Hermafroditismo verdadeiro na espécie suína / True hermaphroditism in the swine specie

Os hermafroditas verdadeiros são animais com intersexualidade, nos quais as gônadas masculinas e femininas se desenvolvem simultaneamente no mesmo indivíduo. Este trabalho relata um caso de hermafrodita na espécie suína após descarte de uma fêmea por diagnóstico de anestro. Tratava-se de uma fêmea com 222 dias de idade e 150 kg a qual havia sido selecionada para reprodução e permanecia em anestro. O indivíduo foi descartado e enviado para o abate em frigorífico sob inspeção federal. Após o abate foi observado no sistema genital aspectos anatômicos sugestivos de hermafroditismo. O sistema genital foi coletado, inspecionado macroscopicamente e conservado em formol a 10% para avaliação microscópica. Durante a análise macroscópica foi verificada a presença de vulva e vagina, contendo um pênis rudimentar. O útero, a cérvix, os cornos uterinos e oviduto estavam presentes e com ausência de anormalidade. Havia um ovário esquerdo com aspectos morfológicos de ciclicidade e folículos contendo oócitos de alta qualidade. À direita, entretanto, foi constatada a presença de um testículo, epidídimo e plexo pampiniforme. A avaliação histopatológica comprovou os achados macroscópicos, demonstrando um ovário contendo folículos, corpos lúteos e cistos foliculares; plexo pampiniforme; testículo e epidídimo com aspecto histológico normal, porém, com ausência de células espermatogênicas. Assim, com base nos achados macro e microscópicos descritos nesse relato de caso, o indivíduo foi considerado como hermafrodita verdadeiro.(AU)

True hermaphrodites are intersexual animals, in which both male and female gonads develop simultaneously in the same individual. This paper reports a case of a true hermaphrodite in the swine species after its culling for anestrus. The specimen was a female of 222 days of age and 150 kg of body weight, that was selected for reproduction and was permanently in anestrus. This individual was culled and sent to an abattoir under federal inspection. After slaughtering, it was observed in the reproductive tract anatomical aspects that suggested hermaphroditism. The reproductive tract was collected, evaluated macroscopically, and preserved in formaldehyde at 10 % to be evaluated by light microscopy. During the macroscopic analysis, the presence of a vulva and a vagina with a rudimentary penis was detected. The uterus, the cervix, uterine horns, and the oviduct were present and abnormalities were not detected. The left ovary exhibited morphological signs of cyclicity and contained follicles with high quality oocytes. On the right side, however, it was observed a testicle, epididymis, and a pampiniform plexus. The histopathological assessment corroborated the macroscopic findings, which demonstrated that the ovary had follicles, corpus luteum, and follicular cysts, and pampiniform plexus, testicle and epididymis were histologically normal, though with the absence of spermatogenic cells. Thus, based on the macro and microscopic findings described herein, the individual was considered a true hermaphrodite.(AU)

Plasma melatonin and progesterone profiles of Suffolk and Romney Marsh ewes implanted with melatonin during anoestrus season at lower latitudes in Southern hemisphere

Background: The subcutaneous implants of melatonin are stimulatory and mimic the positive effects of short photoperiod on reproduction in small ruminants. This study investigated the daily plasma melatonin profiles in ewes treated with melatonin implants and kept under natural photoperiod in Southeastern Brazil. The plasma progesterone concentrations were also investigated before and after melatonin implantation. Materials, Methods & Results: Romney Marsh (n = 11) and Suffolk (n = 10) ewes, which had been isolated from rams for at least 2 months prior to the beginning of the trial, were randomly allocated in two groups based on melatonin implant treatment (with or without melatonin implant). For plasma melatonin concentration, 43 days after melatonin implantation and 3 days before the ram introduction blood samples were collected every 2 hours during 24 hours. For plasma progesterone concentrations, blood samples were collected every once to twice a week for 2 different periods: prior to melatonin implantation and 46 days after the melatonin implantation and at the same day of the introduction of rams. The hormonal concentrations were determined by the radioimmunoassay method (RIA). The data were analyzed according to MIXED procedure (SAS) as repeated measurements for random animal effects. The effect of melatonin treatment on plasma melatonin 24-h period varied according [...](AU)

Plasma melatonin and progesterone profiles of Suffolk and Romney Marsh ewes implanted with melatonin during anoestrus season at lower latitudes in Southern hemisphere

