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A number of collaborators were not acknowledged for their contribution to this published article. The acknowledgements that were missing in this published article can now be found in the associated correction.
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Psychotic symptoms, defined as the occurrence of delusions or hallucinations, are frequent in Alzheimer disease (AD), affecting ~40 to 60% of individuals with AD (AD with psychosis (AD+P)). In comparison with AD subjects without psychosis, AD+P subjects have more rapid cognitive decline and poor outcomes. Prior studies have estimated the heritability of psychosis in AD at 61%, but the underlying genetic sources of this risk are not known. We evaluated a Discovery Cohort of 2876 AD subjects with (N=1761) or without psychosis (N=1115). All subjects were genotyped using a custom genotyping array designed to evaluate single-nucleotide polymorphisms (SNPs) with evidence of genetic association with AD+P and include SNPs affecting or putatively affecting risk for schizophrenia and AD. Results were replicated in an independent cohort of 2194 AD subjects with (N=734) or without psychosis (N=1460). We found that AD+P is associated with polygenic risk for a set of novel loci and inversely associated with polygenic risk for schizophrenia. Among the biologic pathways identified by the associations of schizophrenia SNPs with AD+P are endosomal trafficking, autophagy and calcium channel signaling. To the best of our knowledge, these findings provide the first clear demonstration that AD+P is associated with common genetic variation. In addition, they provide an unbiased link between polygenic risk for schizophrenia and a lower risk of psychosis in AD. This provides an opportunity to leverage progress made in identifying the biologic effects of schizophrenia alleles to identify novel mechanisms protecting against more rapid cognitive decline and psychosis risk in AD.
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Doença de Alzheimer/genética , Transtornos Psicóticos/genética , Esquizofrenia/genética , Idoso , Idoso de 80 Anos ou mais , Alelos , Doença de Alzheimer/complicações , Doença de Alzheimer/psicologia , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Herança Multifatorial , Polimorfismo de Nucleotídeo Único , Transtornos Psicóticos/complicações , Esquizofrenia/complicaçõesRESUMO
BACKGROUND: Herpes virus infections can cause cognitive impairment during and after acute encephalitis. Although chronic, latent/persistent infection is considered to be relatively benign, some studies have documented cognitive impairment in exposed persons that is untraceable to encephalitis. These studies were conducted among schizophrenia (SZ) patients or older community dwellers, among whom it is difficult to control for the effects of co-morbid illness and medications. To determine whether the associations can be generalized to other groups, we examined a large sample of younger control individuals, SZ patients and their non-psychotic relatives (n=1852). Method Using multivariate models, cognitive performance was evaluated in relation to exposures to herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2) and cytomegalovirus (CMV), controlling for familial and diagnostic status and sociodemographic variables, including occupation and educational status. Composite cognitive measures were derived from nine cognitive domains using principal components of heritability (PCH). Exposure was indexed by antibodies to viral antigens. RESULTS: PCH1, the most heritable component of cognitive performance, declines with exposure to CMV or HSV-1 regardless of case/relative/control group status (p = 1.09 × 10-5 and 0.01 respectively), with stronger association with exposure to multiple herpes viruses (ß = -0.25, p = 7.28 × 10-10). There were no significant interactions between exposure and group status. CONCLUSIONS: Latent/persistent herpes virus infections can be associated with cognitive impairments regardless of other health status.
