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)

Correlation between estrus onset and ovarian parameters in dairy goats / Início do estro e sua correlação com os parâmetros ovarianos em cabras leiteiras

This study assessed the effects of social dominance on the behavioral estrus and ovarian parameters of dairy goats subjected to synchronous estrus induction during the non-breeding season. Synchronous estrus was induced in 23 dairy goats allocated to collective pens. Ovarian ultrasonography was performed at 12 h intervals from device removal to ovulation. Upon estrus onset (EO) detection, the goats were immediately removed from the pens. Dominance was scored according to EO in relation to device removal in each pen, with HD - high dominants (<36 h; n = 8), MD - medium dominants (36 to 48 h; n = 10) and LD - low dominants (>48 h; n = 5). Goats in estrus underwent flexible time artificial insemination (FxTAI) according to EO. The estrus response was 100.0%. The interval to estrus was longer (P<0.05) in LD (53.7 ± 6.5 h) than in MD (37.9 ± 5.5 h) and HD goats (32.3 ± 6.6 h), while the interval from device removal to ovulation was similar (P>0.05) among all groups. The interval from EO to FxTAI was longer in HD goats compared to the other groups (P<0.05). In conclusion, although social hierarchy influenced the time of EO, the ovarian parameters, including ovulation, were not affected.

Este estudo avaliou os efeitos da dominância social sobre o comportamento do estro e os parâmetros ovarianos de cabras leiteiras submetidas à indução sincronizada do estro durante a estação não reprodutiva. A sincronização foi induzida em 23 cabras leiteira alocadas em baias coletivas. A ultrassonografia foi realizada em intervalos de 12 horas desde a remoção do dispositivo até a ovulação. Após a detecção do início do estro (EO), as cabras foram imediatamente removidas dos currais. A dominância foi pontuada de acordo com EO em relação à remoção do dispositivo, sendo: HD - alto dominante (<36 h; n = 8), MD - médio dominante (36 a 48 h; n = 10) e LD - baixo dominante (>478 h; n = 5). As cabras em estro foram inseminadas artificialmente em tempo flexível (FxTAI). O intervalo de estro foi maior (P<0,05) em LD (53,7 ± 6,5 h) do que em MD (37,9 ± 5,5 h) e cabras HD (32,3 ± 6,6 h), por sua vez, o intervalo entre a remoção do dispositivo e a ovulação foi semelhante (P> 0,05) em todos os grupos. O intervalo de EO a FxTAI foi maior em cabras HD quando comparado aos outros grupos (P<0,05). Em conclusão, embora a hierarquia social tenha influenciado o tempo de início do estro, os parâmetros ovarianos incluindo a ovulação não foram afetados.

Efficiency and accuracy of different ovulation inducers after progesterone device removal in crossbred multiparous cows / Eficiência e acurácia de diferentes indutores de ovulação após a remoção do dispositivo de progesterona em vacas mestiças multíparas

The aim of this study was to verify the efficiency and ovulation time after the administration of different inducers for synchronization of ovulation in beef cows. One hundred and eight non-lactating cows were distributed into the control group (CG; untreated; n=28), estradiol benzoate (EB) group (EBG; n=28); 17 beta-estradiol (17ßE) group (17ßEG; n=28), and deslorelin (DES) group (DESG; n=24). On day minus 11 (D-11) of the protocol, the CG underwent application of cloprostenol and ultrasound examination (US); on D0, progesterone (P4) was inserted plus EB; on D7, cloprostenol was applied; on D9, P4 was removed and cloprostenol plus 400 IU of equine chorionic gonadotropin (eCG) was injected. The EBG was subjected to treatment identical to that of the CG, except on D10, when the cows received EB. The 17ßE was subjected to the same protocol used in the CG except for the administration of 17ßE on D10. And, the DESG was subjected to the same treatment as the CG, except on D10, when the group received DES acetate. Twelve hours after the administration of EB, 17ßE and DES, ovarian US were performed every 6 hours. The preovulatory follicle (POF) diameters measured before ovulation were 19.5; 14.7; 18.7 and 19.8 mm respectively for CG, EBG, 17ßEG and DESG; and the time intervals between inducer application and ovulation were 20.2; 18.9; 21.0 and 22.5 hours respectively. In conclusion, all ovulation inducers were efficient in promoting ovulation; the inducers caused ovulation between 18.9 and 22.5 hours; EB promoted ovulation in a shorter time (P<0.05); 17ßE and DES showed greater variation in application/ovulation time between groups.

