vocalization in rats to verify whether IVM impairs sexual behavior via motivational mechanisms or motor impairment. Because sexual experience attenuates the impairment of motor performance, rats with sexual experience were also studied. Sexually naive and experienced rats were administered a therapeutic IVM dose and saline. The rats were exposed to receptive females, and the latency to the first mount was evaluated, followed by the 50-kHz USV test. IVM treatment in naïve rats increased the latency to first to mount relative to Saline naïve rats, while no differences were observed between saline and experienced rats. In naïve-IVM rats, a reduced frequency and total calls and increased mean time of calls occur relative to SAL-naïve rats. Experienced IVM rats did not show differences in the frequency, mean, and maximal calls close to Saline experienced rats. However, an increase in the total calls and the dominant frequency of calls were observed in IVM-experienced rats compared to Saline experienced rats. A negative and positive correlation occurred between the latency to the first mount and USVs in groups with and without ivermectin exposure. Hence, we propose that ivermectin increased the sexual motivation of rats exposed to a female in estrous based in USVs despite an increased latency to the first mount that occurred. The increased latency to the first mount resulted from motor incoordination, as previously observed and proposed by our group.(AU)

Em mamíferos, a ivermectina (IVM) atua como agonista do receptor GABAA e estimula a liberação de GABA. Estudos anteriores mostraram que a IVM reduz o desempenho sexual, prejudicando a latência para a primeira monta e intromissão. Esses parâmetros são geralmente considerados parâmetros motivacionais do comportamento sexual. Por outro lado, a IVM aumenta a atividade GABAérgica levando à incoordenação motora. Assim, é possível que a IVM afete o desempenho sexual devido a um impedimento motor. O presente estudo analisou a vocalização ultrassônica em ratos para verificar se a IVM prejudica o comportamento sexual via mecanismos motivacionais ou comprometimento motor. Uma vez que a experiência sexual atenua o comprometimento do desempenho motor, também foram estudados ratos com experiência sexual. Ratos sexualmente inexperientes e experientes foram administrados com uma dose terapêutica de IVM ou solução salina IVM. Os ratos foram expostos a fêmeas receptivas e foi avaliada a latência para a primeira monta, seguida do teste de vocalização ultrassônica (USV) de 50 kHz. O tratamento com IVM em ratos inexperientes aumentou a latência para a primeira monta em relação a ratos inexperientes tratados com solução salina, enquanto não foram observadas diferenças entre ratos experientes tratados com IVM e solução salina. Em ratos inexperientes tratados com IVM ocorreu redução da frequência e total de USVs, bem como aumento do tempo médio de USVs em relação aos ratos sem experiência. Ratos experientes tratados com IVM não mostraram diferenças na frequência, média e máxima das USVs em relação aos ratos experientes tratados com solução salina; no entanto, observou-se aumento no total de USVs e na frequência dominante de USVS em ratos experientes tratados com IVM comparados aos experientes tratados com solução salina. Observou-se correlação negativa e positiva entre a latência para a primeira monta e USVs nos grupos sem e com experiência tratados com IVM, respectivamente. Assim, propomos que a IVM aumentou a motivação sexual de ratos expostos a uma fêmea em estro com base em USVs, apesar de apresentar aumento na latência para a primeira monta. O aumento da latência para a primeira monta foi atribuída à incoordenação motora, conforme observado anteriormente e proposto por nosso grupo.(AU)

