RESUMO
Following the induction of oestrus out of season in small ruminants, low fertility and variations in fertility rates are associated with embryonic losses. One of the main causes of embryonic loss is luteal dysfunction. Gonadotropin Releasing Hormone (GnRH) supports the luteal structure, and increasing progesterone levels may be beneficial in terms of promoting embryonic life. The main objective of the present study was to evaluate the efficacy of GnRH administration following an oestrus induction protocol in the anoestrus season for preventing embryonic loss in goats having failure to conceive during the season. In the study, 106 Damascus goats aged 3-5 years and weighing 45-60 kg were used. The oestrus of 106 goats in the anoestrous group was stimulated with progesterone and pregnant mare serum gonadotropin (PMSG) treatment. Out of breeding season, goats were divided into the 4 following groups: GnRH0 (n = 27), GnRH7 (n = 26), GnRH0+7 (n = 27) and control (n = 26). In each goat, an intravaginal sponge (IS) containing 20 mg of fluorogestone acetate (FGA) was placed into the vagina and left for 9 days. With the withdrawal of the sponge, 550IU PMSG and 125 µg of d-cloprostenol were injected intramuscularly. Oestrus detection was made via teaser bucks for 3 days starting 24 h after withdrawal of the IS. Eighteen bucks known to be fertile were used for breeding. Goats in the oestrus period were mated via natural breeding. The GnRH analogue lecirelin was injected intramuscularly at breeding in the GnRH0 group, on day 7 post-breeding in the GnRH7 group, and both at breeding and on day 7 post-breeding in the GnRH0+7 group. No injections were given to the control group. Blood samples for progesterone measurement were taken by jugular vena puncturing on days 3, 6, 7, 10, 13, 16, and 19 after breeding from 10 randomly chosen goats in all groups. The goats with a level of > 3.5 ng/mL of progesterone on day 21 post-breeding were evaluated as pregnant. Pregnancy was also viewed on day 50 after breeding by real-time ultrasonography (USG) with a 5-7.5 MHz convex probe. The oestrus rate was 96.23% (102/106) in the goats. The rates of onset of oestrus between 36-48 h, 48-60 h and 60 h and beyond were 38.7% (41/106), 21.7% (23/106) and 35.8% (38/106), respectively. The total pregnancy rate was 35.8% (38/106). There were no statistically significant differences (P > 0.05) found for the pregnancy rate, embryonic death rate or progesterone concentration of the groups. However, serum progesterone levels were statistically different in the GnRH7 group compared with the control group (P < 0.05). After synchronisation, various anti-luteolytic strategies can be used to support corpus luteum development and elevate progesterone concentration in the luteal phase to decrease embryonic loss and increase reproductive performance. Therefore, application of GnRH to support the luteal structure and to increase progesterone levels may be beneficial in terms of supporting embryonic life. The results showed that GnRH treatment on the day 7 post-breeding following oestrus induction, including FGA and PMSG, can increase serum progesterone levels in Damascus goats in the anoestrus period. However, following oestrus induction in the anoestrus period, it was seen that GnRH treatment at breeding or on day 7 after breeding did not have any positive effect on embryonic loss or reproductive performance. In conclusion, it was considered that this protocol could be implemented successfully, yielding a 35% pregnancy rate in Damascus goats in the anoestrus period, but embryonic loss must be deeply studied in detail.(AU)
Assuntos
Animais , Feminino , Anestro , Estro/efeitos dos fármacos , Doenças das Cabras/embriologia , Perda do Embrião/veterinária , Gonadotropinas/administração & dosagem , CabrasRESUMO
Plains vizcacha females are able to ovulate up to 800 oocytes per estrus cycle. However, just 10-12 embryos are implanted and only two of them, those located nearest the cervix, are gestated to term. Between 26 and 70 days post-coitum, a constitutive resorption occurs from the embryos located proximal to the ovary, extending progressively toward those distally implanted. Our previous studies on the dynamics of gestation in L. maximus, led us to hypothesize some kind of placental and nutritional insufficiency as the basis for the resorption process. We analyzed histology and arterial architecture of the reproductive tract in pregnant and non-pregnant females. Uterine horns are irrigated through the uterine artery, a branch of the internal iliac artery, in an ascending way from the cervix; segmental arteries irrigating the embryo vesicles become thinner as they approach the ovary. Contrast solution administered during angiographies accumulated in the placenta of embryos closest to cervix. Thus, blood stream favors the embryos nearest the cervix, indicating a gradual nutritional deficiency of those closest to the ovary. Besides, placenta becomes calcified early, at mid-gestation, during the resorption process. Finally, the detection of specialized endothelial venules and inflammatory cells suggest the concurrent participation of immunological processes in embryo vesicles undergoing resorption.