O objetivo do estudo foi verificar a eficiência e a ovulação após a administração de diferentes indutores para a sincronização da ovulação em vacas de corte. Cento e oito vacas não-lactantes foram distribuídas em grupo controle (GC; não tratadas; n=28); grupo benzoato de estradiol (BE) (GBE; n=28); grupo 17 beta-estradiol (17ßE) (G17ßE; n=28) e grupo deslorelina (DES) (GDES; n=24). No dia menos 11 (D-11) do protocolo, o GC recebeu cloprostenol e exame ultrassonográfico (US); ao D0, dispositivo de progesterona (P4) foi inserido mais BE; ao D7, cloprostenol foi aplicado; ao D9, a P4 foi removida e cloprostenol mais 400 UI de gonadotrofina coriônica equina (eCG) foi injetada. O GBE foi submetido a tratamento idêntico ao do GC, exceto ao D10, quando as vacas receberam BE. o G17ßE foi submetido ao mesmo protocolo usado no CG exceto pela administração de 17ßE ao D10. E, o GDES foi submetido ao mesmo tratamento que o CG, exceto ao D10, quando o grupo recebeu o acetato de DES. Doze horas após a administração de BE, 17ßE e DES, US ovarianos foram realizados a cada 6 horas. O diâmetro do folículo pré-ovulatório (FPO) medido antes da ovulação foi de 19,5; 14,7; 18,7 e 19,8 mm respectivamente para GC, GBE, G17ßE e GDES; e o intervalo de tempo entre a aplicação do indutor e ovulação foi 20,2; 18,9; 21;0 e 22,5 horas respectivamente. Em conclusão, todos os indutores da ovulação foram eficientes em promover a ovulação; os indutores acarretaram ovulação entre 18,9 e 22,5 horas; o BE promoveu a ovulação em menor espaço de tempo (P<0,05); 17ßE e DES demonstraram maior variação em aplicação/tempo de ovulação entre os grupos.

Hormonal induction and synchronization in the reproduction of Nile tilapia (Oreochromis niloticus) / Sincronização e indução hormonal na reprodução de tilápia do nilo (Oreochromis niloticus)

The present study aims to evaluate the sexual synchronization of Nile tilapia (Oreochromisniloticus) breeding herds under different distributions and days. This study was carried out during, a period of 21 experimental days. It was conducted in a randomized block design (DBC), in a factorial scheme 2 × 2 × 3, (male and female, with and without hormone induction, and three times blocks of 7, 14 and 21 days). A total of 324 fish were used, 180 females and 144 males, previously microchipped with approximately 250 ± 12.25 g of body weight.. Each tank contained 36 animals, with every three tanks comprising a block of which were repeated in time. Each of the tanks was composed of only males, another with 12 males and 24 females separated by a glass and a screen on the bottom and the third tank with only females. In each treatment, half of the animals (male and female) were applied the hCG hormone, in a single dose at a concentration of 5 IU / gram fish live weight. The animals were evaluated at 7, 14, and 21 days. After 667 hours-degree after application of the hormone was made extrusion and spermatozoa by celomatic massage. It was observed females that showed ease of extrusion of gametes. For the females, spawning index, absolute and relative fecundity, oocyte weight per 1 g, diameters, and germinal vesicle peripheral position were evaluated; the sperm concentration, volume (ml), motility (%), duration of sperm motility (min) and integrity were evaluated in males. The data were submitted to analysis of variance at the 5% level of significance. For females at 14 days there was greater ease of extrusion when separated from males, with hormone application . The distribution influenced the spawning weight, the larger diameter, and for the diameters smaller the days and induction presented interference. In males, the days interfered in the increase in volume and duration of semen motility independent of induction and environment, and finally, the environment interfered significantly in semen concentration.

O presente estudo tem como objetivo avaliar a sincronização sexual de reprodutores de tilápias do Nilo (Oreochromis niloticus) em cativeiro sob diferentes distribuições e dias. Este estudo foi realizado por um período de 21 dias experimentais. Foi conduzido num delineamento de blocos casualizados (DBC), num esquema fatorial 2×2×3, (sendo macho e fêmea, com e sem indução hormonal) e três tempos, 7, 14 e 21 dias (blocos). Foram utilizados 324 peixes, sendo 180 fêmeas e 144 machos, com aproximadamente 250 ± 12,25g de peso corporal, previamente microchipados. Cada tanque continha 36 animais, sendo que a cada três tanques compreendia um bloco do qual foram repetidos no tempo. Cada um dos tanques esteve composto por: somente machos, outro com 12 machos e 24 fêmeas separados por um vidro e uma tela na parte de baixo e o terceiro tanque com apenas fêmeas. Em cada tanque, metade dos peixes (macho e fêmeas) recebeu indução hormonal com hCG (CHORULON®), na concentração de 5000UI/grama de peso vivo por peixe. Os animais foram avaliados aos 7, 14, e 21 dias. Passado 667 horas-grau após aplicação do hormônio foi feita extrusão e espermeação mediante massagem celomática. Foram observadas fêmeas que apresentaram facilidade de extrusão de gametas. Para asfêmeas foram avaliadas as seguintes variáveis: índice de desova, fecundidade absoluta e relativa, o peso dos ovócitos por cada 1g, os diâmetros, e posição periférica da vesícula germinativa; nos machos, foram avaliados a concentração espermática, o volume (ml), motilidade (%), tempo de duração de motilidade espermática (min) e integridade. Os dados obtidos foram submetidos a análise de variância ao nível de 5% de significância. Observou-se para fêmeas aos 14 dias, mantidas separada dos machos e com aplicação de hormônios, maior facilidade de extrusão, peso da desova diâmetro dos ovócitos. Nos machos, os dias interferiram no aumento dovolume e na duração de motilidade do sêmen independente da indução e ambiente, e por fim, o ambiente interferiu significativamente na concentração do sêmen.

