Testosterone serum profile, semen characteristics and testicular biometry of Mangalarga Marchador stallions in a tropical environment.

This study was conducted to characterize the daily profile of testosterone secretion and its mean concentrations in the four seasons as well as to evaluate the semen characteristics and testicular biometry of Mangalarga Marchador stallions throughout the year in a tropical region. Three stallions were submitted to semen collections and evaluation of testicular biometry every 14 days along a year. Blood samples were collected once at the middle of each season, in a 20-min interval during 24 hr in order to evaluate the testosterone secretion profiles among seasons. Testosterone concentrations along the day were higher at the beginning of the afternoon (from 12:00 to 15:00 hr), but a circadian secretion was not clearly observed. Mean testosterone concentrations did not differ among seasons (p > .05), but a pattern of secretion along the day showed variations with higher concentrations in the afternoon during the winter. Ejaculate volume was higher during summer; however, sperm motility decreased in summer and spring. Total sperm in ejaculate, sperm morphology and testicular biometry kept constant along the year showing no differences among the seasons. The results demonstrated that in a tropical region, reproductive aspects of stallions did not show a clearly defined seasonal variation, and months of autumn and winter were not unsuitable for reproduction of the males.

Regressão espontânea do corpo lúteo em bovinos - revisão / Spontaneous corpus luteum regression in cattle: review

O conhecimento do processo de luteólise dentro da fisiologia reprodutiva se torna importante para que ocorra a compreensão do reconhecimento materno da gestação e seja possível formular estratégias anti-luteolíticas que visem manter esta fase conferindo aumentos na eficiência reprodutiva e produtiva. Durante o processo de luteólise, o tecido luteal sofre mudanças bruscas na capacidade esteroidogênica, vascularização e remodelamento, resultando em substituição da glândula por tecido conjuntivo, sendo a PGF2α o principal determinante na indução espontânea da luteólise em bovinos. Simultaneamente, ocorre um íntimo processo entre as relações anatômicas que compreende o ovário, útero e suas vascularizações. A exposição do útero à interação coordenada entre P4, E2 e ocitocina aliada à expressão de seus receptores são essenciais para a secreção pulsátil de PGF2α pelo endométrio a qual induzirá a luteólise. Nesta regressão do corpo lúteo (CL), estão envolvidos ainda os hormônios (LH, prolactina, cortisol) e várias substâncias vasoativas (óxido nítrico, VEGF, EG-VEGF, bFGF, END-1, AngII). A concentração de PGF2α pode ser representada pela mensuração sanguínea da concentração de seu metabólito 13,14-dihidro-15-ceto- PGF2α (PGFM) sendo a pulsatilidade da secreção de PGF2α durante os períodos pré-luteolítico, luteolítico e pós-luteolítico mensurável pelo aumento na concentração de PGFM. Neste artigo de revisão, será possível compreender e discutir os principais aspectos endócrinos e moleculares que ocorrem com as mudanças morfofuncionais no CL durante o processo de luteólise fisiológica em fêmeas bovinas.(AU)

The knowledge of the luteolysis process within reproductive physiology becomes important to occur the understanding of maternal recognition of gestation being possible to formulate anti-luteolytic strategies aimed at maintaining this phase conferring increases in reproductive and productive efficiency. During the luteolysis process, luteal tissue undergoes abrupt changes in steroidogenic capacity, vascularization and remodeling, resulting in replacement of the gland by connective tissue, and PGF2α is the main determinant in the spontaneous induction of luteolysis in cattle. Simultaneously, an intimate process occurs between the anatomical relationships that comprise the ovary, uterus and its vascularizations. The exposure of the uterus to the coordinated interaction between P4, E2 and oxytocin, together with the expression of its receptors, are essential for the pulsating secretion of PGF2α by the endometrium, which will induce luteolysis. In this regression of the corpus luteum (CL), hormones (LH, prolactin, cortisol) and various vasoactive substances (nitric oxide, VEGF, EG-VEGF, bFGF, END-1, AngII) are also involved. The concentration of PGF2α can be represented by the blood measurement of the concentration of its metabolite 13,14-dihydro-15-keto-PGF2α (PGFM),being the pulsatility of PGF2α secretion during the pre-luteolytic, luteolytic and post-luteolytic measured by the increased concentration of PGFM. In this review article, it will be possible to understand and discuss the main endocrine and molecular aspects that occur with the morphofunctional changes in CL during the physiological luteolysis process in bovine females.(AU)

Regressão espontânea do corpo lúteo em bovinos - revisão / Spontaneous corpus luteum regression in cattle: review

O conhecimento do processo de luteólise dentro da fisiologia reprodutiva se torna importante para que ocorra a compreensão do reconhecimento materno da gestação e seja possível formular estratégias anti-luteolíticas que visem manter esta fase conferindo aumentos na eficiência reprodutiva e produtiva. Durante o processo de luteólise, o tecido luteal sofre mudanças bruscas na capacidade esteroidogênica, vascularização e remodelamento, resultando em substituição da glândula por tecido conjuntivo, sendo a PGF2α o principal determinante na indução espontânea da luteólise em bovinos. Simultaneamente, ocorre um íntimo processo entre as relações anatômicas que compreende o ovário, útero e suas vascularizações. A exposição do útero à interação coordenada entre P4, E2 e ocitocina aliada à expressão de seus receptores são essenciais para a secreção pulsátil de PGF2α pelo endométrio a qual induzirá a luteólise. Nesta regressão do corpo lúteo (CL), estão envolvidos ainda os hormônios (LH, prolactina, cortisol) e várias substâncias vasoativas (óxido nítrico, VEGF, EG-VEGF, bFGF, END-1, AngII). A concentração de PGF2α pode ser representada pela mensuração sanguínea da concentração de seu metabólito 13,14-dihidro-15-ceto- PGF2α (PGFM) sendo a pulsatilidade da secreção de PGF2α durante os períodos pré-luteolítico, luteolítico e pós-luteolítico mensurável pelo aumento na concentração de PGFM. Neste artigo de revisão, será possível compreender e discutir os principais aspectos endócrinos e moleculares que ocorrem com as mudanças morfofuncionais no CL durante o processo de luteólise fisiológica em fêmeas bovinas.

