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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Estimativas de parâmetros genéticos de características de carcaças feitas por ultra-sonografia em bovinos da raça Nelore / Genetic parameters for carcass traits measured trough ultrasound in Nelore cattle

Figueiredo, Luís Gustavo Girardi 24 May 2001 (has links)
O presente trabalho teve como objetivo estimar parâmetros genéticos de características de carcaças feitas por ultra-sonografia em bovinos da raça Nelore bem como as suas correlações genéticas com características de desenvolvimento ponderal e com escores visuais. Os dados coletados pertencem a três fazendas, duas pertencentes a Agropecuária CFM (Rebanho 1) que foram analisadas em conjunto com 1696 animais e uma pertencente a Manah Agropastoril Ltda. com 951 animais (rebanho 2). As características analisadas foram: área de olho de lombo (AOL), espessura de gordura subcutânea (EGS), peso a desmama (PESDES), ganho de peso da esmama ao sobreano (GP345), peso ao sobreano (PESSOB) e altura (ALT). E os escores visuais analisados foram: musculosidade (MUSC), conformação (CONF) e precocidade (PREC). Os componentes de (co)variância foram estimados por verossimilhança restrita, utilizando-se o software MTDFREML. Foram realizadas análises uni-características em que foram estimadas as herdabilidades das características AOL e EGS e análises bi-características em que foram estimadas as correlações genéticas das características de AOL e EGS com as características de desempenho ponderal e escores visuais. As estimativas herdabilidades para AOL foram de 0,19 (rebanho 1) e de 0,41 (rebanho 2), para a EGS foram de 0,04 (rebanho 1) e de 0,19 (rebanho 2). Estas herdabilidades sugerem que as características são passíveis de seleção. São sugeridos estudos adicionais de estimativas de componentes de (co)variância para medidas de ultra-sonografia para bovinos da raça Nelore. / This research was conducted to estimate variance components and genetic parameters of carcass traits of Nelore cattle, measured through ultrasound equipment, and also the genetic relationship of those traits with growth traits and visual scores. Data came from three different herds. 1,696 animals were measured in two farms owned by Agro-Pecuaria CFM Ltda. (herd 1) and 951 animals were measured at Fazenda Mundo Novo, owned by Manah Agropastoril Ltda. (herd 2). The traits analyzed were: loin-eye are (AOL, cm2), subcutaneous fat thickness (EGS, mm), weaning weight (PESDES, kg), weight gain from weaning to yearling (GP345, kg), yearling weight (PESSOB, kg), and height (ALT, cm). Visual scores were muscle score (MUSC), body conformation (CONF) e precocity (PREC). (Co)variance components were estimated by REML methods, using the software MTDFREML, under single traits (to estimate components for AOL and EGS) and twotraits analysis to estimate genetic correlations among AOL and EGS and the other traits. Heritability estimates for AOL were 0.19 (herd 1) and 0.41 (herd 2). While for EGS the values estimated were 0.04 (herd 1) and 0.19 (herd 2). The heritability coefficients estimated suggest that the traits can be selected. Further studies are suggested as related to (co)variance components estimation for ultrasound measurements in Nelore cattle.
12

Desempenho, composição da carcaça e características de qualidade da carne de suínos de diferentes genótipos /

