384 research outputs found
Genetic parameters of french beef breeds used in crossbreeding for young bull production. II. – Slaughter performance
Two sets of slaughter data at constant weight of 3098 and 699 crossbred young bulls from 199 and 42 sires of different French beef breeds, tested in 2 stations, were used to estimate the genetic parameters of carcass criteria (carcass yield, composition, morphology and meat quality). Composition criteria included fattening scores and fat and muscle contents estimated by dissection of the 11th rib. Carcass morphology was estimated by carcass length, beef conformation criteria (fleshiness score, thigh compactness) and by rib eye area. Meat quality was measured on the longissimus dorsi muscle (shearing force, pH and water loss). Genetic parameters were computed from paternal and residual components of variances and covariances estimated in mixed models by HENDERSON'S method 3. Only dressing percentage showed non-homogeneous coefficients of heritability between the 2 data sets : .27 and .69. Mean coefficients of heritability were .27 for fattening scores, .27 for beef conformation criteria and .51 for carcass length. Coefficients of heritability were .54 and .50 for carcass fat and muscle contents, .33 for rib eye area, .30 for shearing force, .11 for pH and .08 for water loss. The genetic coefficients of correlation were quite homogeneous between the 2 files for some groups of variables. There were positive genetic relationships between live fleshiness score and beef conformation criteria of the carcass and between all these criteria and dressing percentage. Growth rate during fattening was slightly opposed to these criteria of beef conformation and yield. While in both data sets fatness developed later in animals with greater skeletal development and higher birth weight, genetic correlations between carcass composition and the other variables were different between the 2 sets. However it can be concluded that while the simultaneous improvement of growth potential and carcass beef conformation does not theoreticaly require evaluating slaughtered progeny, it should be done to limit the probable increase of fatness precocity following such selection.Deux fichiers de résultats d’abattage à poids constant de 3 098 et 699 taurillons croisés, descendants de 199 et 42 pères de différentes races à viande françaises et contrôlés dans 2 stations, ont été utilisés pour estimer les paramètres génétiques des performances d’abattage (rendement, composition et morphologie de la carcasse, qualité de la viande). La composition de la carcasse est analysée à partir des notes d’état d’engraissement et des teneurs en gras et en muscle estimées à partir de la dissection de la 11e côte. La morphologie de la carcasse est appréhendée par sa longueur et par des critères de conformation bouchère (note de charnure, compacité de la cuisse et de la surface du muscle long dorsal). Sur ce muscle des mesures de qualité de la viande ont également été effectuées (force de cisaillement, pH, perte en eau). Les paramètres génétiques ont été calculés à partir des composantes paternelles et résiduelles des variances et covariances, estimées dans des modèles mixtes par la méthode 3 d’HENDERSON. Seul le rendement ne présente pas de coefficient d’héritabilité homogène entre les 2 fichiers : 0,27 et 0,69. Les coefficients d’héritabilité moyens sont de 0,27 pour les notes d’état d’engraissement, 0,27 pour les critères de conformation bouchère, 0,51 pour la longueur de la carcasse. Les coefficients d’héritabilité sont de 0,54 et 0,50 pour les teneurs en gras et en muscle de la carcasse, 0,33 pour la surface du muscle long dorsal, 0,30 pour la force de cisaillement, 0,11 pour le pH et 0,08 pour la perte en eau. Les coefficients de corrélation génétique sont assez homogènes entre les 2 fichiers pour certains groupes de variables. Il apparaît ainsi des liaisons génétiques positives marquées entre le pointage de la charnure en vif et les critères de conformation bouchère de la carcasse et entre tous ces critères et le rendement à l’abattage. La vitesse de croissance pendant l’engraissement est légèrement opposée à ces critères de conformation bouchère et de rendement. Alors que dans les 2 fichiers les dépôts adipeux ont un développement plus tardif chez les animaux à grand développement squelettique et poids de naissance élevé, les corrélations génétiques entre la composition des carcasses et les autres variables sont différentes entre les 2 fichiers. Toutefois à la vue de ces résultats il est possible de conclure que si l’amélioration simultanée du potentiel de croissance et de la conformation bouchère de la carcasse ne nécessite théoriquement pas la réalisation d’un contrôle sur descendants abattus, par contre celui-ci s’avère nécessaire pour limiter l’augmentation prévisible de la précocité des dépôts adipeux à la suite d’une telle sélection
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Estimating Effects of Poverty on the Survival of HIV Patients on ART and Food Supplementation in Rural Haiti: A Comparative Evaluation of Socio-Economic Indicators
Background: Because economic conditions are both a risk factor for disease and may themselves be objectives for health delivery interventions, monitoring changes in economic outcomes has become a routine priority for health and development efforts. However, the lack of formal commerce in poor agrarian communities creates challenges for measuring economic status. Data on household finances, such as income, are ideal but are time-consuming, costly, and less reliable, whereas proxy measures of wealth such as indices of durable assets are easier to measure but relatively coarse and are less sensitive to rapid changes in underlying drivers.