The knowledge of the luteolysis process within reproductive physiology becomes important to occur the understanding of maternal recognition of gestation being possible to formulate anti-luteolytic strategies aimed at maintaining this phase conferring increases in reproductive and productive efficiency. During the luteolysis process, luteal tissue undergoes abrupt changes in steroidogenic capacity, vascularization and remodeling, resulting in replacement of the gland by connective tissue, and PGF2α is the main determinant in the spontaneous induction of luteolysis in cattle. Simultaneously, an intimate process occurs between the anatomical relationships that comprise the ovary, uterus and its vascularizations. The exposure of the uterus to the coordinated interaction between P4, E2 and oxytocin, together with the expression of its receptors, are essential for the pulsating secretion of PGF2α by the endometrium, which will induce luteolysis. In this regression of the corpus luteum (CL), hormones (LH, prolactin, cortisol) and various vasoactive substances (nitric oxide, VEGF, EG-VEGF, bFGF, END-1, AngII) are also involved. The concentration of PGF2α can be represented by the blood measurement of the concentration of its metabolite 13,14-dihydro-15-keto-PGF2α (PGFM),being the pulsatility of PGF2α secretion during the pre-luteolytic, luteolytic and post-luteolytic measured by the increased concentration of PGFM. In this review article, it will be possible to understand and discuss the main endocrine and molecular aspects that occur with the morphofunctional changes in CL during the physiological luteolysis process in bovine females.

Influência da condição corporal ao parto no balanço energético e desempenho reprodutivo de cabras leiteiras no pós-parto / Influence of body condition at calving on energy balance and reproductive performance of dairy goats in the postpartum

O estudo teve como objetivo avaliar a influência da condição corporal (CC) ao parto no balanço energético (BE) e o desempenho reprodutivo de cabras Alpinas no pós-parto. Foram utilizadas 68 cabras distribuídas em três grupos (G), sendo: G1- cabras com baixa CC (CC entre 1,5 e 2,5); G2: cabras com moderada CC (entre 2,75 e 3,5) e G3: cabras com alta CC (entre 3,75 e 5,0). Os animais receberam dieta (silagem de milho e concentrado, com 18% de proteína bruta e 1,7Mcal/kg de matéria seca de energia líquida) ad libitum. As avaliações foram feitas nas oito primeiras semanas de lactação, para determinação do BE, do intervalo do parto à primeira ovulação e ao primeiro estro e da concentração plasmática de progesterona. Os dados foram analisados por análise de variância a 5% de probabilidade. Não houve efeito da CC ao parto sobre o BE dos animais. Todas as cabras apresentaram BE negativo ao parto, com mudança para BE positivo aos 51, 58 e 64 dias pós-parto, respectivamente. Não houve diferença na concentração plasmática de progesterona nos três grupos, sendo caracterizada função luteal (concentração ≥1ng/dL) em apenas 5,9% dos animais avaliados. O intervalo do parto à primeira ovulação foi de 46 dias. Apenas 4,4% das cabras exibiram estro. Cabras leiteiras de média produção, entre 2,5 e 3,0kg de leite/dia, entram em BE negativo ao parto, independentemente da CC apresentada, influenciando negativamente o reinício da atividade ovariana no pós-parto.(AU)

The concentration of progesterone in the blood was used to study the effect of body condition score (BCS) on the post-partum ovarian activity of dairy goats. Sixty-eight female goats were distributed between three treatments. Treatment 1: goats with BCS between 1.00 and 2.75; Treatment 2: goats with BCS between 2.75 and 3.50; and Treatment 3: goats with BCS between 3.50 and 5.00. The goats had the blood collected immediately after birth, and from that time up to the eighth week post-partum at three day intervals. The progesterone analysis on the blood was used to determine the interval between the birth and the first ovulation. The females were teasing two times per day for estrus detection and determination of the time interval from birth to first estrus. No significant difference was found on the progesterone concentration between treatments. The luteal functionality was characterized in only 5.9% of goats, with a concentration higher than 1ng/mL. The period from birth to first ovulation was 46 days. The detectable estrus was found in only 4.4% of goats. The BCS at birth did not influence the recovery of ovarian activity of dairy goats.(AU)

Influência da condição corporal ao parto no balanço energético e desempenho reprodutivo de cabras leiteiras no pós-parto / Influence of body condition at calving on energy balance and reproductive performance of dairy goats in the postpartum

O estudo teve como objetivo avaliar a influência da condição corporal (CC) ao parto no balanço energético (BE) e o desempenho reprodutivo de cabras Alpinas no pós-parto. Foram utilizadas 68 cabras distribuídas em três grupos (G), sendo: G1- cabras com baixa CC (CC entre 1,5 e 2,5); G2: cabras com moderada CC (entre 2,75 e 3,5) e G3: cabras com alta CC (entre 3,75 e 5,0). Os animais receberam dieta (silagem de milho e concentrado, com 18% de proteína bruta e 1,7Mcal/kg de matéria seca de energia líquida) ad libitum. As avaliações foram feitas nas oito primeiras semanas de lactação, para determinação do BE, do intervalo do parto à primeira ovulação e ao primeiro estro e da concentração plasmática de progesterona. Os dados foram analisados por análise de variância a 5% de probabilidade. Não houve efeito da CC ao parto sobre o BE dos animais. Todas as cabras apresentaram BE negativo ao parto, com mudança para BE positivo aos 51, 58 e 64 dias pós-parto, respectivamente. Não houve diferença na concentração plasmática de progesterona nos três grupos, sendo caracterizada função luteal (concentração ≥1ng/dL) em apenas 5,9% dos animais avaliados. O intervalo do parto à primeira ovulação foi de 46 dias. Apenas 4,4% das cabras exibiram estro. Cabras leiteiras de média produção, entre 2,5 e 3,0kg de leite/dia, entram em BE negativo ao parto, independentemente da CC apresentada, influenciando negativamente o reinício da atividade ovariana no pós-parto.(AU)