Monteiro, José Mauro Costa. January 2007 (has links)
Resumo: Objetivou-se comparar genótipos de suínos relativos ao desempenho, parâmetros e características de carcaça e da carne em animais abatidos aos 161 dias de idade. Utilizaram-se os seguintes genótipos: G1 - ½ Topigs© (Toppi) x ½ Naïma®; G2 - ½ DB Danbred© (Frederik) x ½ Naïma®; G3 - ½ PIC© (AGPIC 412) x ½ Naïma®; G4 - ½ SG 2030© (Duroc) x ½ Naïma®; e G5 - ½ Pen Ar Lan© (P76) x ½ Naïma®. Estudaram-se o ganho de peso total (GPT), consumo de ração total (CRT), conversão alimentar (CA) e eficiência alimentar (EA). As meias carcaças esquerdas foram, inicialmente, avaliadas quanto ao peso da carcaça quente (PCQ) e fria (PCF), comprimento (CC), área do olho de lombo (AOL), comprimento de olho do lombo (COL) e profundidade do toucinho (PT10ª). Foram feitas ainda, com a pistola de tipificação eletrônica Hennessy, medidas de espessura do músculo (EM1 e EM2) e profundidade do toucinho (PT1 e PT2). Foram feitas medidas de espessura de toucinho na altura da primeira costela (ET1), última costela (ET2), última lombar (ET3) e máxima lombar (ETM), com o auxílio de paquímetro digital. A carcaça foi desdobrada em seus cortes primários: pernil, carré, barriga, barriga ventral, fraldinha, paleta, sobre paleta, ponta do peito, filezinho, antebraço, perna e papada. Após a pesagem desses cortes, foi realizada a desossa dos mesmos, para se determinar os pesos da carne, gordura interna, ossos, pele e gordura subcutânea de cada um. A porcentagem de carne magra (PCM) foi determinada dividindo-se o total de carne magra desossada pelo peso da carcaça fria. Foram estudados os seguintes parâmetros físico-químicos da carne: pH post-mortem, perda de líquido por gotejamento, cor da carne, ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this work it was to compare different swine genotypes with the performance, characteristics of carcass and meat quality in swine slaughtered at 161 days of age. The following genotypes had been used: G1 - ½ Topigs© (Toppi) x ½ Naïma©; G2 - ½ DB Danbred© (Frederik) x ½ Naïma©; G3 - ½ PIC© (AGPIC 412) x ½ Naïma©; G4 - ½ SG 2030© (Duroc) x ½ Naïma©; e G5 - ½ Pen Ar Lan© (P76) x ½ Naïma©. They had been studied the profit of all up weight (BW), consumption of total ration (CTR), feed conversion (FC) and alimentary efficiency (AE). The half left carcasses had been, initially, evaluated to the hot carcass weight (HCW) and cold weight (CCW), carcass length (CL), loin eye area (LEA), loin eye length (LEL) and backfat thickness in tenth rib (BT10th). They had been made still, with the pistol electronic Hennessy, measures of muscle depth (MD1 and MD2) and fat depth (FD1 and FD2). Backfat thickness was measured at four locations: in the first rib (BT1), last rib (BT2), last lumbar (BT3) and maximum lumbar (BTM), with digital paquimeter. The carcass was unfolded in these cuts: ham, loin, belly, ventral belly, cranial belly, shoulder, neck, jowl, tenderloin, front shank, hind shank and cheek. After the weight of these cuts, the composition of each one was determined by physical dissection into lean, fat, bone, and skin. The lean meat percentage (LMP) was determined, dividing the total of boned lean meat by the weight of the cold carcass. The following parameters had been studied in the meat: pH post-mortem, ...(Complete abstract click electronic access below) / Orientador: Jeffrey Frederico Lui / Coorientador: Expedito Tadeu Facco Silveira / Banca: Pedro Eduardo de Felício / Banca: Roberto de Oliveira Roça / Banca: Otto Mack Junqueira / Banca: Hirasilva Borba Alves de Souza / Doutor
13

Estimativas de parâmetros genéticos de características de carcaças feitas por ultra-sonografia em bovinos da raça Nelore / Genetic parameters for carcass traits measured trough ultrasound in Nelore cattle

