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To date, there have been no studies testing the capacity of GnRH analogs and respective doses to induce a LH peak in sheep. In this sense, the present study aimed to evaluate the capacity of different synthetic forms and doses of GnRH in inducing LH release in sheep, and the effect of GnRH administration at timed artificial insemination (TAI) on pregnancy per timed-AI. In experiment 1, ewes (n = 40) received an intravaginal device (IVD) of medroxyprogesterone acetate (MPA; 60 mg) for 7 d and prostaglandin F2α analog on Day 5. On Day 7, the ewes were allocated randomly into one of eight groups (n = 5/group), which received a GnRH analog at a specific dose, as follows: lecirelin (12.5 or 25 µg), gonadorelin (50 or 100 µg), buserelin acetate (4.2 or 8.4 µg), or deslorelin (375 or 750 µg). Blood samples for LH determination were obtained at 0, 2, 4, and 6 h after GnRH and the IVDs were removed after the last blood collection. The maximal LH concentration induced by gonadorelin at doses of 50 µg and 100 µg (12.0 ± 2.4 ng/mL and 28.6 ± 7.1 ng/mL, respectively) was lower (P < 0.05) than serum LH induced by 8.4 µg of buserelin (78.9 ± 12.9 ng/mL), 375 µg and 750 µg of deslorelin (75.6 ± 7.4 ng/mL and 72.1 ± 10.6 ng/mL, respectively) and 12.5 µg and 25 µg of lecirelin (73.3 ± 17.8 ng/mL and 61.6 ± 5.9 ng/mL, respectively). However, the maximal LH concentration induced by 4.2 µg of buserelin (49.4 ± 5.9 ng/mL) was similar (P > 0.05) to the 100 µg of gonadorelin. The total release of LH (area under the curve - AUC) after treatment with 50 µg of gonadorelin (31.7 ± 5.9 ng h/mL) was lower (P < 0.05) than after other agonists. In a second experiment, 330 ewes were treated with IVD containing MPA for 7 d. Simultaneously with IVD removal, 250 µg of cloprostenol and 200 IU of eCG were administered. Then, ewes were assigned randomly to either no further treatment (control); or to receive 4.2 µg of buserelin acetate (GnRH group) at cervical TAI, which was performed with fresh semen 54 h after IVD withdrawal in all the animals. Higher pregnancy per timed-AI was observed for GnRH (50.3 %) compared to control (40.7 %). We conclude that buserelin acetate (8.4 µg), lecirelin (12.5 and 25 µg) and deslorelin (375 and 750 µg) induced a greater stimulatory effect on LH secretion than gonadorelin treatment. Furthermore, buserelin acetate treatment at TAI increased pregnancy per timed-AI in ewes previously treated with MPA and eCG.

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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.

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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)

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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...

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The aim of the study was to determine the time after treatment with a 4.7 mg deslorelin implant until Tomcat spermatogenesis activity was restored, and seminal parameters reached pre-implant values. Tomcats (n = 6) were randomly assigned to one of two treatments. Three cats (n = 3) received a deslorelin implant (4.7 mG; Suprelorin®, Virbac, France) in the interscapular subcutaneous region whereas three (n = 3) received no implant and served as control group. Semen samples were collected by electroejaculation every 4 wk from 3 mo before treatment (pretreatment samples) until reestablishment of pre-treatment sperm quality, 32 mo post-implant insertion (PI). Each semen sample was assessed for motility, velocity, concentration, total sperm count, viability, acrosome integrity, plasma membrane integrity and sperm morphology. After semen collection, testicular volume and presence/absence of penile spines were recorded. Additionally, blood samples were taken to measure testosterone concentration. An increase in sperm concentration and total sperm count was present 1 mo PI despite of an abrupt decrease in serum testosterone concentrations after 2-4 weeks. This initial stimulatory effect was followed by a decrease in seminal parameters, reduction of testicular volume and disappearance of penile spines 2 mo PI. A single Suprelorin® 4.7 mg implant suppressed sperm production for 22-25 months. No clinically side effect was observed during the study period. All toms returned to their initial seminal quality 23-28 months after treatment. Therefore, we conclude that Suprelorin® 4.7 mg is a safe option for reversible reproduction control during long periods in tomcats.

