Effect of two diets on the fecundity of ablated and non-ablated female of Macrobrachium amazonicum

Macrobrachium amazonicum is a species of freshwater shrimp of great importance for aquaculture and to know its reproductive potential, through the study of its fertility is necessary. Therefore, this study aimed to evaluate the effect of two different diets on the reproductive performance of the species, whether or not adopting the ablation procedure. The experiment was carried out in a completely randomized design in a 2 x 2 factorial arrangement, with two types of feed (inert and fresh) and two conditions (ablated and non-ablated females), using six replicates per treatment. After 10 days of spawning, the eggs were removed and counted in their entirety. For each female, three spawns were obtained, totaling 72 samples. The fertility rate, the interval between spawning and the weight gain of the females were analyzed. There was no interaction between the studied factors, except for weight gain, in which ablated females that received fresh feed gained up to three times more weight than non-ablated females. Females that received fresh feed obtained higher fertility (1,373.9 eggs) than those that received only inert feed (1,084.1 eggs). The interval between spawns was 1.6 days shorter in ablated females.(AU)

Impacto da nutrição na reprodução de cães / Impact of nutrition on dog reproduction

A reprodução é altamente influenciada pela nutrição. A ação de minerais e vitaminas influenciam no processo da reprodução. Fatores nutricionais adequados associados e a saúde, ambiente, genética, manejo e bem-estar tem efeitos positivos em índices de reprodução. Deficiências nutricionais, excessos e desequilíbrios são capazes de alterar o desempenho reprodutivo. Estudos em nutrição visam melhorar a performance dos cães machos reprodutores, objetivando a manutenção e melhora da fertilidade.(AU)

Reproduction is highly influenced by nutrition. It is a proven fact that the action of minerals and vitamins influence the process of reproduction. Adequate nutritional factors associated with health, environment, genetics, management, and well-being have positive effects on reproduction rates. Nutritional deficiencies, excesses and imbalances can alter reproductive performance. Studies in nutrition aim to improve the performance of male breeding dogs, aiming at the maintenance and improvement of fertility.(AU)

Reproductive behavior of Pantaneiros sheep, Mato Grosso do Sul, Brazil

The objective was to evaluate fertility, cyclicality behavior, and sexual performance of Pantaneiro sheep throughout the year's photoperiods in Mato Grosso do Sul - Brazil. Two experiments were conducted. In experiment one, the ewes used aged between 2 and 4 years, distributed in three homogeneous groups of 54 animals and subjected to reproductive evaluation in three different predefined luminosity periods, consisting of autumn (11h 45 min.), spring (12h 30 min.), and summer (12h 55 min.). The characteristics studied were body weight (BW), body condition score (BCC), estrus distribution (EST), percentage of pregnant females per cycle (%P), plasma progesterone (PP), and fertility (F) in the three predefined seasons. The mating system used was controlled natural nocturnal and lasted for 45 days. Experiment two, evaluated the ram sexual activity. The males (10) were individually exposed to four ovariectomized ewes. The ewes cycled during evaluated seasons, and the highest fertility was observed in animals with BCC >2.75. The PP concentration differed among periods, and higher conception rates (F) were observed in autumn and spring. The rams (75%) had a medium of sexual performance when they performed more than two ejaculations in 20 min throughout the seasons. Pantaneiro sheep of both genders had a similar fertility index, with early and constant activity throughout the year, displaying no photoperiodism or seasonality.

Relação entre a capacitação espermática e a fertilidade de sêmen criopreservado de bovinos / Relationship between sperm capacitation and fertility in bovine cryopreserved semen

A qualidade do sêmen criopreservado, utilizado na inseminação artificial em tempo fixo (IATF) em bovinos, é um dos principais fatores que impactam sobre a fertilidade, e está relacionada à capacidade de produção espermática dos touros, à criotolerância dos espermatozoides e aos critérios técnicos do processo de criopreservação adotados. Neste sentido, devemos destacar a importância do controle de qualidade das partidas de sêmen antes de serem liberadas para uso na IATF. Nos últimos anos várias técnicas vêm sendo desenvolvidas para avaliar com mais acurácia as partidas de sêmen e evitar o uso daquelas que possam resultar em prejuízos na fertilidade, mas mesmo assim, tem se notado alta variabilidade na taxa de prenhez entre touros e entre partidas de sêmen. Esta divergência se deve ao fato da habilidade fértil do espermatozoide ser multifatorial, ou seja, dependente de diversas características estruturais, morfofuncionais e moleculares. Ademais, os eventos que permitem os espermatozoides passarem por capacitação espermática, um pré-requisito para a fertilidade, têm intrigado os pesquisadores em vista da complexidade dos processos envolvidos e dos efeitos deletérios da criopreservação espermática. Esta revisão tem por objetivo compilar estudos que mostrem a relação entre a capacitação espermática e a fertilidade do sêmen bovino criopreservado, levando em consideração as técnicas de avaliação e os resultados até o momento.(AU)

