Productivity efficiency in the livestock sector depends upon reproduction success at the farms. Evaluation of follicle and corpus luteum hemodynamics by color-Doppler ultrasonography is becoming more commonly used in cattle reproductive management. Improved understanding of the relationships between size and blood flow of the preovulatory follicle (POF) and corpus luteum (CL) with the subsequent systemic progesterone production, and the impact of those factors on fertility, would provide information to help maximize fertility in cattle reproduction. Three studies were conducted in this dissertation with the following general objectives: I) evaluate the relationships between follicle and corpus luteum dimensions and blood flow, and the influence of follicle size and wall blood flow on systemic progesterone production by the subsequent CL; II) study the relationships between follicle wall blood flow within different follicle size categories, between cows and heifers, and the effect on pregnancy rates; and III) develop a novel and reliable objective method for evaluation of follicle wall blood flow. In study one, high positive correlations were found among all POF and CL end points, and progesterone concentrations. Ratios of POF, CL, and progesterone end points ranged from moderate to strong positive correlations. Linear regression dispersions among selected POF and CL end points and progesterone concentrations showed high significance when using POF dimensions to estimate CL dimensions as well as POF blood flow to estimate CL size and blood flow, and plasma progesterone concentrations. In study two, cows had larger and more vascularized follicles than heifers. Pregnant cows had larger follicles and tended to have more vascularized follicles than non-pregnant cows. Follicle blood flow was greater in the large follicle category compared with the small follicles, and tended to be greater than medium-size follicles. Moderate to strong correlations were found between follicle blood flow and small, medium, and large follicles. Pregnancy rates were similar among follicle diameter categories. In study three, a novel objective method (wall under flow, WUF) for evaluation of follicle wall blood flow using color-Doppler ultrasonography was tested. Results indicated that due to differences in follicle morphology and in area and location of the blood flow, the objective pixel analysis previously reported in the literature for evaluation of CL blood flow cannot be translated as a gold standard test to objectively evaluate blood flow in follicles. The WUF was a superior method to evaluate follicle wall blood flow when compared with other methods. Furthermore, pixel area method did not sustain the validation of subjective evaluations of follicle wall blood flow. In conclusion, this work demonstrated novel linear relationships among POF and CL end points which can be used to estimate the subsequent progesterone production by the CL. Additionally, POF wall blood flow was closely associated with an increase in follicle diameter; smaller follicles had lower blood flow when compared with larger follicles. Moreover, the WUF was a more reliable method to objectively evaluate follicle wall blood flow in cows than the pixel area method.

Made available in DSpace on 2015-10-06T13:02:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-08. Added 1 bitstream(s) on 2015-10-06T13:19:16Z : No. of bitstreams: 1 000849551.pdf: 939514 bytes, checksum: 901efdf4cabd26a394b9aabd01d199d2 (MD5) / A progesterona e seus análogos têm sido utilizados para diversas finalidades na reprodução animal. O objetivo deste estudo foi avaliar a influencia da progesterona injetável no número de oócitos recuperados, na qualidade oocitária e produção embrionária de novilhas Nelore pré-púberes. Foram utilizadas 31 fêmeas com idade entre 18 a 20 meses, não gestantes e não cíclicas. As doadoras de oócitos foram divididas em 3 grupos experimentais em delineamento crossover da seguinte maneira: Grupo P0 (n=11), os animais deste grupo receberam duas aplicações de solução placebo (1 mL), com intervalo de 7 dias iniciando 14 dias (D-14) antes da primeira aspiração (D-0); Grupo P7 (n=10): os animais receberam uma aplicação de solução placebo (1 mL) 14 dias (D-14) e uma de progesterona (P4) injetável (150mg) 7 dias (D-7) antes da aspiração; Grupo P14 (n=10), neste grupo os animais receberam duas aplicações de P4 injetável (150mg) com intervalo de 7 dias, a primeira 14 dias (D-14) e a segunda 7 (D-7) dias antes da aspiração. Realizaram-se um total de três aspirações foliculares em intervalos de 28 dias. Os animais que apresentaram CL durante o experimento foram alocados em um grupo separado para serem analisados e comparados com o grupo sem CL. Os oócitos recuperados foram selecionados e submetidos aos procedimentos da PIVE. Após a confirmação da homocedasticidade (BoxCox) e