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O objetivo do estudo foi verificar a eficiência da deslorelina (DES) como indutora da ovulação em protocolos de inseminação artificial em tempo fixo (IATF) sobre as taxas de prenhez (TP) de vacas primíparas Bos taurus indicus. Foram utilizados 176 animais, distribuídos em três grupos: GNDES (Grupo Não DES; n= 59), que recebeu no dia 0 (d0) um dispositivo intravaginal com 0,558 g de progesterona (P4) + 2,0 mg de benzoato de estradiol (BE) (IM); no d8 remoção da P4 + 0,5 mg de cipionato de estradiol (CE) + 150 g de cloprostenol + 400 UI de gonadotrofina coriônica equina (eCG); em d10 foi executada a IATF; GDES (Grupo DES; n=60) o mesmo que GNDES porém 1,0 mg (IM) de DES no momento da IATF; GDES6 (Grupo Deslorelina 6 horas; n=57) o mesmo que GDES, porém com a DES aplicada 6 horas antes da IATF. Os dados foram submetidos à análise estatística mediante o Programa SAS (2014). O estudo resultou em taxa de prenhez (TP) na IATF e no final da estação de monta, respectivamente para GNDES, GDES e GDES6 em 40,6; 53,3; 43,8 % e 72,9; 81,7; 70,2 %. Concluiu-se que a DES proporcionou em números absolutos indicativo de melhoria na TP à IATF nos grupos tratados frente ao controle; o ECC, dias abertos e o status reprodutivo (anestro ou ciclicidade) não influenciaram a TP à IATF, aos 60 dias e ao final da estação de monta.

The aim of the study was to verify the efficiency of deslorelin (DES) as inductor of ovulation in timed-artificial insemination (TAI) protocols on pregnancy rate (PR) in primiparous Bos taurus indicus cows. Hundred seventy six animals were divided into three groups (G): GNDES (Group No Deslorelin; n = 59) which received on day 0 (d0) an intravaginal device with 0.558 g of progesterone (P4) + 2.0 mg estradiol benzoate (EB) (IM); d8 P4 removal + 0.5 mg of estradiol cypionate (EC) + 150 g of cloprostenol + 400 IU of equine chorionic gonadotropin (eCG); in d10 TAI was proceeded; GDES (DES group; n = 60) the same as GNDES + 1.0 mg (IM) DES acetate in TAI day; GDES6 (DES applied 6 hours before TAI, n = 57) the same as GDES, but DES injected 6 hours before TAI. The pregnancy rate (PR) in TAI and at the end of the breeding season (BS) was respectively 40.6; 53.3; 43.8% and 72.9; 81.7; 70.2% in GNDES, GDES and GDES6. In conclusion, the DES brought an indicative of improvement in the PR for TAI, in the treated groups (3.2 to 12.7 % more) than control, however without significance; the BCS, open days and the reproductive status of anestrous or cyclicality, did not influenced the PR in TAI at 60 days or at the end of the BS.

El objetivo del estudio ha sido verificar la eficiencia de la deslorelina (DES) como inductora de la ovulación en protocolos de inseminación artificial en tiempo fijo (IATF) sobre las tasas de preñez (TP) en vacas primíparas Bos taurus indicus. Se han utilizado 176 animales, distribuidos en tres grupos: GNDES (Grupo No DES; n= 59), que recibió en el día 0 (d0) un dispositivo intra vaginal con 0,558 g de progesterona (P4) + 2,0 mg de benzoato de estradiol (BE) (IM); en el d8 remoción de la P4 + 0,5 mg de cipionato de estradiol (CE) + 150 mg de cloprostenol + 400 UI de gonadotrofina coriónica equina (eCG); en el d10 fue ejecutada la IATF; GDES (Grupo DES; n=60) el mismo que GNDES pero 1,0 mg (IM) de DES en el momento de la IATF; GDES6 (Grupo Deslorelina 6 horas); n=57) el mismo que GDES, con la diferencia que la DES ha sido aplicada con 6 horas de antelación relación a la IATF. Los datos han sido sometidos a un análisis estadístico, a través del Programa SAS (2014). El estudio resultó en tasa de preñez (TP) en la IATF y al final del ciclo estral, respectivamente para GNDES, GDES y GDES6 en 40,6; 53,3; 43,8 % y 72,9; 81,7; 70,2 %. Concluyese que la DES proporcionó en números absolutos un indicativo de mejoría en la TP y en la IATF en los grupos tratados frente al controle; el ECC, días abiertos y el status reproductivo (anestro o ciclicidad) no influenciaron la TP ni la IATF, ni a los 60 días ni al final del ciclo estral o periodo de celo.