Luís Gustavo Girardi Figueiredo 24 May 2001 (has links)
O presente trabalho teve como objetivo estimar parâmetros genéticos de características de carcaças feitas por ultra-sonografia em bovinos da raça Nelore bem como as suas correlações genéticas com características de desenvolvimento ponderal e com escores visuais. Os dados coletados pertencem a três fazendas, duas pertencentes a Agropecuária CFM (Rebanho 1) que foram analisadas em conjunto com 1696 animais e uma pertencente a Manah Agropastoril Ltda. com 951 animais (rebanho 2). As características analisadas foram: área de olho de lombo (AOL), espessura de gordura subcutânea (EGS), peso a desmama (PESDES), ganho de peso da esmama ao sobreano (GP345), peso ao sobreano (PESSOB) e altura (ALT). E os escores visuais analisados foram: musculosidade (MUSC), conformação (CONF) e precocidade (PREC). Os componentes de (co)variância foram estimados por verossimilhança restrita, utilizando-se o software MTDFREML. Foram realizadas análises uni-características em que foram estimadas as herdabilidades das características AOL e EGS e análises bi-características em que foram estimadas as correlações genéticas das características de AOL e EGS com as características de desempenho ponderal e escores visuais. As estimativas herdabilidades para AOL foram de 0,19 (rebanho 1) e de 0,41 (rebanho 2), para a EGS foram de 0,04 (rebanho 1) e de 0,19 (rebanho 2). Estas herdabilidades sugerem que as características são passíveis de seleção. São sugeridos estudos adicionais de estimativas de componentes de (co)variância para medidas de ultra-sonografia para bovinos da raça Nelore. / This research was conducted to estimate variance components and genetic parameters of carcass traits of Nelore cattle, measured through ultrasound equipment, and also the genetic relationship of those traits with growth traits and visual scores. Data came from three different herds. 1,696 animals were measured in two farms owned by Agro-Pecuaria CFM Ltda. (herd 1) and 951 animals were measured at Fazenda Mundo Novo, owned by Manah Agropastoril Ltda. (herd 2). The traits analyzed were: loin-eye are (AOL, cm2), subcutaneous fat thickness (EGS, mm), weaning weight (PESDES, kg), weight gain from weaning to yearling (GP345, kg), yearling weight (PESSOB, kg), and height (ALT, cm). Visual scores were muscle score (MUSC), body conformation (CONF) e precocity (PREC). (Co)variance components were estimated by REML methods, using the software MTDFREML, under single traits (to estimate components for AOL and EGS) and twotraits analysis to estimate genetic correlations among AOL and EGS and the other traits. Heritability estimates for AOL were 0.19 (herd 1) and 0.41 (herd 2). While for EGS the values estimated were 0.04 (herd 1) and 0.19 (herd 2). The heritability coefficients estimated suggest that the traits can be selected. Further studies are suggested as related to (co)variance components estimation for ultrasound measurements in Nelore cattle.
14

Arroz integral na dieta de frangos de corte / Whole rice in poultry diets

Souza, Maria Consuelo Silva de 02 May 2012 (has links)
Made available in DSpace on 2014-08-20T14:38:48Z (GMT). No. of bitstreams: 1 dissertacao_maria_consuelo_silva_de_souza.pdf: 1205551 bytes, checksum: 14a81cfa9f2f98f16499fcbb1a656a0b (MD5) Previous issue date: 2012-05-02 / A trial was conducted to evaluate the replacement of corn by whole rice in poultry diets. A total of 384 one day old Coob broilers were used. The chicks were randomly allotted to four treatments and eight replications of 12 birds each. The birds were reared in dark house during 42 days. A completely randomized design was used. Treatment means were compared by orthogonal contrasts and polynomial regression at 5%. The following treatments were tested: T1 100% corn as the main energy source; T2 33% whole rice in replacement of corn; T3 - 66% whole rice in replacement of corn; T4 100% whole rice as the main energy source in full replacement of corn. Body weight, weigh gain, feed consumption and feed per gain ratio were measured. Carcass traits included: thigh and drumstick, back, chest, wing and wing thigh. Birds fed diets containing 33% whole rice in substitution of corn (T2) and also 100% whole rice in substitution of corn (T4) showed a higher average body weight (P<0.01). No significant difference was observed for weigh gain, feed per gain ratio, thigh yield, thigh and drumstick yield, back yield, chest yield, and wing and wing thigh yield. In conclusion, corn can be replaced by whole rice in poultry diets with no negative effects on either performance or carcass traits. / Com o presente trabalho objetivou-se avaliar a substituição do milho por arroz integral na dieta de frangos de corte sobre o desempenho, peso dos cortes e viabilidade econômica, no período de 1 a 42 dias. Foram utilizados 384 pintos da linhagem Cobb de um dia de idade, os quais foram distribuídos ao acaso em quatro tratamentos com oito repetições de 12 animais cada um. As aves foram mantidas em galpão do tipo dark house durante 42 dias. Foi utilizado o delineamento inteiramente casualizado. As médias dos tratamentos foram comparadas por contrastes ortogonais e regressão polinomial a 5%. Quatro dietas diferentes (tratamentos) foram testadas para cada fase de criação: T1 - 100% de milho como principal fonte energética; T2 - 33% de arroz integral em substituição ao milho; T3 - 66% de arroz integral em substituição ao milho; e T4 - 100% de arroz integral, como principal fonte energética, em substituição ao milho. As seguintes variáveis de desempenho foram analisadas: peso corporal, ganho de peso, consumo de ração, conversão alimentar, viabilidade e Índice de Eficiência Produtiva (IEP). Foram também analisados os pesos dos cortes: coxa e sobrecoxa, dorso, peito, asa e coxa da asa. Não foi verificada diferença significativa para as variáveis, peso corporal, ganho de peso, consumo de ração, conversão alimentar, viabilidade, IEP, peso de coxa, peso de sobrecoxa, peso de dorso, peso de peito e peso de asa e coxa da asa no período de 1 a 42 dias. Com base nos dados obtidos a partir do presente estudo pode-se afirmar que a substituição parcial ou total do milho pelo arroz integral na dieta de frangos de corte não altera o desempenho e o peso de cortes das aves.
15