The concentration of progesterone in the blood was used to study the effect of body condition score (BCS) on the post-partum ovarian activity of dairy goats. Sixty-eight female goats were distributed between three treatments. Treatment 1: goats with BCS between 1.00 and 2.75; Treatment 2: goats with BCS between 2.75 and 3.50; and Treatment 3: goats with BCS between 3.50 and 5.00. The goats had the blood collected immediately after birth, and from that time up to the eighth week post-partum at three day intervals. The progesterone analysis on the blood was used to determine the interval between the birth and the first ovulation. The females were teasing two times per day for estrus detection and determination of the time interval from birth to first estrus. No significant difference was found on the progesterone concentration between treatments. The luteal functionality was characterized in only 5.9% of goats, with a concentration higher than 1ng/mL. The period from birth to first ovulation was 46 days. The detectable estrus was found in only 4.4% of goats. The BCS at birth did not influence the recovery of ovarian activity of dairy goats.(AU)

Identification of microsatellite markers in coffee associated with resistance to Meloidogyne exigua.

Meloidogyne species are destructive phytonematodes that result in reduced yields of coffee. The classic test for resistance to Meloidogyne exigua in coffee progenies is both expensive and time-consuming. The use of molecular marker techniques can assist the selection process when it is difficult to measure the phenotype, such as in cases of resistance to nematode infestation. The objective of this study was to identify microsatellite markers associated with resistance to M. exigua in F5 progenies of coffee derived from a cross between Híbrido de Timor 440-10 and Catuaí Amarelo IAC 86. Of the 44 simple sequence repeat (SSR) markers evaluated, 11 showed a polymorphic pattern with a mean number of 4.5 alleles per marker. Clustering analysis classified 82 progenies into three groups related to the response to nematodes and parental genotypes allocated to different groups (resistant and susceptible). SSRCafé 40 allele 2, SSRCafé 15 allele 3, SSRCafé 20 allele 3, and SSRCafé 13 allele 1 were negatively correlated with reproduction factor. In addition, SSRCafé 13 allele 2, SSRCafé 19 allele 3, SSRCafé 40 allele 2, SSRCafé 15 allele 3, and SSRCafé 20 allele 3 were correlated with the root gall index of M. exigua. These SSR markers, which have been validated in this population, represent a potential method to select progenies resistant to nematodes in coffee-breeding programs.

Influência do Hormônio do Crescimento na concentração de testosterona plasmática e nas características seminais de touros jovens e adultos da raça Nelore / Influence of Growth Hormone on plasma testosterone concentration and seminal characteristics of young and adult Nellore bulls

Estudou-se o efeito do Hormônio do Crescimento bovino (bGH) sobre os parâmetros seminais e a concentração sérica de testosterona de touros da raça Nelore. Dezesseis touros foram distribuídos em um delineamento fatorial 2 x 2 (duas idades e dois níveis de r-bST), com quatro animais em cada tratamento. As aplicações de r-bST foram realizadas a cada 14 dias, totalizando nove aplicações por animal, em um período experimental de 120 dias. As coletas de sêmen foram realizadas a cada 15 dias e, para determinar as concentrações de testosterona, foram realizadas coletas de sangue a cada quatro horas, num total de 24 horas, e a cada 30 dias a partir da primeira aplicação de r-bST. O sêmen dos touros adultos tratados com r-bST apresentaram maior motilidade e vigor (P<0,05) em relação aos animais controles (79,70±11,56% vs 64,06±23,65%) e (3,80±0,88 vs 2,92±1,25), respectivamente, entretanto, as demais características seminais não foram influenciadas (P>0,05) pelo tratamento com r-bST. Os aspectos físicos do sêmen dos touros jovens não foram afetados (P>0,05) pelo tratamento com r-bST. Entretanto o tratamento com r-bST diminuiu os defeitos morfológicos menores (delgado, gigante normal, pequeno normal, globoso, cabeça isolada normal, abaxial, cauda dobrada e enrolada levemente e gota distal) em relação aos jovens não tratados (P<0,05). As concentrações séricas de testosterona foram influenciadas (P<0,05) pelo tratamento, aos 120 dias após a primeira aplicação do r-bST, e apresentaram tendência de três picos no período de 24 horas.(AU)

The aim of this trial was to study the effect of Growth Hormone (GH) on the seminal parameters and testosterone profile from Nellore bulls. Sixteen bulls were allocated in a 2 x 2 factorial arrangement (two ages and two r-bST levels), with four animals per treatment. The r-bST was injected every 14 days, with a total of nine injections per animal, during the 120 days of the experimental period. The semen collections were done every 15 days and blood samples were collected in four hour intervals for 24 hours, and in 30 day intervals from the first r-bST injection for testosterone profile. The semen of adult bulls treated with r-bST showed greater MOT and VIG (P<0.05) in relation to the control (79.70±11.56% vs 64.06±23.65%) and (3.80±0.88 vs 2.92±1.25) respectively, however, the other evaluated seminal parameters were not affected (P>0.05) by the r-bST treatment. The physical measurements of the semen of young animals was also unaffected (P>0.05) by r-bST injection. However, the treatment with r-bST decreased the number of minor morphologic defects (narrow head, giant head, small normal head, round head, free normal head, abaxial implantation, simple bent tail and distal droplet) compared to untreated young bulls (P<0.05). The serum testosterone concentration was influenced (P<0.05) by treatment, at 120 days after the first injection of r-bST and they showed a tendency of three picks in a 24 hour period of sampling.(AU)