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Transtornos Cognitivos/epidemiologia , Infecções por Citomegalovirus/epidemiologia , Herpes Simples/epidemiologia , Modelos Estatísticos , Testes Neuropsicológicos/estatística & dados numéricos , Esquizofrenia/epidemiologia , Adulto , Negro ou Afro-Americano/genética , Negro ou Afro-Americano/psicologia , Anticorpos Antivirais/sangue , Encéfalo/virologia , Estudos de Casos e Controles , Doença Crônica , Transtornos Cognitivos/genética , Transtornos Cognitivos/virologia , Citomegalovirus/imunologia , Infecções por Citomegalovirus/sangue , Escolaridade , Emprego , Feminino , Predisposição Genética para Doença , Herpes Simples/sangue , Humanos , Masculino , Análise Multivariada , Fenótipo , Análise de Componente Principal , Esquizofrenia/genética , Esquizofrenia/virologia , Simplexvirus/imunologiaRESUMO
Psychotic symptoms occur in ~40% of subjects with Alzheimer's disease (AD) and are associated with more rapid cognitive decline and increased functional deficits. They show heritability up to 61% and have been proposed as a marker for a disease subtype suitable for gene mapping efforts. We undertook a combined analysis of three genome-wide association studies (GWASs) to identify loci that (1) increase susceptibility to an AD and subsequent psychotic symptoms; or (2) modify risk of psychotic symptoms in the presence of neurodegeneration caused by AD. In all, 1299 AD cases with psychosis (AD+P), 735 AD cases without psychosis (AD-P) and 5659 controls were drawn from Genetic and Environmental Risk in AD Consortium 1 (GERAD1), the National Institute on Aging Late-Onset Alzheimer's Disease (NIA-LOAD) family study and the University of Pittsburgh Alzheimer Disease Research Center (ADRC) GWASs. Unobserved genotypes were imputed to provide data on >1.8 million single-nucleotide polymorphisms (SNPs). Analyses in each data set were completed comparing (1) AD+P to AD-P cases, and (2) AD+P cases with controls (GERAD1, ADRC only). Aside from the apolipoprotein E (APOE) locus, the strongest evidence for association was observed in an intergenic region on chromosome 4 (rs753129; 'AD+PvAD-P' P=2.85 × 10(-7); 'AD+PvControls' P=1.11 × 10(-4)). SNPs upstream of SLC2A9 (rs6834555, P=3.0 × 10(-7)) and within VSNL1 (rs4038131, P=5.9 × 10(-7)) showed strongest evidence for association with AD+P when compared with controls. These findings warrant further investigation in larger, appropriately powered samples in which the presence of psychotic symptoms in AD has been well characterized.
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Doença de Alzheimer/genética , Doença de Alzheimer/psicologia , Estudo de Associação Genômica Ampla/estatística & dados numéricos , Proteínas Facilitadoras de Transporte de Glucose/genética , Neurocalcina/genética , Transtornos Psicóticos/genética , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/complicações , Apolipoproteínas E/genética , Estudos de Casos e Controles , Cromossomos Humanos Par 4/genética , DNA Intergênico/genética , Feminino , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Transtornos Psicóticos/complicações , Transtornos Psicóticos/diagnósticoRESUMO
The major histocompatibility complex (MHC) on chromosome 6p is an established risk locus for ulcerative colitis (UC) and Crohn's disease (CD). We aimed to better define MHC association signals in UC and CD by combining data from dense single-nucleotide polymorphism (SNP) genotyping and from imputation of classical human leukocyte antigen (HLA) types, their constituent SNPs and corresponding amino acids in 562 UC, 611 CD and 1428 control subjects. Univariate and multivariate association analyses were performed, controlling for ancestry. In univariate analyses, absence of the rs9269955 C allele was strongly associated with risk for UC (P = 2.67 × 10(-13)). rs9269955 is a SNP in the codon for amino acid position 11 of HLA-DRß1, located in the P6 pocket of the HLA-DR antigen binding cleft. This amino acid position was also the most significantly UC-associated amino acid in omnibus tests (P = 2.68 × 10(-13)). Multivariate modeling identified rs9269955-C and 13 other variants in best predicting UC vs control status. In contrast, there was only suggestive association evidence between the MHC and CD. Taken together, these data demonstrate that variation at HLA-DRß1, amino acid 11 in the P6 pocket of the HLA-DR complex antigen binding cleft is a major determinant of chromosome 6p association with UC.