The quality of cryopreserved semen, used in fixed-time artificial insemination (FTAI) in cattle, is one of the main factors that impact fertility and is related to the sperm production capacity of bulls, sperm cryotolerance, and the technical criteria for cryopreservation. In this sense, we must highlight the importance of quality control of semen batches before commercialization for the FTAI. In recent years, several techniques have progressed to more accurately evaluate semen batches and avoid using those that may result in impaired fertility. However, we still notice a high variability in the pregnancy rate between bulls and between semen batches. This divergence is due to the multifactorial sperm-fertilizing ability, i.e., it depends on several structural, morphofunctional, and molecular characteristics. In addition, the events that allow sperm to undergo sperm capacitation, a prerequisite for fertility, have intrigued researchers due to the complexity of the processes involved and the adverse effects of sperm cryopreservation. This review aims to compile studies that show the relationship between sperm capacitation and fertility in cryopreserved bovine semen, considering the evaluation techniques and results to date.(AU)

Fertilidade e suscetibilidade à criopreservação espermática: avanços e desafios / Fertility and susceptibility to sperm cryopreservation: advances and challenges

Estudos sobre a fisiologia espermática demonstram que padrões de fertilidade e funcionalidade espermática pós-criopreservação possuem relação importante com a eficiência do metabolismo energético destas células, bem como com a sua capacidade de manter a homeostase oxidativa. Os conhecimentos sobre a relação entre perfil fisiológico de espermatozoides e fertilidade foram e, ainda estão sendo, aprimorados, com o uso de análises de perfis moleculares, com destaque para a metabolômica. As análises moleculares permitiram a identificação de classes de metabólitos importantes na fisiologia espermática, bem como de potenciais biomarcadores de fertilidade, inclusive em bovinos. No entanto, ainda não há disponível uma avaliação isolada capaz de estimar o padrão de fertilidade de amostras seminais. Há vários desafios a serem superados para a validação de biomarcadores de fertilidade, principalmente considerando-se as diferenças entre perfis metabólicos de raças distintas de touros e a heterogeneidade dos ejaculados. A superação destes desafios pode ser iniciada com um maior aproveitamento dos resultados já obtidos e futuros, com a aplicação de análises mais avançadas e com eficácia em elevado número de dados. Para tal, podem ser utilizados modelos estatísticos de inteligência artificial, cuja aplicação pode aumentar a acurácia das observações obtidas, bem como aproximá-las da aplicação pelo setor de produção animal.(AU)

Studies on sperm physiology demonstrate that fertility outcomes and sperm post-cryopreservation have an important relation with sperm energy metabolism efficiency and ability to maintain oxidative homeostasis. Knowledge on sperm physiology has been enhanced, continually, with the application of molecular profiling analysis, focusing on metabolomics. Molecular analysis allowed the identification of important classes of metabolites in sperm physiology, as well as potential fertility biomarkers, including in bovine. Despite all developments, there is still no isolated assessment available capable of estimating fertility on sperm samples. There are several challenges to be overcome for the validation of fertility biomarkers, especially considering the metabolic profiles differences between bull breeds and the ejaculate heterogeneity. Overcoming these challenges could start with the application of more advanced and effective data analysis from research database already obtained, as well as future ones. To this end, statistical models of artificial intelligence can be used, whose application can increase the accuracy of the observations obtained, as well as bringing them closer to the application by the animal production sector.(AU)

Análises computadorizadas da motilidade espermática (CASA): conceitos e possibilidades de padrões / Computerized analysis of sperm motility (CASA): concepts and possibilities of standards

O melhoramento genético possibilitou a evolução da eficiência e taxas de desfrute da pecuária nacional. A biotécnica da IATF (Inseminação Artificial por Tempo Fixo) consolidou-se como a principal ferramenta de disseminação de genética melhorada em rebanhos de leite e de corte. A avaliação espermática laboratorial tem o objetivo de analisar o potencial de reprodutores/partidas de sêmen e buscar a desafiadora tarefa de determinar e estabelecer características confiáveis que possam ser utilizadas como indicadores de fertilidade. Nesse contexto emerge o sistema CASA (Computer-Assisted Sperm Analysis) como ferramenta promissora para obtenção de parâmetros indicativos de fertilidade seminal.(AU)

Genetic improvement enabled the evolution and efficiencies of national livestock activity. The IATF (Fixed Time Artificial Insemination) biotechnology, has established itself as the main tool for the dissemination of improved genetics in dairy and beef herds. Laboratory sperm evaluation aims to analyze the potential of a sires/semen batches and seek the challenging task of determining and establishing reliable characteristics that can be used as fertility indicators. In this context, the computerized system of sperm motility (CASA) emerges as a promising tool for obtaining parameters indicative of seminal fertility.(AU)

Growth performance, reproductive parameters and fertility measures in young Nellore bulls with divergent feed efficiency