Tópicos do ciclo estral em cadelas / Estrous cycle topics in bitches

As cadelas possuem características especiais da fisiologia da reprodução que as diferenciam das outras espécies domésticas. Elas são monoéstricas não sazonais com ovulação espontânea. A puberdade ocorre com variação entre 6 e 24 meses de idade conforme raça, tamanho individual e predisposições individuais. O interestro ocorre com intervalos de 5 a 12 meses sendo em média com 6 meses. O ciclo reprodutivo das cadelas é composto de 4 fases distintas: proestro (duração de 5 a 20 dias), estro (duração de 5 a 15 dias), diestro (duração de 50 a 80 dias) e anestro (duração de 80 a 240 dias). O diagnóstico e acompanhamento das fases do ciclo estral é feito com observação de comportamento reprodutivo, sintomas e sinais anatômicos e fisiológicos, citologia vaginal, dosagem do nível sérico de progesterona, vaginoscopia e utrassonografia dos órgãos do sistema reprodutivo, em especial dos ovários em cada fase do ciclo estral.(AU)

Female dogs have special features of reproduction physiology that differentiate them from other domestic species. Theu are non-seasonal monoestrus with spontaneous ovulation. Puberty occurs with a variation between 6 and 24 months of age according to breed, individual size, and individual predispositions. The inter-estrus occurs at intervals of 5 to 12 months, with an average of 6 months. The reproductive cycle of bitches is composed of 4 distinct phases: proestrus (duration from 5 to 20 days), estrus (duration from 5 to 15 days), diestrus (duration from 50 to 80 days) and anestrus (duration from 80 to 240 days). The diagnosis and monitoring of the phases of the estrous cycle is made with observation of reproductive behavior, symptoms and anatomical and physiological signs, vaginal cytology, measurement of serum progesterone levels, vaginoscopy and ultrasound of the organs of the reproductive system, especially the ovaries in each phase of the estrus cycle.(AU)

Vaginal cytology in mares in the different stages of the estral cycle associated with the seasons of the year / Citologia vaginal em éguas nas diferentes fases do ciclo estral associadas as estações do ano

The reproductive biotechnologies directly assist in the development of different methods of reproductive evaluation. The objective of this study was to develop a new method to determine the estrous cycle phase in equine females through vaginal cytology throughout the seasons, as well as to establish an estimate of inflammatory cells present in the vagina. Six mares were evaluated at different ages without a defined breed and reproductive activity and were subjected to ultrasound evaluation of the reproductive system and cytological analysis of the vaginal region. In the summer, there was a predominance of keratinized epithelial cells in the estrus and intermediate in the diestrus. In the autumn, there was a predominance of keratinized cells in estrus and parabasal cells in estrus and diestrus. In anestrus (winter), a greater number of parabasal cells was identified in relation to the other cell types. In estrus (spring), there was a predominance of parabasal and intermediate cells. Conversely, in diestrus, parabasals were found in greater numbers. The evaluation of inflammatory cells of the vaginal epithelium of mares showed greater activity in the summer; however, there are no reference values for healthy animals in the literature, and it is necessary to conduct studies on the subject. It is concluded that there is an influence of cyclicity on the vaginal epithelium of the equine species, varying according to the season. Additionally, vaginal cytological evaluation is an important complementary tool in the diagnosis of vaginitis in mares, requiring further research on the subject.(AU)

As biotecnologias reprodutivas auxiliam diretamente no desenvolvimento de diferentes métodos de avaliação repro-dutiva. O objetivo deste estudo foi desenvolver um novo método para determinar a fase do ciclo estral em fêmeas equinas através da citologia vaginal ao longo das estações, bem como estabelecer uma estimativa das células inflamatórias presentes na vagina. Seis éguas foram avaliadas em diferentes idades, sem raça definida e em atividade reprodutiva, e foram submetidas à avaliação ultrassonográfica do aparelho reprodutor e análise citológica da região vaginal. No verão, houve predomínio de células epiteliais queratinizadas no estro e intermediárias no diestro. No outono, houve predomínio de células queratinizadas no estro e células parabasais no estro e diestro. No anestro (inverno), foi identificado maior número de células parabasais em relação aos demais tipos celulares. No estro (primavera), houve predomínio de células parabasais e intermediárias. Por outro lado, no diestro, os parabasais foram encontrados em maior número. A avaliação das células inflamatórias do epitélio vaginal de éguas mostrou maior atividade no verão; entretanto, não há valores de referência para animais saudáveis na literatura, sendo necessário a rea-lização de estudos sobre o assunto. Conclui-se que há influência da ciclicidade no epitélio vaginal da espécie equina, variando de acordo com a estação do ano. Além disso, a avaliação citológica vaginal é uma importante ferramenta complementar no diagnóstico da vaginite em éguas, necessitando de mais pesquisas sobre o assunto.(AU)