Assuntos
Desnutrição , Doenças dos Roedores , Animais , Perda do Embrião/veterinária , Feminino , Desnutrição/veterinária , Ovário , Placenta , Gravidez , RoedoresRESUMO
An epidemiological study of risk factors for fetal losses was carried out on 62,403 high-yielding Holstein cows in 29 large highly technified dairy herds in northern Mexico (25° N; 23.5 °C mean annual temperature). Multivariate multiple-group response model indicated that fetal losses between 43 and 260 days of pregnancy were 23 %. Heat-stressed cows at conception (temperature-humidity index, THI >82) were 14 times more likely (P < 0.01) to present fetal losses than not heat-stressed cows (27 vs. 18 %). Heat-stressed cows at 60 days of pregnancy (THI >82) were 4.5 times more likely (P < 0.01) to present fetal losses than cows suffering heat stress in early gestation (29.1 vs. 17.7 %). The proportion of cows experiencing fetal loss was lower for multiparous than primiparous cows (odds ratio; OR = 0.7). Cows with twin pregnancies had significantly increased chances of losing their fetuses than cows with a single fetus (33.6 vs. 20.7 %; P < 0.01). Cows with three milkings per day were 30 % more likely (P < 0.01) to lose their fetuses than cows milked twice daily. Cows calving in winter and spring had significantly increased chances of losing their fetuses than cows calving in summer and fall (30-35 vs. 4-5 %; P < 0.01). It was concluded that, in this particular environment, heat stress exert a great influence on fetal losses in high producing Holstein cows.
Assuntos
Doenças dos Bovinos/epidemiologia , Transtornos de Estresse por Calor/veterinária , Complicações na Gravidez/veterinária , Aborto Animal/epidemiologia , Criação de Animais Domésticos , Animais , Bovinos , Doenças dos Bovinos/fisiopatologia , Indústria de Laticínios , Perda do Embrião/etiologia , Perda do Embrião/veterinária , Feminino , Transtornos de Estresse por Calor/epidemiologia , Lactação/fisiologia , México/epidemiologia , Leite/metabolismo , Paridade , Gravidez , Complicações na Gravidez/epidemiologia , Gravidez Múltipla , Fenômenos Reprodutivos Fisiológicos , Fatores de Risco , Estações do Ano , Clima TropicalRESUMO
The objective of this retrospective study was to evaluate the effect of management strategies aiming to improve animal well-being on pregnancy and embryonic death (ED) rates. Breeding records of a cohort of 1206 Thoroughbred mares brought to a stallion station facility, to be bred with the stallions housed there, were evaluated during ten breeding seasons. Mares were blocked according to management strategies in two groups: Stress and Relax. Strategies used to improve animal well-being (Relax group) were as follows: stopping the teasing routine, reducing or eliminating stall confinement, reducing the number of mares per group and maintaining herd stability during the breeding season. In barren mares, the pregnancy rate was higher in the Relax group (91.8%) when compared to the observed in Stress group (84.7%). However, no difference in pregnancy rates were observed (Stress = 85.2% vs. Relax = 86.2) in foaling mares. ED rate was higher in barren and foaling mares of the Stress group mares (25.5% and 26.8%, respectively) compared with the Relax group (16.1% and 14.7%, respectively). No significant differences were observed on foal heat pregnancy rate between groups; yet, the embryo loss on foal heat was significant reduced in Relax mares (Relax = 8.7% vs Stress = 24.5%). In conclusion, management strategies aimed to reduce social stress can reduce early pregnancy losses and the average cycles per pregnancy, improving reproductive performance in mares.
