Heritability estimates and genetic correlations for body weight and scrotal circumference adjusted to 12 and 18 months of age for male Nellore cattle

Heritability estimates and genetic correlations were obtained for body weight and scrotal circumference, adjusted, respectively, to 12 (BW12 and SC12) and 18 (BW18 and SC18) months of age, for 10 742 male Nellore cattle. The adjustments to SC12 and SC18 were made using a nonlinear logistic function, while BW12 and BW18 were obtained by linear adjustment. The contemporary groups (CGs) were defined from animals born on the same farm, in the same year and birth season. The mean heritability estimates obtained using the restricted maximum likelihood method in bi-trait analysis were 0.25, 0.25, 0.29 and 0.42 for BW12 BW18, SC12 and SC18, respectively. The genetic correlations were 0.30 +/- 0.11, 0.21 +/- 0.13, 0.21 +/- 0.11, -0.08 +/- 0.15, 0.16 +/- 0.12 and 0.89 +/- 0.04 between the traits BW12 and BW18; BW12 and SC12; BW12 and SC18; BW18 and SC12; BW18 and SC18; and SC12 and SC18. The heritability for SC18 was considerably greater than for SC12 suggesting that this should be included as a selection criterion. The genetic correlation between BW18 and SC12 was close to zero, indicating that these traits did not influence each other The contrary occurred between SC12 and SC18, indicating that selection using one of these could alter the other Because of the mean magnitudes of heritabilities in the various measurements of weight and scrotal perimeter it is suggested that the practice of individual selection for these traits is possible.

Factores que influenciam o peso e crescimento de cabritos da raça Murciana-granadina, em aleitamento artificial

A exploração caprina de leite tem evoluído no sentido de alguma intensificação, com recurso a raças de elevado potencial produtivo, de que é exemplo a raça Murciana- Granadina. O leite constitui a principal fonte de receita destas explorações. Complementarmente, vendem animais para carne e, as de melhor nível genético, animais para reprodutores. Analisaram-se os pesos de 241 cabritos da raça Murciana-Granadina, numa exploração comercial, com o objectivo de quantificar os pesos e crescimento de cabritos, e identificar os factores que os influenciam. Os cabritos foram aleitados artificialmente, em regime ad libitum, com leite de substituição comercial, dispondo ainda de concentrado comercial, feno de luzerna e palha. Os cabritos foram pesados ao nascimento e, posteriormente, semanalmente, até aos 60 dias de idade. Calcularam-se os respetivos pesos ajustados, bem como os ganhos médios diários, a diferentes idades padrão. Procedeu-se a uma análise de variância com um modelo linear que incluiu os efeitos da época de parto, tipo de parto, sexo e idade da cabra. Foram registados pesos superiores nos partos simples e duplos, relativamente aos triplos, e nos machos, relativamente às fêmeas. Os ganhos médios diários, a partir do mês de idade, registaram valores inferiores na época inverno-primavera, comparativamente com a época primavera-verão. Dairy goat farming has evolved towards intensification, with increased use of high milk-yielding breeds, including the Murciano-Granadina breed. Milk is the main source of farm income. Secondary income sources are the sale of animals for meat and, in genetically superior herds, the sale of breeding animals. The weights of 241 commercial farms artificially reared Murciano-Granadina kids were analyzed with the objective of quantifying weight and growth and identifying variation factors. Kids were artificially reared to weaning, on ad libitum commercial milk replacer, commercial concentrate, lucerne hay and straw. Kids were weighed at birth and at weekly intervals until 60 days of age. Age adjusted weights and growth-rates were calculated. A variance analysis was performed with a model including the effects of season of birth, number of kids per kidding, sex and age of dam. Single and twin-born kids had higher weights than triplets, and males had higher weights than females. Average daily gain after one month of age was lower for kids born in winter-spring than for those born in spring-summer