Sazonalidade reprodutiva no gato doméstico / Estacionalidad reproductiva en el gato doméstico / Reproductive seasonality in the domestic cat

Algunas especies de animales como equinos, pequeños rumiantes, algunos roedores y caninos y felinos silvestres presentan un período de reposo sexual estacional de duración e intensidad variable. Esta estacionalidad está directamente relacionada con las horas luz diarias (fotoperiodo) a las que se hallan sometidos los animales y se evidencia en las localizaciones geográficas en las que existen marcadas variaciones en la duración del día durante el año. En el felino doméstico (Felis silvestris catus) la estacionalidad ovulatoria y estral de la hembra se halla bien documentada y ocurre durante los días que presentan más de 12 horas de luz (primavera-verano). Sin embargo, la estacionalidad reproductiva del gato ha sido definida más tardíamente. Es así que se ha observado que, si bien los gatos producen espermatozoides todo el año, la producción espermática es mayor en la estación reproductiva acompañando la estacionalidad de la hembra. Estos hallazgos han permitido utilizar estos conocimientos para el control de la reproducción y aplicación de biotecnología en felinos domésticos. Asimismo, los conocimientos obtenidos pueden ser aplicados a felinos silvestres tomando al gato doméstico como modelo.(AU)

Algumas espécies de animais como equinos, pequenos ruminantes, alguns roedores e os caninos e felinos selvagens apresentam um período de repouso sexual sazonal de duração e intensidade variáveis. Essa sazonalidade está diretamente relacionada às horas diárias de luz (fotoperíodo) a que os animais são submetidos e é evidenciada em localizações geográficas onde ocorrem variações marcantes na duração do dia durante o ano. No felino doméstico (Felis silvestris catus) a sazonalidade ovulatória e estral da fêmea é bem documentada e ocorre em dias com mais de 12 horas de luz (primavera-verão). No entanto, a sazonalidade reprodutiva do gato foi definida posteriormente, quando foi observado que, embora os gatos produzam espermatozoides ao longo do ano, a produção de espermatozoides é maior na estação reprodutiva, acompanhando a sazonalidade da fêmea. A utilização desses conhecimentos possibilitaram o controle da reprodução e aplicação da biotecnologia em felinos domésticos. Da mesma forma, tomando o gato doméstico como modelo, os conhecimentos obtidos podem ser aplicados aos gatos selvagens.(AU)

Early puberty in short-haired Guinea pigs kept in laboratory animal facilities

Lab animals, such as Guinea pigs (Cavia porcellus), are crucial for scientific development, as they play an important role in the development and quality control chain of vaccines and drugs distributed by the Brazilian public health system. Investigating their biological and physiological parameters is fundamental to raise and keep these animals, so the handling of the facilities that hold them can be updated whenever new information comes up, with the well-being of the animals and alignment with the 3 Rs in mind. In the search for understanding reproductive aspects of Guinea pigs, the present study had the main goal of studying puberty by means of estrous cycle analysis in short-haired Guinea pigs. Guinea pigs have a vaginal occlusive membrane that covers the vaginal orifice. Its rupture takes place gradually and naturally, moments before labor and during estrus. The present study followed 42 females as for the presentation of the vaginal occlusive membrane. Once the membranes ruptured spontaneously, a swab was collected to study vaginal cytology. Membrane rupture was observed in 39 females; six females showed membrane rupture with less than 21 days of age (17 to 21 days). Twenty-three females were characterized as being in estrus due to cytology showing a prevalence of anucleated superficial cells. One of these females was younger than 21 days old. The opening of the vaginal occlusive membrane took place most frequently in intervals between 17 and 18 days, and the membrane remained open between one and three consecutive days. It was possible to follow three cycles of membrane opening on six females. The present study showed the need to adapt handling guidelines for C. porcellus kept in research animal facilities. The early age of puberty imposes the need of separate the female daughters from their fathers at 16 days old.(AU)