normalidade (teste de Cramér-von Mises) dos dados, realizou-se a análise de variância (ANOVA). O teste de Tukey foi utilizado para as comparações das médias das variáveis, para as correlações dos dados foi utilizado o teste de correlação de Pearson, e significantes quando p≤ 0,05. Não foram verificadas diferenças significativas (p>0,05) quanto ao número de oócitos recuperados (oócitos totais), oócitos viáveis (G I, II, III), entre os animais tratados (grupos P7 e P14) em relação aos animais que não receberam P4 (grupo P0). As... / Progesterone has been used for various purposes in the animal reproduction. The objective of this study was to evaluate the influence of exogenous progesterone injection in the number of recovered oocyte, oocyte quality and embryo production of prepubertal Nelore heifers. We used 31 females (18 to 20 months) non pregnant and without corpus luteum (CL). Cows were divided in 3 groups in a cross-over design: Group I P0 (n=11), animals received two placebo solution applications (1 mL), 7-day interval and starting 14 days (D-14) before the first aspiration (D-0); Group II P7 (n=10) treated group, the animals received a placebo solution application (1 mL) 14 days (D-14) and injecting progesterone (P4; 150 mg) 7 days (D-7) before aspiration; Group III P14 (n = 10), animals received two injections of P4 (150mμg) with an interval of 7 days, the first 14 days (D-14) and the second 7 days (D-7) before aspiration. We conducted 3 aspiration with 28-day intervals. The animals with CL during the experiment were placed in a separate group to be analyzed and compared with the group without CL. The recovered oocytes were selected and submitted to the procedures of the in vitro embryo production (IVEP). After confirming the homocedasticity (BoxCox) and normality (Cramér-von Mises test) of the data, carried out the analysis of variance (ANOVA). Tukey's test was used to compare the means of the variables and the pearson correlation test was used for correlations of the data, considered significant when p ≤ 0.05. There were no significant differences (p> 0.05) in the number of oocytes retrieved (total oocytes), viable oocytes (GI, II, III), between the animals treated (P7 and P14 groups) and animals that did not receive P4 (P0 group). The animals showed an average of 14.98 ± 10.82 oocytes collected by aspiration session. The mean and standard deviation of rates (%) of viable oocytes and embryos produced did not differ (p> 0.05) between groups. The ...

Made available in DSpace on 2014-06-11T19:35:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-03-30Bitstream added on 2014-06-13T20:06:40Z : No. of bitstreams: 1 oliveira_cb_dr_jabo.pdf: 442407 bytes, checksum: be6648eb5ab8b4cba1b22c5554dd2b9d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi determinar o número de células luteais bovinas, comparando fêmeas taurinas com zebuínas no início e final do ciclo estral. Foram coletados corpos lúteos de 16 fêmeas sendo 8 taurinas e 8 zebuínas, distribuídas em 4 grupos sendo coletados os ovários nos dias 3 a 5 (2 grupos: taurino e zebuíno) e 16 a 18 (2 grupos: taurino e zebuíno) do ciclo estral. Os corpos lúteos foram processados para microscopia óptica e avaliouse as células luteais pequenas, grandes e intermediárias, quanto ao número celular, diâmetro, área e perímetro. Os animais taurinos apresentaram maior quantidade de células luteais pequenas que os zebuínos no início do ciclo estral (p<O,05) e final do ciclo estral (p<O,05). Registrou-se diferença nos valores médios do diâmetro, perímetro e área das células luteais grandes, pequenas e intermediárias entre animais taurinos e zebuínos, tanto no início quanto no final do ciclo estral. / The aim of this work was to determine the number of bovine luteal cells comparing 80S taurus females with 80S indicus females at the beginning and at the end of estrous cycle. Sixteen corpus luteum were collected in eight 80S taurus cattle and in eight 80S indicus cattle, distributed into four groups. The ovaries were collected from the third and the fifth days (two groups: 80S taurus females and 80S indicus females) and from the sixteenth and the eighteenth days (two groups: 80S taurus caUle and 80S indicus cattle) of the estrous cycle. The corpus luteum was processed to optical microscopy and the small, big and intermediate-sized luteal cells were evaluated considering the number of cells, diameter, area and perimeter. The 80S taurus females presented a bigger amount of smallluteal cells than the 80S indicus females at the beginning of the estrous cycle (p,O,05) and at the end of the estrous cycle (p<O,05). The difference in the average values of the diameter, perimeter and the area of big, small and intermediate-sized luteal cells have been registered among 80S taurus cattle and 80S indicus cattle, at the beginning and also at the end of the estrous cycle.