Background: The subcutaneous implants of melatonin are stimulatory and mimic the positive effects of short photoperiod on reproduction in small ruminants. This study investigated the daily plasma melatonin profiles in ewes treated with melatonin implants and kept under natural photoperiod in Southeastern Brazil. The plasma progesterone concentrations were also investigated before and after melatonin implantation. Materials, Methods & Results: Romney Marsh (n = 11) and Suffolk (n = 10) ewes, which had been isolated from rams for at least 2 months prior to the beginning of the trial, were randomly allocated in two groups based on melatonin implant treatment (with or without melatonin implant). For plasma melatonin concentration, 43 days after melatonin implantation and 3 days before the ram introduction blood samples were collected every 2 hours during 24 hours. For plasma progesterone concentrations, blood samples were collected every once to twice a week for 2 different periods: prior to melatonin implantation and 46 days after the melatonin implantation and at the same day of the introduction of rams. The hormonal concentrations were determined by the radioimmunoassay method (RIA). The data were analyzed according to MIXED procedure (SAS) as repeated measurements for random animal effects. The effect of melatonin treatment on plasma melatonin 24-h period varied according [...]

Utilização de diferentes períodos de fotoestimulação em éguas acíclicas para o controle da sazonalidade reprodutiva / Use of different periods of photostimulation in acyclic mares for reproductive seasonal control / Utilización de diferentes periodos de fotoestimulación en yeguas acíclicas para el control de la estacionalidad reproductiva

As éguas apresentam um período de atividade reprodutiva durante o verão e, no inverno, pouca atividade folicular (anestro). A fim de antecipar a fase reprodutiva, este estudo teve como objetivo avaliar o efeito de diferentes períodos de fotoestimulação sobre a ocorrência da primeira ovulação da estação de monta em éguas em anestro sazonal. O experimento foi conduzido durante as estações reprodutivas de 2009 e 2010, do dia 1 de junho ao dia 1 de agosto, para isso foram utilizadas 45 éguas mestiças, em anestro, entre quatro e 12 anos, em São Simão - SP, Brasil. Na ausência de corpo lúteo e folículos maiores de 20 mm, as éguas foram aleatoriamente separadas nos seguintes grupos: G1 - controle, sem estímulo com luz artificial (G1; n=15), G2 - estimulação com luz artificial por 35 dias (G2; n=15) e G3 -estimulação com luz artificial por 60 dias (G3; n=15). Utilizou-se o teste de Fisher para comparar a proporção de éguas que ovularam até os primeiros 60 dias do experimento entre os grupos de estudo. O método de Bonferroni foi usado para ajustar o nível a para comparações múltiplas. Curvas de sobrevivência e modelos de risco proporcional de Cox foram usados para comparar a taxa de ovulação entre os grupos de estudo (expressa estimando a razão dos riscos). Significância estatística foi definida como P<0,05 ou P<0,02 para o teste de Fisher com comparações múltiplas. A proporção de éguas que ovularam até 60 dias após o início do tratamento foi significantemente maior (84,6%) no grupo tratado com luz artificial por 60 dias, quando comparado ao grupo controle (15,4%, P=0,001). Houve diferença estatística entre o grupo controle e o grupo tratado com luz artificial por 35 dias (61,5%, P=0,041), porém não houve diferença entre os grupos tratados por 35 e 60 dias (P=0,378). O tempo mediano de ovulação no grupo tratado com luz artificial por 60 dias foi 53 dias, enquanto éguas no grupo tratado com luz artificial por 35 ou éguas no grupo controle ovularam aos 56 e 125 dias, respectivamente. Conclui-se que a redução do tratamento com luz artificial para 35 dias não foi tão eficaz quanto o protocolo convencional de 60 dias.