In vitro sperm characteristics and in vivo fertility of sex-sorted and conventional semen in suckled Nelore cows at a traditional schedule for timed-AI with estrus detection / Características espermáticas in vitro e fertilidade in vivo de sêmen convencional e sexado em vacas Nelore pósparto submetidas à IATF tradicional com detecção de estro

The aim of this study was to assess in vitro sperm characteristics and pregnancies/AI (P/AI) of conventional and sex-sorted semen at timed-AI of suckled, multiparous Nelore cows. All cows (n=348) were submitted to a traditional estradiol/progesterone (P4)-based protocol. At 48h after P4-device removal, the estrous behavior was recorded, and AI was performed with conventional or sex-sorted semen from two bulls. The following sperm assessments were performed: CASA, Hyposmotic Test, sperm morphometry and chromatin structure by TB staining. P/AI were reduced (P<0.001) for sex-sorted compared to conventional semen in cows expressing estrus (27vs47%) or not (11vs.37%). Membrane integrity (Bull1: 30.3±9.6 vs. 52.3±12.4%, P=0.01; Bull2: 24.5±3.0 vs. 48.7±1.6%, P=0.006) and sperm concentration (Bulll: 23.2±0.6 vs. 43.0±0.8x10 sperm/mL, P<0.001; Bull2: 25.1+2.8 VS. 42.1±0.7x10 sperm/mL; P<0.001) were reduced in sex-sorted compared to conventional semen, for both bulls. Total and progressive motility were reduced in sex-sorted semen for Bull1 (TM: 49.7±15.9 vs. 94.9±1.9%, P=0.007; PM: 16.7±3.4 vs. 44.1±13.2%, P=0.009) and no differences were detected for Bull2 (TM: 45.0±17.5 vs. 68.2±19.1%, P=0.098; PM: 12.8±4.7 vs. 30.0±13.0%, P=0.065). Sperm ellipticity from sex-sorted was lower than conventional semen for Bull2 (0.306±0.01 vs. 0.342±0.02, P=0.02) and no difference was detected for Bull1 (0.332±0.01 vs. 0.330±0.01, P=0.55). Reduced in vivo fertility was observed for sex-sorted semen, regardless of estrous behavior. In vitro sperm quality of sex-sorted semen was compromised for both bulls, but differently affected for each sire.

