Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-11-17T16:39:06Z No. of bitstreams: 2 flaviana_miranda_goncalves.pdf: 300142 bytes, checksum: 2ec2cd0e2beed3299f69e5cdd73e9002 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-11-17T16:39:31Z (GMT) No. of bitstreams: 2 flaviana_miranda_goncalves.pdf: 300142 bytes, checksum: 2ec2cd0e2beed3299f69e5cdd73e9002 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2015-11-17T16:39:31Z (GMT). No. of bitstreams: 2 flaviana_miranda_goncalves.pdf: 300142 bytes, checksum: 2ec2cd0e2beed3299f69e5cdd73e9002 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 2011-07-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se com este estudo realizar a avalia??o gen?tica do crescimento de codornas de corte utilizando modelos de regress?o aleat?ria. Os dados utilizados s?o provenientes de 28.076 observa??es mensuradas em 4.507 codornas de corte de uma linhagem f?mea (LF1) pertencente ao Programa de Melhoramento Gen?tico de Codornas do Departamento de Zootecnia da Universidade Federal dos Vales do Jequitinhonha e Mucuri, em Diamantina/ MG. A caracter?stica peso corporal das codornas foi mensurada ao nascimento, aos 7, 14, 21, 28, 35 e 42 dias de idade, e avaliada por meio de modelos de regress?o aleat?ria. Nas an?lises, seis diferentes classes de vari?ncia residual, de homog?nea a heterog?nea, foram consideradas, segundo diferentes idades: Classe 1: vari?ncia residual homog?nea; Classe 2: vari?ncia residual heterog?nea em dois per?odos; Classe 3: vari?ncia residual heterog?nea em tr?s per?odos; Classe 4: vari?ncia residual heterog?nea em quatro per?odos; Classe 5: vari?ncia residual heterog?nea em cinco per?odos e, Classe 6: vari?ncia residual heterog?nea em seis per?odos. Cada classe foi testada com diferentes ordens de ajuste das fun??es polinomiais de Legendre, as quais variaram de segunda ? sexta ordem, para averiguar qual o modelo (classe de heterogeneidade de vari?ncia juntamente com a ordem de polin?mio de Legendre) apresentou o melhor ajuste para descrever as estruturas de (co)vari?ncias em fun??o do tempo (idade das codornas). De acordo com todos os crit?rios avaliados (AIC ? Crit?rio de Informa??o de Akaike, BIC ? crit?rio de Informa??o Bayesiano de Schwarz e LRT ? teste da raz?o de verossimilhan?a), o modelo com seis classes de vari?ncias residuais e de sexta ordem do polin?mio de Legendre foi o que apresentou o melhor ajuste, dado pelos menores valores de AIC e BIC, al?m de LRT significativo. Verificou-se que, com o aumento da idade das codornas, todas as vari?ncias apresentaram tend?ncia de crescimento. A estimativa de vari?ncia gen?tica aditiva aumentou do nascimento at? os 35 dias de idade, apresentando ligeira queda dos 35 aos 42 dias. As herdabilidades estimadas foram decrescentes ao longo da curva de crescimento, variando de 0,51 (1 dia) a 0,16 (42 dias). As estimativas de correla??es gen?ticas e de ambiente permanente de animal entre os pesos nas v?rias idades foram sempre altas e positivas, exceto para peso ao nascimento. No estudo do crescimento das codornas de corte, recomenda-se adotar seis classes (uma para cada semana de idade) de heterogeneidade de vari?ncia, juntamente com a utiliza??o de polin?mios de Legendre de sexta ordem. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011. / ABSTRACT The objective of this study was the genetic evaluation of the growth of quails using random regression models. The data used come from 28.076 observations measured in 4507 quails of a female line (LF1) belonging to the Quail Breeding program of the Animal Science Department of the University of the Jequitinhonha and Mucuri Valleys in Diamantina, MG. The characteristic of quails body weight of was measured at birth, 7, 14, 21, 28, 35 and 42 days years old. The analysis were made using random regression models, where six different classes of residual variance, heterogeneous or homogeneous, were considered, according to different age groups: Class 1: homogeneous residual variance, Class 2: heterogeneous residual variance in two periods, Class 3: heterogeneous residual variance into three periods: Class 4: heterogeneous residual variance in four periods, Class 5: heterogeneous residual variance in five periods, and Class 6: heterogeneous residual variance in six periods. Each class was tested with different orders of fit to Legendre polynomial functions, which ranged from second to sixth order, to determine which model (class of variance heterogeneity with the Legendre polynomial order) presented the best fit to describe (co)variances structures as a function of time (age of the quail). According to all five criteria (AIC - Akaike information criterion, BIC - Bayesian information criterion of Schwarz and LRT - likelihood ratio test), the model with six classes of residual variances and the sixth-order of Legendre polynomial, presented the best fit, given by the lowest values of AIC and BIC, as well as significant LRT. It was found that with increasing age of the quail, all variances tended to increase. The estimate of additive genetic variance increased from birth to 35 days old, showing a slight drop from 35 to 42 days. The estimated heritability was decreasing along the growth curve, ranging from 0.51 (one day) to 0.16 (42 days). The estimative of genetic correlations and permanent animal environment among weights in several ages have always been high and positive, except for birth weight. For study of the growth of quails it is recommended the use of six classes (one for each week of age) of variance heterogeneity, with the use of Legendre polynomials of sixth order.