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Cromossomos Humanos Par 6 , Colite Ulcerativa/genética , Predisposição Genética para Doença , Cadeias beta de HLA-DR/genética , Alelos , Substituição de Aminoácidos , Doença de Crohn/genética , Frequência do Gene , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
We investigated 383 bone candidate genes for associations between single nucleotide polymorphisms and vertebral trabecular volumetric bone mineral density (vBMD) and cross-sectional area (CSA) in 2,018 Caucasian men aged ≥ 65 years. SNPs in TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE were associated with vBMD and SNPs in CYP11B1, DVL2, DLX5, WNT4, and PAX7 were associated with CSA in independent study samples (p < 0.005). INRODUCTION: Vertebral bone mineral density and cross-sectional area are important determinants of vertebral bone strength. Little is known about the specific genetic variants that influence these phenotypes in humans. METHODS: We investigated the potential genetic variants associated with vertebral trabecular volumetric BMD and CSA measured by quantitative computed tomography. We initially tested for association between these phenotypes and 4608 tagging and potentially functional single nucleotide polymorphisms (SNPs) in 383 candidate genes in 862 community-dwelling Caucasian men aged ≥ 65 years in the Osteoporotic Fractures in Men Study. RESULTS: SNP associations were then validated by genotyping an additional 1,156 randomly sampled men from the same cohort. We identified 11 SNPs in 10 genes (TGFBR3, SOST, KL, CALCR, LEP, CSF1R, PTN, GNRH2, FGFR2, and MEPE) that were consistently associated with trabecular vBMD and five SNPs in five genes (CYP11B1, DVL2, DLX5, WNT4, and PAX7) that were consistently associated with CSA in both samples (p < 0.005). CONCLUSION: None of the SNPs associated with trabecular vBMD were associated with CSA. Our findings raise the possibility that at least some of the loci for vertebral trabecular BMD and bone size may be distinct.
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Densidade Óssea/genética , Vértebras Lombares/fisiologia , Polimorfismo de Nucleotídeo Único , Idoso , Idoso de 80 Anos ou mais , Frequência do Gene , Estudos de Associação Genética , Genótipo , Humanos , Vértebras Lombares/anatomia & histologia , Masculino , Tomografia Computadorizada por Raios X/métodosRESUMO
While many studies have sought a window into the genetics of schizophrenia, few have focused on African-American families. An exception is the Project among African-Americans to Explore Risks for Schizophrenia (PAARTNERS), which seeks to identify novel and known risk variation for schizophrenia by genetic analyses of African-American families. We report a linkage study of diagnostic status in 217 African-American families using the Illumina Linkage Panel. Due to assumed incomplete and time-dependent penetrance, we performed linkage analysis using two different treatments of diagnosis: (1) treating both affected and unaffected individuals as informative for linkage (using the program SIBPAL) and (2) treating only affected individuals as informative (using the program MERLIN). We also explore three definitions of affected status: narrowly defined schizophrenia; one broadened to include schizoaffective disorder; and another including all diagnoses indicating psychosis. Several regions show a decrease in the evidence for linkage as the definition broadens 8q22.1 (rs911, 99.26 cM; SIBPAL p-value [p] goes from 0.006 to 0.02), 16q24.3 (rs1006547, 130.48 cM; p from 0.00095 to 0.0085), and 20q13.2 (rs1022689, 81.73 cM; p from 0.00015 to 0.032). One region shows a substantial increase in evidence for linkage, 11p15.2 (rs722317, 24.27 cM; p from 0.0022 to 0.0000003); MERLIN results support the significance of the SIBPAL results (p=0.00001). Our linkage results overlap two broad, previously-reported linkage regions: 8p23.3-p12 found in studies sampling largely families of European ancestry; and 11p11.2-q22.3 reported by a study of African-American families. These results should prove quite useful for uncovering loci affecting risk for schizophrenia.