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

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

Antral follicle count, productive and reproductive parameters in Bos indicus and Bos indicus-taurus prepubertal heifers with early puberty induction / Contagem de folículos antrais, parâmetros produtivos e reprodutivos em novilhas pré-púberes Bos indicus e Bos indicus-taurus com indução precoce de puberdade

Prepubertal Nelore (G-N = 15) and crossbred Nelore x Aberdeen Angus heifers (G-NA = 15) were used for this study. AFC, live weight, body condition score (BCS), ovary and dominant follicle (DF) diameters were determined in each animal. Puberty induction was performed by insertion of a 4th use progesterone device (D0) which was removed on D12. Also, 1 mg estradiol benzoate was administered, and estrus intensity was classified (D12). At D21, the presence and diameter of the corpus luteum (CL) were registered. AFC was highly repeatable, regardless of hormone induction in both G-N (r=0.79) and G-NA (r=0.90). The mean AFC was greater in G-N compared to G-NA (24.2±8.5 vs. 17.7±9.0 follicles). A variation in BCS throughout the study occurred in G-NA, but not in G-N. The average weight gain (AWG) was greater in G-NA compared to G-N (0.69±0.33 vs. 0.40±0.29kg/day). The G-NA resulted in a larger diameter of DF at D12 than G-N (11.6±2.7 vs. 9.3±1.5mm). In conclusion, AFC was greater in Nelore heifers, although in both breeds this count was highly repeatable during puberty induction. Crossbred heifers had greater BCS and AWG with greater diameter of DF, indicating higher precocity when compared to Nelore heifers.

Novilhas pré-púberes Nelore (G-N=15) e mestiças Nelore x Aberdeen Angus (G-NA=15) foram utilizadas neste estudo. CFA, peso vivo, escore de condição corporal (ECC), diâmetros do ovário e folículo dominante (FD) foram determinados em cada animal. A indução da puberdade foi realizada pela inserção de um dispositivo de progesterona de quarto uso (D0), que foi retirado no D12. Além disso, 1mg de benzoato de estradiol foi administrado e a intensidade do estro foi classificada (D12). No D21, foram registrados a presença e o diâmetro do corpo lúteo (CL). A CFA foi altamente repetível, independentemente da indução hormonal em G-N (r=0,79) e G-NA (r=0,90). A CFA média foi maior em G-N em comparação com G-NA (24,2±8,5 vs. 17,7±9,0 folículos). Uma variação no ECC ao longo do estudo ocorreu em G-NA, mas não em G-N. O ganho de peso médio (GPM) foi maior em G-NA em comparação com G-N (0,69±0,33 vs. 0,40±0,29kg/dia). O G-NA resultou em um diâmetro maior de FD em D12 do que o G-N (11,6±2,7 vs. 9,3±1,5mm). Em conclusão, a CFA foi maior em novilhas Nelore, embora em ambas as raças essa contagem tenha sido altamente repetível durante a indução da puberdade. Novilhas mestiças apresentaram maior ECC e GPM com maior diâmetro de FD, indicando maior precocidade quando comparadas às novilhas Nelore.

Management of dairy calves and heifers and the economic impact on first lactation / Manejos de bezerras e novilhas leiteiras e seu impacto econômico na primeira lactação

Management of calves and heifers directly influence the future productivity of dairy animals. However, the pre-production stage is often neglected by farmers, as young cows do not yet produce milk and, therefore, revenue, while representing an important part of the total cost of the property. This study aimed to identify and determine the economic value of factors influencing the production in the first lactation of heifers in a herd. This was a case study carried out on a family property in the municipality of Patrocínio, state of Minas Gerais, using data from 54 heifers. Qualitative characteristics (sire, maternal grandsire, amount of colostrum consumed, antibiotics use on the first day of life; application of prostaglandin to induce estrus, application of prostaglandin for resynchronization, use of progesterone implant for resynchronization, occurrence of retention of placenta and/or abortion, induction of lactation) and quantitative characteristics (weight at 90 days, average daily gain at 90 days and age at first mating) were evaluated. Variables influencing the production in the first lactation were the application of antibiotics, retained placenta, induction of lactation and age at mating. The differences in milk revenue were -R$ 2,381.21 for the use of antibiotics in each female, -R$ 299.85 for each heat loss for the first mating, -R$ 5,043.11 for each lactation induction, -R$6,841.16 for each retained placenta with abortion and - R$1,060.96 for each case of retained placenta without abortion. Knowing the productive and economic consequences of each of these items provides the producer with subsidies for decision making, such as planning management strategies that avoid such losses, and choosing options to maximize the economic efficiency of production.

