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1.
牛脊柱畸形综合征检测方法的建立与应用   总被引:2,自引:1,他引:1  
牛脊柱畸形综合征(Complex vertebral malformation, CVM)是近年来新发现的致死性牛常染色体隐性遗传缺陷病。由于编码UDP-N-乙酰葡糖胺载体的SLC35A3基因发生G→T的突变而引起本病的发生, 可引起胎牛死胎、流产、早产。为了解我国正常的荷斯坦牛(黑白花奶牛)的CVM携带和发生情况, 建立、应用创造酶切位点PCR(Created restriction site PCR, CRS-PCR)、等位基因特异性PCR(Allele-specific polymerase chain reaction, AS-PCR)检测方法检测了表型正常的436头荷斯坦母牛和93头荷斯坦公牛, 检测到3头CVM携带者, 其中杂合母牛1头, 杂合公牛2头, 携带率分别为0.60%、2.20%。此方法简便、可靠, 为奶牛CVM有害基因的分型和筛选提供了新的方法和思路, 为我国奶牛的分子选育提供了可靠的理论依据。  相似文献   

2.

Background

A number of methods are available to scan a genome for selection signatures by evaluating patterns of diversity within and between breeds. Among these, “extended haplotype homozygosity” (EHH) is a reliable approach to detect genome regions under recent selective pressure. The objective of this study was to use this approach to identify regions that are under recent positive selection and shared by the most representative Italian dairy and beef cattle breeds.

Results

A total of 3220 animals from Italian Holstein (2179), Italian Brown (775), Simmental (493), Marchigiana (485) and Piedmontese (379) breeds were genotyped with the Illumina BovineSNP50 BeadChip v.1. After standard quality control procedures, genotypes were phased and core haplotypes were identified. The decay of linkage disequilibrium (LD) for each core haplotype was assessed by measuring the EHH. Since accurate estimates of local recombination rates were not available, relative EHH (rEHH) was calculated for each core haplotype. Genomic regions that carry frequent core haplotypes and with significant rEHH values were considered as candidates for recent positive selection. Candidate regions were aligned across to identify signals shared by dairy or beef cattle breeds. Overall, 82 and 87 common regions were detected among dairy and beef cattle breeds, respectively. Bioinformatic analysis identified 244 and 232 genes in these common genomic regions. Gene annotation and pathway analysis showed that these genes are involved in molecular functions that are biologically related to milk or meat production.

Conclusions

Our results suggest that a multi-breed approach can lead to the identification of genomic signatures in breeds of cattle that are selected for the same production goal and thus to the localisation of genomic regions of interest in dairy and beef production.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-015-0113-9) contains supplementary material, which is available to authorized users.  相似文献   

3.
Complex vertebral malformation (CVM) is a recently described monogenic autosomal recessive hereditary defect of Holstein dairy cattle that causes premature birth, aborted fetuses and stillborn calves. Guanine is substituted by thymine (G>T) in the solute carrier family 35 member A3 gene (SLC35A3). A valine is changed to a phenylalanine at position 180 of uridine 5'-diphosphate-N-acetyl-glucosamine transporter protein. CVM is expected to occur in many countries due to the widespread use of sire semen. We developed a created restriction site PCR (CRS-PCR) method to diagnose CVM in dairy cows. This was tested on 217 cows and 125 bulls selected randomly from a Holstein cattle population in south China. Five Holstein cows and five Holstein bulls were identified to be CVM carriers; the percentages of CVM carriers were estimated to be 2.3, 4.0 and 2.9% in the cows, bulls and entire Holstein cattle sample, respectively.  相似文献   