Assuntos
Perda do Embrião/veterinária , Doenças dos Cavalos/prevenção & controle , Animais , Comportamento Animal , Cruzamento/métodos , Perda do Embrião/prevenção & controle , Perda do Embrião/psicologia , Feminino , Doenças dos Cavalos/psicologia , Cavalos , Gravidez , Estudos Retrospectivos , Estações do Ano , Comportamento Social , Predomínio Social , Estresse Psicológico/prevenção & controleRESUMO
Estudou-se o efeito da idade sobre a fertilidade de éguas inseminadas com sêmen asinino diluído, resfriado e armazenado. Os ciclos foram acompanhados por palpação transretal e rufiação, sendo as inseminações realizadas às terças, quintas e sábados, a partir da detecção de um folículo de 3,0 a 3,5cm de diâmetro, em um dos ovários, até a ovulação. O sêmen de cinco jumentos da raça Pêga foi diluído nos diluidores de leite em pó desnatado-glicose ou glicina-gema de ovo, resfriado a 5ºC e armazenado por 12 horas, sendo a dose inseminante de 400 x 106 espermatozoides móveis (no momento da diluição final, pré-resfriamento). Os resultados de 195 ciclos estrais, referentes a 141 éguas, foram agrupados em classes, de acordo com a idade das éguas: 2,5 a 6 anos, 6,5 a 10 anos, 10,5 a 14 anos e 14,5 a 19 anos. As taxas de concepção, ao primeiro ciclo, foram de 68,42%, 50,75%, 46,88% e 52,17% e, após quatro ciclos, de 69,57%, 47,92%, 46,34% e 45,71% para as faixas etárias de 2,5 a 6, 6,5 a 10, 10,5 a 14 e 14,5 a 19 anos, respectivamente (P>0,05). A idade não teve efeito sobre a fertilidade das éguas inseminadas com sêmen asinino diluído e resfriado...
The effect of the mare age on fertility of mares inseminated with diluted, cooled and stored jackass semen was studied. The females were controlled by transrectal palpation and teasing, and inseminated every Tuesday, Thursday and Saturday, since the detection of a 3.0 to 3.5cm follicle diameter, in one of the ovaries, until ovulation. The semen of five Pêga jackasses was diluted in skim milk-glucose or in egg yolk-glicine extender and cooled at 5ºC for 12 hours, with the inseminate dose of 400 x 106 motile spermatozoa (at the moment of the final dilution, before cooling). The results of 195 cycles of 141 mares were grouped, in accordance with the age: 2.5 to 6 years, 6.5 to 10 years, 10.5 to 14 years and 14.5 to 19 years. The pregnancy rates for the first cycle were 68.42%, 50.75%, 46.88% and 52.17%, and after four cycles, the pregnancy rates/cycle were 69.57%, 47.92%, 46.34% and 45.71%, respectively for 2.5 to 6, 6.5 to 10, 10.5 to 14 and 14.5 to 19 years (P>0,05). The mare age had no influence on fertility, using diluted and cooled jackass semen...