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No. of bitstreams: 1 cuervo_jco_me_bot.pdf: 1620368 bytes, checksum: d662e09785a2bb73aaa15aaf92df4d19 (MD5) Previous issue date: 2016-09-29 / Em ruminantes a luteólise natural é caraterizada pela liberação de vários pulsos de prostaglandina F2alfa (PGF) produzidos pelo útero. A PGF é o hormônio luteolítico, enquanto a prostaglandina E1 (PGE1) é considerada um mediador luteoprotetor. Em estudos anteriores, infusões com doses baixas de PGF no útero com intervalos de 6 horas (h) resultou em regressão do corpo luteo (CL). A proposta deste experimento é desenvolver um modelo para avaliar o efeito de baixas doses de PGE1, também infundidas no lúmen uterino sobre a resposta luteal à PGF intrauterina (IU). Vacas no dia 10 do ciclo estral receberam infusões IU de salina (0,1 ml de salina + 0,1 ml de DMSO), PGE (2 mg de PGE1 em 0,1ml de DMSO) ou PGF (0,25 mg of PGF em 0,1 ml de salina) em intervalos de 6 h em um desenho experimental 2 X 2. Portanto os animais foram agrupados em quatro tratamentos: SALINA (4 infusões de salina; n=5), PGE (4 infusões de PGE1; n=5), PGF (4 infusões de PGF; n=5) e PGE+PGF (4 infusões de PGE1+PGF; n=5). As concentrações plasmáticas de progesterona (P4) foram dosadas por radioimunoensaio e o volume luteal foi determinado por ultrassonografia transretal. As concentrações circulantes de PGFM e PGEM foram dosadas antes e 10 minutos após as primeiras duas infusões. Biopsias luteais foram coletadas de cada vaca 30 minutos após cada infusão para determiner a expressão de genes em resposta a cada tratamento. As concentrações circulantes de PGFM 10 minutos após as infusões foram maiores em vacas que receberam tratamentos com PGF e PGE+PGF em comparação com as vacas tratadas com salina e PGE. Da mesma forma, as concentrações de PGEM 10 minutos após cada infusão foram maiores em vacas tratadas com PGE e PGE+PGF em comparação com vacas dos grupos salina e PGF. As concentrações de P4 diminuiram no grupo PGF em comparação com o grupo Salina no tempo 12-h (48,9% do controle) após a primeira infusão de PGF, no tempo 24-h (20,2% do controle), e em todos tempos subsequentes (P < 0,05). Não foram encontradas diferenças nas concentrações circulantes de P4 entre os grupos Salina, PGE e PGF+PGE. Houve também uma diminuição do volume luteal entre o grupo PGF e os outros três grupos que foi observada nos tempos 24-h (56,4% do controle), 48-h (30,6% do controle), e 72-h (20,4% do controle) após o tratamento com PGF (P<0.05). Não houve diferenças no volume luteal entre os tratamentos salina, PGE e PGE+PGF. Por tanto, infusões IU simultâneas de baixas doses de PGE1 bloquearam a ação luteolitica de pulsos IU de PGF em vacas, como observado nas mudanças circulantes de P4 e volume luteal. Análises da expressão génica nas biopsias luteais coletadas após o terceiro pulso de PGF, indicam o padrão tipico de expressão de genes em resposta ao tratamento com PGF (FGF2, EGR1, FOS e FAS aumentaram; PTGFR, VEGFA, NR5A1 e STAR diminuiram) e o tratamento PGE+PGF bloqueou completamente as mudanças na expressão destes genes. Infusões IU de PGF e PGE1 parecem ser um excelente modelo para determiner o padrão de expressão de genes envolvidos no efeito luteoprotetor da PGE1. / In ruminants, natural luteolysis is characterized by the release of several pulses of prostaglandin F2alpha (PGF) produced by the uterus. Prostaglandin F2alpha is the luteolytic hormone, whereas prostaglandin E1 (PGE1) is considered to be a luteoprotective mediator. In previous studies, low doses of PGF infused into the uterus at 6 hour (h) intervals resulted in regression of the corpus luteum (CL). This study was designed to develop a model to study the effect of low doses of PGE1, also infused into the uterine lumen, on the luteal