Influência do Hormônio do Crescimento na concentração de testosterona plasmática e nas características seminais de touros jovens e adultos da raça Nelore / Influence of Growth Hormone on plasma testosterone concentration and seminal characteristics of young and adult Nellore bulls

Estudou-se o efeito do Hormônio do Crescimento bovino (bGH) sobre os parâmetros seminais e a concentração sérica de testosterona de touros da raça Nelore. Dezesseis touros foram distribuídos em um delineamento fatorial 2 x 2 (duas idades e dois níveis de r-bST), com quatro animais em cada tratamento. As aplicações de r-bST foram realizadas a cada 14 dias, totalizando nove aplicações por animal, em um período experimental de 120 dias. As coletas de sêmen foram realizadas a cada 15 dias e, para determinar as concentrações de testosterona, foram realizadas coletas de sangue a cada quatro horas, num total de 24 horas, e a cada 30 dias a partir da primeira aplicação de r-bST. O sêmen dos touros adultos tratados com r-bST apresentaram maior motilidade e vigor (P<0,05) em relação aos animais controles (79,70±11,56% vs 64,06±23,65%) e (3,80±0,88 vs 2,92±1,25), respectivamente; entretanto, as demais características seminais não foram influenciadas (P>0,05) pelo tratamento com r-bST. Os aspectos físicos do sêmen dos touros jovens não foram afetados (P>0,05) pelo tratamento com r-bST. Entretanto o tratamento com r-bST diminuiu os defeitos morfológicos menores (delgado, gigante normal, pequeno normal, globoso, cabeça isolada normal, abaxial, cauda dobrada e enrolada levemente e gota distal) em relação aos jovens não tratados (P<0,05). As concentrações séricas de testosterona foram influenciadas (P<0,05) pelo tratamento, aos 120 dias após a primeira aplicação do r-bST, e apresentaram tendência de três picos no período de 24 horas.

The aim of this trial was to study the effect of Growth Hormone (GH) on the seminal parameters and testosterone profile from Nellore bulls. Sixteen bulls were allocated in a 2 x 2 factorial arrangement (two ages and two r-bST levels), with four animals per treatment. The r-bST was injected every 14 days, with a total of nine injections per animal, during the 120 days of the experimental period. The semen collections were done every 15 days and blood samples were collected in four hour intervals for 24 hours, and in 30 day intervals from the first r-bST injection for testosterone profile. The semen of adult bulls treated with r-bST showed greater MOT and VIG (P<0.05) in relation to the control (79.70±11.56% vs 64.06±23.65%) and (3.80±0.88 vs 2.92±1.25) respectively; however, the other evaluated seminal parameters were not affected (P>0.05) by the r-bST treatment. The physical measurements of the semen of young animals was also unaffected (P>0.05) by r-bST injection. However, the treatment with r-bST decreased the number of minor morphologic defects (narrow head, giant head, small normal head, round head, free normal head, abaxial implantation, simple bent tail and distal droplet) compared to untreated young bulls (P<0.05). The serum testosterone concentration was influenced (P<0.05) by treatment, at 120 days after the first injection of r-bST and they showed a tendency of three picks in a 24 hour period of sampling.

Use of cholesterol-loaded cyclodextrin in donkey semen cryopreservation improves sperm viability but results in low fertility in mares.

The use of cholesterol-loaded cyclodextrin (CLC) on semen cryopreservation has been related with better sperm viability in several species; however, the effect on fertility is not known in donkey semen. Ejaculates (n = 25) from five donkeys were diluted in S-MEDIUM with 0, 1, 2 or 3 mg of CLC/120 × 10(6) spermatozoa. Semen was frozen, and thawed samples were evaluated by computer-assisted sperm analyser system (CASA), supravital test, hyposmotic swelling test and fluorescent dyes to assess the integrity of sperm membranes. Mares (n = 60) were inseminated with frozen-thawed semen treated with the doses of 0 or 1 mg CLC. Percentages of sperm with progressive motility and with functional plasma membrane were greater (p < 0.05) in the CLC-treated groups than in the control. Percentages of intact plasma membrane and intact plasma membrane and acrosome detected by fluorescent dyes were also greater (p < 0.05) in CLC-treated groups. Although no difference (p > 0.05) in conception rates was detected between groups (control, 3/30, 10%; CLC-treated, 1/30, 3.3%), fertility was low for artificial insemination programs in mares. Therefore, we firstly demonstrated that frozen semen treated with CLC in S-MEDIA extender before freezing improves the in vitro sperm viability, but semen treated or not with CLC in S-MEDIUM extender results in a very low conception rate in mares inseminated with thawed donkey semen.

Impact of using a fast-freezing technique and different thawing protocols on viability and fertility of frozen equine spermatozoa.

The effects of freezing technique and thawing protocol on thawed semen viability and fertility were studied. Ejaculates from 5 stallions (n = 25) were frozen by conventional or a fast-freezing technique. Frozen semen was thawed by two thawing protocols (37 °C 30 s(-1) or 75 °C 7 s(-1) ). Thawed semen was evaluated by progressive motility, vigour, morphology and plasma membrane integrity. Mares (n = 25) were inseminated with 300 (n = 11) or 150 (n = 14) million spermatozoa. A greater (P < 0.05) vigour and progressively motile spermatozoa were detected, respectively, at thawing and after 20 min post-thawing in the fast-freezing technique than in the conventional one. Plasma membrane integrity was also greater (P < 0.05) in semen frozen with the fast-freezing technique. Semen viability was not affected by thawing protocol. Pregnancy rate using the fast-freezing technique was 76% (19/25), and did not differ (P > 0.05) between insemination doses. We concluded that the 150 million progressively motile spermatozoa per dose using a deep-horn insemination maximises the use of equine semen. The fast-freezing technique, as compared to the conventional one, efficiently preserves the viability and fertilising capacity of spermatozoa, indicating a new method to improve the fertility of frozen equine semen.