Manejo reprodutivo pós-parto de vacas primíparas e desenvolvimento de terneiros

O trabalho teve por objetivo avaliar os efeitos de cargas animais de 240 e 320 kg PV/ha em campo nativo (T1 e T2, respectivamente), de 400 kg PV/ha em pastagem melhorada com azevém (Lolium multiflorum L.) por 80 dias pós-parto e, após, carga animal igual a T2 em campo nativo (T3), e do desmame dos terneiros aos 100 dias (DP) ou aos 180 dias (DC) de idade sobre o desempenho reprodutivo de vacas de corte primíparas Hereford e Braford, e sobre o desenvolvimento de seus terneiros. A taxa de prenhez (TP) não foi influenciada (P>0,05) pelos tratamentos (T1 = 93,8%; T2= 90,6%; T3= 100%), nem pela idade de desmame (DP= 97,8%; DC= 91,3%). Houve efeito significativo dos tratamentos (P<0,05) sobre a TP aos 21 dias (T1= 15,6%; T2= 0,0%; T3= 17,9%) e aos 42 dias (T1= 46,9%; T2= 37,5%; T3= 71,4%) após iniciada a estação de acasalamento. O intervalo entre partos (IEP) e o intervalo parto-concepção (IPC) foram influenciados (P<0,01) pelos tratamentos. O IEP e o IPC para T1, T2 e T3 foram 390,9; 399,0 e 386,8 dias e 105,9; 114,0 e 101,8 dias, respectivamente Terneiros filhos de vacas Braford no T2 foram mais pesados ao desmame (P<0,05) do que terneiros filhos de vacas da mesma raça no T1 e filhos de vacas Hereford no T2. Os terneiros do DP tiveram pesos ajustados aos 180 dias menores (P<0,01) do que os do DC (174,6 kg vs. 197,2 kg, respectivamente). Não houve efeito (P>0,05) dos tratamentos, nem da idade de desmame sobre o peso dos terneiros aos 365 dias de idade. Os novilhos do DP tiveram pesos de abate e de carcaça, aos 14 meses, inferiores (P<0,01) aos novilhos do DC. Entretanto, o ganho de peso e o rendimento de carcaça dos novilhos do DP foram superiores (P<0,01) aos novilhos do DC. Não houve efeito (P>0,05) da idade de desmame sobre a espessura de gordura subcutânea.

Abordagens freqüentista e bayesiana para avaliação genética de bovinos da raça Canchim para características de crescimento

This study aimed to: a) to compare the covariance components obtained by Restricted Maximum Likelihood (REML) and by bayesian inference (BI): b) to run genetic evaluations for weights of Canchim cattle measured at weaning (W240) and at eighteen months of age (W550), adjusted or not to 240 and 550 days of age, respectively, using the mixed model methodology with covariance components obtained by REML or by BI; and c) to compare selection decisions from genetic evaluations using observed or adjusted weights and by REML or BI. Covariance components, heritabilities and genetic correlation for W240 and W550 were estimated and the predicted breeding values were used to select 10% and 50% of the best bulls and cows, respectively. The covariance components obtained by REML were smaller than the a posteriori means obtained by Bl. Selected animals from both procedures were not the same, probably because the covariance components and genetic parameters were different. The inclusion of age of animal at weighing as a covariate in the statistical model fitted by BI did not change the selected bulls and cows.

Análise da heterogeneidade de variância em características de crescimeno de bovinos da raça nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da interação genótipo-ambiente em rebanhos da raça Nelore na Amazônia Legal

Dados de pesos padronizados aos 120 (P120), 210 (P210), 450 (P450) dias de idade, perímetro escrotal aos 450 dias de idade (PE450) e idade ao primeiro parto (IPP), de 211.744 registros de animais Nelore, provenientes de fazenda localizadas na região da Amazônia Legal, foram utilizados na análise. O efeito da interação genótipo-ambiente foi estudado por meio de estimativas de herdabilidade e de correlações entre classificações, comparando os animais da Amazônia Legal com a base geral de animais do PMGRN – Nelore Brasil. As análises bi-característica consideraram o P120 como característica-âncora, com P210, P450 e PE450. O modelo de análise considerou grupo de contemporâneos de P120, P210, P450 e da classe de idade da vaca ao parto (CIVP) como efeitos fixos e os efeitos aleatórios genéticos aditivos diretos, maternos e residuais. Nas análises de P120 com P450 e com PE450 foi desconsiderado o efeito materno no modelo. A covariância aditivo-materna foi fixada em zero, conforme protocolo estabelecido nas análises do PMGRN – Nelore Brasil. A característica IPP foi analisada separadamente, em análise de característica única e considerando como efeito fixo o GCIPP e como aleatórios os efeitos aditivos genéticos e residual. Para realizar a comparação entre classificações, por meio do procedimento PROC CORR opção spearman do SAS. As estimativas de herdabilidade para P120, P210, P450, PE450 e IPP nos dados da Amazônia Legal foram: 0,20 a 0,49; 0,21; 0,48; 0,45 e 0,21, respectivamente, e nos dados gerais do PMGRN – Nelore Brasil foram: 0,23; 0,25; 0,34; 0,43 e 0,11, respectivamente. As correlações entre classificações de rank para P120, P210, P450, PE450 e IPP foram iguais a 0,77; 0,79; 0,82; 0,78 e 0,38, respectivamente. As análises da interação genótipo-ambiente evidenciaram maiores efeitos sobre os aspectos maternos, de peso ao sobreano e IPP, enquanto que as correlações entre classificações mostraram fortes evidências de interação genótipo-ambiente em quase todas as características estudadas.