responses to intrauterine (IU) PGF. Cows on day 10 of the estrous cycle received IU infusions of saline (0,1 ml of saline + 0,1 ml of DMSO), PGE (2 mg of PGE1 in 0,1ml of DMSO) or PGF (0,25 mg of PGF in 0,1 ml of saline) at 6-h intervals in a 2 X 2 experimental design. Thus, there were four treatment groups: SALINE (4 saline infusions; n=5), PGE (4 PGE1 infusions; n=5), PGF (4 PGF infusions; n=5), and PGE+PGF (4 PGE1+PGF infusions; n=5). Radioimmunoassay was used to measure circulating progesterone (P4) concentrations and luteal volume was determined by transrectal ultrasonography. Circulating concentrations of PGFM and PGEM were measured before and 10 minutes after the first two infusions. A luteal biopsy was collected from each cow at 30 minutes after each infusion for later determination of gene expression in response to each treatment. Circulating concentrations of PGFM 10 minutes after infusions were greater in cows receiving treatments with PGF and PGE+PGF than in Saline or PGE-treated cows. In the same way, concentrations of PGEM 10 minutes after infusions, were greater in cows that were treated with PGE and PGE+PGF than in saline and PGF-treated cows. Concentrations of P4 in the PGF group decreased compared to those in the saline group by 12-h (48.9% of control) after first infusion of PGF, at 24-h (20,2% of control), and all subsequent time points (P < 0,05). No differences in circulating P4 concentrations were found between Saline, PGE, and PGF+PGE. There was also a decrease of luteal volume between the PGF group and the other three groups that was detectable at 24 (56,4% of control), 48 (30,6% of control), and 72 (20,4% of control) h after PGF treatment (P<0.05). There were no differences in luteal volume between Saline, PGE, or PGE+PGF. Thus, simultaneous IU infusion of a low dose of PGE1 blocked the luteolytic actions of IU PGF pulses in cattle, as measured by changes in circulating P4 and luteal volume. Analyses of gene expression in the luteal biopsy taken after the third PGF pulse indicate a typical pattern of gene expression in response to the PGF treatments (FGF2, EGR1, FOS and FAS increased; PTGFR, VEGFA, NR5A1 and STAR decreased) and that simultaneous PGE1 treatment completely blocked these gene expression changes. Thus, IU infusion of PGF and PGE1 seems to provide an excellent model for determining the patterns of gene expression involved in the luteoprotective effect of PGE1.

A gonadotrofina coriônica equina (eCG) tem sido utilizada em programas de sincronização para inseminação artificial em tempo fixo e normalmente promove o aumento do volume do corpo lúteo e a da produção de progesterona. Além disso, esta mesma gonadotrofina pode ser utilizada para superovulação. Desse modo, hipóteses relativas aos mecanismos pelos quais gonadotrofinas exógenas alteram as funções celulares nos corpos lúteos resultantes foram formuladas. Para testar tais hipóteses, 18 vacas (Bos indicus) foram divididas em grupos: controle (n=5), estimulado (n=6) e superovulado (n=7) e a ovulação das mesmas foi sincronizada usando um protocolo já estabelecido com dispositivo de progesterona. Os animais estimulados receberam 400 UI de eCG no dia de remoção do dispositivo de progesterona e os animais superovulados 4 dias antes. No dia 7 após injeção de GnRh, os animais foram abatidos para a coleta de CLL e sangue. Análises de peso e volume de CL, concentração de progesterona (P4), bem como da expressão gênica e proteica de fatores angiogênicos e de proteínas esteroidogênicas foram realizadas. Além disso, o transcriptoma foi analisado por microarranjo. Foi observado que o volume do CL foi maior nos animais do grupo estimulado (1177,37 ± 167,07 mm3) e ainda maior nos do superovulado (1495,18 ± 137,01 mm3) quando comparados ao grupo controle (830,33 ± 234,99 mm3; p = 0,03). A concentração média de progesterona por CL nos animais do grupo estimulado foi maior que nos animais do grupo controle (5,95 ± 0,17 vs 3,69 ± 0,72 ng/ml; p = 0,03) e que nos superovulados (4,11 ± 0.73; p = 0,01). Além disso, os tratamentos com eCG aumentaram a expressão do FGFR2 e também da STAR nos animais estimulados e superovulados (p < 0,05). Quanto aos resultados do microarranjo, no total 242 transcritos foram aumentados e 111 foram diminuídos nos animais estimulados e 111 foram aumentados e 113 diminuídos nos animais superovulados em relação aos animais controle (~1,5 vezes, p 0.05). Entre os genes diferencialmente expressos, muitos estavam envolvidos na síntese de lipídios e na produção de progesterona, tais como: PPARG, HMGCR, STAR, receptores de prolactina e folistatina. Estes achados demonstraram que os tratamentos com eCG modularam a expressão gênica diferencialmente, dependendo do tratamento, e que nossos dados contribuem para entender as vias relacionadas ao aumento do volume do CL e da produção de progesterona observada após os tratamentos. Em um segundo experimento, foi realizado análises da influência do FSH na expressão de VEGF no cultivo de células da granulosa. Neste experimento foi possível observar que o FSH aumentou a expressão gênica e proteica do VEGF, colaborando com a ideia de que as gonadotrofinas têm propriedades angiogênicas. / Equine chorionic gonadotropin (eCG) has been widely used in synchronization protocol to artificial insemination program and usually promote corpus luteum (CL) volume increases and stimulates progesterone production. Furthermore the same gonadotropin can be used to superovulation protocols. Thus, hypotheses concerning the mechanisms by which exogenous gonadotropins alter cellular functions in resulting corpora lutea were formulated. To test that hypothesis, 18 (Bos indicus) cows were divided into control (n=5), stimulated (n=6) and superovulated groups (n=7). Ovulation was synchronized using a progesterone device-based protocol. Stimulated animals received 400 IU of eCG of device removal and superovulated animals received 2000 IU of eCG 4 days prior. Corpora lutea (CLL) and blood samples were collected seven days after GnRH administration. Analyses of CL weight and volume, progesterone (P4) concentration, as well as the gene and protein expression of angiogenic and steroidogenic proteins were performed. Furthermore, the transcriptome was evaluated by microarray. The CL volume was higher in superovulated (1495.18 ± 137.01) than in stimulated (1177.37 ± 167.07) cows and higher in stimulated than in the control (830.33 ± 234.99) cows, and the P4 concentration per CL was higher in stimulated (5.95 ± 0.17 ng/ml) animals than in the control (3.69 ± 0.72 ng/ml) and superovulated (4.11 ± 0.73 ng/ml; P = 0.01) animals. Overall, 242 transcripts were up-regulated and 111 transcripts were downregulated in stimulated cows (P 0.05) and 111 were up-regulated and 113 down-regulated in superovulated cows in relation to the control (1.5 fold, P 0.05). Among the differentially expressed genes, many were involved in lipid biosynthesis and progesterone production, as PPARG, HMGCR, STAR, prolactin receptors and follistatin. In conclusion, eCG modulates gene expression differently depending on the treatment. Our data contribute to the understanding of the pathways involved in increased CL volume and progesterone levels observed after eCG treatment. In a second experiment, analyzes were performed about the influence of FSH on the expression of VEGF in the culture of granulosa cells. In this experiment it was observed that FSH increases the expression of the VEGF gene and protein, these finding collaborate with the idea that gonadotrophins have angiogenic properties.