O manejo e os cuidados com as bezerras e novilhas influenciam diretamente a produtividade futura das fêmeas leiteiras. No entanto, muitas vezes a fase pré-produtiva é negligenciada pelos produtores, pois ao mesmo tempo que representam uma parcela importante do custo total da propriedade, as fêmeas jovens ainda não produzem leite e, portanto, receita. Objetivou-se identificar e determinar o valor econômico de fatores que influenciam na produção na primeira lactação de novilhas em um rebanho. O estudo de caso foi realizado em uma propriedade familiar na cidade de Patrocínio/MG, utilizando os dados de 54 novilhas. Foram avaliadas características qualitativas (pai, avô materno, quantidade de colostro consumida, uso de antibiótico no primeiro dia de vida; aplicação de prostaglandina para indução do cio, aplicação de prostaglandina para ressincronização, uso de implante de progesterona para ressincronização, ocorrência de retenção de placenta e/ou aborto, indução de lactação) e quantitativas (peso aos 90 dias, ganho médio diário aos 90 dias e idade à primeira cobertura). As variáveis que influenciaram a produção na primeira lactação foram a aplicação de antibióticos, retenção de placenta, indução à lactação e idade cobertura. As diferenças na receita do leite foram de -R$ 2.381,21 para o uso de antibióticos em cada fêmea, -R$ 299,85 para cada cio perdido para a primeira cobertura, -R$ 5.043,11 para cada indução de lactação, de -R$ 6.841,16 para cada ocorrência de retenção de placenta com aborto e de -R$ 1.060,96 para cada caso de retenção de placenta sem aborto. Conhecer as implicações produtivas e econômicas de cada um destes itens fornece ao produtor tem subsídios para tomadas de decisão, como planejar estratégias de manejo que evitem tais prejuízos, e escolher as opções que maximizem a eficiência econômica da produção.

The effect of Gonadotropin releasing hormone administration on fertility and embryonic loss in goats during the anoestrus period

Following the induction of oestrus out of season in small ruminants, low fertility and variations in fertility rates are associated with embryonic losses. One of the main causes of embryonic loss is luteal dysfunction. Gonadotropin Releasing Hormone (GnRH) supports the luteal structure, and increasing progesterone levels may be beneficial in terms of promoting embryonic life. The main objective of the present study was to evaluate the efficacy of GnRH administration following an oestrus induction protocol in the anoestrus season for preventing embryonic loss in goats having failure to conceive during the season. In the study, 106 Damascus goats aged 3-5 years and weighing 45-60 kg were used. The oestrus of 106 goats in the anoestrous group was stimulated with progesterone and pregnant mare serum gonadotropin (PMSG) treatment. Out of breeding season, goats were divided into the 4 following groups: GnRH0 (n = 27), GnRH7 (n = 26), GnRH0+7 (n = 27) and control (n = 26). In each goat, an intravaginal sponge (IS) containing 20 mg of fluorogestone acetate (FGA) was placed into the vagina and left for 9 days. With the withdrawal of the sponge, 550IU PMSG and 125 µg of d-cloprostenol were injected intramuscularly. Oestrus detection was made via teaser bucks for 3 days starting 24 h after withdrawal of the IS. Eighteen bucks known to be fertile were used for breeding. Goats in the oestrus period were mated via natural breeding. The GnRH analogue lecirelin was injected intramuscularly at breeding in the GnRH0 group, on day 7 post-breeding in the GnRH7 group, and both at breeding and on day 7 post-breeding in the GnRH0+7 group. No injections were given to the control group. Blood samples for progesterone measurement were taken by jugular vena puncturing on days 3, 6, 7, 10, 13, 16, and 19 after breeding from 10 randomly chosen goats in all groups. The goats with a level of > 3.5 ng/mL of progesterone on day 21 post-breeding were evaluated as pregnant. Pregnancy was also viewed on day 50 after breeding by real-time ultrasonography (USG) with a 5-7.5 MHz convex probe. The oestrus rate was 96.23% (102/106) in the goats. The rates of onset of oestrus between 36-48 h, 48-60 h and 60 h and beyond were 38.7% (41/106), 21.7% (23/106) and 35.8% (38/106), respectively. The total pregnancy rate was 35.8% (38/106). There were no statistically significant differences (P > 0.05) found for the pregnancy rate, embryonic death rate or progesterone concentration of the groups. However, serum progesterone levels were statistically different in the GnRH7 group compared with the control group (P < 0.05). After synchronisation, various anti-luteolytic strategies can be used to support corpus luteum development and elevate progesterone concentration in the luteal phase to decrease embryonic loss and increase reproductive performance. Therefore, application of GnRH to support the luteal structure and to increase progesterone levels may be beneficial in terms of supporting embryonic life. The results showed that GnRH treatment on the day 7 post-breeding following oestrus induction, including FGA and PMSG, can increase serum progesterone levels in Damascus goats in the anoestrus period. However, following oestrus induction in the anoestrus period, it was seen that GnRH treatment at breeding or on day 7 after breeding did not have any positive effect on embryonic loss or reproductive performance. In conclusion, it was considered that this protocol could be implemented successfully, yielding a 35% pregnancy rate in Damascus goats in the anoestrus period, but embryonic loss must be deeply studied in detail.(AU)