4.
BackgroundWith the availability of massive SNP data for several economically important cattle breeds, haplotype tests have been performed to identify unknown recessive disorders. A number of so-called lethal haplotypes, have been uncovered in Holstein Friesian cattle and, for at least seven of these, the causative mutations have been identified in candidate genes. However, several lethal haplotypes still remain elusive. Here we report the molecular genetic causes of lethal haplotype 5 (HH5) and cholesterol deficiency (CDH). A targeted enrichment for the known genomic regions, followed by massive parallel sequencing was used to interrogate for causative mutations in a case/control approach.MethodsTargeted enrichment for the known genomic regions, followed by massive parallel sequencing was used in a case/control approach. PCRs for the causing mutations were developed and compared to routine imputing in 2,100 (HH5) and 3,100 (CDH) cattle.ResultsHH5 is caused by a deletion of 138kbp, spanning position 93,233kb to 93,371kb on chromosome 9 (BTA9), harboring only dimethyl-adenosine transferase 1 (TFB1M). The deletion breakpoints are flanked by bovine long interspersed nuclear elements Bov-B (upstream) and L1ME3 (downstream), suggesting a homologous recombination/deletion event. TFB1M di-methylates adenine residues in the hairpin loop at the 3’-end of mitochondrial 12S rRNA, being essential for synthesis and function of the small ribosomal subunit of mitochondria. Homozygous TFB1M-/- mice reportedly exhibit embryonal lethality with developmental defects. A 2.8% allelic frequency was determined for the German HF population. CDH results from a 1.3kbp insertion of an endogenous retrovirus (ERV2-1-LTR_BT) into exon 5 of the APOB gene at BTA11:77,959kb. The insertion is flanked by 6bp target site duplications as described for insertions mediated by retroviral integrases. A premature stop codon in the open reading frame of APOB is generated, resulting in a truncation of the protein to a length of only <140 amino acids. Such early truncations have been shown to cause an inability of chylomicron excretion from intestinal cells, resulting in malabsorption of cholesterol. The allelic frequency of this mutation in the German HF population was 6.7%, which is substantially higher than reported so far. Compared to PCR assays inferring the genetic variants directly, the routine imputing used so far showed a diagnostic sensitivity of as low as 91% (HH5) and 88% (CDH), with a high specificity for both (≥99.7%).ConclusionWith the availability of direct genetic tests it will now be possible to more effectively reduce the carrier frequency and ultimately eliminate the disorders from the HF populations. Beside this, the fact that repetitive genomic elements (RE) are involved in both diseases, underline the evolutionary importance of RE, which can be detrimental as here, but also advantageous over generations.  相似文献   

5.
6.
With the recent advent of genomic tools for cattle, several recessive conditions affecting fertility have been identified and selected against, such as deficiency of uridine monophosphate synthase, complex vertebral malformation, and brachyspina. The current report refines the location of a recessive haplotype affecting fertility in Jersey cattle using crossover haplotypes, discovers the causative mutation using whole genome sequencing, and examines the gene’s role in embryo loss. In an attempt to identify unknown recessive lethal alleles in the current dairy population, a search using deep Mendelian sampling of 5,288 Jersey cattle was conducted for high-frequency haplotypes that have a deficit of homozygotes at the population level. This search led to the discovery of a putative recessive lethal in Jersey cattle on Bos taurus autosome 15. The haplotype, denoted JH1, was associated with reduced fertility, and further investigation identified one highly-influential Jersey bull as the putative source ancestor. By combining SNP analysis of whole-genome sequences aligned to the JH1 interval and subsequent SNP validation a nonsense mutation in CWC15 was identified as the likely causative mutation underlying the fertility phenotype. No homozygous recessive individuals were found in 749 genotyped animals, whereas all known carriers and carrier haplotypes possessed one copy of the mutant allele. This newly identified lethal has been responsible for a substantial number of spontaneous abortions in Jersey dairy cattle throughout the past half-century. With the mutation identified, selection against the deleterious allele in breeding schemes will aid in reducing the incidence of this defect in the population. These results also show that carrier status can be imputed with high accuracy. Whole-genome resequencing proved to be a powerful strategy to rapidly identify a previously mapped deleterious mutation in a known carrier of a recessive lethal allele.  相似文献   

7.
The emergence of a new hereditary disease, called "Complex vertebral malformation" (CVM), has been described in Holstein cattle population. This paper studied the incidence of mating concerning Holstein dairy cattle with CVM in Brittany and the possible influences of CVM status for sires and dams on return-to-service at different intervals post-service in cows and heifers. It was carried out based on a set of data for first and second inseminations between 1998 and 2001 in cows (n=530,538) and heifers (n=248,140). Incidence of matings between CVM gene carriers, between a carrier bull and a non-carrier cow and between a non-carrier bull and a carrier cow were estimated to be 1.4, 10.6 and 9%, respectively (1.1, 9.3 and 10.9%, respectively in heifers). Compared to CVM-free mating, the relative risk of return-to-service was increased when the sire was a CVM carrier and the dam was at risk of being a carrier, especially for late return (>25 days post-service). When the sire alone was a carrier, the relative risk was increased whenever the return occurred at a low but significant level. Following mating between a non-carrier bull and a dam at risk of being a carrier, the risk of return-to-service decreased at a low but significant level, whatever the interval in the heifers but only for 19-25 days intervals in the cows.  相似文献   