Assuntos
Animais , Fatores Etários , Equidae/embriologia , Fármacos para a Fertilidade , Perda do Embrião/veterinária , Inseminação Artificial/veterinária , SêmenRESUMO
Estudou-se o efeito da idade sobre a fertilidade de éguas inseminadas com sêmen asinino diluído, resfriado e armazenado. Os ciclos foram acompanhados por palpação transretal e rufiação, sendo as inseminações realizadas às terças, quintas e sábados, a partir da detecção de um folículo de 3,0 a 3,5cm de diâmetro, em um dos ovários, até a ovulação. O sêmen de cinco jumentos da raça Pêga foi diluído nos diluidores de leite em pó desnatado-glicose ou glicina-gema de ovo, resfriado a 5ºC e armazenado por 12 horas, sendo a dose inseminante de 400 x 106 espermatozoides móveis (no momento da diluição final, pré-resfriamento). Os resultados de 195 ciclos estrais, referentes a 141 éguas, foram agrupados em classes, de acordo com a idade das éguas: 2,5 a 6 anos, 6,5 a 10 anos, 10,5 a 14 anos e 14,5 a 19 anos. As taxas de concepção, ao primeiro ciclo, foram de 68,42%, 50,75%, 46,88% e 52,17% e, após quatro ciclos, de 69,57%, 47,92%, 46,34% e 45,71% para as faixas etárias de 2,5 a 6, 6,5 a 10, 10,5 a 14 e 14,5 a 19 anos, respectivamente (P>0,05). A idade não teve efeito sobre a fertilidade das éguas inseminadas com sêmen asinino diluído e resfriado. (AU)
The effect of the mare age on fertility of mares inseminated with diluted, cooled and stored jackass semen was studied. The females were controlled by transrectal palpation and teasing, and inseminated every Tuesday, Thursday and Saturday, since the detection of a 3.0 to 3.5cm follicle diameter, in one of the ovaries, until ovulation. The semen of five Pêga jackasses was diluted in skim milk-glucose or in egg yolk-glicine extender and cooled at 5ºC for 12 hours, with the inseminate dose of 400 x 106 motile spermatozoa (at the moment of the final dilution, before cooling). The results of 195 cycles of 141 mares were grouped, in accordance with the age: 2.5 to 6 years, 6.5 to 10 years, 10.5 to 14 years and 14.5 to 19 years. The pregnancy rates for the first cycle were 68.42%, 50.75%, 46.88% and 52.17%, and after four cycles, the pregnancy rates/cycle were 69.57%, 47.92%, 46.34% and 45.71%, respectively for 2.5 to 6, 6.5 to 10, 10.5 to 14 and 14.5 to 19 years (P>0,05). The mare age had no influence on fertility, using diluted and cooled jackass semen.(AU)
Assuntos
Animais , Equidae/embriologia , Fármacos para a Fertilidade , Fatores Etários , Perda do Embrião/veterinária , Inseminação Artificial/veterinária , SêmenRESUMO
Assisted reproduction techniques have improved agricultural breeding in the bovine. However, important development steps may differ from the situation in vivo and there is a high mortality rate during the first trimester of gestation. To better understand these events, we investigated the development of embryos and fetal membranes following fixed-time AI (FTAI), IVF and nuclear transfer (NT). The onset of yolk-sac development was not normal in cloned embryos. Later steps differed from conditions in vivo in all three groups; the yolk-sac was yellowish and juxtaposed with the amniotic membrane. Vascularisation of the chorioallantoic membrane was relatively late and low in NT gestations, but normal in the others. The overall development of the embryos was normal, as indicated by morphology and regression analysis of growth rate. However, NT conceptuses were significantly smaller, with the livers in some embryos occupying the abdominal cavity and others exhibiting heart abnormalities. In conclusion, the yolk-sac and the cardiovascular system seem to be vulnerable to morphogenetic alterations. Future studies will focus on gene expression and early vascularisation processes to investigate whether these changes may be responsible for the high incidence of intrauterine mortality, especially in clones.
Assuntos