Induction of accessory corpus luteum in goats and sheep: From physiological basis to reproductive effects / Indução de corpo lúteo acessório em caprinos e ovinos: Das bases fisiológicas aos efeitos reprodutivos

A identificação das ondas foliculares ovarianas e de seu padrão hormonal revelou que os folículos ovarianos dominantes da onda ovulatória (FDOO) crescem em ambiente hormonal com predominância crescente de estradiol, diferentemente daqueles da primeira (FDPO) e das ondas foliculares intermediárias (FDOI), que crescem sob forte impacto da progesterona (P4). O hormônio luteinizante (LH) é considerado o hormônio gonadotrófico decisivo para direcionar se um folículo dominante ovulará (↑ LH) ou não (↓ LH). Estratégias foram desenvolvidas para aumentar o LH endógeno (administração de GnRH) ou fornecer LH exógeno de origem suína (pLH) ou, ainda, gonadotrofinas semelhantes ao LH, como gonadotrofina coriônica humana (hCG). Estas medidas são capazes de disponibilizar LH para maturação final, ovulação e/ou luteinização de FDPO ou FDOI, formando corpos lúteos acessórios (CLa). Como consequência, a P4 aumenta e favorece o estabelecimento da gestação, sobretudo em condições em que a P4 for o fator limitante para a implantação e manutenção embrionária. Em ovelhas e cabras, em diferentes estudos, a hCG foi administrada de cinco a sete dias após o início do estro e revelou que o FDPO responde positivamente à administração de hCG, formando CLa e/ou promovendo a hipertrofia do CL formado originalmente, aumentando a área luteal. O incremento da P4 normalmente acompanha o aumento de área do tecido luteal. Como efeito final e mais desejável, a gestação e o nascimento de cordeiros/cabritos também aumentam. Esses conceitos serão discutidos na presente revisão sobre indução de CLa em ovinos e caprinos.

The identification of ovarian follicular waves and associated hormonal milieux has revealed that dominant follicles of the ovulatory wave (OWDF) grow in a hormonal environment where there is an increasing predominance of estradiol, unlike first-wave dominant follicles (FWDF) and intermediatewave dominant follicles (IWDF), which grow under increasing progesterone (P4) concentrations. The luteinizing hormone (LH) is considered the decisive gonadotropic hormone to direct whether a dominant follicle will (↑ LH) or will not (↓ LH) ovulate. Based on this, strategies have been developed to either increase endogenous LH (GnRH administration) or provide exogenous LH of porcine origin (pLH) or LH-like gonadotropins, such as human chorionic gonadotropin (hCG). Such strategies are able to provide LH for final maturation, ovulation, and/or luteinization of the FWDF or IWDF, forming accessory corpora lutea (aCL). As a consequence, P4 increases and favors the establishment of pregnancy, particularly when P4 is the limiting factor for the success of the conceptus implantation and maintenance. In sheep and goats, previous studies have administered hCG five to seven days after the onset of estrus and revealed that FWDF positively respond to hCG administration by either forming aCLs and/or promoting hypertrofia of the original CL which, in turn, increases its luteal tissue area. Normally, P4 synthesis increases along with the increase in luteal tissue area. As a final and most desirable outcome, pregnancy and the birth of lambs/kids also increase. These concepts will be discussed in this review, focusing on aCL induction in sheep and goats.

Inseminação artificial em tempo fixo em pequenos ruminantes: desafio de um programa comercial / Artificial insemination at a fixed time in small ruminants: challenge of a commercial program

A Inseminação Artificial é uma das biotécnicas da reprodução animal mais utilizadas em pequenos ruminantes, contribuindo na incessante busca pelo melhoramento animal nesta espécie e apresentando-se viável ao pequeno, médio e grande produtor. Pelo método convencional, com observação de cio, ou com a utilização de protocolos de sincronização do estro e indução de ovulação, com uso da Inseminação Artificial em Tempo Fixo (IATF), diversos são os desafios encontrados quando da execução de um programa comercial. Entendendo a não padronização de manejo nas diversas unidades produtivas, bem como, a pouca ou nenhuma atenção dada, por grande parte destas, a questões de bem-estar animal, envolvendo conforto térmico, atendimento as necessidades nutricionais especificas de cada fase, a utilização de práticas rudimentares desencadeadoras de estresse, com conseguinte liberação de cortisol e, a pouca valorização da equipe de colaboradores, fatos estes, em diferentes níveis, têm contribuído na obtenção de resultados pouco desejáveis. Maior atenção carece ser dada na organização de toda cadeia produtiva e em especial, das unidades de produção de pequenos ruminantes.