The mares have a period of reproductive activity during the summer and in winter, poor follicular activity (anestrous). In order to anticipate the reproductive phase, this study aimed to evaluate the effect of different periods of photic stimulation on the occurrence of first ovulation of the breeding season in mares in seasonal anestrous. The experiment was conducted during the breeding seasons of 2009 and 2010, from 1 July to 1 August, were used 45 mares crossbred in anestrous between four and 12 years in São Simão - SP, Brazil. In the absence of the corpus luteum and follicles larger than 20 mm, mares were randomly separated into the following groups: G1 - control, without stimulation with artificial light (G1, n=15), G2 - stimulation with artificial light for 35 days (G2; n=15) and G3 - stimulation with artificial light for 60 days (G3, n=15). We used the Fisher exact test for analysis of ovulation rate to the first 60 days of the experiment and ANOVA followed by Tukey test to analyze the average number of days to first ovulation, all statistics were considered significant when P<0.05. The Fisher test was used to compare the mare proportion that ovulated until the first 60 days of experiment between the study groups. The Bonferroni method was used to adjust the a level for multiple comparisons. Survival curves and Cox proportional hazards model were used to compare the ovulation rate between the study groups (estimating the expression of hazard ratio. Statistical significance was defined as P<0.05 or P<0.02 for the Fisher test with multiple comparisons. The proportion of mares that ovulated until 60 days after the beginning of the treatment was significantly larger (84.6%) in the group treated with artificial light by 60 days, when compared to the control group (15.4%, P=0.001). There was statistical difference between the control group and the group treated with artificial light by 35 days (61.5%, P=0.041), however was not statistical difference between the groups treated by 35 and 60 days (P=0.378). The average ovulation time in the group treated with artificial light by 60 days was 53 days, while mares in the group treated with artificial light by 35 or mares in the control group ovulated at the 56 and 125 days, respectively. It concluded that the reduction of treatment with artificial light for 35 days was not as effective as the conventional protocol of 60 days.

Las yeguas presentan el período de actividad reproductiva durante el verano y poca actividad folicular (anestro) durante el invierno. Con la intención de anticipar la temporada de monta, este estudio tuvo como objetivo evaluar el efecto de diferentes períodos de fotoestimulación en la presentación de la primera ovulación de la temporada reproductiva. El experimento se llevó a cabo durante las temporadas reproductivas de 2009 y 2010, del 1 día del mes de junio al 1 de agosto, se utilizaron 45 yeguas mestizas, en anestro, de cuatro a 12 años, en São Simão/SP, Brasil. En la ausencia de cuerpo lúteo y de folículos mayores de 20 mm, las yeguas fueron separadas al azar en los siguientes grupos: Grupo 1- testigo, sin estímulo con luz artificial (G1, n=15), Grupo 2 - estimulación con luz artificial por 35 días (G2; n=15), y Grupo 3 - estimulación con luz artificial por 60 días (G3; n=15). Se utilizó el teste exacto de Fischer para la análisis del porcentaje de ovulación hasta los primeros 60 días del experimento y el ANOVA seguido del teste de Tukey para el análisis del número medio de días hasta la ovulación, todas las estadísticas se consideraron significativas cuando P<0,05. Se utilizó la prueba de Fisher para comparar la proporción de yeguas que ovularon hasta los primeros 60 días del experimento entre los grupos de estudio. El método de Bonferroni fue utilizado para ajustar el nivel o para múltiples comparaciones. Las curvas de sobrevivencia y los modelos de riesgo proporcional de Cox fueron usados para comparar la tasa de ovulación entre los grupos de estudio (expresa la relación entre los riesgos estimados). La significancia estadística se definió como P<0,05 o P<0,02 para la prueba de Fisher con comparaciones múltiples. La proporción de yeguas que ovularon hasta 60 días después del inicio del tratamiento fue significativamente mayor (84,6%) en el grupo tratado con la luz artificial por 60 días, cuando son comparados con el grupo control (15,4%, P=0,001). Diferencia estadística entre los grupos control y el grupo tratado con la luz artificial por 35 días (61,5%, P=0,041), pero no hubo diferencia entre los grupos tratados por 35 y 60 días (P=0,378). El tiempo medio de la ovulación en el grupo tratado con luz artificial durante 60 días fue de 53 días, mientras que las yeguas en el grupo tratado con luz artificial por 35 o las yeguas en el grupo de control ovularon a los 56 y 125 días, respectivamente. Se concluye que la reducción del tratamiento con luz artificial para 35 días no fue tan eficiente cuanto el protocolo convencional de 60 días.

Aspectos relacionados à fisiologia do anestro pós-parto em bovinos / Aspects related to the physiology of postpartum anestrus in bovine

Para chegar a uma pecuária eficiente e lucrativa é preciso a cada dia melhorar os índices zootécnicos de produção, tornando a atividade cada vez mais sustentável. O Brasil possui o maior rebanho bovino comercial do mundo, mas apresenta índices de eficiência reprodutiva abaixo do potencial. A fertilidade pós-parto é negativamente influenciada pelo anestro, que pode ser um indicativo de condições inadequadas, como subnutrição ou condições patológicas. O anestro pós-parto é um estado de completa inatividade sexual que compreende o período do parto até a manifestação do primeiro cio fértil. Diversos fatores podem influenciar no período de anestro, entre eles interação mãe-cria, balanço energético negativo, déficit de progesterona, escore de condição corporal e deficiência de alguns metabólitos essenciais à reprodução. Esses mecanismos fisiológicos podem agir separadamente ou em conjunto de forma a atrasar ou impedir a ovulação, prejudicando a eficiência reprodutiva das fêmeas de cria do rebanho. Objetivou-se com esta revisão abordar os principais mecanismos fisiológicos relacionados diretamente com o anestro pós-parto em bovinos, e estratégias que visem minimizar esse período de retorno a atividade reprodutiva.