Bovinos/fisiologia , Embrião de Mamíferos/embriologia , Desenvolvimento Embrionário , Técnicas Reprodutivas/veterinária , Animais , Animais Endogâmicos , Brasil , Bovinos/genética , Clonagem de Organismos/métodos , Clonagem de Organismos/veterinária , Cruzamentos Genéticos , Perda do Embrião/etiologia , Perda do Embrião/veterinária , Embrião de Mamíferos/anormalidades , Membranas Extraembrionárias/anormalidades , Membranas Extraembrionárias/irrigação sanguínea , Feminino , Fertilização in vitro/efeitos adversos , Fertilização in vitro/veterinária , Morte Fetal/etiologia , Morte Fetal/veterinária , Cardiopatias Congênitas/etiologia , Cardiopatias Congênitas/veterinária , Inseminação Artificial/efeitos adversos , Inseminação Artificial/veterinária , Técnicas de Transferência Nuclear/efeitos adversos , Técnicas de Transferência Nuclear/veterinária , Placentação , Gravidez , Técnicas Reprodutivas/efeitos adversos , Saco Vitelino/anormalidadesRESUMO
This study reported the effects of prostaglandin (PGF2a) administration 10 days apart on reproductive parameters of cyclic artificial inseminated (AI) nulliparous Alpine (n=9) and Saanen (n=9) goats. Animals received two doses of 22.5mg PGF2a 10 days apart. After 1st and 2nd PGF2a administrations, estrus was monitored at 12 h intervals, with a buck teaser. Plasma progesterone concentration (ng/mL) was determined from blood sampled on day 0 (1st PGF2a) and the following 5, 10 (2nd PGF2a), 15, 20, 25 and 30 days. After the onset of the second estrus, females were transrectally (5 MHz probe) scanned at 4 hour intervals until at least 8h after ovulation. Pregnancy was checked through transrectal ultrasound on days 20, 25, 30, 35 and 90 after insemination. All parameters studied did not differ between breeds (P>0.05). Estrous response and interval to estrus, respectively, after 1st (78.9% and 50.6±17.2h) and 2nd PGF2a (88.9% and 50.0±14.8h) administration did not differ (P>0.05). Overall animals ovulating (100.0%), interval to ovulation after 2nd PGF2a (64.5±19.5h) and after estrous onset (18.0±9.1h), ovulation rate (1.3±0.5), diameter of ovulatory follicle (8.1±1.1mm) were recorded. Embryo loss occurred before day 30 of pregnancy. Estrus can be efficiently synchronized in nulliparous Alpine and Saanen goats with two doses of prostaglandin 10 days apart.(AU)
Relataram-se os efeitos da aplicação de prostaglandina sobre características reprodutivas de cabras leiteiras nulíparas cíclicas. Cabras Alpinas (n=9) e Saanen (n=9) receberam duas doses de 22,5mg PGF2a com 10 dias de intervalo. A progesterona plasmática (ng/mL) foi determinada a partir de amostras de sangue coletadas nos dias 0 (primeira dose), 5, 10 (segunda dose), 15, 20, 25 e 30. Após início do segundo estro, as fêmeas foram monitoradas por ultrassonografia transretal a cada quatro horas até oito horas após a ovulação. A gestação foi verificada por ultrassonografia transretal nos dias 20, 25, 30, 35 e 90 após a segunda dose. As características estudadas foram semelhantes entre as raças (P>0,05). Animais em estro e o intervalo parto-estro de, respectivamente, 78,9% e 50,6±17,2h e 88,9% e 50,0±14,8h após a primeira e segunda administrações de prostaglandina, não diferiram (P>0,05). Todas as cabras ovularam e registraram-se valores do intervalo parto-ovulação após a segunda aplicação de prostaglandina de 64,5±19,5h e após início do estro de 18,0±9,1h, a taxa de ovulação de 1,3±0,5 e diâmetro do folículo ovulatório de 8,1±1,1mm. Perda embrionária ocorreu antes de 30 dias de gestação. O estro pode ser eficientemente sincronizado em cabras leiteiras núliparas com duas doses de prostaglandina intervaladas de 10 dias.(AU)
Assuntos
Animais , Cabras , Ovulação , Progesterona/administração & dosagem , Perda do Embrião/veterinária , Inseminação , Ultrassonografia/veterináriaRESUMO
A análise morfológica da casca do ovo da avestruz é importante, pois diversos fatores morfológicos podem estar relacionados com a eclodibilidade do ovo desta espécie no Brasil. Para tanto foram analisadas 60 amostras de ovos aparentemente normais (ovos eclodidos e com morte embrionária). Foram efetuadas observações que permitiram estabelecer: a espessura média da casca do ovo, a porosidade da casca destes ovos, e correlacionar estas variáveis com a eclodibilidade. Os resultados foram analisados estatisticamente mediante o teste de Duncan, o que mostrou que ovos com menor porosidade tem também uma menor eclodibilidade. A porosidade média dos ovos eclodidos é de 19,87 poros/cm², e dos ovos com morte embrionária é de 16,78 poros/cm². Não houve diferença estatística entre a espessura da casca nas regiões estudada, nem interação entre viabilidade e as regiões.