Artificial Insemination is one of the most used animal reproduction biotechniques in small ruminants, contributing to the incessant search for animal improvement in this species and presenting itself as viable to small, medium and large producers. By the conventional method, with estrus observation, or with the use of estrus synchronization and ovulation induction protocols, using Fixed Time Artificial Insemination (IATF), there are several challenges encountered when executing a commercial program. Understanding the non-standardization of management in the various production units, as well as the little or no attention given, by most producers, to animal welfare issues, involving thermal comfort, meeting the specific nutritional needs of each phase, the use rudimentary practices that trigger stress, with the consequent release of cortisol and, the low appreciation of the team of employees, facts that, at different levels, have contributed to the achievement of undesirable results. Greater attention needs to be paid to the organization of the entire production chain and, in particular, of small ruminant production units.

Evaluation of corpus luteum vascularization in recipient mares by using color Doppler ultrasound

Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryotransfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Dopplerimaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in severalorgans, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound,the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were givenad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterineconsistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a lineartransducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 andsubjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated bycolor Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentrationon the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM).Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and...

Evaluation of corpus luteum vascularization in recipient mares by using color Doppler ultrasound

Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryotransfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Dopplerimaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in severalorgans, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound,the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were givenad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterineconsistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a lineartransducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 andsubjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated bycolor Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentrationon the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM).Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and...(AU)

Saliva crystallization in sheep subjected to estrus induction and synchronization protocols

Background: The crystallization of bodily fluids, primarily saliva, has been the subject of study in many species and is asimple alternative to detect estrus because it demands neither a significant financial investment nor qualified professionalsto execute the examination. Fern pattern crystallization has been described in the cervical and nasal mucus, saliva andtear secretion, and in colostrum. Changes in salivary crystallization during the reproduction cycle are related to differenthormonal concentrations in this period. Thus, the present study has evaluated the patterns of saliva crystallization in sheepsubjected to estrus induction and synchronization protocols.Materials, Methods & Results: The sample consisted of 11 crossbreed Corriedale sheep, which were evaluated during twoexperimental periods (spring and autumn), and that underwent induction and synchronizing estrus protocols. In a randomphase of the estrus cycle (day 0), each sheep was implanted with an intravaginal device (Primer®), impregnated with 0.36g of progesterone for seven days. This device was inserted according to manufacturer’s instructions of the manufacturerand with the assistance of a specific applicator. On the day of device removal (day 7), the animals received 0.0375 mg ofD-Cloprostenol (Prolise®) and 10 mg of Folltropin® extracted from the swine pituitary (NIH-FSH-P1 of Folltropin-V) byintramuscular administration. The saliva was collected at six points during the experimental periods: day 1 (3 days beforeplacement of the implant); day 4 (day of insertion of the implant); day 9 (5 days after the insertion of the implant); day11 (day of removal of the implant and application of hormones); day 12 (24 h after removal of the implant [presumableestrus]); and day 13 (48 h after removal of the implant). Smears containing 10 µL of saliva were observed under an opticallight microscope...

Saliva crystallization in sheep subjected to estrus induction and synchronization protocols

Background: The crystallization of bodily fluids, primarily saliva, has been the subject of study in many species and is asimple alternative to detect estrus because it demands neither a significant financial investment nor qualified professionalsto execute the examination. Fern pattern crystallization has been described in the cervical and nasal mucus, saliva andtear secretion, and in colostrum. Changes in salivary crystallization during the reproduction cycle are related to differenthormonal concentrations in this period. Thus, the present study has evaluated the patterns of saliva crystallization in sheepsubjected to estrus induction and synchronization protocols.Materials, Methods & Results: The sample consisted of 11 crossbreed Corriedale sheep, which were evaluated during twoexperimental periods (spring and autumn), and that underwent induction and synchronizing estrus protocols. In a randomphase of the estrus cycle (day 0), each sheep was implanted with an intravaginal device (Primer®), impregnated with 0.36g of progesterone for seven days. This device was inserted according to manufacturers instructions of the manufacturerand with the assistance of a specific applicator. On the day of device removal (day 7), the animals received 0.0375 mg ofD-Cloprostenol (Prolise®) and 10 mg of Folltropin® extracted from the swine pituitary (NIH-FSH-P1 of Folltropin-V) byintramuscular administration. The saliva was collected at six points during the experimental periods: day 1 (3 days beforeplacement of the implant); day 4 (day of insertion of the implant); day 9 (5 days after the insertion of the implant); day11 (day of removal of the implant and application of hormones); day 12 (24 h after removal of the implant [presumableestrus]); and day 13 (48 h after removal of the implant). Smears containing 10 µL of saliva were observed under an opticallight microscope...(AU)

Hormonal protocols for the synchronization and induction of synchronized estrus in dairy ewes kept under tropical conditions