Reproductive parameters of Mangalarga Marchador mares in a commercial embryo transfer programme.

The objective of this study is to evaluate the reproductive efficiency in donors and recipient Mangalarga Marchador mares in commercial programmes of embryo transfer (ET) and the effects of some reproductive characteristics and ET methodology on conception rates in the recipient mares. A total of 1140 flushing procedures were performed and 830 embryos (72.8%) were recovered. There were no differences between the rates of embryonic recovery in the different breeding seasons (p > 0.05) and 92.8% of the recovered embryos were 8-9 days old. There was no difference in the embryonic recovery regarding the collection order from the first to the ninth embryo collection along the breeding season, as well as among mares inseminated during the foal heat or subsequent cycles (p > 0.05). Pregnancy rates observed in the total period of all reproductive seasons at 15, 30, 45 and 60 days of pregnancy were 73.4, 69.9, 66.7 and 64.5%, respectively. Differences in pregnancy rate and early embryonic loss rates were not observed between embryos transferred immediately after collection (66.8% and 13.5%) and embryos transported at room temperature for periods of < 1 h (62.9% and 14.4%; p > 0.05). Pregnancy rates were higher when the interval between ovulations of donor and recipient mares remained between -3 and -2 days (p < 0.05), and the lowest rates were observed for intervals of -6 days (p < 0.05) with intermediary values for intervals of -1, 0 and +1 (p > 0.05). Embryonic loss rates, however, did not differ between intervals of ovulation's synchronism between donor and recipient mares (p > 0.05). This flexibilization in the ovulatory synchronism between donor and recipient mares optimizes the use of recipient mares, thus reducing costs and facilitating management of horse breeding farms.

Sexual behavior and ejaculate characteristics in Pêga donkeys (Equus asinus) mounting estrous horse mares (Equus caballus).

The objectives were to (i) characterize sexual behavior of donkey stallions (jacks; Equus asinus) during on-farm semen collection using estrous horse mares (mares; Equus caballus); (ii) compare behavior of young (less experienced) versus older (more experienced) jacks; (iii) determine whether semen suitable for artificial insemination (AI) could be collected using mares; and (iv) determine the suitability of using mares in field collection of semen from jacks. Six Pêga jacks (3.5 to 16 yr old), previously conditioned to breed mares, were used. Mount mares were confirmed in estrus by a teaser horse stallion (stallion) and a jack. Semen was collected with an artificial vagina, at intervals of 48 to 72h (180 collections). The mean+/-SD (young [3.5 yr] vs. old [14 to 16 yr]) were Flehmen response frequency, 7.4+/-5.8 (8.1+/-3.0 vs. 7.0+/-2.0); number of mounts without erection, 1.1+/-1.3 (2.1+/-1.4 vs. 1.2+/-0.4, P<0.05); latency from first exposure to mare to full erection on the ejaculatory mount, 18.3+/-17.7min (25.3+/-21.3 vs. 12.2+/-6.2, P<0.05); latency from erection to insertion, 5.1+/-3.5sec (5.3+/-3.8 vs. 4.8+/-3.2); and duration of copulation from insertion to dismount after ejaculation, 25.4+/-7.8sec (22.1+/-2.9 vs. 28.1+/-9.3). In all jacks, sexual behavior was generally normal, with the notable absence of open mouth behavior. Mare estrous behavior was markedly less intense than that in the presence of a stallion and usually absent. Semen characteristics were gel free volume, 47.3+/-28.7mL; gel volume, 71.8+/-54.8mL; total motility, 84.3+/-6.0%; progressive motility, 74.3+/-74.5%; sperm vigor, 3.9+/-0.5 (scale 1 to 5); sperm concentration, 253x10(6) cells/mL; and total number of sperm, 10.3x10(9) cells. Copulation duration was significantly correlated with gel free volume (r=0.9) and gel volume (r=0.7). We concluded that (i) the sexual behavior of jacks during semen collection using mares was similar to that reported for natural mating to jennies, (ii) precopulatory and copulatory behavior for the young (less experienced) jacks and older (more experienced) jacks were generally similar (except number of mounts without erection and latency to full erection); (iii) semen obtained using mares as stimulus and mount females was similar to that reported with estrous jennies; and (iv) semen collection from previously conditioned jacks, using estrous mares, was appropriate for field collection of semen.

Fertilidade de éguas inseminadas no corpo ou no ápice do corno uterino com diferentes concentrações espermáticas / Fertility of mares inseminated in the uterine corpus or tip with different sperm concentrations

Foram utilizados 72 ciclos estrais de 37 éguas mestiças, com idade variando de quatro a 20 anos, distribuídas ao acaso em dois grupos experimentais (G I e G II) para estudar o efeito do local de deposição do sêmen no sistema genital sobre a fertilidade. As inseminações no ápice do corno uterino (G II) foram realizadas por via intravaginal profunda, utilizando-se a pipeta de inseminação IVI pippette (75cm), contendo 1/5 (3mL) da dose inseminante utilizada para o corpo do útero (15mL-G I). As éguas foram rufiadas diariamente e inseminadas às segundas, quartas e sextas-feiras, a partir de um folículo de 3,0 a 3,5cm de diâmetro, com sêmen fresco diluído em diluidor de leite desnatado-glicose. Apenas um garanhão de 20 anos e de fertilidade conhecida foi utilizado. As taxas de concepção/ciclo para as inseminações realizadas no corpo (42,9 por cento-15/35) e ápice do corno uterino (45,9 por cento-17/37) com concentrações médias de 489 e 102 milhões de espermatozoides móveis, respectivamente, não foram diferentes (P>0,05).(AU)