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Negro ou Afro-Americano/genética , Família , Ligação Genética , Esquizofrenia/genética , Mapeamento Cromossômico , Feminino , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Fatores de RiscoRESUMO
Elevated levels of arsenite, the trivalent form of arsenic, in drinking water correlates with increased vascular disease and vessel remodeling. Previous studies from this laboratory demonstrated that environmentally relevant concentrations of arsenite caused oxidant-dependent increases in nuclear transcription factor levels in cultured porcine vascular endothelial cells. The current studies characterized the reactive species generated in these cells exposed to levels of arsenite that initiate cell signaling. These exposures did not deplete 5'-triphosphate, nor did they affect basal or bradykinin-stimulated intracellular free Ca2+ levels, indicating that they were not lethal. Electron paramagnetic resonance (EPR) spectroscopy, including spin trapping with carboxy-PTIO (cPTIO), demonstrated that 5 microM or less of arsenite did not increase *NO levels over a 30-min period relative to *NO release stimulated by bradykinin. However, these same levels of arsenite rapidly increased both oxygen consumption and superoxide formation, as measured by EPR oximetry and spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), respectively. Pretreatment of the cells with DPI, apocynin, or superoxide dismutase abolished arsenite-stimulated DMPO-OH adduct formation. Finally arsenite increased extracellular accumulation of H2O2, measured as oxidation of homovanillic acid, with the same time and dose dependence, as seen for superoxide formation. These data suggest that superoxide and H2O2 are the predominant reactive species produced by endothelial cells after arsenite exposures that stimulate cell signaling and activate transcription factors.
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Arsenitos/farmacologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Aorta , Arsenitos/administração & dosagem , Benzoatos , Cálcio/metabolismo , Células Cultivadas , Óxidos N-Cíclicos , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres , Peróxido de Hidrogênio/metabolismo , Imidazóis , Óxidos de Nitrogênio/metabolismo , Consumo de Oxigênio , Marcadores de Spin , Superóxidos/metabolismo , SuínosRESUMO
A study was conducted to determine whether differences in regional performance could be attributed to different selection goals among Simmental breeders. Using data obtained from the spring 1993 National Simmental Cattle Evaluation, breeders were identified by region of the country as defined by the American Simmental Association: South Central (SC), North Central (NC), West (W), and East (E). Animals included in the analysis were at least 87.5% Simmental and from breeders who recorded data every year from 1978 to 1991. The number of breeders and animals from each region were 154 and 62,830 in the SC, 260 and 139,053 in the NC, 102 and 57,434 in the W, and 143 and 39,786 in the E. Phenotypic, genetic, and environmental trends were estimated in each region for birth weight (BWT), weaning weight (WWT), and postweaning gain (PWG). The growth genetic trends were increasing at similar rates in the regions over time. For maternal milk (MMK), breeders in the NC and W decreased maternal breeding value slightly compared to SC and E breeders. For BWT, the average environmental trends ranged from .0 kg/yr in the SC to .11 kg/yr in the NC. The regional WWT environmental trend ranged from 1.4 to 2.2 kg/yr. The environmental trends for PWG varied from -3.1 kg/yr in the SC to .3 kg/yr in the W. Selected parents had higher estimated breeding values than their birth year averages each year for BWT, WWT, and PWG. The average maternal breeding values for selected parents were essentially zero compared with their birth year averages.(ABSTRACT TRUNCATED AT 250 WORDS)
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Cruzamento , Bovinos/crescimento & desenvolvimento , Bovinos/genética , Animais , Peso ao Nascer/fisiologia , Bovinos/fisiologia , Meio Ambiente , Feminino , Masculino , Leite/normas , Fenótipo , Seleção Genética , Estados Unidos , Aumento de Peso/fisiologiaRESUMO
Due to computational demand, elements of genetic correlation matrices may have been estimated separately and then combined together into a single correlation matrix at a later stage. Because these matrices should be positive definite (PD) a statistical method commonly known as "bending" is used to make them positive definite. The conventional bending method ignores the reliability of different correlations and may subject any of them to change in order to make a positive definite correlation matrix. A simple method to obtain a weighted bended matrix to be used in animal breeding applications is proposed, and the implementation of the method is demonstrated by an example.