Background: Lacaune is an important sheep breed and shows reproductive seasonality which affects dairy product supply. The most common hormonal protocols are based on progesterone-releasing devices in order to reach reproductive activity. Due to international consumer demand for natural, green, and clean methods, such issues encourage the minimal or absent use of synthetic hormones in livestock. In this sense, the present study tested the efficiency of induction and estrus synchronization protocols in lacaune ewes, considering: application interval of synthetic prostaglandin at the breeding season; length of synthetic progesterone exposure; and eCG dose at the outbreeding season. Materials, Methods & Results: In study 1: 52 ewes were submitted to estrus synchronization protocol using two doses of d-cloprostenol 7 or 9 days apart. In study 2: 47 ewes were submitted to estrus induction protocol using an intravaginal device containing 60 mg of medroxyprogesterone acetate maintained for 6, 9, or 12 days. In study 3: 46 ewes were submitted to synchronized estrus induction protocol using intravaginal progesterone device for six days. On the fifth day, d-cloprostenol and 300 IU or 400 IU of eCG were administered. For all studies, signs of estrus beginning/ending were recorded and natural mating was performed. After 30 days, transrectal ultrasound was performed for pregnancy diagnosis. In study 1, groups presented similar rate of estrus behavior (78.8%) and pregnancy (average 75.6%). Meanwhile, compared to G9days (37.8 ± 7.2 h), interval between the second dose of prostaglandin and beginning of estrus was smaller in G7days (31.5 ± 7.8 h). No difference was found among variables studied in study 2 (P > 0.05), nevertheless the SD for the estrus duration was shorter (P < 0.05) in G6days and G12 days when compared with the G9days . Equally, the SD...

Indução do estro e métodos para controle das fases do ciclo estral em cadelas / Induction of estrus and methods for control of estrous cycle in bitches

Os estudos referentes à manipulação do ciclo estral em cadelas aumentaram significativamente ao longo dos anos. Com a criação comercial de cães ganhando destaque a nível internacional, há uma busca por incrementação no manejo reprodutivo desses animais, bem como o tratamento de condições prejudiciais à fertilidade na cadela, outro motivo é o fato dos cães domésticos também poderem atuar como modelos experimentais para várias espécies de canídeos silvestres e para o homem. Isso tem sido associado a uma maior disponibilidade de fármacos indutores de estro, como agonistas dopaminérgicos, análogos do GnRH e protocolos com gonadotrofinas, a exemplo do eCG. A manipulação eficiente do ciclo estral é de grande valia para o aperfeiçoamento das biotecnologias da reprodução nessa espécie e, mesmo com o avanço das pesquisas, os fármacos ainda não foram suficientemente testados para se obter o conhecimento das suas completas ações, bem como para apontar seus pontos fortes e fracos. Essa revisão de literatura tem como objetivo ampliar as informações a respeito do assunto, abordando aspectos relacionados à fisiologia e endocrinologia reprodutiva na cadela, as particularidades do ciclo estral canino, descrevendo as alterações anatômicas, citológicas e hormonais, bem como os principais moduladores do ciclo estral de cadelas, apontando seus efeitos e controvérsias e proporcionando o surgimento de protocolos eficientes para a indução do estro nesses animais.

Studies on the manipulation of estrous cycle in bitches have increased significantly over the years. With the commercial breeding of dogs gaining prominence internationally, there has been a need for improvement of the reproductive management of these animals, as well as the treatment of conditions which are detrimental to bitches’ fertility. Another reason is that domestic dogs can also act as experimental models to several species of wild dogs and to man. This has been associated with a greater availability of estrus-induction pharmacological drugs, such as dopamine agonists, GnRH analogue and protocols with gonadotropin, such as eCG. Efficient manipulation of the estrous cycles is of great importance for the improvement of the reproductive biotechnology in this species. Notwithstanding the advances in research, the drugs have not yet been sufficiently tested in order to have their action fully understood, nor to identify their strengths and weakness. This literature review aims to expand the information on subject, addressing aspects related to the reproductive physiology and endocrinology in bitches, as well as the main modulators of the estrous cycle, pointing out their effects and differences and providing information for the creation of new efficient protocols for induction of estrus in those animals.

Indução do estro e métodos para controle das fases do ciclo estral em cadelas / Induction of estrus and methods for control of estrous cycle in bitches

Os estudos referentes à manipulação do ciclo estral em cadelas aumentaram significativamente ao longo dos anos. Com a criação comercial de cães ganhando destaque a nível internacional, há uma busca por incrementação no manejo reprodutivo desses animais, bem como o tratamento de condições prejudiciais à fertilidade na cadela, outro motivo é o fato dos cães domésticos também poderem atuar como modelos experimentais para várias espécies de canídeos silvestres e para o homem. Isso tem sido associado a uma maior disponibilidade de fármacos indutores de estro, como agonistas dopaminérgicos, análogos do GnRH e protocolos com gonadotrofinas, a exemplo do eCG. A manipulação eficiente do ciclo estral é de grande valia para o aperfeiçoamento das biotecnologias da reprodução nessa espécie e, mesmo com o avanço das pesquisas, os fármacos ainda não foram suficientemente testados para se obter o conhecimento das suas completas ações, bem como para apontar seus pontos fortes e fracos. Essa revisão de literatura tem como objetivo ampliar as informações a respeito do assunto, abordando aspectos relacionados à fisiologia e endocrinologia reprodutiva na cadela, as particularidades do ciclo estral canino, descrevendo as alterações anatômicas, citológicas e hormonais, bem como os principais moduladores do ciclo estral de cadelas, apontando seus efeitos e controvérsias e proporcionando o surgimento de protocolos eficientes para a indução do estro nesses animais.(AU)