Abstract Apoptosis is a genetically programmed mechanism for a multicellular organism to remove cells that are unnecessary, or potentially harmful. The female reproductive system is characterised by a high rate of cellular proliferation. At the same time, apoptosis is also abundant during the normal physiological function of the ovary and endometrium. More than half of the 7 million oocytes that are produced during human ovarian development are deleted before birth and only about 400 oocytes reach the stage of ovulation during the female fertile lifespan. The fate of the non-ovulatory follicles is atresia, occurring through the mechanism of apoptosis. The endometrium goes through radical renewal processes during each menstrual cycle. Apoptosis has been suggested to participate in the regulation of endometrial cellular homeostasis. Errors in this mechanism can result in endometrial diseases such as hyperplasia and cancer. In this work, apoptosis and its regulation were studied in the human fetal and adult ovary, normal endometrium and endometrial pathologies. In fetal ovaries, apoptosis was already abundantly present in oocytes at 13 weeks of gestation. The maximum rate of apoptosis was seen between the 14th and 20th weeks, after which apoptosis decreased towards term. Ovarian Bcl-2 expression was detected in early fetal life during weeks 13 and 14. Bax expression was observed throughout the studied period, from week 13 to 40. The expression of transcription factor GATA-4, which is linked to follicular survival, was localised to the granulosa cells and was high in early fetal life and decreased somewhat towards term. In adult life apoptosis was located in the granulosa cells of the growing follicles. In ovarian biopsies from women homozygous for the inactivating C566T mutation of the FSH receptor, apoptosis or GATA-4 expression was not detected. During corpus luteum regression a peak in apoptosis was detected 10 - 12 days after the LH surge, and was preceded by an increase in 17HSD type 1 and TNF-α expression. During normal menstrual cycles, the highest rate of apoptosis was observed in the menstrual endometrium. This increase in apoptosis was preceded by a decreased Bcl-2/Bax ratio. In endometrial hyperplasia, the rate of apoptosis was similar to that seen during normal proliferation of the endometrium, but an apparent increase was observed in grade II endometrial carcinoma. In grade III carcinoma, the rate of apoptosis was lower than in grade II carcinoma but higher than in hyperplasia. These results indicate that apoptosis is the mechanism behind the substantial oocyte demise during ovarian development. During adult life, apoptosis was mainly localised to the granulosa cells of the growing follicles which do not reach the stage of a dominant follicle. In ovaries where FSH action is abolished, folliculogenesis was impaired and ovarian apoptosis was negligible. Apoptosis is also the underlying mechanism of corpus luteum regression. In the endometrium, apoptosis has a role in rejuvenating the endometrium for growth during the next endometrial cycle and in regulating cellular homeostasis.

Prolonging function of the corpus luteum (CL) is a method of suppressing estrus that maintains secretion of endogenous progesterone to keep mares out of heat naturally. The use of oxytocin to prolong CL function is becoming more popular. In these therapies, upregulation of cyclooxygenase-2 is inhibited, which impairs prostaglandin F2α ( PGF2α) production. Intramuscular (IM) administration of 60 IU of oxytocin once daily from 7 to 14 days after ovulation is currently the most common treatment protocol. Although that protocol is efficacious in ≥70% of treated mares, the need for daily administration is a drawback to its use. A proprietary slow-release oxytocin formulation (SR-OT) with a two-injection protocol to prolong CL function was evaluated in the first experiment. Mares were examined to determine the day of ovulation (day 0) and then randomly assigned either to a non-treated control group or an SR-OT treatment group (n = 8 mares/group). Mares in the treated group received 1.0 mL of SR-OT containing 2,400 IU oxytocin IM once on Day 7 and again on Day 10 after ovulation. Jugular blood samples were collected on day 0 and then every M, W, and F continuously. Serum progesterone concentrations were evaluated to assess CL function, which was prolonged in 0/8 (0%) control mares and 6/8 (75%) of the SR-OT treated mares (p< 0.01). In a second study, the ability of the endometrium to synthesize PGF2α was evaluated in mares in a state of prolonged CL function. Mares were designated into groups 50-59, 60-69, or 70-79 days post-ovulation (50s, 60s, 70s) and 14-day post-ovulation controls. PGF2α synthesis was evaluated by measurement of a prostaglandin metabolite in response to a single 10 IU intravenous oxytocin bolus (0 minutes). Blood samples were collected serially from 30 minutes before until 120 minutes after oxytocin administration. The metabolite response was significantly higher in the 70s versus the 50s and 70s versus the 60s groups (p< 0.001; p< 0.02, respectively); and there was no significant difference between the 70s group and the control group (P>0.36). Luteal function was maintained after oxytocin administration in 4/4, 3/4, and 0/3 mares in the 50s, 60s, and 70s groups, respectively. Collectively, these results indicate that the luteolytic mechanism returns approximately 70 days into the period of prolonged CL function.