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Cruzamento/métodos , Bovinos/genética , Seleção Genética , Algoritmos , Animais , Feminino , Masculino , Matemática , Locos de Características Quantitativas/genéticaRESUMO
Low-level arsenite treatment of porcine aortic endothelial cells (PAEC) stimulated superoxide accumulation that was attenuated by inhibitors of NAD(P)H oxidase. To demonstrate whether arsenite stimulated NADPH oxidase, intact PAEC were treated with arsenite for up to 2 h and membrane fractions were prepared to measure NADPH oxidase activity. Arsenite (5 microM) stimulated a twofold increase in activity by 1 h, which was inhibited by the oxidase inhibitor diphenyleneiodonium chloride. Direct treatment of isolated membranes with arsenite had no effect. Analysis of NADPH oxidase components revealed that p67(phox) localized exclusively to membranes of both control and treated cells. In contrast, cytosolic Rac1 translocated to the membrane fractions of cells treated with arsenite or angiotensin II but not with tumor necrosis factor. Immunodepletion of p67(phox) blocked oxidase activity stimulated by all three compounds. However, depleting Rac1 inhibited responses only to arsenite and angiotensin II. These data demonstrate that stimulus-specific activation of NADPH oxidase in endothelial cells was the source of reactive oxygen in endothelial cells after noncytotoxic arsenite exposure.
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Arsenitos/farmacologia , Endotélio Vascular/enzimologia , NADPH Oxidases/metabolismo , Animais , Aorta/citologia , Aorta/enzimologia , Transporte Biológico/efeitos dos fármacos , Membrana Celular/enzimologia , Células Cultivadas , Relação Dose-Resposta a Droga , Endotélio Vascular/citologia , Ativação Enzimática , Suínos , Fatores de Tempo , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
Human epidemiological and animal studies have associated inhalation of nickel dusts with an increased incidence of pulmonary fibrosis. At the cellular level, particulate nickel subsulfide inhibits fibrinolysis by transcriptionally inducing expression of plasminogen activator inhibitor (PAI)-1, an inhibitor of the urokinase-type plasminogen activator. Because nickel is known to mimic hypoxia, the present study examined whether nickel transcriptionally activates PAI-1 through the hypoxia-inducible factor (HIF)-1 alpha signaling pathway. The involvement of the NADPH oxidase complex, reactive oxygen species, and kinases in mediating nickel-induced HIF-1 alpha signaling was also investigated. Addition of nickel to BEAS-2B human airway epithelial cells increased HIF-1 alpha protein levels and elevated PAI-1 mRNA levels. Pretreatment of cells with the extracellular signal-regulated kinase inhibitor U-0126 partially blocked HIF-1 alpha protein and PAI-1 mRNA levels induced by nickel, whereas antioxidants and NADPH oxidase inhibitors had no effect. Pretreating cells with antisense, but not sense, oligonucleotides to HIF-1 alpha mRNA abolished nickel-stimulated increases in PAI-1 mRNA. These data indicate that signaling through extracellular signal-regulated kinase and HIF-1 alpha is required for nickel-induced transcriptional activation of PAI-1.
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Proteínas de Ligação a DNA/fisiologia , Níquel/farmacologia , Proteínas Nucleares/fisiologia , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Fatores de Transcrição , Antioxidantes/farmacologia , Linhagem Celular , Proteínas de Ligação a DNA/genética , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Transporte de Elétrons/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Fator 1 Induzível por Hipóxia , Subunidade alfa do Fator 1 Induzível por Hipóxia , Membranas Intracelulares/metabolismo , Mitocôndrias/metabolismo , NADPH Oxidases/antagonistas & inibidores , Proteínas Nucleares/genética , Oligonucleotídeos Antissenso/farmacologia , Oxirredução/efeitos dos fármacos , Fosfotransferases/fisiologia , Inibidor 1 de Ativador de Plasminogênio/genética , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/metabolismo , Rotenona/farmacologia , Transdução de Sinais , Fatores de TempoRESUMO
Inhalation of nickel dust has been associated with an increased incidence of pulmonary fibrosis. Nickel may promote fibrosis by transcriptionally activating plasminogen activator inhibitor (PAI)-1 and inhibiting fibrinolysis. The current studies examined whether nickel stimulated the PAI-1 promoter though an oxidant-sensitive activator protein (AP)-1 signaling pathway. Addition of nickel to BEAS-2B human airway epithelial cells stimulated intracellular oxidation, induced c-Jun and c-Fos mRNA levels, increased phospho- and total c-Jun protein levels, and elevated PAI-1 mRNA levels over a 24-h time course. Pretreatment of the cells with antioxidants did not affect increased c-Jun protein or PAI-1 mRNA levels. Expression of the dominant negative inhibitor of AP-1, TAM67, prevented nickel-stimulated AP-1 DNA binding, AP-1-luciferase reporter construct activity, and PAI-1 mRNA levels. Overexpression of c-Jun, however, failed to induce the AP-1 luciferase reporter construct or PAI-1 mRNA levels. These data indicated that nickel activated AP-1 through an oxidant-independent pathway and that basal AP-1 is necessary for nickel-induced expression of PAI-1.