8.
中国荷斯坦牛CVM的基因检测及其与产奶性状的关联分析   总被引:1,自引:0,他引:1  
初芹  张毅  孙东晓  俞英  王雅春  张沅 《遗传》2010,32(7):732-736
脊椎畸形综合征(Complex vertebral malformation, CVM)是由位于牛第3号染色体(BTA3)的SLC35A3基因外显子4的一个单碱基突变(G559T)所致。该致病基因在世界许多国家的荷斯坦牛群中都有一定的比例。文章对北京地区38头优秀种公牛进行分析, 发现了4头携带者, 进而检测了这些携带者公牛的555头女儿的基因型, 其中携带者占检测母牛数的44.0%。此外, 关联分析结果表明, 携带者母牛与非携带者母牛的生产性能之间存在显著差异(P<0.01)。携带者母牛的5个产奶性状育种值均显著高于非携带者, 泌乳持续力和体细胞评分SCS的育种值也比非携带者略高。CVM致病基因可能与BTA3上影响产奶性状的QTL或基因连锁。因此, 建议生产中对CVM携带者进行逐步淘汰  相似文献   

9.
Linkage disequilibrium in the North American Holstein population   总被引:2,自引:0,他引:2  
Linkage disequilibrium was estimated using 7119 single nucleotide polymorphism markers across the genome and 200 animals from the North American Holstein cattle population. The analysis of maternally inherited haplotypes revealed strong linkage disequilibrium ( r 2   >   0.8) in genomic regions of ∼50 kb or less. While linkage disequilibrium decays as a function of genomic distance, genomic regions within genes showed greater linkage disequilibrium and greater variation in linkage disequilibrium compared with intergenic regions. Identification of haplotype blocks could characterize the most common haplotypes. Although maximum haplotype block size was over 1 Mb, mean block size was 26–113 kb by various definitions, which was larger than that observed in humans (∼10 kb). Effective population size of the dairy cattle population was estimated from linkage disequilibrium between single nucleotide polymorphism marker pairs in various haplotype ranges. Rapid reduction of effective population size of dairy cattle was inferred from linkage disequilibrium in recent generations. This result implies a loss of genetic diversity because of the high rate of inbreeding and high selection intensity in dairy cattle. The pattern observed in this study indicated linkage disequilibrium in the current dairy cattle population could be exploited to refine mapping resolution. Changes in effective population size during past generations imply a necessity of plans to maintain polymorphism in the Holstein population.  相似文献   

10.
Fertility is one of the most important traits in dairy cattle, and has been steadily declining over the last decades. We herein use state-of-the-art genomic tools, including high-throughput SNP genotyping and next-generation sequencing, to identify a 3.3 Kb deletion in the FANCI gene causing the brachyspina syndrome (BS), a rare recessive genetic defect in Holstein dairy cattle. We determine that despite the very low incidence of BS (<1/100,000), carrier frequency is as high as 7.4% in the Holstein breed. We demonstrate that this apparent discrepancy is likely due to the fact that a large proportion of homozygous mutant calves die during pregnancy. We postulate that several other embryonic lethals may segregate in livestock and significantly compromise fertility, and propose a genotype-driven screening strategy to detect the corresponding deleterious mutations.  相似文献   

11.
Huang YZ  He H  Sun JJ  Wang J  Li ZJ  Lan XY  Lei CZ  Zhang CL  Zhang EP  Wang JQ  Chen H 《Génome》2011,54(6):507-516
The aim of this study was to examine the association of the SREBP-1c polymorphism with growth traits in cattle breeds. Five sequence variants (SVs) were identified within the bovine sterol regulatory element-binding protein-1c gene (SREBP-1c), using DNA sequencing, PCR, PCR–RFLP, and forced PCR–RFLP methods. These polymorphisms include three missense mutations (SV1, SV4, and SV5) in exons 7, 9, and 12, a silent mutation (SV3) in exon 9, and a large deletion (SV2) in intron 7. Overall, we report the validation of polymorphisms within the bovine SREBP-1c gene, and the haplotype variability and extent of linkage disequilibrium (LD) in 1061 individuals representing the five main cattle breeds from China. We also investigated haplotype frequencies and LD coefficients for five SVs in all study populations. LD and haplotype structure of SREBP-1c were different between breeds. The result of haplotype analysis of five SVs showed that 27 different haplotypes were identified by all breeds. Two haplotypes (Hap1 and Hap2) shared by all five populations accounted for 42.75%, 35.68%, 36.44%, 25.43%, and 96.26% of all haplotypes observed in the cattle breeds Nanyang, Qinchuan, Jiaxian, Jinnan, and Chinese Holstein, respectively. The statistical analyses indicated that one single SV and 38 combined haplotypes were significantly associated with growth traits in the Nanyang cattle population (P < 0.05 or P < 0.01). The results of this study suggest that the SREBP-1c gene possibly is a strong candidate gene that affects growth traits in the Chinese beef cattle breeding program.  相似文献   