Estudo do peso metabólico e índice de Kleiber na estimação de parâmetros genéticos de características ponderais em uma população de bovinos de raça brahman

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: A systematic analysis for the Global Burden of Disease Study 2010

BACKGROUND Measuring disease and injury burden in populations requires a composite metric that captures both premature mortality and the prevalence and severity of ill-health. The 1990 Global Burden of Disease study proposed disability-adjusted life years (DALYs) to measure disease burden. No comprehensive update of disease burden worldwide incorporating a systematic reassessment of disease and injury-specific epidemiology has been done since the 1990 study. We aimed to calculate disease burden worldwide and for 21 regions for 1990, 2005, and 2010 with methods to enable meaningful comparisons over time. METHODS We calculated DALYs as the sum of years of life lost (YLLs) and years lived with disability (YLDs). DALYs were calculated for 291 causes, 20 age groups, both sexes, and for 187 countries, and aggregated to regional and global estimates of disease burden for three points in time with strictly comparable definitions and methods. YLLs were calculated from age-sex-country-time-specific estimates of mortality by cause, with death by standardised lost life expectancy at each age. YLDs were calculated as prevalence of 1160 disabling sequelae, by age, sex, and cause, and weighted by new disability weights for each health state. Neither YLLs nor YLDs were age-weighted or discounted. Uncertainty around cause-specific DALYs was calculated incorporating uncertainty in levels of all-cause mortality, cause-specific mortality, prevalence, and disability weights. FINDINGS Global DALYs remained stable from 1990 (2·503 billion) to 2010 (2·490 billion). Crude DALYs per 1000 decreased by 23% (472 per 1000 to 361 per 1000). An important shift has occurred in DALY composition with the contribution of deaths and disability among children (younger than 5 years of age) declining from 41% of global DALYs in 1990 to 25% in 2010. YLLs typically account for about half of disease burden in more developed regions (high-income Asia Pacific, western Europe, high-income North America, and Australasia), rising to over 80% of DALYs in sub-Saharan Africa. In 1990, 47% of DALYs worldwide were from communicable, maternal, neonatal, and nutritional disorders, 43% from non-communicable diseases, and 10% from injuries. By 2010, this had shifted to 35%, 54%, and 11%, respectively. Ischaemic heart disease was the leading cause of DALYs worldwide in 2010 (up from fourth rank in 1990, increasing by 29%), followed by lower respiratory infections (top rank in 1990; 44% decline in DALYs), stroke (fifth in 1990; 19% increase), diarrhoeal diseases (second in 1990; 51% decrease), and HIV/AIDS (33rd in 1990; 351% increase). Major depressive disorder increased from 15th to 11th rank (37% increase) and road injury from 12th to 10th rank (34% increase). Substantial heterogeneity exists in rankings of leading causes of disease burden among regions. INTERPRETATION Global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with disability. In sub-Saharan Africa, however, many communicable, maternal, neonatal, and nutritional disorders remain the dominant causes of disease burden. The rising burden from mental and behavioural disorders, musculoskeletal disorders, and diabetes will impose new challenges on health systems. Regional heterogeneity highlights the importance of understanding local burden of disease and setting goals and targets for the post-2015 agenda taking such patterns into account. Because of improved definitions, methods, and data, these results for 1990 and 2010 supersede all previously published Global Burden of Disease results.

Common values in assessing health outcomes from disease and injury: Disability weights measurement study for the Global Burden of Disease Study 2010