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O objetivo do estudo foi verificar a eficiência da deslorelina (DES) como indutora da ovulação em protocolos de inseminação artificial em tempo fixo (IATF) sobre as taxas de prenhez (TP) de vacas primíparas Bos taurus indicus. Foram utilizados 176 animais, distribuídos em três grupos: GNDES (Grupo Não DES; n= 59), que recebeu no dia 0 (d0) um dispositivo intravaginal com 0,558 g de progesterona (P4) + 2,0 mg de benzoato de estradiol (BE) (IM); no d8 remoção da P4 + 0,5 mg de cipionato de estradiol (CE) + 150 g de cloprostenol + 400 UI de gonadotrofina coriônica equina (eCG); em d10 foi executada a IATF; GDES (Grupo DES; n=60) o mesmo que GNDES porém 1,0 mg (IM) de DES no momento da IATF; GDES6 (Grupo Deslorelina 6 horas; n=57) o mesmo que GDES, porém com a DES aplicada 6 horas antes da IATF. Os dados foram submetidos à análise estatística mediante o Programa SAS (2014). O estudo resultou em taxa de prenhez (TP) na IATF e no final da estação de monta, respectivamente para GNDES, GDES e GDES6 em 40,6; 53,3; 43,8 % e 72,9; 81,7; 70,2 %. Concluiu-se que a DES proporcionou em números absolutos indicativo de melhoria na TP à IATF nos grupos tratados frente ao controle; o ECC, dias abertos e o status reprodutivo (anestro ou ciclicidade) não influenciaram a TP à IATF, aos 60 dias e ao final da estação de monta.(AU)

The aim of the study was to verify the efficiency of deslorelin (DES) as inductor of ovulation in timed-artificial insemination (TAI) protocols on pregnancy rate (PR) in primiparous Bos taurus indicus cows. Hundred seventy six animals were divided into three groups (G): GNDES (Group No Deslorelin; n = 59) which received on day 0 (d0) an intravaginal device with 0.558 g of progesterone (P4) + 2.0 mg estradiol benzoate (EB) (IM); d8 P4 removal + 0.5 mg of estradiol cypionate (EC) + 150 g of cloprostenol + 400 IU of equine chorionic gonadotropin (eCG); in d10 TAI was proceeded; GDES (DES group; n = 60) the same as GNDES + 1.0 mg (IM) DES acetate in TAI day; GDES6 (DES applied 6 hours before TAI, n = 57) the same as GDES, but DES injected 6 hours before TAI. The pregnancy rate (PR) in TAI and at the end of the breeding season (BS) was respectively 40.6; 53.3; 43.8% and 72.9; 81.7; 70.2% in GNDES, GDES and GDES6. In conclusion, the DES brought an indicative of improvement in the PR for TAI, in the treated groups (3.2 to 12.7 % more) than control, however without significance; the BCS, open days and the reproductive status of anestrous or cyclicality, did not influenced the PR in TAI at 60 days or at the end of the BS.(AU)