The growth, sexual maturity and fertility-related parameters related of young Nellore bulls with divergent residual feed intake (RFI) raised on pasture were evaluated. After classification of 48 young males as low and high RFI (more and less efficient, respectively), the animals were evaluated for growth and reproductive parameters at 28-day intervals from 14.3 to 24.6 months of age. The semen was cryopreserved in the last sampling and fresh and post-thaw semen samples were evaluated. Low RFI bulls exhibited higher initial and final body weight (P < 0.05), but feed intake, body condition score and growth measures evaluated by carcass ultrasound were unaffected by RFI (P > 0.05). The scrotal circumference, sperm concentration, defects, and quality of fresh semen, and ultrasonographic testicular characteristics were unaffected by RFI (P > 0.05). However, velocity parameters such as average path and curvilinear velocities determined by computer-assisted sperm analysis of thawed semen submitted to the rapid thermoresistance test were improved (P < 0.05) in low RFI bulls, but this improvement in quality did not enhance in vitro sperm fertilizing ability. Our results demonstrated significant differences in metabolism and growth performance between bulls of divergent RFI. In addition, there was slight improvement in the semen quality of bulls with low RFI bulls, but this did not enhance in vitro fertilizing ability. Selection of beef bulls for RFI can be performed, which will result in economic benefits by improving the growth performance of the animals without affecting reproductive parameters.(AU)

Fertility disorders in male dogs

Male dog fertility disorders are usually troublesome and challenging for a practicing veterinarian. It may be generally assumed, that reproductive potential in this species is lower than in farm animals and it is still decreasing. This situation starts to be similar to human medicine, where we observe dramatic drop of reproductive capacity, which resulted in the need of implementation of Assisted Reproductive Technologies (ART). Situation in dogs is more complicated owing the fact, that the use of ART meets many obstacles. Low fertility potential in dogs appears to be the result of variable factors such as: specific criteria of selection for reproduction in which fertility performance in not a priority, lack of periodical obligatory fertility check, species specific predisposition for many reproductive diseases and no age limit for reproductive use of males. Dogs are kept in human environment and exposition for civilizational byproducts influences negatively not only on our health, but also on health our 'minor brothers'. It should be bear in mind, that reproductive organs are very sensitive for environmental factors disrupting homeostatic balance. The decline in male dog fertility over the past decades was proved, with potential link to environmental contaminants (4). They were found in pet foods and were also detected in the sperm and testes of adult dogs causing a detrimental effects on sperm function. Over the 26 years of the study of Lea et al. (4), authors found a decrease in the percentage of normal motile sperm. Between 1988 and 1998, sperm motility declined by 2.5 per cent per year. Then from 2002 to 2014 sperm motility continued to decline at a rate of 1.2% per year. In addition, the male pups had an increased incidence of cryptorchidism. Basics of physiology of reproduction of male dogs. Normally the puberty in males is associated with presence of normal sperm cells in genital organs. It is reached in male dogs at age around 5-6 months. Such a young dog obviously cannot be used for reproduction. Reproductive maturity is associated later, with development of normal sexual behavior and production of sufficient number of normal, fertilizing competent spermatozoa. It corresponds with 12-18 months of animal age. Testicular descent is completed usually before weaning period, but sometimes testicles may reach scrotum later, but never after the end of 6 month of age. That time inguinal canals start to be so narrow, that caudal passing of gonads is unlikely. Male dogs have only one accessory sexual gland - prostate, which produces vast portion of seminal plasma.(AU)

Morfologia espermática em touros: quais os principais defeitos e o porquê ocorrem / Sperm morphology in bulls: which are the main defects and why they occur

A morfologia espermática é uma característica seminal que está associada à fertilidade e é, portanto, um componente importante na rotina do controle de qualidade em Centros de Coleta e Processamento de Sêmen (CCPS). É utilizada para caracterizar e quantificar os vários tipos de anormalidades nas células espermáticas do touro, usando preparação em montagem úmida para microscopia de Contraste de Interferência Diferencial (DIC), Contraste de Fase (CF) e Lâmina Corada (LC). O perfil da morfologia espermática permite a tomada de decisão sobre o aproveitamento ou descarte de um ejaculado para criopreservação e predizer a fertilidade de uma amostra de sêmen. Alterações no espermograma, com evidências do histórico e exame físico do touro, levam a interpretação da função testicular anormal, e consequentemente, ao diagnóstico, tratamento e prognóstico, se for o caso. As causas mais comuns de uma espermatogênese anormal nos touros incluem: termorregulação testicular anormal, desequilíbrios hormonais, estresse de manejo, ambiental e nutricional, efeitos de toxinas ou expressão de genes deletérios, além de defeitos de origem genética. Conhecendo-se a estrutura do espermatozoide, torna-se mais fácil a identificação das anormalidades espermáticas bem como a descrição das mesmas e uma melhor compreensão de sua origem.(AU)