BACKGROUND Measurement of the global burden of disease with disability-adjusted life-years (DALYs) requires disability weights that quantify health losses for all non-fatal consequences of disease and injury. There has been extensive debate about a range of conceptual and methodological issues concerning the definition and measurement of these weights. Our primary objective was a comprehensive re-estimation of disability weights for the Global Burden of Disease Study 2010 through a large-scale empirical investigation in which judgments about health losses associated with many causes of disease and injury were elicited from the general public in diverse communities through a new, standardised approach. METHODS We surveyed respondents in two ways: household surveys of adults aged 18 years or older (face-to-face interviews in Bangladesh, Indonesia, Peru, and Tanzania; telephone interviews in the USA) between Oct 28, 2009, and June 23, 2010; and an open-access web-based survey between July 26, 2010, and May 16, 2011. The surveys used paired comparison questions, in which respondents considered two hypothetical individuals with different, randomly selected health states and indicated which person they regarded as healthier. The web survey added questions about population health equivalence, which compared the overall health benefits of different life-saving or disease-prevention programmes. We analysed paired comparison responses with probit regression analysis on all 220 unique states in the study. We used results from the population health equivalence responses to anchor the results from the paired comparisons on the disability weight scale from 0 (implying no loss of health) to 1 (implying a health loss equivalent to death). Additionally, we compared new disability weights with those used in WHO's most recent update of the Global Burden of Disease Study for 2004. FINDINGS 13,902 individuals participated in household surveys and 16,328 in the web survey. Analysis of paired comparison responses indicated a high degree of consistency across surveys: correlations between individual survey results and results from analysis of the pooled dataset were 0·9 or higher in all surveys except in Bangladesh (r=0·75). Most of the 220 disability weights were located on the mild end of the severity scale, with 58 (26%) having weights below 0·05. Five (11%) states had weights below 0·01, such as mild anaemia, mild hearing or vision loss, and secondary infertility. The health states with the highest disability weights were acute schizophrenia (0·76) and severe multiple sclerosis (0·71). We identified a broad pattern of agreement between the old and new weights (r=0·70), particularly in the moderate-to-severe range. However, in the mild range below 0·2, many states had significantly lower weights in our study than previously. INTERPRETATION This study represents the most extensive empirical effort as yet to measure disability weights. By contrast with the popular hypothesis that disability assessments vary widely across samples with different cultural environments, we have reported strong evidence of highly consistent results.

Cross-national compartability of burden of disease estimates:the European disability weights project

Objective: To investigate the sources of cross-national variation in disability-adjusted life-years (DALYs) in the European Disability
Weights Project.

Methods: Disability weights for 15 disease stages were derived empirically in five countries by means of a standardized procedure and the cross-national differences in visual analogue scale (VAS) scores were analysed. For each country the burden of dementia in women, used as an illustrative example, was estimated in DALYs. An analysis was performed of the relative effects of cross-national variations in demography, epidemiology and disability weights on DALY estimates.

Findings: Cross-national comparison of VAS scores showed almost identical ranking orders. After standardization for population size and age structure of the populations, the DALY rates per 100 000 women ranged from 1050 in France to 1404 in the Netherlands. Because of uncertainties in the epidemiological data, the extent to which these differences reflected true variation between countries was difficult to estimate. The use of European rather than country-specific disability weights did not lead to a significant change in the burden of disease estimates for dementia.

Conclusions: Sound epidemiological data are the first requirement for burden of disease estimation and relevant between-countries comparisons. DALY estimates for dementia were relatively insensitive to differences in disability weights between European countries.

Equity weights in the allocation of health care: the rank-dependent QALY model

This paper introduces the rank-dependent quality-adjusted life-years (QALY) model, a new method to aggregate QALYs in economic evaluations of health care. The rank-dependent QALY model permits the formalization of influential concepts of equity in the allocation of health care, such as the fair innings approach, and it includes as special cases many of the social welfare functions that have been proposed in the literature. An important advantage of the rank-dependent QALY model is that it offers a straightforward procedure to estimate equity weights for QALYs. We characterize the rank-dependent QALY model and argue that its central condition has normative appeal. (C) 2003 Elsevier B.V. All rights reserved.

The sample complexity of pattern classification with neural networks: the size of the weights is more important than the size of the network

Sample complexity results from computational learning theory, when applied to neural network learning for pattern classification problems, suggest that for good generalization performance the number of training examples should grow at least linearly with the number of adjustable parameters in the network. Results in this paper show that if a large neural network is used for a pattern classification problem and the learning algorithm finds a network with small weights that has small squared error on the training patterns, then the generalization performance depends on the size of the weights rather than the number of weights. For example, consider a two-layer feedforward network of sigmoid units, in which the sum of the magnitudes of the weights associated with each unit is bounded by A and the input dimension is n. We show that the misclassification probability is no more than a certain error estimate (that is related to squared error on the training set) plus A3 √((log n)/m) (ignoring log A and log m factors), where m is the number of training patterns. This may explain the generalization performance of neural networks, particularly when the number of training examples is considerably smaller than the number of weights. It also supports heuristics (such as weight decay and early stopping) that attempt to keep the weights small during training. The proof techniques appear to be useful for the analysis of other pattern classifiers: when the input domain is a totally bounded metric space, we use the same approach to give upper bounds on misclassification probability for classifiers with decision boundaries that are far from the training examples.