Seventy-two estral cycles of 37 mares, aging from four to 20-year-old, were randomly distributed in two experimental groups (G I and G II). The aim of the study was to evaluate the effect of the semen deposition placed in the female genital system on the fertility. The inseminations in uterine horn tip (G II) were carried out by deep intravaginal way, using the pipette of insemination IVI pippette (75cm), containing 1/5 (3mL) of the inseminant dose of that utilized in uterine body or horn (15mL-G I). The mares were daily teased and inseminated on Mondays, Wednesdays, and Fridays, starting from a follicle from 3.0 to 3.5cm diameter, with fresh semen diluted in skim milk glucose extender. Only one 20 year-old stallion with wellknown fertility was utilized. The conception rates/cycles for inseminations carried out in the uterine body (42,9 percent-15/35) and in the uterine horn tip (45,9 percent-17/37) utilizing average concentrations of 489 and 102 million of mobile spermatozoa, respectively, did not present difference (P>0.05).(AU)

Fertilidade de éguas inseminadas no corpo ou no ápice do corno uterino com diferentes concentrações espermáticas / Fertility of mares inseminated in the uterine corpus or tip with different sperm concentrations

Foram utilizados 72 ciclos estrais de 37 éguas mestiças, com idade variando de quatro a 20 anos, distribuídas ao acaso em dois grupos experimentais (G I e G II) para estudar o efeito do local de deposição do sêmen no sistema genital sobre a fertilidade. As inseminações no ápice do corno uterino (G II) foram realizadas por via intravaginal profunda, utilizando-se a pipeta de inseminação IVI pippette (75cm), contendo 1/5 (3mL) da dose inseminante utilizada para o corpo do útero (15mL-G I). As éguas foram rufiadas diariamente e inseminadas às segundas, quartas e sextas-feiras, a partir de um folículo de 3,0 a 3,5cm de diâmetro, com sêmen fresco diluído em diluidor de leite desnatado-glicose. Apenas um garanhão de 20 anos e de fertilidade conhecida foi utilizado. As taxas de concepção/ciclo para as inseminações realizadas no corpo (42,9 por cento-15/35) e ápice do corno uterino (45,9 por cento-17/37) com concentrações médias de 489 e 102 milhões de espermatozoides móveis, respectivamente, não foram diferentes (P>0,05).

Seventy-two estral cycles of 37 mares, aging from four to 20-year-old, were randomly distributed in two experimental groups (G I and G II). The aim of the study was to evaluate the effect of the semen deposition placed in the female genital system on the fertility. The inseminations in uterine horn tip (G II) were carried out by deep intravaginal way, using the pipette of insemination IVI pippette (75cm), containing 1/5 (3mL) of the inseminant dose of that utilized in uterine body or horn (15mL-G I). The mares were daily teased and inseminated on Mondays, Wednesdays, and Fridays, starting from a follicle from 3.0 to 3.5cm diameter, with fresh semen diluted in skim milk glucose extender. Only one 20 year-old stallion with wellknown fertility was utilized. The conception rates/cycles for inseminations carried out in the uterine body (42,9 percent-15/35) and in the uterine horn tip (45,9 percent-17/37) utilizing average concentrations of 489 and 102 million of mobile spermatozoa, respectively, did not present difference (P>0.05).

Dinâmica folicular em cabras da raça Toggenburg em lactação tratadas ou não com somatotropina bovina recombinante / Follicular dynamics of lactating Toggenburg does treated with recombinant bovine somatotropin

Avaliou-se o efeito da injeção de somatotropina bovina recombinante (r-bST) sobre o ciclo estral de cabras. Foram utilizadas 24 fêmeas da raça Toggenburg, distribuídas em dois tratamentos: T1 (n=12), cabras tratadas com r-bST; e T2 (n=12), cabras tratadas com solução salina (controle). A partir da primeira injeção do tratamento, acompanhou-se o ciclo dos animais em estro até o estro subseqüente. O comprimento médio do ciclo estral e o período interovulatório não diferiram (P>0,05) entre os tratamentos. Foram verificados ciclos estrais de duas, três e quatro ondas de crescimento folicular. Não houve diferença (P>0,05) entre os tratamentos quanto ao número de ondas do ciclo estral. O número de folículos detectados com diâmetro >3mm nas cabras do T1 foi maior (P<0,05) que naquelas do T2 nos ciclos com duas (15,3±1,2 x 8,1±2,0), três (12,2±0,8 x 8,3±1,9) e quatro (12,7±1,7 x 8,8±2,5) ondas. O folículo dominante da segunda onda foi menor (P<0,05) que o da primeira e terceira ondas e também menor que o da onda ovulatória tanto para T1 quanto para T2. A concentração sérica de progesterona durante o ciclo estral não foi influenciada pelos tratamentos com r-bST (P>0,05). A r-bST não alterou a dinâmica folicular de cabras lactantes da raça Toggenburg, mas promoveu o aumento do número de folículos recrutados ³3mm durante o ciclo estral(AU)

The effect of the r-bST injection was evaluated on the goats estrous cycles. Twenty-four Toggenburg does were used in two treatments: T1 (n=12) treated with r-bST; and T2 (n=12) treated with saline solution (control). After the first r-bST injection, the estrous cycles were checked between two estrus. The estrous cycle length and interovulatory period of the goats did not differ between treatments (P>0.05). Estrous cycles with two, three and four waves of follicular growth were observed. The number of waves during the estrous cycle were not affected by the r-bST treatment (P>0.05). The number of 3mm follicles was different between T1 and T2 (P<0.05) for estrous cycles with two (15.3±1.2 x 8.1±2.0), three (12.2±0.8 x 8.3±1.9) or four (12.7±1.7 x 8.8±2.5) waves. The dominant follicle of the second wave was smaller (P<0.05) than the one of the first and third waves and smaller than the one of the ovulatory wave. The progesterone concentration during the estrous cycle of the animals did not differ (P>0.05) between treatments. The r-bST did not affect the ovarian response during the estrous cycle. The r-bST not affected the follicular dynamic of Toggenburg lactating does, but increased the number of emerging follicles >3mm during the estrous cycle(AU)