El objetivo del estudio ha sido verificar la eficiencia de la deslorelina (DES) como inductora de la ovulación en protocolos de inseminación artificial en tiempo fijo (IATF) sobre las tasas de preñez (TP) en vacas primíparas Bos taurus indicus. Se han utilizado 176 animales, distribuidos en tres grupos: GNDES (Grupo No DES; n= 59), que recibió en el día 0 (d0) un dispositivo intra vaginal con 0,558 g de progesterona (P4) + 2,0 mg de benzoato de estradiol (BE) (IM); en el d8 remoción de la P4 + 0,5 mg de cipionato de estradiol (CE) + 150 mg de cloprostenol + 400 UI de gonadotrofina coriónica equina (eCG); en el d10 fue ejecutada la IATF; GDES (Grupo DES; n=60) el mismo que GNDES pero 1,0 mg (IM) de DES en el momento de la IATF; GDES6 (Grupo Deslorelina 6 horas); n=57) el mismo que GDES, con la diferencia que la DES ha sido aplicada con 6 horas de antelación relación a la IATF. Los datos han sido sometidos a un análisis estadístico, a través del Programa SAS (2014). El estudio resultó en tasa de preñez (TP) en la IATF y al final del ciclo estral, respectivamente para GNDES, GDES y GDES6 en 40,6; 53,3; 43,8 % y 72,9; 81,7; 70,2 %. Concluyese que la DES proporcionó en números absolutos un indicativo de mejoría en la TP y en la IATF en los grupos tratados frente al controle; el ECC, días abiertos y el status reproductivo (anestro o ciclicidad) no influenciaron la TP ni la IATF, ni a los 60 días ni al final del ciclo estral o periodo de celo.(AU)

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A população de gatos domésticos já excede a de cães em muitos países do mundo e o crescimentopopulacional dos gatos domésticos domiciliados cresce paralelamente ao da população de animais abandonados.Esse fato nos coloca frente a uma problemática referente a procriação excessiva e a todas as consequênciasrelativas a essa situação. A escolha de métodos contraceptivos adequados para a espécie felina ainda necessitamde experimentos controlados e de observações a longo prazo para a determinação das vantagens e desvantagensde determinados procedimentos e do conhecimento dos mecanismos de ação de fármacos com indicaçãocontraceptiva. A proposta dessa revisão de literatura é abordar os contraceptivos mais utilizados nos felinosdomésticos, enfatizando o mecanismo de ação, dosagens utilizadas, vantagens e desvantagens de cada fármacoconsiderado.(AU)

The number of domestic cats already exceeds dog population in many countries around the world. Alsothe number of housed cats grows in the same scale of abandoned animals. This fact makes us face the problem ofexcessive procreation and all consequences related this issue. The choice of an appropriated contraceptivemethod for felines still needs controlled experiments and long term observations in order to determine all prosand cons of some procedures and to increase the knowledge regarding the action mechanism of drugs that mayact as contraceptive. This review objective is to approach the most used contraceptive treatments in domesticfelines, emphasizing the action mechanism, recommended dosage, pros and cons from each contraceptivemethods.(AU)

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A população de gatos domésticos já excede a de cães em muitos países do mundo e o crescimentopopulacional dos gatos domésticos domiciliados cresce paralelamente ao da população de animais abandonados.Esse fato nos coloca frente a uma problemática referente a procriação excessiva e a todas as consequênciasrelativas a essa situação. A escolha de métodos contraceptivos adequados para a espécie felina ainda necessitamde experimentos controlados e de observações a longo prazo para a determinação das vantagens e desvantagensde determinados procedimentos e do conhecimento dos mecanismos de ação de fármacos com indicaçãocontraceptiva. A proposta dessa revisão de literatura é abordar os contraceptivos mais utilizados nos felinosdomésticos, enfatizando o mecanismo de ação, dosagens utilizadas, vantagens e desvantagens de cada fármacoconsiderado.

The number of domestic cats already exceeds dog population in many countries around the world. Alsothe number of housed cats grows in the same scale of abandoned animals. This fact makes us face the problem ofexcessive procreation and all consequences related this issue. The choice of an appropriated contraceptivemethod for felines still needs controlled experiments and long term observations in order to determine all prosand cons of some procedures and to increase the knowledge regarding the action mechanism of drugs that mayact as contraceptive. This review objective is to approach the most used contraceptive treatments in domesticfelines, emphasizing the action mechanism, recommended dosage, pros and cons from each contraceptivemethods.