12.
Using genomic data, lethal recessives may be discovered from haplotypes that are common in the population but never occur in the homozygote state in live animals. This approach only requires genotype data from phenotypically normal (i.e. live) individuals and not from the affected embryos that die. A total of 7,937 Nordic Holstein animals were genotyped with BovineSNP50 BeadChip and haplotypes including 25 consecutive markers were constructed and tested for absence of homozygotes states. We have identified 17 homozygote deficient haplotypes which could be loosely clustered into eight genomic regions harboring possible recessive lethal alleles. Effects of the identified haplotypes were estimated on two fertility traits: non-return rates and calving interval. Out of the eight identified genomic regions, six regions were confirmed as having an effect on fertility. The information can be used to avoid carrier-by-carrier mattings in practical animal breeding. Further, identification of causative genes/polymorphisms responsible for lethal effects will lead to accurate testing of the individuals carrying a lethal allele.  相似文献   

13.

Background

Genomic selection is increasingly widely practised, particularly in dairy cattle. However, the accuracy of current predictions using GBLUP (genomic best linear unbiased prediction) decays rapidly across generations, and also as selection candidates become less related to the reference population. This is likely caused by the effects of causative mutations being dispersed across many SNPs (single nucleotide polymorphisms) that span large genomic intervals. In this paper, we hypothesise that the use of a nonlinear method (BayesR), combined with a multi-breed (Holstein/Jersey) reference population will map causative mutations with more precision than GBLUP and this, in turn, will increase the accuracy of genomic predictions for selection candidates that are less related to the reference animals.

Results

BayesR improved the across-breed prediction accuracy for Australian Red dairy cattle for five milk yield and composition traits by an average of 7% over the GBLUP approach (Australian Red animals were not included in the reference population). Using the multi-breed reference population with BayesR improved accuracy of prediction in Australian Red cattle by 2 – 5% compared to using BayesR with a single breed reference population. Inclusion of 8478 Holstein and 3917 Jersey cows in the reference population improved accuracy of predictions for these breeds by 4 and 5%. However, predictions for Holstein and Jersey cattle were similar using within-breed and multi-breed reference populations. We propose that the improvement in across-breed prediction achieved by BayesR with the multi-breed reference population is due to more precise mapping of quantitative trait loci (QTL), which was demonstrated for several regions. New candidate genes with functional links to milk synthesis were identified using differential gene expression in the mammary gland.

Conclusions

QTL detection and genomic prediction are usually considered independently but persistence of genomic prediction accuracies across breeds requires accurate estimation of QTL effects. We show that accuracy of across-breed genomic predictions was higher with BayesR than with GBLUP and that BayesR mapped QTL more precisely. Further improvements of across-breed accuracy of genomic predictions and QTL mapping could be achieved by increasing the size of the reference population, including more breeds, and possibly by exploiting pleiotropic effects to improve mapping efficiency for QTL with small effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-014-0074-4) contains supplementary material, which is available to authorized users.  相似文献   