O estudo teve como objetivo avaliar características espermáticas in vitro e a taxa de concepção (TC) de sêmen convencional e sexado em um programa de IATF tradicional de vacas Nelore pós-parto. Todas as vacas (n=348) foram submetidas ao mesmo protocolo de IATF à base de estradiol e de progesterona. Após 48 horas da retirada do implante, foi determinada a expressão de estro dos animais e a IA foi realizada com sêmen convencional e sexado de dois touros Angus. As seguintes características espermáticas foram avaliadas: análise computadorizada do sêmen, teste hiposmótico, morfometria espermática e estrutura cromatinica por meio da coloração com azul de toluidina. A TC foi menor (P<0,001) para sêmen sexado comparado ao convencional, em vacas que expressaram estro (27 vs. 47%) e que não apresentaram estro (11 vs. 37%). A integridade da membrana plasmática (Touro 1: 30,319,6 vs. 52,3+12,4%, P=0,010; Touro 2: 24,5+3,0 vs. 48,7±1,6%, P=0,006) e a concentração espermática (Touro 1: 23,2±0,6 vs. 43,0±0,8x10 sperm/mL, P<0,001; Touro 2: 25,1+2,8 vs. 42,1 +0,7x10'sperm/mL, P<0,001) foram menores no sêmen sexado comparado ao convencional, para ambos os touros. Motilidades total e progressiva foram menores no sêmen sexado comparado ao convencional para o Touro 1 (MT: 49,7±15,9 vs. 94,9±1,9%, P=0,007; MP: 16,7+3,4 vs. 44,1+13,2%, P=0,009), enquanto diferenças não foram detectadas no Touro 2 (MT: 45,0±17,5 vs. 68,2±19,1%, P=0,098; MP: 12,8±4,7 vs. 30,0±13,0%, P=0,065). Elipticidade espermática do sêmen sexado foi menor do que do sêmen convencional no Touro 2 (0,306±0,01 vs. 0,342±0,02, P=0,020), mas não houve diferença no Touro 1 (0,332±0,01 vs. 0,330±0,01, P=0,552). Reduzida fertilidade in vivo foi observada para o sêmen sexado em relação ao convencional, independentemente da expressão de cio das vacas. A qualidade seminal in vitro do sêmen sexado foi comprometida para ambos os touros, mas diferentemente afetada para cada reprodutor.

Tumor ovariano de células de Sertoli em fêmea canina / Ovarian tumor of Sertoli cells in a female dog

O tumor de células de Sertoli, classificado como tumor do cordão sexual puro, é caracterizado por provocar manifestações clínicas endócrinas. É encontrado mais comumente em machos e é raro em fêmeas. O presente estudo objetivou relatar um caso de tumor ovariano de células de Sertoli em uma cadela. A paciente era uma fêmea canina, de cinco anos de idade da raça Shi Tzu, que apresentava queixa de "posição de prece" com frequência e anestro há dois anos. O exame físico determinou alopecia difusa e simétrica, hiperpigmentação de pele, pelos frágeis e comedões, com aumento de volume no flanco esquerdo e sensibilidade à palpação abdominal. O exame ultrassonográfico evidenciou estrutura arredondada, de bordas definidas em topografia de ovário esquerdo, medindo aproximadamente 5,27cm em seu maior eixo; além de piometra incipiente. Após ovariossalpingohisterectomia, realizou-se avaliação histopatológica do ovário, com diagnóstico de tumor do cordão sexual/estroma, com padrão de células de Sertoli infiltrativo. Conclui-se que, apesar de incomum, é importante incluir o tumor de células de Sertoli como diagnóstico diferencial, em casos de sinais de desregulação hormonal e alterações no ciclo estral e do pelame do animal. Ressalta-se a importância dos exames de imagem e histopatológicos para o diagnóstico, prognóstico e tratamento adequado.

Sertoli cells tumor, classified as a pure sexual cord tumor, is characterized by causing endocrine clinical manifestations. It is commonly found in males and is rare in females. The present study aimed to report a case of a Sertoli cell ovarian tumor in a female dog. The patient was a five-year-old female Shi Tzu dog, who complained of prayer position frequently and anestrus for two years. The physical examination determined diffuse and symmetrical alopecia, skin hyperpigmentation, fragile hair, and comedones, with increased volume in the left flank and sensitivity to abdominal palpation. The ultrasound examination evidenced the presence of a rounded structure, with defined edges in the topography of the left ovary, measuring approximately 5.27cm in its longest axis, in addition to incipient pyometra. After ovariosalpingohysterectomy, a histopathological evaluation of the ovary was performed with a diagnosis of sexual cord/stroma with an infiltrative Sertoli cell pattern. It is concluded that, although uncommon, it is important to include the Sertoli cell tumor as a differential diagnosis in cases of signs of hormonal dysregulation and changes in the estrous cycle, and animal's coat. The importance of imaging and histopathological exams for diagnosis, prognosis, and appropriate treatment is highlighted.