Sperm morphology is a seminal trait that is associated with fertility and is therefore an important component of routine quality control in Semen Collection and Processing Centers (SCPC). It is used to characterize and quantify the various types of abnormalities in bull sperm cells, using wet mount preparation for Differential Interference Contrast (DIC), Phase Contrast (PC) and Slides Smear (SS) microscopy. The sperm morphology profile allows decision making on the use or disposal of an ejaculate for cryopreservation and predicts the fertility of a semen sample. Changes in sperm morphology may indicate that fertility may be impacted and therefore it is important to routinely monitor ejaculates. An abnormal spermogram with evidence from a history and physical examination of the bull can lead to the interpretation of abnormal testicular function, and consequently, to the diagnosis, treatment and prognosis, if any. The most common causes of abnormal spermatogenesis in bulls include: abnormal testicular thermoregulation, hormonal imbalances, management, environmental and nutritional stress, effects of toxins or expression of deleterious genes, in addition to defects of genetic origin. Knowledge in the structure of the sperm makes easier the identification of sperm abnormalities, as well as their description and provides a better understanding of their origin.(AU)

Low versus high antral follicle count on the fertility of timed AI Nelore heifers / Baixa versus alta contagem de folículos antrais na fertilidade de novilhas Nelore inseminadas em tempo-fixo

This study aimed to determine the effect of antral follicle count (AFC), and pubertal status on the fertility of beef heifers. In this study, 230 Nelore heifers, 20±2 months of age, were subjected to an estradiol progesterone-based timed artificial insemination (TAI) program. On Day 0 of the TAI protocol, the heifers were examined by transrectal ultrasound to record videos of the ovaries. Later, in the darkroom of the laboratory of images, the videos were analyzed for AFC (≥ 3 mm) of each ovary. Females who failed the first TAI were resynchronized with the same hormonal protocol. The pregnancy status was evaluated by ultrasonography 30 days after each FTAI. The general mean of the AFC was 22.0 follicles. Thus, the heifers were divided into 2 groups according to AFC: Low AFC (˂ 22 follicles, n = 114), and High AFC (≥ 22 follicles, n = 116). No differences (P > 0.05) in the pregnancy per AI (P/AI) were observed between the Low and High AFC groups, and between pubertal and prepubertal categories. The P/AI was not different between heifers that displayed or did not estrus (P = 0.2). However, considering the estrus response of each AFC group, High AFC heifers that displayed estrus had greater P/AI (P = 0.01) than High AFC heifers that did not display estrus. In summary, AFC and pubertal status did not affect the fertility of Nelore heifers. In contrast, the P/AI of heifers that did not display estrus was lower than heifers observed in estrus only in the High AFC group.(AU)

Esse estudo teve como objetivo determinar o efeito da contagem de folículos antrais (CFA) e da maturidade sexual na fertilidade de novilhas de corte. Neste estudo, 230 novilhas Nelore, com 20 ± 2 meses de idade, foram submetidas a um protocolo de inseminação em tempo-fixo (IATF) a base de estradiol e progesterona. No Dia 0 do protocolo de IATF as novilhas foram examinadas por ultrassonografia transretal e vídeos dos ovários foram gravados para posterior CFA (≥ 3 mm) realizada na sala escura do laboratório de imagens. Trinta dias após a ultrassonografia, as fêmeas que falharam na primeira IATF foram ressincronizadas com o mesmo protocolo hormonal. A prenhez foi avaliada por ultrassonografia 30 dias após cada IATF. A média geral da CFA foi de 22 folículos; assim, as novilhas foram divididas em 2 grupos de acordo com a CFA: CFA baixa (˂ 22 folículos, n=114) e CFA alta (≥ 22 folículos, n=116). A prenhez por IA (P/IA) foi semelhante (P > 0,05) entre os grupos CFA baixa e alta e entre novilhas púberes e pré-púberes. A P/IA não foi diferente entre as novilhas que apresentaram ou não cio (P = 0,2). No entanto, novilhas com CFA alta que apresentaram cio tiveram maior P/IA (P = 0,01) do que novilhas com CFA alta que não apresentaram cio. Em conclusão, a CFA e a maturidade sexual não afetaram a fertilidade de novilhas. Por outro lado, a P/IA das novilhas que apresentaram cio foi maior do que das novilhas não observadas em cio apenas no grupo CFA alta.(AU)

Classificação andrológica por pontos e características andrológicas na avaliação reprodutiva de touros da raça Gir candidatos ao teste de progênie / Andrological points classification and andrological reproductive evaluation characteristics in Gir bulls candidates for progenietest

A eficiência reprodutiva deve ser avaliada em propriedades leiteiras para identificação de indivíduos com problemas reprodutivos ligados tanto à fêmea quanto ao macho, visando minimizar perdas na produção. A reprodução está entre os fatores que afetam a produtividade dos rebanhos e chama atenção, em alguns momentos, pelos baixos índices na pecuária tradicional. Objetivou-se estudar a ferramenta de avaliação espermática denominada índice CAP e sua correlação com as análises biométricas e morfológicas do sêmen de touros da raça Gir. Foram utilizados 34 touros da raça Gir (Bos taurus indicus) aptidão leiteira, hígidos, com 17 a 31 meses de idade e 450 kg de massa corporal média. Os touros foram submetidos a exame andrológico (avaliação física incluindo biometria testicular e morfológica do sêmen), seguido pela classificação andrológica por pontos (índice CAP). Foram realizadas três coletas independentes para avaliar a qualidade espermática por touro durante o período do experimento. De acordo com a avaliação do índice CAP, os animais foram classificados como excelentes (17 %) e muito bons (83 %). O índice CAP correlacionou-se positivamente com o perímetro escrotal e as características físicas do sêmen.