Genetic Analyses of Growth, Carcass and Meat Quality Traits in Maternal Lines of Rabbits and Their Diallel Cross/ Análisis Genético de Caracteres de Crecimiento, Matadero y Calidad de Carne en Lineas Maternales de Conejo y en su Cruzamiento Dialélico

Mínguez Balaguer, Carlos 09 June 2014 (has links)
El gazapo engordado en explotaciones comerciales proviene de un cruzamiento a tres vías, y por tanto su madre (cruce de dos líneas maternales) aporta el 50% de sus genes y es necesario estudiar los caracteres de crecimiento y consumo de pienso de estos gazapos. Por otro lado, existen gran cantidad de estudios que demuestran que la carne de conejo es una carne con poca grasa, poco colesterol y un elevado contenido en proteina, por lo que se debe estudiar estas características se pueden ver afectadas estas como consecuencia de la mejora genética. / Mínguez Balaguer, C. (2014). Genetic Analyses of Growth, Carcass and Meat Quality Traits in Maternal Lines of Rabbits and Their Diallel Cross/ Análisis Genético de Caracteres de Crecimiento, Matadero y Calidad de Carne en Lineas Maternales de Conejo y en su Cruzamiento Dialélico [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/37981 / TESIS
16

Pre-weaning growth performance of hair x mutton sheep crosses and post-weaning growth and physiological reaction in response to different feeding levels and high ambient temperature

Simukali, Willard Lumoma Bboonko 28 March 2001 (has links)
Die Erhöhung der tierischen Leistung von Nutztieren in den Tropen kann am schnellsten durch Kreuzungszucht realisiert werden. Ziel der vorliegenden Arbeit war es, die Leistung von Kamerun-Schafen (C) und Ihren Kreuzungen (Kamerun x Fleischschaf, F1) und (F2 aus Kamerun x Milchschaf) unter verschiedenen Fütterungs- und Haltungsbedingungen zu vergleichen. Folgende Merkmale wurden analysiert: - Wachstum vor dem Absetzen über 90 Tage; 127 Tiere; C, F1 und F2, - Wachstum nach dem Absetzen unter verschiedenen Fütterungsbedingungen; Wechsel vom 1,5-fachen des Erhaltungsbedarfs zu ad libitum Fütterung und umgekehrt; 6 Wochen Dauer; 30 Tiere; C, F1 und F2, - Haltung der Lämmer unter zeitlich begrenztem Temperaturstress (8 Stunden täglich bei 31°C und 50% rel. Luftfeuchte): Dauer 12 Wochen; 10 Tiere C und F, - Analyse von Schlachtkörpern nach Versuchsende jeden Versuches; 40 Lämmer, C, F1 und F2. Ergebnisse: - Während der ersten Aufzugphase zeigten die Kreuzungstiere mit 213g/Tag (F1) und 236 g/Tag (F2) eine um 50 bzw. 65% erhöhte Lebendmassezunahme gegenüber den Kamerun-Lämmern (143g/Tag). Die Differenz zwischen F1 und F2 resultierte aus der unterschiedlichen Milchleistung der Muttertiere. - Der zeitlich begrenzte Hitzestress führte zu keinen unterschiedlichen physiologischen Reaktionen zwischen den Rassen. - Es gab keine signifikanten Unterschiede hinsichtlich der relativen Körperzusammensetzung zwischen den Rassen. Die Kreuzungstiere hatten eine signifikant erhöhte Masse des Verdauungstraktes. Schlußfolgerungen: Kreuzungszucht zwischen indigenen und exotischen Rassen ist in den Tropen eine geeignete Methode die Fleischerzeugung zu erhöhen, allerdings nur, wenn die Futterversorgung gesichert ist. Hitzestress über eine begrenzte Zeit am Tag ist für die getesteten Rassen ohne Leistungseinbußen verträglich. / Crossbreeding between indigenous and exotic sheep breeds is the fastest method of increasing the performance of sheep in the tropics. The aim of this work was to assess the performance of Cameroon sheep (C) and their crossbreds (Cameroon x Mutton, F1) and (F2 from Cameroon x Milk sheep) under different housing and feeding conditions. The following traits were analysed: - Pre-weaning performance during the first 90 days; 127 animals, C, F1 and F2. - Post-weaning growth performance at different feeding levels; changing from 1.5 x maintenance to ad libitum feed intake and vice versa; duration 6 weeks; 30 animals; C, F1 and F2. - Housing of lambs under temporal heat stress (8 hours daily at 31°C and 50% relative humidity); duration 12 weeks; 10 animals, C and F2 - Carcass traits; 40 lambs, C, F1 and F2. Results: - During the pre-weaning period the crossbred lambs showed a higher live weight gain than the Cameroon lambs, 213g/d (F1); 236g/d (F2) and 143g/d (C) respectively, that is an increase of 50% and 65% resp. The differences between the F1 and F2 resulted from the different milk yields of the ewes. - The heat stress over 8 hours did not lead to different physiological reactions between the breeds. - There were no significant differences in the relative carcass traits between the breeds. The GIT-weight was increased significantly in the crossbreds. Conclusion: Crossbreeding of indigenous and exotic sheep breeds is a suitable method for increasing meat production in the tropics if the feed supply is guaranteed. Heat stress over a limited time is not crucial for the performance of all breeds.
17