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The experiment aimed to compare the efficiency of deslorelin and hCG to induce ovulation Quarter Horsemares. This experiment was conducted at the Center for Equine Pernambuco - CEPE, in the town of Gravatá-PE, in February 2013. The animals were divided in Group 1 (n=10) received, intramuscular, Deslorelin 1000mg while Group 2 (n = 10) received, Intravenous, 5000 IU of hCG. 24 hours after administration of theovulation inducing were inseminated with semen from a stallion. After 15 days of AI, the pregnancy diagnosiswas made. The data from this study were analyzed using the statistical package SAS, (P < 0.05). The fertilityrate found was 80.0% in group 1 and 70% in group 2 (P > 0.05). The drugs tested successfully induce ovulation.(AU)

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The experiment aimed to compare the efficiency of deslorelin and hCG to induce ovulation Quarter Horsemares. This experiment was conducted at the Center for Equine Pernambuco - CEPE, in the town of Gravatá-PE, in February 2013. The animals were divided in Group 1 (n=10) received, intramuscular, Deslorelin 1000mg while Group 2 (n = 10) received, Intravenous, 5000 IU of hCG. 24 hours after administration of theovulation inducing were inseminated with semen from a stallion. After 15 days of AI, the pregnancy diagnosiswas made. The data from this study were analyzed using the statistical package SAS, (P 0.05). The drugs tested successfully induce ovulation.

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The aim of this work was to study estrus synchronization and fixed time artificial insemination (FTAI) in dairy buffaloes during season anestrus. One hundred thirty-nine dairy buffaloes in seasonal anestrus were divided in two groups as G1(n=66) and G2(n=73). The protocols for both the groups were the same until day (D)14:D0 administration of 2.0 mg estradiol benzoate and implantation of progesterone device (P4) for 14 days; D14 removal of P4 plus 150 mg of cloprostenol and 400 IU of equine chorionic gonadotropin. On D16, G1 received 10 mg of buserelin and G2 100 mg deslorelin acetate. On D17, both the groups were submitted to FTAI. Ultrasonographic examinations of ovaries were performed on D0, D14, D16 and D17. Results showed that pregnancy rates in G1 and G2 were 20 and 41% (p<0.05) and the ovulation rates were 16.6 and 37%, respectively (p<0.05). The dominant follicle (DF) diameter on D16 was 7.9 mm in G1 and 8.9 mm in G2 (p>0.05). Thirty-five percent of the animals in G1 and 54.1% in G2 showed a diameter DF greater than 8.0 mm on D16 (p>0.05). Thus, it could be concluded that the protocols synchronized the estrus, leading the concentration of the parturitions in the period of low milk production. Deslorelin was more efficient than buserelin due the higher percentage of DF ovulation and higher pregnancy rates.

RESUMO

The aim this study was to compare two protocols of induction for ovulation by desloreline acetate and hCG in Quarter Horse mares. The choice of the animals was based on the observations by the estrus, by rectal palpation of the ovaries and by ultrassonography of the follicular dynamics. After estrus detection and follicle control, the measurement of the follicles and the classification of uterus were carried out. The animals that had dominant follicle (diameter more than 35 mm) and swollen uterus were used. In these conditions, the mares received hCG or desloreline acetate. Once ovulation occurred, the artificial insemination was carried. Two groups were performed: G1 (20 animals) received 1.5 mg desloreline acetate and G2 (20 animals) received 1700 IU of hCG. Following 6h intervals, the control follicular was performed by ultrasonography. The follicular average diameter was 42.6 cm for the groups and set up a score of 0 to 3 of uterine edema displayed by the device as well as the time of ovulation. In conclusion, the desloreline acetate showed better performance than hCG, because the ovulation was induced in less time (nine hours than hCG) (p<0.05).The pregnancy rate was 80 and 75 percent, respectively in G1 and G2.