Orientador: Lindsay Unno Gimenes / Resumo: No presente estudo os objetivos foram avaliar a resposta luteolítica de meia dose (50%) ou dose inteira (100%) de cloprostenol sódico (CS) e dinoprost trometamina (DT) administrados em fêmeas bovinas de corte não lactantes cíclicas, nas fases de metaestro e diestro do ciclo estral (4 ou 11 dias após a ovulação (D0), respectivamente), quanto a: dinâmica luteínica, vascularização central e periférica, quantificação de pixels na área vascularizada do CL e dosagem de progesterona sérica (Exp.1) e morfometria das células luteínicas, imunomarcação de caspase-3 e dosagem de progesterona (P4; Exp.2). No Exp. 1, 54 fêmeas tiveram a ovulação sincronizada e receberam os seguintes tratamentos: CS 0 µg (CS0%; n=3/ grupo), CS 250 µg (CS50%; n=5/D4 e n=7/D11), CS 500 µg (CS100%; n=5/ grupo), DT 0 mg (DT0%; n=2/ grupo), DT 12,5 mg (DT50%; n=5/D4 e n=6/D11) ou DT 25 mg (DT100%; n=5/D4 e n=6/D11). No Exp. 2, 25 fêmeas foram sincronizadas, alocadas nos tratamentos no D4 e D11: CS50%; CS100%; DT50%; DT100% (n=3/ grupo, exceto DT100% no D11, n=2) e abatidas dois dias após. Os dados foram analisados por ANOVA em arranjo fatorial (2x2x3, no Exp. 1 e 2x2x2, no Exp. 2) com medidas repetidas no tempo (exceto para morfometria e imunomarcação) e teste de Tukey, com significância a 5%. No Exp. 1, animais avaliados no D4 apresentaram redução numérica da concentração de P4, das dimensões e vascularização luteais. Já animais avaliados a partir de D11 apresentaram redução para todos os parâmetros avaliados a... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the present study the objectives were to evaluate the luteolytic response of half-dose (50%) or full dose (100%) of sodium cloprostenol (SC) and dinoprost tromethamine (DT) administered in beef cattle cyclic non-lactating, at the metaestrous and diestrous stages of the estrous cycle (4 or 11 days after ovulation (D0), respectively), regarding: luteal dynamics, central and peripheral vascularization, quantification of pixels in vascularized area of CL and serum progesterone levels (Exp.1) and luteal cell morphometry, caspase-3 immunolocation and progesterone levels (P4; Exp.2). In Exp. 1, 54 females were synchronized ovulation and received the following treatments: SC0µg (SC0%; n=3/group), SC250µg (SC50%; n=5/D4 and n=7/D11), SC500µg (SC100%; n=5/group), DT0mg (DT0%; n=2/group), DT12.5mg (DT50%; n=5/D4 and n=6/D11) or DT25mg (DT100%; n=5/D4 and n=6/D11). In Exp. 2, 25 females were synchronized, assigned to treatments on D4 and D11: SC50%; SC100%; DT50%; DT100% (n=3/group, except DT100% on D11, n=2) and slaughtered two days later. Data were analyzed by ANOVA in factorial arrangement (2x2x3, in Exp. 1 and 2x2x2, in Exp. 2) with repeated measures in time (except for morphometry and immunolocation) and Tukey test, at 5% level of significance. In Exp. 1, animals evaluated in D4 showed numerical reduction of P4 levels, luteal dimensions and vascularization. Animals evaluated at D11 showed reduction for all parameters evaluated over the experimental moments. The use of 50% or 100%... (Complete abstract click electronic access below) / Mestre

Undesirable and variable behavior in mares related to the estrous cycle is a common issue reported in the equine industry, especially for mares in a performance setting. These behaviors can interfere with, as well as decrease, overall performance. The objective of this study was to determine if administration of sixty units of oxytocin once daily for 29 days, regardless of when treatment was initiated during the estrous cycle, would induce prolonged corpus luteum (CL) function in cycling mares. Mares were randomly assigned to two groups: 1) saline-treated control (n=7) and 2) oxytocintreated (n=9). Control mares received 3 cc saline and oxytocin-treated mares received sixty units (3 cc) of oxytocin intramuscularly (IM) for 29 consecutive days. Treatment was initiated in all mares on the same day, independent of the day of the cycle. Jugular blood samples for determination of progesterone concentration were collected three times weekly (M, W, F) for 21 days before treatment was initiated. Beginning on the first day of treatment, blood samples were collected daily for seven days, three times weekly for the remainder of the treatment period, and then three times weekly for 45 days after the last treatment. Mares were considered to have prolonged CL function if serum progesterone remained >1.0 ng/mL for at least 30 days during/after the treatment period. The proportion of mares with prolonged CL function was higher in the oxytocin-treated group compared to the saline-treated group (7/9 vs. 1/7, respectively; P1.0 ng/mL throughout the treatment period and into the post-treatment period. All mares with prolonged CL function maintained elevated progesterone concentrations through at least day 56 of the study. Sixty units of exogenous oxytocin treatment for 29 consecutive days was effective in prolonging CL function as a means of estrus suppression in mares.

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