Évaluation génétique et génomique de nouveaux caractères en bovins laitiers / Genetic and genomic evaluations of new traits in dairy cattle

Croué, Iola 14 November 2017 (has links)
La mise en place de la sélection génomique rend possible l’inclusion de nouveaux caractères dans les objectifs de sélection, en profitant des marges offertes par l’augmentation du progrès génétique sur les caractères historiques. En parallèle, les attentes des éleveurs, de la société et des filières orientent la sélection génétique vers des objectifs plus larges et complexes. Deux groupes de nouveaux caractères ont été analysés dans le cadre de l’amélioration génétique des bovins laitiers : les caractères de carcasse des jeunes bovins de races mixtes et les caractères de résistance aux lésions podales en race Holstein, afin de préparer la mise en place d’une sélection génétique et génomique de ces caractères. Pour ces deux caractères, les modèles d’évaluation polygénique les plus pertinents ont été développés et les paramètres génétiques correspondant ont été estimés. Ces derniers révèlent que la sélection génétique des caractères de carcasse des jeunes bovins sera relativement aisée, alors que celle de la résistance aux lésions podales sera plus difficile, mais possible, du fait de l’existence d’une variabilité génétique. Ils mettent également en évidence qu’un progrès génétique sur les caractères de carcasse des jeunes bovins n’est pas génétiquement opposé à un progrès génétique sur la production laitière. Ils mettent enfin en évidence deux groupes de lésions podales génétiquement distinctes. Par ailleurs, plusieurs stratégies pour prendre en compte la nonexhaustivité des données de lésions podales ont été testées. Plusieurs approches d’évaluation ont été comparées. Pour les deux groupes de caractères, l’approche dite « Single-Step Genomic BLUP » s’est révélée la plus prometteuse, même si les autres approches génomiques « en deux étapes », donnaient des résultats aux caractéristiques relativement proches. Ces études ont mené à la mise en place d’évaluations génétiques et génomiques en routine pour les deux groupes de caractères, pour lesquelles les méthodes d’évaluation classiques ont été retenues par souci de cohérence avec les évaluations actuelles, tout en démontrant l’intérêt d’une évolution vers l’approche en une étape à moyen terme. Les principales questions soulevées et les grandes étapes identifiées lors des études de ces deux caractères ont été rassemblées au sein d’une ébauche de méthodologie pour le développement d’évaluations génétiques pour de nouveaux caractères. / The implementation of genomic selection makes possible the inclusion of new traits in breeding goals, by taking advantage of the opportunities coming from the increased genetic trend on traits currently under selection. Breeders, breeding companies and society all have changing expectations regarding genetic selection. Two groups of new traits were analyzed in the context of genetic improvement of dairy cattle: carcass traits of young bulls in dual-purpose breeds and claw health traits in Holstein, in order to prepare the implementation of genetic and genomic selection on these traits. For both sets of traits, suitable genetic evaluation models were developed and genetic parameters were estimated. Genetic parameters reveal that genetic selection of carcass traits of young bulls appears to be fairly easy and that selection of claw health traits is going to be more difficult, but possible, given the existing genetic variation. They also highlight that there is no strong negative genetic correlation between carcass traits of young bulls and dairy production traits. Finally, they reveal that there are two genetically distinct groups of claw health traits. Several strategies to account for non-exhaustive recording of cows for trimming were tested. Several evaluation approaches were compared. For both sets of traits, Single-Step Genomic BLUP was the most promising approach, although other (two-step) genomic approaches allowed for relatively similar accuracies and control of bias. These studies led to the implementation of routine genetic and genomic evaluations for both sets of traits, for which a usual two-step genomic approach was preferred over Single-Step Genomic BLUP for consistency with the current evaluation of other traits. However these two examples illustrate the benefit of implementing routine Single-Step Genomic BLUP evaluations. The main questions and principal steps identified in these studies were gathered into tentative guidelines for the development of genetic evaluations for new traits.
18