To achieve successful profitability and efficiency in livestock production it is important to improve productivity indexes every day, in order to turn the activity sustainable. Brazil has the world's largest herd of commercial cattle, but the current reproductive efficiency levels are inadequate. The postpartum fertility is negatively influenced by prolonged anestrus, which can be an indicative of inadequate conditions, such as inadequate nutrition or pathological conditions. The postpartum anestrus is a condition of complete sexual inactivity. It comprises the period of calving until the first fertile ovulation. Several factors can influence the anestrus period, including cow-calf interaction, negative energy balance, progesterone deficit, low body condition score and lack of some essential reproductive metabolites. These mechanisms can act separately or together delaying or inhibiting ovulation, which can decrease the reproductive efficiency of females of the herd. This review aimed to address the main physiological mechanisms directly related with the postpartum anestrus in bovine, and the strategies that intend to reduce this period of return to the reproductive activity.

Aspectos relacionados à fisiologia do anestro pós-parto em bovinos / Aspects related to the physiology of postpartum anestrus in bovine

Para chegar a uma pecuária eficiente e lucrativa é preciso a cada dia melhorar os índices zootécnicos de produção, tornando a atividade cada vez mais sustentável. O Brasil possui o maior rebanho bovino comercial do mundo, mas apresenta índices de eficiência reprodutiva abaixo do potencial. A fertilidade pós-parto é negativamente influenciada pelo anestro, que pode ser um indicativo de condições inadequadas, como subnutrição ou condições patológicas. O anestro pós-parto é um estado de completa inatividade sexual que compreende o período do parto até a manifestação do primeiro cio fértil. Diversos fatores podem influenciar no período de anestro, entre eles interação mãe-cria, balanço energético negativo, déficit de progesterona, escore de condição corporal e deficiência de alguns metabólitos essenciais à reprodução. Esses mecanismos fisiológicos podem agir separadamente ou em conjunto de forma a atrasar ou impedir a ovulação, prejudicando a eficiência reprodutiva das fêmeas de cria do rebanho. Objetivou-se com esta revisão abordar os principais mecanismos fisiológicos relacionados diretamente com o anestro pós-parto em bovinos, e estratégias que visem minimizar esse período de retorno a atividade reprodutiva.(AU)

To achieve successful profitability and efficiency in livestock production it is important to improve productivity indexes every day, in order to turn the activity sustainable. Brazil has the world's largest herd of commercial cattle, but the current reproductive efficiency levels are inadequate. The postpartum fertility is negatively influenced by prolonged anestrus, which can be an indicative of inadequate conditions, such as inadequate nutrition or pathological conditions. The postpartum anestrus is a condition of complete sexual inactivity. It comprises the period of calving until the first fertile ovulation. Several factors can influence the anestrus period, including cow-calf interaction, negative energy balance, progesterone deficit, low body condition score and lack of some essential reproductive metabolites. These mechanisms can act separately or together delaying or inhibiting ovulation, which can decrease the reproductive efficiency of females of the herd. This review aimed to address the main physiological mechanisms directly related with the postpartum anestrus in bovine, and the strategies that intend to reduce this period of return to the reproductive activity.(AU)