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Níquel/farmacologia , Inibidor 1 de Ativador de Plasminogênio/genética , Fator de Transcrição AP-1/fisiologia , Fatores de Transcrição , Linhagem Celular , DNA/antagonistas & inibidores , DNA/metabolismo , Proteínas de Ligação a DNA/fisiologia , Regulação da Expressão Gênica/fisiologia , Humanos , Fator 1 Induzível por Hipóxia , Subunidade alfa do Fator 1 Induzível por Hipóxia , Níquel/antagonistas & inibidores , Proteínas Nucleares/fisiologia , Fosfoproteínas/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-jun/genética , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição AP-1/antagonistas & inibidores , Fator de Transcrição AP-1/genética , Ativação Transcricional/efeitos dos fármacosRESUMO
Conformation final scores obtained by the Holstein Association were used in this study. Five subsets were sampled from the original complete data, which contained about 7 million records, and (co)variance components for additive genetic, permanent environmental, and residual effects were estimated with a multiple-trait (MT) model at different ages of cows and with a random regression model. Transmitting abilities were predicted with the random-regression (RR) model and with the repeatability model for the national evaluation, using the entire data set. The RR model included fixed and random regressions on age at classification for additive genetic and permanent environmental effects. Additive genetic and residual variances estimated with the MT model increased with aging. Genetic correlations between age groups decreased with their distance. Heritability and repeatability estimates with the RR model were 0.27 and 0.88 on average, increasing with cow's age. Correlations between transmitting abilities predicted with the RR model at various ages and with the repeatability model were in the range of 0.89 to 0.99. In the 1980s, predicted transmitting abilities (PTA) of sires increased with their daughters' age, but in 1991 and 1995, the PTA decreased. In general, sires whose daughters were evaluated at mature ages tended to have higher PTA. For sires and cows, genetic trends estimated from the repeatability model and from the RR model were similar. The low genetic trend of cows at 60 mo for recent years was due to many grade cows that had only single records and little pedigree information.
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Envelhecimento , Cruzamento , Bovinos/genética , Locos de Características Quantitativas , Animais , Feminino , Masculino , Modelos Genéticos , Modelos Estatísticos , Linhagem , Análise de RegressãoRESUMO
The objectives of this study were to estimate genetic correlations among body condition score (BCS), dairy form, milk yield, and days open in US Holsteins and investigate the potential of using BCS or dairy form evaluations as early indicators of days open. Dairy form and BCS obtained from the Holstein Association USA, Inc., were merged with mature equivalents (ME) for milk yields and days open data from AIPL-USDA. Cows were required to be classified between 24 and 60 mo of age, before 335 d in milk (DIM) and have ME milk of at least 4537 kg. A minimum of 20 daughters per sire and 10 cows per herd-classification visit (HV) or herd-year-season of calving (HYS) were required. The final data set included 159,700 records. Heritabilities and correlations among dairy form, BCS, milk yield, and days open were estimated with multiple trait sire models. Fixed effects included age at classification for dairy form and BCS, age at calving for milk yield, HV for dairy form and BCS, HYS for milk yield and days open, DIM within lactation group for dairy form and BCS and lactation group for milk yield and days open. Correlations among dairy form, BCS, and days open were generated with and without a ME milk covariable. Correlations between ME milk and days open were generated with and without covariables for dairy form or BCS. Random effects included sire and error. The genetic correlation estimates of days open with dairy form, BCS, and ME milk were 0.48, -0.30, and 0.38, respectively. The genetic correlation estimate between days open and dairy form was 0.38 after adjustment for ME milk, whereas the genetic correlation between days open and BCS was -0.24 after adjustment for ME milk. Combining dairy form evaluations with days open evaluations for 19 recently proven bulls resulted in an average increase of 0.06 for reliability of days open evaluations. The addition of BCS evaluations did not increase reliability when dairy form observations were available.