Reproductive efficiency should be evaluated in dairy farms, when they are related to reproductive problems in both female and male. Breeding is among factors that affect herd productivity and draws attention by low rates of traditional livestock breeding. The aim was to study sperm evaluation tool known as the CAP index and its correlation with the biometric and morphological analyzes of Gir bulls semen. Thirty four healthy Gir bulls (Bos taurus indicus), dairy fitness, with 17 to 31 months of age with 450 kg of body mass were used. The bulls were submitted to andrological examination (physical evaluation including testicular biometry and semen morphological analysis) follow by andrological classification by points (CAP index). Three independent collections were carried out to evaluate sperm quality per bull during the experiment period According to the CAP index, animals were classified as excellent (17%) and as very good (83%). The CAP Index correlated positively with scrotal perimeter and semen physical characteristics.

Classificação andrológica por pontos e características andrológicas na avaliação reprodutiva de touros da raça Gir candidatos ao teste de progênie / Andrological points classification and andrological reproductive evaluation characteristics in Gir bulls candidates for progenietest

A eficiência reprodutiva deve ser avaliada em propriedades leiteiras para identificação de indivíduos com problemas reprodutivos ligados tanto à fêmea quanto ao macho, visando minimizar perdas na produção. A reprodução está entre os fatores que afetam a produtividade dos rebanhos e chama atenção, em alguns momentos, pelos baixos índices na pecuária tradicional. Objetivou-se estudar a ferramenta de avaliação espermática denominada índice CAP e sua correlação com as análises biométricas e morfológicas do sêmen de touros da raça Gir. Foram utilizados 34 touros da raça Gir (Bos taurus indicus) aptidão leiteira, hígidos, com 17 a 31 meses de idade e 450 kg de massa corporal média. Os touros foram submetidos a exame andrológico (avaliação física incluindo biometria testicular e morfológica do sêmen), seguido pela classificação andrológica por pontos (índice CAP). Foram realizadas três coletas independentes para avaliar a qualidade espermática por touro durante o período do experimento. De acordo com a avaliação do índice CAP, os animais foram classificados como excelentes (17 %) e muito bons (83 %). O índice CAP correlacionou-se positivamente com o perímetro escrotal e as características físicas do sêmen.(AU)

Reproductive efficiency should be evaluated in dairy farms, when they are related to reproductive problems in both female and male. Breeding is among factors that affect herd productivity and draws attention by low rates of traditional livestock breeding. The aim was to study sperm evaluation tool known as the CAP index and its correlation with the biometric and morphological analyzes of Gir bulls semen. Thirty four healthy Gir bulls (Bos taurus indicus), dairy fitness, with 17 to 31 months of age with 450 kg of body mass were used. The bulls were submitted to andrological examination (physical evaluation including testicular biometry and semen morphological analysis) follow by andrological classification by points (CAP index). Three independent collections were carried out to evaluate sperm quality per bull during the experiment period According to the CAP index, animals were classified as excellent (17%) and as very good (83%). The CAP Index correlated positively with scrotal perimeter and semen physical characteristics.(AU)

Métodos de coleta de amostra para exame de citologia endometrial em éguas com endometrite / Sample collection methods for endometrial cytology examination in mares with endometritis

A endometrite é definida como uma inflamação do endométrio, podendo ser aguda ou crônica, infecciosa ou não infecciosa. Essa afecção é de grande importância econômica na medicina veterinária, podendo resultar em morte embrionária, aborto e até tornar a égua infértil, sendo uma das afecções que mais comprometem a sanidade uterina, colocando em risco os índices de prenhez obtidos pós-cobertura, pós-inseminação, e pós-inovulação de embriões. Existem diversos métodos para diagnóstico e o mais utilizado a campo é a citologia endometrial/uterina. Também existem algumas formas de coleta de amostra para análise laboratorial pela citologia, tais como: escova ginecológica, swab uterino guiado por mandril metálico ou plástico descartável e lavado uterino de baixo volume, seguido de sedimentação ou centrifugação podendo ser complementada por citocentrifugação. O diagnóstico pela citologia endometrial por meio da técnica da escova ginecológica é a mais utilizada entre os médicos veterinários, pois trata-se de um método prático para execução e rápido quanto à obtenção dos resultados sobre a presença ou não da endometrite, facilitando a conduta terapêutica quanto à utilização das éguas para reprodução ou descarte. Objetivou-se com esse estudo citaras formas de diagnóstico da endometrite em éguas, enfatizando a citologia endometrial e técnicas para obtenção de amostra, identificando a técnica mais indicada por diversos autores.(AU)