Dinâmica folicular em cabras da raça Toggenburg em lactação tratadas ou não com somatotropina bovina recombinante / Follicular dynamics of lactating Toggenburg does treated with recombinant bovine somatotropin

Avaliou-se o efeito da injeção de somatotropina bovina recombinante (r-bST) sobre o ciclo estral de cabras. Foram utilizadas 24 fêmeas da raça Toggenburg, distribuídas em dois tratamentos: T1 (n=12), cabras tratadas com r-bST; e T2 (n=12), cabras tratadas com solução salina (controle). A partir da primeira injeção do tratamento, acompanhou-se o ciclo dos animais em estro até o estro subseqüente. O comprimento médio do ciclo estral e o período interovulatório não diferiram (P>0,05) entre os tratamentos. Foram verificados ciclos estrais de duas, três e quatro ondas de crescimento folicular. Não houve diferença (P>0,05) entre os tratamentos quanto ao número de ondas do ciclo estral. O número de folículos detectados com diâmetro >3mm nas cabras do T1 foi maior (P<0,05) que naquelas do T2 nos ciclos com duas (15,3±1,2 x 8,1±2,0), três (12,2±0,8 x 8,3±1,9) e quatro (12,7±1,7 x 8,8±2,5) ondas. O folículo dominante da segunda onda foi menor (P<0,05) que o da primeira e terceira ondas e também menor que o da onda ovulatória tanto para T1 quanto para T2. A concentração sérica de progesterona durante o ciclo estral não foi influenciada pelos tratamentos com r-bST (P>0,05). A r-bST não alterou a dinâmica folicular de cabras lactantes da raça Toggenburg, mas promoveu o aumento do número de folículos recrutados ³3mm durante o ciclo estral

The effect of the r-bST injection was evaluated on the goats estrous cycles. Twenty-four Toggenburg does were used in two treatments: T1 (n=12) treated with r-bST; and T2 (n=12) treated with saline solution (control). After the first r-bST injection, the estrous cycles were checked between two estrus. The estrous cycle length and interovulatory period of the goats did not differ between treatments (P>0.05). Estrous cycles with two, three and four waves of follicular growth were observed. The number of waves during the estrous cycle were not affected by the r-bST treatment (P>0.05). The number of 3mm follicles was different between T1 and T2 (P<0.05) for estrous cycles with two (15.3±1.2 x 8.1±2.0), three (12.2±0.8 x 8.3±1.9) or four (12.7±1.7 x 8.8±2.5) waves. The dominant follicle of the second wave was smaller (P<0.05) than the one of the first and third waves and smaller than the one of the ovulatory wave. The progesterone concentration during the estrous cycle of the animals did not differ (P>0.05) between treatments. The r-bST did not affect the ovarian response during the estrous cycle. The r-bST not affected the follicular dynamic of Toggenburg lactating does, but increased the number of emerging follicles >3mm during the estrous cycle

Dinâmica folicular em cabras da raça Toggenburg em lactação tratadas ou não com somatotropina bovina recombinante

The effect of the r-bST injection was evaluated on the goats estrous cycles. Twenty-four Toggenburg does were used in two treatments: T1 (n=12) treated with r-bST; and T2 (n=12) treated with saline solution (control). After the first r-bST injection, the estrous cycles were checked between two estrus. The estrous cycle length and interovulatory period of the goats did not differ between treatments (P>0.05). Estrous cycles with two, three and four waves of follicular growth were observed. The number of waves during the estrous cycle were not affected by the r-bST treatment (P>0.05). The number of 3mm follicles was different between T1 and T2 (P 0.05) for estrous cycles with two (15.3±1.2 x 8.1±2.0), three (12.2±0.8 x 8.3±1.9) or four (12.7±1.7 x 8.8±2.5) waves. The dominant follicle of the second wave was smaller (P 0.05) than the one of the first and third waves and smaller than the one of the ovulatory wave. The progesterone concentration during the estrous cycle of the animals did not differ (P>0.05) between treatments. The r-bST did not affect the ovarian response during the estrous cycle. The r-bST not affected the follicular dynamic of Toggenburg lactating does, but increased the number of emerging follicles >3mm during the estrous cycle.

Avaliou-se o efeito da injeção de somatotropina bovina recombinante (r-bST) sobre o ciclo estral de cabras. Foram utilizadas 24 fêmeas da raça Toggenburg, distribuídas em dois tratamentos: T1 (n=12), cabras tratadas com r-bST; e T2 (n=12), cabras tratadas com solução salina (controle). A partir da primeira injeção do tratamento, acompanhou-se o ciclo dos animais em estro até o estro subseqüente. O comprimento médio do ciclo estral e o período interovulatório não diferiram (P>0,05) entre os tratamentos. Foram verificados ciclos estrais de duas, três e quatro ondas de crescimento folicular. Não houve diferença (P>0,05) entre os tratamentos quanto ao número de ondas do ciclo estral. O número de folículos detectados com diâmetro >3mm nas cabras do T1 foi maior (P 0,05) que naquelas do T2 nos ciclos com duas (15,3±1,2 x 8,1±2,0), três (12,2±0,8 x 8,3±1,9) e quatro (12,7±1,7 x 8,8±2,5) ondas. O folículo dominante da segunda onda foi menor (P 0,05) que o da primeira e terceira ondas e também menor que o da onda ovulatória tanto para T1 quanto para T2. A concentração sérica de progesterona durante o ciclo estral não foi influenciada pelos tratamentos com r-bST (P>0,05). A r-bST não alterou a dinâmica folicular de cabras lactantes da raça Toggenburg, mas promoveu o aumento do número de folículos recrutados ³3mm durante o ciclo estral.