14.
Bovine mastitis is a very complex and common disease of dairy cattle and a major source of economic losses to the dairy industry worldwide. In this study, the bovine TLR4 was taken as a candidate gene for mastitis resistance. This study aimed to analyze the associations of single nucleotide polymorphisms (SNP) or haplotype and somatic cell score (SCS) in 404 Chinese commercial dairy cattle including Chinese Holstein, Sanhe cattle and Chinese Simmental breeds. The polymerase chain reaction and sequencing methods were used for detecting genotype and allele frequency distribution of the two SNPs (rs8193062, rs8193064), statistical results showed that T allele at rs8193062 and C allele at rs8193064 were the predominate alleles. Moreover, six SNPs, including two SNPs (rs8193062, rs8193064) and four SNPs (rs8193060, rs8193069, rs29017188, rs8193046) which were chosen according the polymorphism level for the same cattle populations in previous studies, were used for haplotype analysis, the results revealed that twenty-one haplotypes were found in the mentioned animals, of which, Hap1 (30.5 %) and Hap2 (30.4 %) were the most common haplotypes. Hap2, Hap4 and Hap12 might negatively effect on milk SCS, whereas Hap13 might positively effect on milk SCS. The results in this study might assist in marker assisted selection and provided some reference to be implemented in breeding programs to improve the mastitis resistance of dairy cattle.  相似文献   

15.
荷斯坦奶牛脊柱畸形综合征的研究进展   总被引:1,自引:0,他引:1  
王帅  王栋  杜卫华  郝海生  朱化彬  王宗礼 《遗传》2007,29(9):1049-1054
荷斯坦奶牛脊柱畸形综合征是近年新发现的一种常染色体隐性遗传病,该病对纯合子胎儿是致死性的。当荷斯坦牛的育种核心群中携带者达到一定比例,脊柱畸形综合征就会对奶业造成巨大损失。文章综述了脊柱畸形综合征的主要症状和影响、致病基因及检测方法的研究进展以及我国潜在的荷斯坦奶牛脊柱畸形综合征携带者的状况。  相似文献   

16.

Background

Cattle breeding populations are susceptible to the propagation of recessive diseases. Individual sires generate tens of thousands of progeny via artificial insemination. The frequency of deleterious alleles carried by such sires may increase considerably within few generations. Deleterious alleles manifest themselves often by missing homozygosity resulting from embryonic/fetal, perinatal or juvenile lethality of homozygotes.

Results

A scan for homozygous haplotype deficiency in 25,544 Fleckvieh cattle uncovered four haplotypes affecting reproductive and rearing success. Exploiting whole-genome resequencing data from 263 animals facilitated to pinpoint putatively causal mutations in two of these haplotypes. A mutation causing an evolutionarily unlikely substitution in SUGT1 was perfectly associated with a haplotype compromising insemination success. The mutation was not found in homozygous state in 10,363 animals (P = 1.79 × 10−5) and is thus likely to cause lethality of homozygous embryos. A frameshift mutation in SLC2A2 encoding glucose transporter 2 (GLUT2) compromises calf survival. The mutation leads to premature termination of translation and activates cryptic splice sites resulting in multiple exon variants also with premature translation termination. The affected calves exhibit stunted growth, resembling the phenotypic appearance of Fanconi-Bickel syndrome in humans (OMIM 227810), which is also caused by mutations in SLC2A2.

Conclusions

Exploiting comprehensive genotype and sequence data enabled us to reveal two deleterious alleles in SLC2A2 and SUGT1 that compromise pre- and postnatal survival in homozygous state. Our results provide the basis for genome-assisted approaches to avoiding inadvertent carrier matings and to improving reproductive and rearing success in Fleckvieh cattle.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1483-7) contains supplementary material, which is available to authorized users.  相似文献   

17.
A. Lagziel  E. Lipkin    M. Soller 《Genetics》1996,142(3):945-951
The bovine Growth Hormone gene (bGH) is an attractive candidate gene for milk production in cattle. Single-strand conformation polymorphisms at bGH were identified and used to define haplotype configurations at this gene in the Israeli Holstein dairy cattle population (Bos taurus) and in the parent animals of the International Bovine Reference Family Panel (a collection of B. taurus and B. indicus crosses). B. taurus and B. indicus haplotypes at the bGH gene differed qualitatively, confirming the previously proposed long evolutionary separation of these cattle subraces. Only a small number of bGH haplotypes were present in the Israel Holstein population. One of the haplotypes, apparently of B. indicus origin, was found to have a highly significant positive effect on milk protein percentage. This illustrates the utility of the haplotype approach for uncovering candidate gene involvement in quantitative genetic variation in agricultural populations. The strong effect of an indicine haplotype in a taurine background raises the possibility that indicine alleles at other candidate genes may comprise a genetic resource for improvement of taurine populations. It is proposed that haplotype analysis may be a useful adjunct to measures of genetic distance for evaluating rare breeds with respect to gene conservation.  相似文献   