RESUMO

GnRH (gonadotrophin releasing hormone) is a key hormone of reproductive function in mammals; agonist forms have been largely developed, and data concerning their use in small animal reproduction are now abundant. GnRH agonists act by a two-step mechanism. First, their agonist properties on the pituitary will cause marked LH (luteinizing hormone) and FSH (follicle-stimulating hormone) secretion into the bloodstream, accompanied by an increase in the concentrations of sex steroid hormones. Then, in case of constant administration, GnRH agonists will lead to pituitary desensitization, and FSH and LH levels will collapse. These two effects have been widely documented, and these compounds have many potential benefits in a clinical context, capitalizing both on their stimulating and sterilizing effects.

O hormônio liberador de gonadotrofinas (GnRH) é um hormônio chave na função reprodutiva dos mamíferos. Formas agonistas têm sido amplamente desenvolvidas e atualmente existem muitas informações sobre sua utilização na reprodução de pequenos animais. Os agonistas do GnRH atuam por meio de um mecanismo que envolve duas etapas. Inicialmente, suas propriedades agonistas irão causar secreção marcante de hormônio luteinizante (LH) e folículo-estimulante (FSH) pela hipófise, acompanhado pelo aumento das concentrações dos hormônios esteróides sexuais. Em seguida, no caso de administração contínua, os agonistas do GnRH irão causar dessensibilização e as concentrações de LH e FSH irão declinar. Estes dois efeitos já foram amplamente discutidos e estes compostos possuem vários benefícios no contexto clínico, devido aos às suas características estimulantes e contraceptivas.

Assuntos

RESUMO

GnRH (gonadotrophin releasing hormone) is a key hormone of reproductive function in mammals; agonist forms have been largely developed, and data concerning their use in small animal reproduction are now abundant. GnRH agonists act by a two-step mechanism. First, their agonist properties on the pituitary will cause marked LH (luteinizing hormone) and FSH (follicle-stimulating hormone) secretion into the bloodstream, accompanied by an increase in the concentrations of sex steroid hormones. Then, in case of constant administration, GnRH agonists will lead to pituitary desensitization, and FSH and LH levels will collapse. These two effects have been widely documented, and these compounds have many potential benefits in a clinical context, capitalizing both on their stimulating and sterilizing effects.(AU)

O hormônio liberador de gonadotrofinas (GnRH) é um hormônio chave na função reprodutiva dos mamíferos. Formas agonistas têm sido amplamente desenvolvidas e atualmente existem muitas informações sobre sua utilização na reprodução de pequenos animais. Os agonistas do GnRH atuam por meio de um mecanismo que envolve duas etapas. Inicialmente, suas propriedades agonistas irão causar secreção marcante de hormônio luteinizante (LH) e folículo-estimulante (FSH) pela hipófise, acompanhado pelo aumento das concentrações dos hormônios esteróides sexuais. Em seguida, no caso de administração contínua, os agonistas do GnRH irão causar dessensibilização e as concentrações de LH e FSH irão declinar. Estes dois efeitos já foram amplamente discutidos e estes compostos possuem vários benefícios no contexto clínico, devido aos às suas características estimulantes e contraceptivas.(AU)

Assuntos

RESUMO

The efficacy of one or multiple doses of an injectable formulation of deslorelin (a GnRH agonist) was evaluated to induce estrus in anestrous bitches. Thirteen animals composed three groups: group 1 (n=5, single IM injection of 2mg deslorelin), group 2 (n=5, four IM injections of 2mg deslorelin in alternate days), and control group (n=3, four IM saline injections in alternate days). Daily clinical evaluations, sexual behavior, vaginal cytology, plasma progesterone concentration, ovaryhysterectomy and macroscopic evaluation of the uterus and ovaries were done. In group 1, none of the bitches showed signs of estrus, while two developed clinical signs and vaginal cytology of proestrus. In group 2, all animals presented proestrus, four presented estrus, and three ovulated; resulting in a functional corpus luteum and high progesterone concentration until day 25 of diestrus, when ovaryhysterectomy was performed. The duration of the stages of deslorelin induced cycles and the progesterone profile were similar to those described in the literature, and no side effects were observed. In conclusion, injectable formulation of deslorelin in multiple injections was effective to induce fertile estrus in anestrous bitches.

