共查询到19条相似文献，搜索用时 250 毫秒
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异性孪生不孕多发生在母牛,马、猪、羊等少发,这是因为异性双胎的胎儿在胚胎生长期里绒毛膜血管之间形成吻合支,在生物的雄性发育优势的影响下,雄性胎儿的激素通过吻合支的血液首先流入雌性胎儿体内,抑制了雌性胎儿性器官的正常发育并雄性化,致使雌性胎 相似文献
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<正> 奶牛生双胎,多数人认为是不受欢迎的。其原因有二,一方面双胎犊牛初生重较小,往往导致后天生长发育不良;另一方面异性孪生双胎雌性个体是动物雌雄间性的一种,成年后有92%不能生育,称为异性孪生雌性不育。给繁殖带来影响。目前对奶牛产双胎资料的报道尚不多见。为弄清奶牛孪生双胎基本情况,对我场30多年繁殖资料进行统计分析。 相似文献
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《河南畜牧兽医(综合版)》2008,(1):47-47
异性双胎中的母犊长大后多不能生育,其原因在于,胚胎时期,雄性胎儿的睾丸先发育,产生的雄性激素,通过绒毛膜血管,流向雌性胎儿,影响了雌性胎儿的性腺分化。没有生育能力的异性双胎母牛阴门狭小,且位置较低,阴蒂较长,乳房极不发达,乳头与公牛相似。因此,要注意对异性双胎母犊的生殖器官检查。对没有繁殖能力的异性双胎母犊,不要作繁殖母牛卖出。在外购犊牛或育成牛时,一定要注意了解和检查。 相似文献
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<正>1双侧生殖腺萎缩引起的永久性乏情或不育这是异性孪生母犊不孕症中的常见表现,多数见于雌雄双胎的雌犊。也可发生双侧性卵巢发育不全,这是一种罕见的遗传病,致病基因通过子代引起单侧性生殖腺萎缩。2母牛在产犊时或产犊前后的各种异常难产、胎衣不下、子宫炎、子宫内膜炎以及其他产后疾病都可以引起发情周期恢复延迟。3卵巢囊肿引起母牛乏情传统上将卵巢囊肿定义为一种直径大于 相似文献
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R. JurasT. Raudsepp PhD P.J. DasE. Conant PhD E.G. Cothran 《Journal of Equine Veterinary Science》2010
Cytogenetic analysis and microsatellite genotyping were conducted on a pair of phenotypically normal dizygotic heterosexual equine twins of the American Bashkir Curly breed. The animals had a mixture of 64,XX and 64,XY cells in blood lymphocytes, with their own cells being predominant. Therefore, the 64,XX cells comprised 81% of the lymphocyte population in the female twin and 64,XY comprised 79% in the male twin. Blood chimerism was confirmed by genotyping 30 microsatellite markers. Of these, 15 microsatellites showed the presence of three alleles and all four parental alleles in the blood lymphocytes for both animals. No chimerism was detected in the genomic deoxyribonucleic acid isolated from hair follicles. These results are in agreement with earlier observations that vascular anastomoses can infrequently occur during equine multiple pregnancies resulting in blood lymphocyte chimerism without significant effect on the phenotype. 相似文献
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Congenital retroflexion of the penis and inguinal cryptorchidism in a presumptive bovine twin with a 60,XY/60,XX/61,XX,+cen chromosome constitution. 
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下载免费PDF全文 W C Hare 《Canadian journal of veterinary research》1976,40(4):429-433
Studies were carried out on a yearling Holstein with external genitalia resembling those of a freemartin whose birth and developmental history was unknown. Dissection following slaughter showed testes close to the external inguinal rings, an underdeveloped penis coiled up subcutaneously in the perineum and terminating in a deep fossa at the level of the ischial arch and no evidence of a female genital tract. Chromosome analyses showed 60,XY cells in the blood and 60,XX and 61,XX,+cen cells in other tissues. It is postulated that the animal had a basic 60,XX/61,XX+cen mixoploid chromosome constitution, that the centric fragment functioned as a Y chromosome or as an autosomal modifier of the X chromosome in sex determination which accounted for the animal's Klinefelter syndrome-like abnormalities, and that animal was also twin to a bull which accounted for the presence of 60,XY cells in the blood. 相似文献
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Anti Müllerian Hormone, AMH, is believed to be the main agent in the freemartin syndrome. Supposing an active role of freemartin gonads in AMH secretion, in the present study, we aimed at investigating the presence and the localization of AMH producing cells either in fetal or in adult freemartin gonads. Our finding of positive AMH cells in a 26-week-old freemartin fetus indicates an active role of masculinized freemartin gonads in AMH secretion. However, the positive reaction, limited to few cells grouped in 'nests' in proximity to testis cord-like structures, supports a chimeric origin of such cells, migrated from the male co-twin. No adult freemartin, irrespective from the degree of masculinization, showed any AMH positive cell. 相似文献
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Cytogenetic studies of a closed herd of Booroola Merino sheep were carried out over six consecutive years and covered 167 (90 females and 77 males) sheep originating from 77 heterosexual multiple births. Lymphocyte 54XX/XY chimerism was revealed in 24 litters including 20 (11.98%) ewes and 22 (13.17%) rams, i.e. 25.14% of the karyotyped group of animals and 11.17% of all animals weaned in the herd. Familial and pedigree relations revealed in the study indicate a hereditary tendency to develop placental anastomoses in sheep. Fifteen chimeric litters were sired by six rams. Three rams were carriers of XX/XY chimerism and each sired a chimeric litter. Coefficients of inbreeding ranged from 0.06525 to 0.125 with a mean of 0.094. The pedigree analysis up to the fifth generations showed that two rams were ancestors of all chimeric litters. Based on the analysis of the reproductive performance of dams and sires which produced 32 litters of which three-quarters were chimeric suggested, that the formation of anastomoses is controlled by a dominant gene. 相似文献
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Andrés Rogberg-Muñoz Nadia S. Castillo María E. Zappa Julián A. Crespi Egle E. Villegas-Castagnasso Paula M. Gómez Pilar Peral-García Guillermo Giovambattista 《Reproduction in domestic animals》2020,55(9):1267-1270