Morphological analysis of the ostrich eggshell is important because several factors can be related to morphological hatchability of eggs of this species in Brazil. Therefore, 60 samples of apparently normal eggs were analyzed (eggs hatched and with embryonic death). The observations were allowed to establish that: the average thickness of the eggshell, the porosity of the shell of the eggs, and correlate these variables with hatchability. The results were statistically analyzed by Duncan's test, which showed that eggs with less porosity also have a lower hatchability. The average porosity of hatched eggs is 19.87 pores/cm², and of eggs with embryonic death is pores/cm2 16.78. There was no statistical difference between the thickness of the shell in the regions studied, no interaction between viability and the regions studied.
Assuntos
Animais , Casca de Ovo/anatomia & histologia , Struthioniformes , Biometria , Perda do Embrião/veterináriaRESUMO
A análise morfológica da casca do ovo da avestruz é importante, pois diversos fatores morfológicos podem estar relacionados com a eclodibilidade do ovo desta espécie no Brasil. Para tanto foram analisadas 60 amostras de ovos aparentemente normais (ovos eclodidos e com morte embrionária). Foram efetuadas observações que permitiram estabelecer: a espessura média da casca do ovo, a porosidade da casca destes ovos, e correlacionar estas variáveis com a eclodibilidade. Os resultados foram analisados estatisticamente mediante o teste de Duncan, o que mostrou que ovos com menor porosidade tem também uma menor eclodibilidade. A porosidade média dos ovos eclodidos é de 19,87 poros/cm², e dos ovos com morte embrionária é de 16,78 poros/cm². Não houve diferença estatística entre a espessura da casca nas regiões estudada, nem interação entre viabilidade e as regiões.(AU)
Morphological analysis of the ostrich eggshell is important because several factors can be related to morphological hatchability of eggs of this species in Brazil. Therefore, 60 samples of apparently normal eggs were analyzed (eggs hatched and with embryonic death). The observations were allowed to establish that: the average thickness of the eggshell, the porosity of the shell of the eggs, and correlate these variables with hatchability. The results were statistically analyzed by Duncan's test, which showed that eggs with less porosity also have a lower hatchability. The average porosity of hatched eggs is 19.87 pores/cm², and of eggs with embryonic death is pores/cm2 16.78. There was no statistical difference between the thickness of the shell in the regions studied, no interaction between viability and the regions studied.(AU)
Assuntos
Animais , Struthioniformes , Casca de Ovo/anatomia & histologia , Biometria , Perda do Embrião/veterináriaRESUMO
Early pregnancy failure or loss (EPL) represents a major source of wastage and inefficiency in livestock production systems, with increasing evidence that male factors can play a significant role in this loss. Of those adverse male effects which have been identified, those associated with sperm damage, particularly sperm DNA, have been best characterized. Here the case is made that there are a limited number of mechanisms by which the spermatogenic epithelium can respond to stressors, leading to a predictable trail of detectable biomarkers. Potential stressors include pathogens, especially viruses, which can directly damage sperm as well as be transmitted in semen and/or sperm with important implications for both natural and artificial breeding.
A falta ou perda precoce da gestação representa uma grande fonte de perda e ineficiência em sistemas de produção bovina, com crescente evidência de que fatores ligados ao macho podem ter um papel significativo nestas perdas. Dos efeitos adversos que foram identificados, os associados com danos do esperma, particularmente o seu DNA, foram mais bem caracterizados. Aqui se defende que há um número limitado de mecanismos pelos quais a membrana do espermatozoide pode responder a desafios deletérios, levando a uma trilha previsível de biomarcadores detectáveis. Desafios potenciais incluem elementos patogênicos, especialmente vírus, que podem danificar o espermatozoide diretamente, além de serem transmitidos no sêmen com implicações importantes para a reprodução natural e artificial.