Endometritis is defined as an inflammation of the endometrium, which may be acute or chronic, infectious or noninfectious. This condition is of great economic importance in veterinary medicine, and may result in embryonic death, abortion and even render the mare infertile, being one of the conditions that most compromise uterine health, putting at risk the pregnancy rates obtained post-coverage, postinsemination, and post-embryo transfer. There are several methods for diagnosis and the most used in the field is endometrial/uterine cytology. There are also some forms of sample collection for laboratory analysis by cytology, such as: gynecological brush, uterine swab guided by metallic mandrel or disposable plastic and low volume uterine lavage, followed by sedimentation or centrifugation and may be complemented by cytocentrifugation. Diagnosis by endometrial cytology using the gynecological brush technique is the most used among Veterinary Practitioners, because it is a practical method to execute and fast to obtain the results in the presence of endometritis, facilitating the therapeutic conduct regarding the use of mares for breeding or discarding. The objective of this study was to cite the diagnostic methods of endometritis in mares, emphasizing endometrial cytology and its techniques for obtaining a sample, identifying the most indicated technique by several authors.(AU)

Métodos de coleta de amostra para exame de citologia endometrial em éguas com endometrite / Sample collection methods for endometrial cytology examination in mares with endometritis

A endometrite é definida como uma inflamação do endométrio, podendo ser aguda ou crônica, infecciosa ou não infecciosa. Essa afecção é de grande importância econômica na medicina veterinária, podendo resultar em morte embrionária, aborto e até tornar a égua infértil, sendo uma das afecções que mais comprometem a sanidade uterina, colocando em risco os índices de prenhez obtidos pós-cobertura, pós-inseminação, e pós-inovulação de embriões. Existem diversos métodos para diagnóstico e o mais utilizado a campo é a citologia endometrial/uterina. Também existem algumas formas de coleta de amostra para análise laboratorial pela citologia, tais como: escova ginecológica, swab uterino guiado por mandril metálico ou plástico descartável e lavado uterino de baixo volume, seguido de sedimentação ou centrifugação podendo ser complementada por citocentrifugação. O diagnóstico pela citologia endometrial por meio da técnica da escova ginecológica é a mais utilizada entre os médicos veterinários, pois trata-se de um método prático para execução e rápido quanto à obtenção dos resultados sobre a presença ou não da endometrite, facilitando a conduta terapêutica quanto à utilização das éguas para reprodução ou descarte. Objetivou-se com esse estudo citaras formas de diagnóstico da endometrite em éguas, enfatizando a citologia endometrial e técnicas para obtenção de amostra, identificando a técnica mais indicada por diversos autores.

Endometritis is defined as an inflammation of the endometrium, which may be acute or chronic, infectious or noninfectious. This condition is of great economic importance in veterinary medicine, and may result in embryonic death, abortion and even render the mare infertile, being one of the conditions that most compromise uterine health, putting at risk the pregnancy rates obtained post-coverage, postinsemination, and post-embryo transfer. There are several methods for diagnosis and the most used in the field is endometrial/uterine cytology. There are also some forms of sample collection for laboratory analysis by cytology, such as: gynecological brush, uterine swab guided by metallic mandrel or disposable plastic and low volume uterine lavage, followed by sedimentation or centrifugation and may be complemented by cytocentrifugation. Diagnosis by endometrial cytology using the gynecological brush technique is the most used among Veterinary Practitioners, because it is a practical method to execute and fast to obtain the results in the presence of endometritis, facilitating the therapeutic conduct regarding the use of mares for breeding or discarding. The objective of this study was to cite the diagnostic methods of endometritis in mares, emphasizing endometrial cytology and its techniques for obtaining a sample, identifying the most indicated technique by several authors.

Factors influencing establishment of the ovarian reserve and their effects on fertility

A reserve of primordial follicles is set up in the ovaries of fetuses or neonates, depending on the species, and serves as the source of developing follicles throughout the reproductive lifespan. This review focuses on the cellular and molecular mechanisms currently known to control the establishment of this reserve, and their regulation by environmental factors. Most mutations in genes controlling germ cell proliferation and survival, meiosis or follicle assembly lead to the absence of primordial follicles or a sharp reduction in their number, incompatible with fertility in adults. Inadequate maternal nutrition affects the cellular metabolism, increases the oxidative stress and delays follicle formation in fetal ovaries. Despite the existence of compensation mechanisms of some developmental processes, the early-life nutritional environment imprints the long-term ability of follicles to enter growth and develop in adult ovaries. However, maternal undernutrition, overfeeding or high-fat diet during the establishment of the ovarian reserve does not seem to affect the fertility of the female offspring, unless their metabolism or neuroendocrine status is altered. Exposure of fetal or neonatal ovaries to excess steroids inhibits or stimulates follicle formation in a complex manner depending on the nature of the steroid, the dose and the animal species. Estrogens can control follicle formation through intra-ovarian mechanisms involving members of the TGF-beta family such as activin and BMP2. Early-life exposure to synthetic estrogens or environmental pollutants with estrogen-like activity impairs meiotic progression and follicle assembly, and affects long-term primordial follicle activation in adult ovaries. The effects of compounds with estrogen-like activity on the ovarian reserve can be transmitted to several generations through the female germline. Further investigations are needed to establish the earlylife effects of the environmental factors on the female reproductive lifespan and decipher the mechanisms of their epigenetic effects on the size and quality of the ovarian reserve.(AU)