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Composição Corporal/genética , Bovinos/genética , Bovinos/fisiologia , Indústria de Laticínios/métodos , Fertilidade/genética , Lactação/genética , Envelhecimento , Animais , Cruzamento , Feminino , Masculino , Gravidez , Registros/veterinária , Estações do Ano , Fatores de TempoRESUMO
The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation.
Assuntos
Envelhecimento , Composição Corporal/genética , Bovinos/anatomia & histologia , Bovinos/genética , Lactação/genética , Animais , Cruzamento , Feminino , Variação Genética , Genótipo , Masculino , Matemática , Modelos Estatísticos , Fenótipo , Análise de RegressãoRESUMO
The objectives of this study were to estimate the heritability of body condition score (BCS) with data that could be used to generate genetic evaluations for BCS in the US, and to estimate the relationship among BCS, dairy form and selected type traits. Body condition score and linear type trait records were obtained from Holstein Association USA Inc. Because BCS was a new trait for classifiers, scoring distribution and accuracy was not normal. Records from 11 of 29 classifiers were eliminated to generate a data set that should represent BCS data recorded in the future. Edited data included 128,478 records for analysis of first lactation cows and 207,149 records for analysis of all cows. Heritabilities and correlations were estimated with ASREML using sire models. Models included age at calving nested within lactation, 5th order polynomials of DIM, fixed herd-classification visit effects and random sire and error. Genetic correlation estimates were generated between first lactation data that had records from 11 classifiers removed and data with no classifiers removed. Genetic correlation estimates were 0.995 and above between data with and without classifiers removed for scoring distributions, but heritability estimates were higher with the classifiers edited from the data. Heritability estimates for type traits and final score were similar to previously reported estimates. The heritability estimate for BCS was 0.19 for first lactation cows and 0.22 for all cows. The genetic correlation estimate for first lactation cows between BCS and dairy form was -0.73, whereas the genetic correlation estimate between BCS and strength was 0.72. Genetic correlation estimates were nearly identical when cows from all lactations were included in the analyses. Body condition score had a genetic correlation with final score closer to zero (0.08) than correlations of final score with dairy form, stature or strength.
Assuntos
Composição Corporal/genética , Bovinos/genética , Animais , Constituição Corporal/genética , Peso Corporal/genética , Cruzamento , Bovinos/anatomia & histologia , Indústria de Laticínios , Feminino , Variação Genética , Lactação/genética , Masculino , Modelos Estatísticos , Fenótipo , Locos de Características Quantitativas/genéticaRESUMO
Eight Holstein cows in midlactation were selected for low milk somatic cell count (SCC) and the absence of the pathogens that cause mastitis. Milk collection and cottage cheese manufacture from low SCC milk were replicated on each of 4 d (control period). Each cow was infused with 1000 cfu of Streptococcus agalactiae. One week after infusion, milk from the same eight cows was collected and commingled. On each of 4 d, cottage cheese was made from milk with high SCC (treatment period). A mass-balance protocol, accounting for protein and total solids, was used to determine recoveries in whey, wash water, and uncreamed curd. Actual yields, yields adjusted for composition, and theoretical yields of uncreamed curd were calculated. Mean milk SCC for the periods with the low SCC (control) and the high SCC (treatment) were 83 x 10(3) and 872 x 10(3) cells/ml, respectively. The recovery of protein in the uncreamed curd was higher during the low SCC period than during the high SCC period (75.85% vs. 74.35%). High SCC and the associated higher proteolytic activity caused higher protein loss in the whey and wash water and more curd fines. The percentage of total solids recovery in uncreamed curd was higher for high SCC milk because the lactose content of the high SCC milk was 0.27% lower than that of the low SCC milk. The moisture content of the curd was higher for the high SCC milk (82.75% vs. 83.81%). Proteolysis during refrigerated storage was faster in cottage cheese made from high SCC milk. The yield efficiency of uncreamed curd, adjusted for composition based on 81% moisture, was 4.34% lower for the cottage cheese curd made from high SCC milk.