18.
The objectives of this study were to identify single nucleotide polymorphisms (SNPs) and resulting haplotypes in the bovine CXCR2 gene. A 311-bp segment of the bovine CXCR2 gene was amplified and sequenced. Five SNPs at positions 612, 684, 777, 858, and 861 were expressed in both Holstein and Jersey dairy cattle. Four SNPs resulted in synonymous substitutions, while a non-synonymous switch at position 777 (GC) resulted in a glutamine to histidine substitution at amino acid residue 245. Strong linkage disequilibrium was exhibited for both breeds among all five loci (P<0.001). Both allele and genotype frequencies differed significantly with respect to breed at four of the five loci (P<0.001). The five polymorphisms generated ten distinct haplotypes. Six haplotypes were common between the two breeds, while Holsteins and Jerseys each uniquely expressed two haplotypes. Of the six common haplotypes, two represented 83% of the Jersey population; whereas four of these haplotypes represented 95% of the Holstein population.  相似文献   

19.
The Eastern European Grey cattle are regarded as the direct descendants of the aurochs (Bos taurus primigenius). Nowadays in Romania, less than 100 Grey animals are being reared and included in the national gene reserve. We examined the genetic diversity among Romanian Grey, Brown, Spotted and Black and White cattle breeds, with a particular focus on Romanian Grey through the use of (i) 11 bovine specific microsatellite markers on 83 animals and (ii) 638 bp length of mitochondrial DNA (mtDNA) D-loop region sequence data from a total of 81 animals. Both microsatellite and mtDNA analysis revealed a high level of genetic variation in the studied breeds. In Romanian Grey a total of 100 alleles were found, the mean number of observed alleles per locus was 9.091; the average observed heterozygosity was 0.940; the Wright’s fixation index (FIS) was negative (-0.189) and indicates that there is no inbreeding and no selection pressure. MtDNA analysis revealed 52 haplotypes with 67 variable sites among the Romanian cattle breeds without any insertion or deletion. Haplotype diversity was 0.980 ± 0.007 and ranged from 0.883 ± 0.056 (Brown) to 0.990 ± 0.028 (Spotted and Black and White). The highest genetic variability of the mtDNA was recorded in the Grey breed, where 18 haplotypes were identified. The most frequent mtDNA D-loop region belonged to T3 haplogroup (80.247%), which was found across all studied breeds, while T2 haplotypes (16.049%) was only found in Grey, Spotted and Black and White genotypes. The T1 haplotypes (3.704%) were found in the Grey and Spotted. The current results contribute to the general knowledge on genetic diversity found in Eastern European cattle breeds and could prove a valuable tool for the conservation efforts of animal genetic resources (FAnGR).  相似文献   

20.
Complex vertebral malformation (CVM) is an autosomal recessive inherited defect in the Holstein breed. It causes intra-uterine mortality leading to repeat breeding and involuntary culling of cows. This study was carried out to show the prevalence of CVM carriers among Holstein cows in five dairy farms in Hiroshima Prefecture, South Western Japan and whether the defect could be inherited to crossbred F1 generation, when Japanese Black semen was used to inseminate a Holstein cow. Two hundreds Holstein cows were used in the study. Blood samples were collected from all cows in a heparinized tubes and genomic DNA was extracted with a commercial kit. Apart of the bovine solute carrier family 35 member 3 (SLC35A3) gene around the suspected mutation (G to T) was amplified with an allele specific polymerase chain reaction (AS-PCR). For DNA sequencing, PCR products of 522 bp were obtained from the genomic DNA of the cows. Out of 200 examined cows, 26 cows (13.0%) were found to be CVM carriers. Wild type cows showed amplification with the G-specific primer pair but not with the T-specific primer pair, while carrier ones showed amplification of both the G- and T-specific primers, exhibited two DNA bands of 395 bp. Based on the clinical history of the cows, lowered reproductive performance was noticed in carrier ones. Out of four crossbred F1 calves (Holstein x Japanese Black), two were CVM carrier. Crossbred F1 could inherit the CVM defect when Japanese Black semen used to inseminate a carrier Holstein cow. In conclusion, the study reports the occurrence of CVM among Holstein cows in Hiroshima Prefecture, Japan; moreover, it describes the first cases of CVM in crossbred F1 generation.  相似文献   

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