Methods: We used data from a cohort of 528 people living with HIV/AIDS (PLHA) enrolled in a food intervention study on household demographics, agricultural production, cash income, in-kind income, household durable assets and health status, including CD4 count. We created a household economic index using principal components analysis (PCA) and compared it with three other economic indicators generated from the data (income, expenditures, poverty score). Through multivariate logistic regression analysis we evaluated the effect of the economic metric on probability of survival within the first year of study.
Results: Socioeconomic status determined by PCA of durable assets, weighted by the square root of the household size, was the only consistently significant economic predictor of probability of death. It remained significant even after controlling for direct health indicators such as CD4 count. There was no significant correlation between CD4 count and the economic indicators, which may be attributable to uniform access to ART among study participants.
Conclusion: Among people who have HIV and are all enrolled in ART and food programs, household socioeconomic status is an important predictor of mortality rates, even after controlling for direct health measurements such as CD4 count and other health-related covariates. The SES indicator from PCA is also a simple metric to estimate. The study underscores that poverty is a social determinant of mortality even in the context of equal access to health services, and is suggestive of the importance of poverty alleviation activities as an important supplement to clinical interventions
Genetic parameters of beef traits of Limousin and Charolais progeny-tested AI sires
Sire selection efficiency depends on the knowledge of accurate genetic parameters. In France, artificial insemination (AI) sires are selected according to their own performances and those of their progeny, which are both recorded in test stations. Genetic parameters among progeny traits were estimated using multi-trait REML ( restricted estimation of maximum likelihood) analyses in Charolais and Limousin breeds. The expected decrease in genetic variability algebraically calculated among progeny traits due to the selection of sires was not observed. This selection was not a strict truncation. Heritabilities of traits measured on progeny are moderate for growth traits, morphology and live fatness scores (from 0.14 to 0.38) and slightly higher for dressing percentage and carcass fatness score (0.50 and 0.44, respectively). Genetic correlations among progeny traits depended on traits, selection programme and breed. Carcass weight and morphology were highly genetically linked to corresponding live traits (live weight and conformation, respectively). They can, therefore, be easily improved through indirect selection in contrast to carcass fatness which has only a small genetic correlation with live traits
Genetic variability of muscle biological characteristics of young Limousin bulls
Genetic parameters of 4 muscle biological characteristics (protein to DNA ratio (Pro/DNA), lactate dehydrogenase (LDH) activity, isocitrate dehydrogenase (ICDH) activity and the proportion of type I myosin heavy chains (MHC I)), in the Semitendinosus and the Longissimus thoracis, were estimated simultaneously with average daily gain (ADG), 480-d final weight (FW), carcass lean and fat contents (CL% and CF% respectively) in a sample of young Limousin bulls tested in station. The data came from 144 animals, the progeny of 15 sires. Sire and residual variances and covariances were estimated u using an expectation maximization restricted maximum likelihood (EM-REML) procedure applied to a multitrait mixed model. Heritability coefficients of production traits, ADG, FW, CL% and CF%, were 0.19, 0.49, 0.39 and 0.43, respectively, while heritability coefficients of muscle characteristics, Pro/DNA, LDH, ICDH and MHC I, were 0.11, 0.26, 1.03 and 0.35 respectively, in the Semitendinosus muscle and 0.29, 0.31, 0.28 and 0.41, respectively, in the Longissimus thoracis muscle. In both muscles, the oxidative activity of the ICDH appeared to be genetically associated with the proportion of type I myosin heavy chains and opposed to the glycolytic activity of the LDH. The LDH activity was clearly associated with higher muscle-to-fat ratio, while the opposite relationship was observed between that ratio and the ICDH activity or the MHC I proportion.Les paramètres génétiques de 4 caractéristiques biologiques - le rapport protéines /ADN (Pro/DNA), les activités de la lactate déshydrogénase (LDH) et de l’isocitrate déshydrogénase (ICDH) et la proportion en chaînes lourdes de myosine lente (MHC I) - des muscles Semitendinosus et Longissimus thoracis, et ceux du gain moyen quotidien (ADG), du poids vif finaL à 480 j (FW) et des teneurs de la carcasse en muscles et en dépôts adipeux (CL% and CF% respectivement), ont été estimés simultanément à partir d’un échantillon de taurillons Limousins contrôlés en station. Le fichier comprenait 144 veaux issus de 15 pères testés sur descendance. Les variances et covariances paternelles et résiduelles ont été estimées par la méthode du maximum de vraisemblance restreinte, avec l’algorithme d’espérance-maximisation, appliquée à un modèle mixte multicaractère (EM-REML). Les coefficients d’héritabilité des variables de production, ADG, FW, CL% et CF%, s’élevaient respectivement à 0,19, 0,49, 0,39 et 0,43, tandis que les coefficients d’héritabilité des caractéristiques musculaires, Pro/DNA, LDH, ICDH et MHC I, valaient respectivement 0,11, 0,26, 1,03 et 0,35 dans le muscle Semitendinosus et 0,29, 0,31, 0,28 et 0,41 dans le muscle Longissimus thoracis. Dans les 2 muscles, l’activité oxidative de l’ICDH était génétiquement associée à la proportion de myosine lente et opposée à l’activité glycolytique du LDH. Cette activité du LDH était positivement corrélée avec le rapport muscles / dépôts adipeux, alors qu’une relation inverse était observée avec l’activité de l’ICDH et la proportion de MHC I
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