Indução da ovulação em cabras, fora da estação reprodutiva, com LH e GnRH e com estro induzido por progestágenos / Induction of the out-of-season ovulation (with LH and GnRH) and estrus (with progesterone) in goats

Quarenta e cinco cabras foram sincronizadas com o uso de esponjas intravaginais impregnadas com 60mg de acetato de medroxiprogesterona (MAP) por nove dias, associadas com 200UI de gonadotrofina coriônica equina (eCG) e 37,5µg de cloprostenol no sétimo dia. Os animais foram separados em três grupos e receberam, 24 horas após a retirada das esponjas, solução salina ou hormônios, no seguinte esquema: T1 (controle) - 1ml de solução salina; T2 - 5mg de hormônio luteinizante (LH) e T3 - 12,5µg do hormônio liberador de gonadotrofina (GnRH). Houve diferença (P<0,05) na porcentagem de animais em estro, 100,0%, 73,3% e 66,6%, para T1, T2 e T3, respectivamente. Na mesma ordem, não houve diferença (P>0,05) quanto ao intervalo da retirada da esponja ao aparecimento do estro, que foi, em média, 34,8, 29,3 e 31,5 horas, respectivamente. O intervalo médio da retirada da esponja à ovulação foi de 46,6, 52,1 e 41,6 horas, respectivamente, com diferença significativa entre T2 e T3 (P<0,01). As ovulações ocorreram, em média, 21,3, 26,8 e 22,3 horas após as aplicações (P>0,05). A aplicação de LH e do GnRH para induzir e sincronizar a ovulação em cabras fora da estação reprodutiva não apresentou resultados satisfatórios.(AU)

In order to achieve estrous synchronization, intravaginal sponges impregnated with 60mg of medroxyprogesterone acetate (MPA) were implanted in 45 goats for nine days. On day 7, 200IU of equine chorionic gonadotropin (eCG) and 37.5µg of cloprostenol were administered to each doe. The animals were randomly allocated in three treatments with 15 animals each. Twenty four hours after intravaginal sponge removal, does were administered 1ml saline solution (control T1), 5mg LH (T2) and 2.5µg GnRH (T3) intramuscular injection. Percentages of animals in estrus were 100.0; 73.3 and 66.6 (P<0.05) and average intervals from sponge removal to start of estrus were 34.8, 29.3 and 31.5 hours for T1, T2 and T3, respectively, being those differences not statistically significant. The average intervals from sponge removal to ovulation were 46.6, 52.1 and 41.6 hours for T1, T2 and T3, respectively, with the difference between T2 and T3 being statistically significant (P<0.01). Ovulation time averages were 21.3, 26.8 and 22.3 hours after injections for T1, T2 and T3 , respectively.(AU)

Indução da ovulação em cabras, fora da estação reprodutiva, com LH e GnRH e com estro induzido por progestágenos / Induction of the out-of-season ovulation (with LH and GnRH) and estrus (with progesterone) in goats

Quarenta e cinco cabras foram sincronizadas com o uso de esponjas intravaginais impregnadas com 60mg de acetato de medroxiprogesterona (MAP) por nove dias, associadas com 200UI de gonadotrofina coriônica equina (eCG) e 37,5µg de cloprostenol no sétimo dia. Os animais foram separados em três grupos e receberam, 24 horas após a retirada das esponjas, solução salina ou hormônios, no seguinte esquema: T1 (controle) - 1ml de solução salina; T2 - 5mg de hormônio luteinizante (LH) e T3 - 12,5µg do hormônio liberador de gonadotrofina (GnRH). Houve diferença (P<0,05) na porcentagem de animais em estro, 100,0 por cento, 73,3 por cento e 66,6 por cento, para T1, T2 e T3, respectivamente. Na mesma ordem, não houve diferença (P>0,05) quanto ao intervalo da retirada da esponja ao aparecimento do estro, que foi, em média, 34,8, 29,3 e 31,5 horas, respectivamente. O intervalo médio da retirada da esponja à ovulação foi de 46,6, 52,1 e 41,6 horas, respectivamente, com diferença significativa entre T2 e T3 (P<0,01). As ovulações ocorreram, em média, 21,3, 26,8 e 22,3 horas após as aplicações (P>0,05). A aplicação de LH e do GnRH para induzir e sincronizar a ovulação em cabras fora da estação reprodutiva não apresentou resultados satisfatórios.

In order to achieve estrous synchronization, intravaginal sponges impregnated with 60mg of medroxyprogesterone acetate (MPA) were implanted in 45 goats for nine days. On day 7, 200IU of equine chorionic gonadotropin (eCG) and 37.5µg of cloprostenol were administered to each doe. The animals were randomly allocated in three treatments with 15 animals each. Twenty four hours after intravaginal sponge removal, does were administered 1ml saline solution (control T1), 5mg LH (T2) and 2.5µg GnRH (T3) intramuscular injection. Percentages of animals in estrus were 100.0; 73.3 and 66.6 (P<0.05) and average intervals from sponge removal to start of estrus were 34.8, 29.3 and 31.5 hours for T1, T2 and T3, respectively, being those differences not statistically significant. The average intervals from sponge removal to ovulation were 46.6, 52.1 and 41.6 hours for T1, T2 and T3, respectively, with the difference between T2 and T3 being statistically significant (P<0.01). Ovulation time averages were 21.3, 26.8 and 22.3 hours after injections for T1, T2 and T3 , respectively.