Avaliou-se a eficácia de uma formulação injetável de deslorelina (agonista do GnRH) na indução de estro em cadelas no anestro e seus efeitos no aparelho genital, com uma ou múltiplas aplicações. Treze animais compuseram os grupos: grupo 1 (n=5, 2mg de deslorelina via IM), grupo 2 (n=5, quatro injeções IM de 2mg de deslorelina em dias alternados) e grupo-controle (n=3, quatro injeções IM de solução salina em dias alternados). Foram realizadas avaliações clínicas diárias do comportamento sexual, da citologia vaginal, da dosagem de progesterona plasmática, da ovario-histerectomia e avaliação macroscópica do útero e dos ovários. No grupo 1, as cadelas não exibiram sinais de estro, mas duas apresentaram sinais clínicos e citologia vaginal compatíveis com proestro. No grupo 2, todas apresentaram sinais de proestro, quatro de estro e três ovularam, resultando em corpos lúteos funcionais e concentração elevada de progesterona plasmática até o 25º dia de diestro, quando foi realizada a ovario-histerectomia. Os sinais clínicos, a duração das fases e a curva de progesterona dos ciclos induzidos foram semelhantes aos descritos na literatura, e não foi observado efeito colateral do tratamento. Concluiu-se que a formulação injetável de deslorelina com múltiplas aplicações foi eficaz na indução de estro em cadelas em anestro.

Assuntos

RESUMO

The efficacy of one or multiple doses of an injectable formulation of deslorelin (a GnRH agonist) was evaluated to induce estrus in anestrous bitches. Thirteen animals composed three groups: group 1 (n=5, single IM injection of 2mg deslorelin), group 2 (n=5, four IM injections of 2mg deslorelin in alternate days), and control group (n=3, four IM saline injections in alternate days). Daily clinical evaluations, sexual behavior, vaginal cytology, plasma progesterone concentration, ovaryhysterectomy and macroscopic evaluation of the uterus and ovaries were done. In group 1, none of the bitches showed signs of estrus, while two developed clinical signs and vaginal cytology of proestrus. In group 2, all animals presented proestrus, four presented estrus, and three ovulated; resulting in a functional corpus luteum and high progesterone concentration until day 25 of diestrus, when ovaryhysterectomy was performed. The duration of the stages of deslorelin induced cycles and the progesterone profile were similar to those described in the literature, and no side effects were observed. In conclusion, injectable formulation of deslorelin in multiple injections was effective to induce fertile estrus in anestrous bitches.(AU)

Avaliou-se a eficácia de uma formulação injetável de deslorelina (agonista do GnRH) na indução de estro em cadelas no anestro e seus efeitos no aparelho genital, com uma ou múltiplas aplicações. Treze animais compuseram os grupos: grupo 1 (n=5, 2mg de deslorelina via IM), grupo 2 (n=5, quatro injeções IM de 2mg de deslorelina em dias alternados) e grupo-controle (n=3, quatro injeções IM de solução salina em dias alternados). Foram realizadas avaliações clínicas diárias do comportamento sexual, da citologia vaginal, da dosagem de progesterona plasmática, da ovario-histerectomia e avaliação macroscópica do útero e dos ovários. No grupo 1, as cadelas não exibiram sinais de estro, mas duas apresentaram sinais clínicos e citologia vaginal compatíveis com proestro. No grupo 2, todas apresentaram sinais de proestro, quatro de estro e três ovularam, resultando em corpos lúteos funcionais e concentração elevada de progesterona plasmática até o 25º dia de diestro, quando foi realizada a ovario-histerectomia. Os sinais clínicos, a duração das fases e a curva de progesterona dos ciclos induzidos foram semelhantes aos descritos na literatura, e não foi observado efeito colateral do tratamento. Concluiu-se que a formulação injetável de deslorelina com múltiplas aplicações foi eficaz na indução de estro em cadelas em anestro.(AU)

Assuntos