Factors influencing establishment of the ovarian reserve and their effects on fertility

A reserve of primordial follicles is set up in the ovaries of fetuses or neonates, depending on the species, and serves as the source of developing follicles throughout the reproductive lifespan. This review focuses on the cellular and molecular mechanisms currently known to control the establishment of this reserve, and their regulation by environmental factors. Most mutations in genes controlling germ cell proliferation and survival, meiosis or follicle assembly lead to the absence of primordial follicles or a sharp reduction in their number, incompatible with fertility in adults. Inadequate maternal nutrition affects the cellular metabolism, increases the oxidative stress and delays follicle formation in fetal ovaries. Despite the existence of compensation mechanisms of some developmental processes, the early-life nutritional environment imprints the long-term ability of follicles to enter growth and develop in adult ovaries. However, maternal undernutrition, overfeeding or high-fat diet during the establishment of the ovarian reserve does not seem to affect the fertility of the female offspring, unless their metabolism or neuroendocrine status is altered. Exposure of fetal or neonatal ovaries to excess steroids inhibits or stimulates follicle formation in a complex manner depending on the nature of the steroid, the dose and the animal species. Estrogens can control follicle formation through intra-ovarian mechanisms involving members of the TGF-beta family such as activin and BMP2. Early-life exposure to synthetic estrogens or environmental pollutants with estrogen-like activity impairs meiotic progression and follicle assembly, and affects long-term primordial follicle activation in adult ovaries. The effects of compounds with estrogen-like activity on the ovarian reserve can be transmitted to several generations through the female germline. Further investigations are needed to establish the earlylife effects of the environmental factors on the female reproductive lifespan and decipher the mechanisms of their epigenetic effects on the size and quality of the ovarian reserve.

Physiological and cellular requirements for successful elongation of the preimplantationconceptus and the implications for fertility in lactating dairy cows

Elongation of the preimplantation conceptus is a prerequisite for maternal recognition of pregnancy and implantation in ruminants. Failures in this phase of development likely contribute for the subfertility of lactating dairy cows. This review will discuss our current understanding of the physiological and cellular requirements for successful elongation of the preimplantation conceptus and their potential deficiency in subfertile lactating dairy cows. Major requirements include the priming of the endometrium by ovarian steroids, reprogramming of trophectoderm cells at the onset of elongation, and intensification of the crosstalk between elongating conceptus and endometrium. Conceptus elongation and survival in dairy cows does not seem to be affected by lactation per se but seem to be altered in subgroups of cows with endocrine, metabolic and nutritional imbalances or deficiencies. These subgroups of cows include those suffering diseases postpartum, anovular cows enrolled in synchronization programs, and cows with low concentration of circulating steroids and IGF1. Success of conceptus elongation starts long before breeding and entails optimization of health and nutrition programs, especially during the transition period, and might be extended to the supplementation of endocrine and nutritional shortages at the time of breeding. Genetic selection will eventually become more important as researchers unravel the molecular control of reproduction and develop new fertility traits focused on pregnancy survival.

Physiological and cellular requirements for successful elongation of the preimplantationconceptus and the implications for fertility in lactating dairy cows

Elongation of the preimplantation conceptus is a prerequisite for maternal recognition of pregnancy and implantation in ruminants. Failures in this phase of development likely contribute for the subfertility of lactating dairy cows. This review will discuss our current understanding of the physiological and cellular requirements for successful elongation of the preimplantation conceptus and their potential deficiency in subfertile lactating dairy cows. Major requirements include the priming of the endometrium by ovarian steroids, reprogramming of trophectoderm cells at the onset of elongation, and intensification of the crosstalk between elongating conceptus and endometrium. Conceptus elongation and survival in dairy cows does not seem to be affected by lactation per se but seem to be altered in subgroups of cows with endocrine, metabolic and nutritional imbalances or deficiencies. These subgroups of cows include those suffering diseases postpartum, anovular cows enrolled in synchronization programs, and cows with low concentration of circulating steroids and IGF1. Success of conceptus elongation starts long before breeding and entails optimization of health and nutrition programs, especially during the transition period, and might be extended to the supplementation of endocrine and nutritional shortages at the time of breeding. Genetic selection will eventually become more important as researchers unravel the molecular control of reproduction and develop new fertility traits focused on pregnancy survival.(AU)

Comparison of sexual performance and testicular characteristics of melatonin treated Kivircik and Charollais rams during the non-breeding season / Comparação de desempenho reprodutivo e características testiculares de carneiros Kivircik e Charollais tratados com melatonina durante a estação não reprodutiva