Assuntos
Masculino , Animais , Gravidez , Bovinos , Análise do Sêmen/veterinária , Desenvolvimento Embrionário/genética , Perda do Embrião/genética , Perda do Embrião/veterinária , Espermatozoides , Fertilização in vitro/veterinária , Gravidez , Transferência Embrionária/métodos , Transferência Embrionária/veterináriaRESUMO
Early pregnancy failure or loss (EPL) represents a major source of wastage and inefficiency in livestock production systems, with increasing evidence that male factors can play a significant role in this loss. Of those adverse male effects which have been identified, those associated with sperm damage, particularly sperm DNA, have been best characterized. Here the case is made that there are a limited number of mechanisms by which the spermatogenic epithelium can respond to stressors, leading to a predictable trail of detectable biomarkers. Potential stressors include pathogens, especially viruses, which can directly damage sperm as well as be transmitted in semen and/or sperm with important implications for both natural and artificial breeding.(AU)
A falta ou perda precoce da gestação representa uma grande fonte de perda e ineficiência em sistemas de produção bovina, com crescente evidência de que fatores ligados ao macho podem ter um papel significativo nestas perdas. Dos efeitos adversos que foram identificados, os associados com danos do esperma, particularmente o seu DNA, foram mais bem caracterizados. Aqui se defende que há um número limitado de mecanismos pelos quais a membrana do espermatozoide pode responder a desafios deletérios, levando a uma trilha previsível de biomarcadores detectáveis. Desafios potenciais incluem elementos patogênicos, especialmente vírus, que podem danificar o espermatozoide diretamente, além de serem transmitidos no sêmen com implicações importantes para a reprodução natural e artificial.(AU)
Assuntos
Animais , Masculino , Gravidez , Bovinos , Desenvolvimento Embrionário/genética , Perda do Embrião/genética , Perda do Embrião/veterinária , Análise do Sêmen/veterinária , Gravidez , /genética , Espermatozoides , Fertilização in vitro/veterinária , Transferência Embrionária/métodos , Transferência Embrionária/veterináriaRESUMO
The aim of this study was to evaluate the reproductive performance of gilts that had a similar age but different weights at the onset of puberty stimulation by boar exposure at 144 days. Gilts were divided into two groups according to their lifetime growth rate from birth to approximately 144 days of age. Mean growth rates at this moment were 577 and 724 g/day for group 1 (G1; n = 58) and group 2 (G2; n = 58), respectively. After selection, gilts were weighed at approximately 155, 165 and 175 days of age, on the insemination day and at slaughter. Gilts were inseminated, on average, at 193 days of age and were slaughtered 32 days after insemination, when the number of corpora lutea and embryos were recorded. Higher growth rate gilts (G2) reached puberty earlier (155.3 vs 164.1 days; p < 0.01). More gilts of G2 group attained puberty by 190 days of age (p = 0.004) than G1 gilts (95%; 55/58 vs 76%; 44/58). The anoestrous rate, until 60 days after the onset of boar exposure was higher (p < 0.01) in G1 (19.0%; 11/58) than in G2 (3.4%; 2/58) group. However, there were no differences in the pregnancy rate (90.7 vs 94.5), ovulation rate (15.9 vs 16.5), total embryos (12.9 vs 11.7), viable embryos (12.0 vs 11.1) and embryo survival (73.7% vs 68.5%), between G1 gilts and G2 gilts, respectively (p > 0.05). High growth rate gilts attain puberty earlier and have a lower anoestrous rate than low growth rate gilts.
Assuntos
Reprodução/fisiologia , Maturidade Sexual/fisiologia , Suínos/crescimento & desenvolvimento , Tecido Adiposo/anatomia & histologia , Envelhecimento , Anestro/fisiologia , Animais , Peso Corporal , Perda do Embrião/epidemiologia , Perda do Embrião/veterinária , Desenvolvimento Embrionário , Feminino , Inseminação Artificial , Masculino , Ovulação , Gravidez , Taxa de Gravidez , Análise de Regressão , Suínos/anatomia & histologia , Suínos/fisiologiaRESUMO
Visando esclarecer o mecanismo da açäo embriotóxica do barbatimäo, pesquisaram-se os efeitos da administraçäo de sementes de barbatimäo sobre as principais glândulas endócrinas de ratas grávidas. Encontrou-se diminuiçäo do peso dos ovários e do peso e medidas dos corpos lúteos gravídicos no grupo tratado. Numa segunda etapa, foi feita administraçäo de progesterona em ratas tratadas com sementes de barbatimäo. Näo houve alteraçäo dos índices de reabsorçäo dos embriöes, que permaneceram elevados, indicando que o efeito embriotóxico näo seria devido à déficit dos níveis de progesterona. Propöe-se que o efeito do barbatimäo seja através de alteraçöes da zona basal da placenta, acarretando a morte embrionária e atrofia do corpo lúteo