Einfluss von Herkunft und Alter auf Schlachtkörper- und Fleischqualitätsmerkmale von Puten / Effect of line and age on carcass- and meat-quality-traits in turkeys

Riegel, Joachim 01 February 2007 (has links)
No description available.
19

Análise dos índices de classificação de bovinos avaliados em provas de ganho em peso, em confinamento / Analysis of the classification indexes of cattle valued evidence of weight gain in feedlot

MARQUES, Ednira Gleida 15 February 2011 (has links)
Made available in DSpace on 2014-07-29T15:07:32Z (GMT). No. of bitstreams: 1 Ednira Gleida Marques.pdf: 2045120 bytes, checksum: a9d1a7c6c5b3034708f573ea924fba17 (MD5) Previous issue date: 2011-02-15 / Weight gain performance trials (PGP) in feedlot evaluate the weight gain capacity of the animals, making possible the selection based on phenotypical information. Animals are classified based on pondered indexes for productive traits as average daily weight gain, final weight, type or morphological evaluation, scrotal perimeter, ribeye area and fat thickness. Using data from the Brazilian Association of Zebu Breeders (ABCZ), the aim of this study was to evaluate classification indexes of weight gain performance tests applied to Nellore cattle in feedlot, and to estimate the variance components and the genetic correlations among the traits that compose such indexes. Covariance components and genetic parameters were estimated by the animal model commonly applied in the Restricted Maximum Likelihood Model (REML), using MTDFREML software. Heritability estimates for all traits were medium to high. Genetic correlation estimates were low regarding final weight and average daily weight gain, scrotal perimeter and carcass traits. Final weight, ribeye area, average daily weight gain and fat thickness were considered medium. Therefore, major genetic gain can be obtained when using selection indexes aimed at final weight / As provas de ganho em peso (PGP) em regime de confinamento avaliam a capacidade individual dos animais para ganho em peso, fornecendo subsídios para seleção com base na informação fenotípica individual. A partir das informações obtidas durante a PGP, a classificação final dos animais é baseada em índices ponderados para características produtivas como ganho médio diário, peso final, avaliação de tipo ou morfológica, perímetro escrotal, área de olho de lombo e espessura de gordura. Objetivou-se com esse trabalho avaliar os índices de classificação das provas de ganho em peso em regime de confinamento, bem como estimar os componentes de variância e as correlações genéticas entre as características que compõem esses índices. Foram utilizados dados de PGPs da Associação Brasileira dos Criadores de Zebu (ABCZ), referente a raça Nelore. As estimativas dos componentes de (co)variância e parâmetros genéticos foram estimados usando modelos animais comumente aplicados no método de Máxima Verossimilhança Restrita (REML) por meio do aplicativo MTDFREML. As estimativas de herdabilidade para todas as características foram altas. Já as estimativas entre as características peso final e ganho médio diário, perímetro escrotal e características de carcaça foram de baixa magnitude. As estimativas entre peso final e área de olho de lombo, ganho médio diário e espessura de gordura foram consideradas medianas. Os resultados deste trabalho concluíram que ao utilizar os índices de seleção, tendo como objetivo de seleção o peso final, levou a obtenção de maiores valores genéticos.
20

Forage quality, animal performance, and carcass traits of steers finished on winter annual ryegrass (Lolium multiflorum Lam.) pasture with varying levels of corn supplementation

Roberts, Sean David, Kerth, Christopher R. January 2005 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

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