Assuntos
Bovinos , Contagem de Células , Laticínios , Leite/citologia , Animais , Caseínas/análise , Queijo/análise , Laticínios/análise , Feminino , Tecnologia de Alimentos , Concentração de Íons de Hidrogênio , Lactação , Proteínas do Leite/análise , Nitrogênio/análise , Água , Proteínas do Soro do LeiteRESUMO
Lactations were divided into three periods: early (1 to 99 d), mid (100 to 199 d), and late (200 to 299 d). One hundred Holsteins were randomly split into four groups that were balanced for parity. Groups 222 and 333 were milked twice and three times a day, respectively, throughout lactation. Group 233 was switched from twice to three times daily milking at 100 d, and group 223 was switched at 200 d. Compared with group 222, milk yield for group 333 increased by 10.4%, and fat and protein yields increased by 4.7 and 7.3%, respectively. Mean milk SCC for all groups was < 175,000 cells/ml within each lactation period. The percentage of CP was lower for cows milked three times a day than for cows milked twice a day during each stage of lactation (early, 2.78 and 2.91; mid, 3.08 and 3.19; and late, 3.16 and 3.28, respectively). Casein as a percentage of CP was significantly higher for cows milked three times a day during midlactation. The acid degree values (milliequivalents of FFA/ 100 g of fat) were significantly higher for milk from cows milked three times a day than for cows milked twice a day during early and midlactation, (early, 0.75 and 0.55; mid, 0.82 and 0.61; and late, 0.88 and 0.75, respectively). No differences were detected in milk flavor or plasmin activity because of milking frequency. Casein as a percentage of CP decreased, and plasmin activity increased, as parity and stage of lactation increased.
Assuntos
Bovinos/fisiologia , Lactação/fisiologia , Leite , Animais , Caseínas/análise , Contagem de Células , Indústria de Laticínios/métodos , Feminino , Fibrinolisina/metabolismo , Lipídeos/análise , Leite/química , Leite/citologia , Proteínas do Leite/análise , Paridade , Controle de Qualidade , Fatores de TempoRESUMO
Cheddar cheese was made from milk collected from two groups of cows milked either two or three times daily during early, mid, and late lactation. Milk from cows in late lactation had lower casein as a percentage of true protein and a higher acid degree value than did milk from cows in early lactation. Milk from cows milked three times daily had lower concentrations of milk fat and casein and higher acid degree values than did milk from cows milked twice daily, and thus this milk would be expected to result in decreased cheese yield. Cheese composition was not affected by milking frequency. Stage of lactation effects on cheese composition were confined to differences in salt content and a trend for higher moisture in cheese made from milk of cows in late lactation. Stage of lactation influenced the pH and degradation of alpha s-casein in cheese during aging. Fat and protein losses in whey at draining were higher for milk from cows in late lactation than from milk from cows in early lactation. The typical differences in fatty acid composition of milk from cows in early lactation that cause lower melting point may have caused higher fat loss in press whey. Fat loss in whey at draining was higher in cheese made from milk from cows milked three times daily than in cheese made from milk from cows milked twice daily, but the protein loss was not influenced. The ADV of milk was positively correlated to the fat loss in whey. Lower recoveries of fat and protein in cheese from milk of cows in late lactation were observed and may cause small but economically important decreases in cheese yield. Low SCC of milk from cows in late lactation may have minimized the changes in cheese composition and yield from stage of lactation.