Cattle are a monotocous species, despite naturally conceived multiple births are sometimes observed. Although the number of twins has consistently increased, triplet and quadruplet pregnancies represent 0.015% and 0.004% of the total births, respectively. Multiple births are the result of multiple ovulation and/or the spontaneous cleavage of one fertilized oocyte, which is known as monozygotic (MZ) twinning. In cattle, approximately 5% to 14% of all twin births are MZ, and births with more than two MZ calves are extremely rare. Monozygotic animals are genetically identical, and those derived from two or more zygotes are genetically different. Furthermore, the presence of placental vascular anastomosis can result in foetal chimerism. Notwithstanding, animals born as single calves can be chimeras when one of the foetal twins dies undetected in utero. Here, we used DNA testing to study the zygotic condition of an unusual female quadruplet born from a Braford cow bred in a multi-sire natural mating system without hormone stimulation. Two tissues with different embryological origin were sampled to test zygosity and possible chimerism. The results showed an identical genotype, confirming they all originated in an MZ pregnancy and suggesting the lack of chimerism in all animals. The use of MZ twins in breeding and selection systems provides an alternative to the conventional progeny testing. Some works have suggested a genetic background of MZ twins in humans. This female and her daughters could be the founders of a lineage to study the possible inheritance of MZ multiple births in cattle. 相似文献
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Fiegler H Knabel M Franz M Kolb HJ Just U 《Veterinary immunology and immunopathology》2002,84(1-2):61-70
Dogs are used in preclinical transplantation models to study methods of allogeneic bone marrow transplantation (BMT). The evaluation of chimerism is of major significance for the investigation of graft-vs.-host (GvH) and host-vs.-graft (HvG) reactions. To detect and quantitate male donor cells after a sex-mismatched (male to female) allogeneic BMT, we established a semi-quantitative polymerase chain reaction (PCR) assay. Based on the canine Y-chromosome sex-determining region (Sry) sequence, we designed primer specific for the detection of male DNA and optimised PCR conditions and cycle numbers. Artificial mixtures of male and female leukocytes were used to analyse the sensitivity of the assay. To validate our established method, we determined the percentage of chimerism in three transplanted female dogs. Under optimised conditions, the established PCR assay specifically detected male cells down to 0.01%, which corresponds to 0.1ng of transplanted male DNA. The percentage of chimerism could be quantitated either by agarose gel analysis or Southern blot analysis. Using our assay, we could confirm the percentage of chimerism in blood samples of three transplanted female canines, previously determined by karyotype analysis as 0, 100 and 100%, respectively. The established semi-quantitative PCR assay offers a quick, simple, accurate and sensitive way of evaluating and quantitating the percentage of chimerism in a sex-mismatched canine BMT model. 相似文献
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A case of intersexuality in a Dorset horn ewe is described. Although possessing female external genitalia this animal had a male internal reproductive tract with inguinal testes, epididymes, vasa deferentia and seminal vesicles. No traces of cervix or uterus were present and the vagina was represented in its caudal part only. Chromosomal studies revealed chimaerism in peripheral leucocytes of the type 54, XX/54, XY, while other tissues revealed the normal female karyotype 54, XX. The ewe was born in a set of triplets with one dead male fetus and one living male. It was therefore concluded that the animal was a freemartin. The significance of this case and of the phenomenon of freemartisism in sheep is discussed. 相似文献
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Monika Bugno-Poniewierska Barbara Kij Wojciech Witarski Magdalena Wojtaszek Anna Radko Angelika Podbielska Izabela Szczerbal William J. Murphy 《Reproduction in domestic animals》2020,55(9):1139-1144
The tortoiseshell coat colour is characteristic to female cats, and its occurrence in tomcats is very rare and associated with chromosome abnormalities (additional copy of X chromosome). The aim of this study was identification of the genetic basis of a case of tortoiseshell colour in a fertile Maine coon tomcat. Cytogenetic and molecular genetic studies were carried out with painting molecular probes (WCPP) specific to the X and Y sex chromosomes as well as a DNA microsatellite panel for the parentage verification of cats. Cytogenetic analysis revealed only a single set of sex chromosomes typical for male – 38,XY. The results of the microsatellite polymorphism obtained from DNA showed three alleles in locus FCA201 and four alleles in loci FCA149 and FCA441 in different tissues (blood, hair roots and testicles). Based on these results, the case was diagnosed as a true chimerism 38,XY/38,XY. To the best of our knowledge, this is the first case of a 38,XY/38,XY chimera diagnosed in cats, confirmed by genetic analysis. 相似文献