This study was conducted to investigate the effects of melatonin implantation on basic testicular characteristics and reproductive performance of Kivircik and Charollais rams and ewes during the non-breeding season. In this study, 8 Kivircik and 6 Charollais rams were used. Rams were implanted with 54 mg melatonin according to the manufacturer's instructions. At melatonin implantation and at ram introduction the reproductive performance and testicular characteristics were evaluated. Throughout the experimental period, rams were permanently kept outdoors under conditions of natural day length and at ambient temperature. The effects of exogenous melatonin treatments on the reproductive performances of rams and ewes, estrus response, pregnancy rate, litter size and twinning rate of ewes were evaluated in all groups. Libido values were significantly higher in Charollais rams compared to Kivircik rams (P<0.001). Testicular volume (TV) was increased in both ram breeds. Scrotal length (SL) was also increased in both Kivircik and Charollais rams (P<0.01). In conclusion, we showed that the treatment of rams with slow release melatonin implants increased scrotal diameters and testicular volumes in both Kivircik and Charollais rams. Furthermore, melatonin implantation improved the reproductive performances of ewes naturally mated with these melatonin implanted rams during non-breeding season.(AU)

Esse estudo foi conduzido para investigar os efeitos de implantação de melatonina em características testiculares básicas e desempenho reprodutivo de carneiros Kivircik e Charollais durante a estação não reprodutiva. Nesse estudo, oito carneiros Kivircik e 6 Charollais foram utilizados. Foi implantado 54 mg de melatonina nos cordeiros de acordo com as instruções do produtor. Ao implantar a melatonina e à introdução do carneiro, foram avaliados o desempenho reprodutivo e as características testiculares. Ao longo do período experimenta, os cordeiros foram mantidos em ambiente externo sob condições de luz e ritmo circadiano naturais e à temperatura ambiente. O efeito de tratamento com melatonina exógena no desempenho reprodutivo de carneiros e ovelhas, resposta estral, taxa de prenhez, tamanho de ninhada e taxa de gemelaridade foram avaliados em todos os grupos. Valores de libido foram significativamente maiores em Charollais comparados a Kivircik (P<0.001). Volume testicular (VT) estava aumentado em ambas as raças. Comprimento escrotal (CE) também estava aumentado tanto em Kivircik quanto em Charollais (P<0.01). Conclui-se que o tratamento de carneiros com implantes de liberação lenta de melatonina aumentou diâmetro e volume testiculares tanto em carneiros Kivircik quanto em Charollais. Ademais, implantação de melatonina melhorou o desempenho reprodutivo de ovelhas naturalmente cruzadas com esses carneiros implantados com melatonina durante o período não reprodutivo.(AU)

Comparison of sexual performance and testicular characteristics of melatonin treated Kivircik and Charollais rams during the non-breeding season / Comparação de desempenho reprodutivo e características testiculares de carneiros Kivircik e Charollais tratados com melatonina durante a estação não reprodutiva

This study was conducted to investigate the effects of melatonin implantation on basic testicular characteristics and reproductive performance of Kivircik and Charollais rams and ewes during the non-breeding season. In this study, 8 Kivircik and 6 Charollais rams were used. Rams were implanted with 54 mg melatonin according to the manufacturer's instructions. At melatonin implantation and at ram introduction the reproductive performance and testicular characteristics were evaluated. Throughout the experimental period, rams were permanently kept outdoors under conditions of natural day length and at ambient temperature. The effects of exogenous melatonin treatments on the reproductive performances of rams and ewes, estrus response, pregnancy rate, litter size and twinning rate of ewes were evaluated in all groups. Libido values were significantly higher in Charollais rams compared to Kivircik rams (P<0.001). Testicular volume (TV) was increased in both ram breeds. Scrotal length (SL) was also increased in both Kivircik and Charollais rams (P<0.01). In conclusion, we showed that the treatment of rams with slow release melatonin implants increased scrotal diameters and testicular volumes in both Kivircik and Charollais rams. Furthermore, melatonin implantation improved the reproductive performances of ewes naturally mated with these melatonin implanted rams during non-breeding season.(AU)

Esse estudo foi conduzido para investigar os efeitos de implantação de melatonina em características testiculares básicas e desempenho reprodutivo de carneiros Kivircik e Charollais durante a estação não reprodutiva. Nesse estudo, oito carneiros Kivircik e 6 Charollais foram utilizados. Foi implantado 54 mg de melatonina nos cordeiros de acordo com as instruções do produtor. Ao implantar a melatonina e à introdução do carneiro, foram avaliados o desempenho reprodutivo e as características testiculares. Ao longo do período experimenta, os cordeiros foram mantidos em ambiente externo sob condições de luz e ritmo circadiano naturais e à temperatura ambiente. O efeito de tratamento com melatonina exógena no desempenho reprodutivo de carneiros e ovelhas, resposta estral, taxa de prenhez, tamanho de ninhada e taxa de gemelaridade foram avaliados em todos os grupos. Valores de libido foram significativamente maiores em Charollais comparados a Kivircik (P<0.001). Volume testicular (VT) estava aumentado em ambas as raças. Comprimento escrotal (CE) também estava aumentado tanto em Kivircik quanto em Charollais (P<0.01). Conclui-se que o tratamento de carneiros com implantes de liberação lenta de melatonina aumentou diâmetro e volume testiculares tanto em carneiros Kivircik quanto em Charollais. Ademais, implantação de melatonina melhorou o desempenho reprodutivo de ovelhas naturalmente cruzadas com esses carneiros implantados com melatonina durante o período não reprodutivo.(AU)