Studies on the manipulation of estrous cycle in bitches have increased significantly over the years. With the commercial breeding of dogs gaining prominence internationally, there has been a need for improvement of the reproductive management of these animals, as well as the treatment of conditions which are detrimental to bitches fertility. Another reason is that domestic dogs can also act as experimental models to several species of wild dogs and to man. This has been associated with a greater availability of estrus-induction pharmacological drugs, such as dopamine agonists, GnRH analogue and protocols with gonadotropin, such as eCG. Efficient manipulation of the estrous cycles is of great importance for the improvement of the reproductive biotechnology in this species. Notwithstanding the advances in research, the drugs have not yet been sufficiently tested in order to have their action fully understood, nor to identify their strengths and weakness. This literature review aims to expand the information on subject, addressing aspects related to the reproductive physiology and endocrinology in bitches, as well as the main modulators of the estrous cycle, pointing out their effects and differences and providing information for the creation of new efficient protocols for induction of estrus in those animals.(AU)

Indução do estro pós-parto de cabras suplementadas com diferentes fontes de ácidos graxos poliinsaturados / Induction of the post-breeding stem of additional goats with different sources of polynesaturated fatty acids

O objetivo deste trabalho foi avaliar o efeito da inclusão de diferentes fontes de ácidos graxos poliinsaturados sobre a resposta à indução do estro pós-parto em cabras. Trinta e oito cabras prenhes, homogêneas em peso escore e idade, foram divididas em três grupos alimentares: Grupo Controle (GC), Linhaça (GL) e Alga (GA). O estro foi sincronizado aos 40 dias pós-parição e foram avaliadas a taxa de sincronização, taxa de ovulação e a funcionalidade do corpo lúteo. Os animais do GA, 76,9% apresentaram estro após o protocolo hormonal, superior aos 33,3% do GC. O GL não diferiu estatisticamente de GC e GA, com uma taxa de 57,9%. A taxa de ovulação e a área luteal não foram influenciadas pelas diferentes dietas experimentais.

The objective of this work was to evaluate the effect of the inclusion of different sources of polyunsaturated fatty acids on the response to induction of postpartum estrus in goats. Thirty-eight pregnant goats, homogeneous in weight and age, were divided into three groups: Control Group (CG), Linseed (GL) and Algae (GA). Estrus was synchronized at 40 days postpartum and the synchronization rate, ovulation rate and corpus luteum function were evaluated. The GA animals, 76.9% presented estrus after the hormonal protocol, superior to 33.3% of the CG. The GL did not differ statistically from GC and GA, with a rate of 57.9%. The ovulation rate and the luteal area were not influenced by the different experimental diets.

Indução do estro pós-parto de cabras suplementadas com diferentes fontes de ácidos graxos poliinsaturados / Induction of the post-breeding stem of additional goats with different sources of polynesaturated fatty acids

O objetivo deste trabalho foi avaliar o efeito da inclusão de diferentes fontes de ácidos graxos poliinsaturados sobre a resposta à indução do estro pós-parto em cabras. Trinta e oito cabras prenhes, homogêneas em peso escore e idade, foram divididas em três grupos alimentares: Grupo Controle (GC), Linhaça (GL) e Alga (GA). O estro foi sincronizado aos 40 dias pós-parição e foram avaliadas a taxa de sincronização, taxa de ovulação e a funcionalidade do corpo lúteo. Os animais do GA, 76,9% apresentaram estro após o protocolo hormonal, superior aos 33,3% do GC. O GL não diferiu estatisticamente de GC e GA, com uma taxa de 57,9%. A taxa de ovulação e a área luteal não foram influenciadas pelas diferentes dietas experimentais.(AU)

The objective of this work was to evaluate the effect of the inclusion of different sources of polyunsaturated fatty acids on the response to induction of postpartum estrus in goats. Thirty-eight pregnant goats, homogeneous in weight and age, were divided into three groups: Control Group (CG), Linseed (GL) and Algae (GA). Estrus was synchronized at 40 days postpartum and the synchronization rate, ovulation rate and corpus luteum function were evaluated. The GA animals, 76.9% presented estrus after the hormonal protocol, superior to 33.3% of the CG. The GL did not differ statistically from GC and GA, with a rate of 57.9%. The ovulation rate and the luteal area were not influenced by the different experimental diets.(AU)

Technical recommendations for artificial insemination in sheep

Artificial insemination (AI) was the first important biotechnology applied to improve the genetics of farm animals. It allows the rapid and massive diffusion of desirable characteristics of males with high productive potential. We describe the different types of estrus induction and synchronization techniques and the use of the AI with fresh, chilled or frozen semen. Through the adequacy of the protocols of estrus synchronization and AI to the different production systems, the efficient use of reproductive techniques is possible, reaching acceptable pregnancy rates. Summary of reproductive results obtained using cervical and laparoscopic AI are presented.(AU)