Endocrine control of ovarian function in dogs and other carnivores

Ovarian function in dogs is minimally but successfully evolved and adapted for fertility, and represents a basic model for examining the more complex evolution of ovarian activity in other carnivores and mammals in general. Canids are monoestrous, polytocous, spontaneous ovulators with a spontaneous luteal function producing progesterone for the duration of a normal 2-month pregnancy and unaffected by hysterectomy. They have no acute luteolytic mechanism in the absence of pregnancy although PGF is luteolytic and participates in prepartum luteolysis. The cellular mechanisms of luteal and follicular tissues appear unlikely to differ meaningfully from those described in other species, with the spontaneously prolonged luteal function being similar to, and in some instances shorter than, the luteal lifespan of hysterectomized polyestrous species. All or nearly all female caniform carnivore species have photo-entrained annual life-cycles and annual or biennial reproduction. However, the domestic dog, a subspecies of the grey wolf, is an exception and non-seasonal; but, as an exception to the exception, the basenji dog like the dingo, another wolf subspecies, is seasonal, having its cycle in the autumn. The canine obligate anestrus lasts 2-10 months and is terminated by increased GnRH and LH pulsatility. The timing is under multiple regulatory inputs. These include recovery from progesterone effects at variable times after progesterone declines to nadir values; increased dopaminergic and/or decreased opioidergic tones and/or sensitivities, presumably under the influence of an endogenous circannual cycle assumed to persists despite the lack of photoresponsiveness; and, stimulatory pheromonal input from other females (as well as photoperiod in the case of Basenji). The only clear adaptations or unique attributes seen in dogs that are likely beyond what occurred in a more primitive ancestor are two. One, there is a pregnancy specific increase in prolactin that as a potent luteotrophin (as in rodents) acts to enhance progesterone production during pregnancy, which appears likely to be the case in all carnivores. And, two, the bitch has a fertile-mating window as wide as 11 days, and up to 8 days after ovulation. The latter involves the delayed post-ovulatory maturation of oocytes (also seen in foxes), prolonged post-maturation oocyte viability, and a uterine environment hospitable to sperm survival for up to 7 days during estrus. This relative simplicity contrasts to more complicated adaptive strategies like (1) delayed implantation seen in many caniform carnivores (including many mustelids, ursids, and phocid and otarid seals); (2) reflex, induced ovulation (as seen in many feliform carnivores); and (3) prolongation of post-implantation gestation via placental secretion of progesterone (some feliform, some artiodactyls, primates) or gonadotrophin (primates, equids). Also considered in the review are the endocrine mechanisms triggering the LH surge and estrus behavior in dogs, and factors involved in termination of obligate anestrus.

Endocrine control of ovarian function in dogs and other carnivores

Ovarian function in dogs is minimally but successfully evolved and adapted for fertility, and represents a basic model for examining the more complex evolution of ovarian activity in other carnivores and mammals in general. Canids are monoestrous, polytocous, spontaneous ovulators with a spontaneous luteal function producing progesterone for the duration of a normal 2-month pregnancy and unaffected by hysterectomy. They have no acute luteolytic mechanism in the absence of pregnancy although PGF is luteolytic and participates in prepartum luteolysis. The cellular mechanisms of luteal and follicular tissues appear unlikely to differ meaningfully from those described in other species, with the spontaneously prolonged luteal function being similar to, and in some instances shorter than, the luteal lifespan of hysterectomized polyestrous species. All or nearly all female caniform carnivore species have photo-entrained annual life-cycles and annual or biennial reproduction. However, the domestic dog, a subspecies of the grey wolf, is an exception and non-seasonal; but, as an exception to the exception, the basenji dog like the dingo, another wolf subspecies, is seasonal, having its cycle in the autumn. The canine obligate anestrus lasts 2-10 months and is terminated by increased GnRH and LH pulsatility. The timing is under multiple regulatory inputs. These include recovery from progesterone effects at variable times after progesterone declines to nadir values; increased dopaminergic and/or decreased opioidergic tones and/or sensitivities, presumably under the influence of an endogenous circannual cycle assumed to persists despite the lack of photoresponsiveness; and, stimulatory pheromonal input from other females (as well as photoperiod in the case of Basenji). The only clear adaptations or unique attributes seen in dogs that are likely beyond what occurred in a more primitive ancestor are two. One, there is a pregnancy specific increase in prolactin that as a potent luteotrophin (as in rodents) acts to enhance progesterone production during pregnancy, which appears likely to be the case in all carnivores. And, two, the bitch has a fertile-mating window as wide as 11 days, and up to 8 days after ovulation. The latter involves the delayed post-ovulatory maturation of oocytes (also seen in foxes), prolonged post-maturation oocyte viability, and a uterine environment hospitable to sperm survival for up to 7 days during estrus. This relative simplicity contrasts to more complicated adaptive strategies like (1) delayed implantation seen in many caniform carnivores (including many mustelids, ursids, and phocid and otarid seals); (2) reflex, induced ovulation (as seen in many feliform carnivores); and (3) prolongation of post-implantation gestation via placental secretion of progesterone (some feliform, some artiodactyls, primates) or gonadotrophin (primates, equids). Also considered in the review are the endocrine mechanisms triggering the LH surge and estrus behavior in dogs, and factors involved in termination of obligate anestrus.(AU)