Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-26T18:49:07Z No. of bitstreams: 1 ThalitaPolyanaMonteiroAraujo_DISSERT.pdf: 714240 bytes, checksum: 48b4952fbffbffb699a18c66d59e2d99 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-26T18:59:59Z (GMT) No. of bitstreams: 1 ThalitaPolyanaMonteiroAraujo_DISSERT.pdf: 714240 bytes, checksum: 48b4952fbffbffb699a18c66d59e2d99 (MD5) / Made available in DSpace on 2017-04-26T18:59:59Z (GMT). No. of bitstreams: 1 ThalitaPolyanaMonteiroAraujo_DISSERT.pdf: 714240 bytes, checksum: 48b4952fbffbffb699a18c66d59e2d99 (MD5) Previous issue date: 2014-03-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Na bovinocultura leiteira, o desempenho econ?mico de um sistema de produ??o est? diretamente relacionado ao desempenho zoot?cnico do rebanho. Assim, no primeiro cap?tulo deste trabalho, o objetivo foi verificar a influ?ncia do escore de condi??o corporal (ECC) sobre as caracter?sticas produtivas de vacas zebu?nas. Para tanto, foram utilizados dados de 98 vacas das ra?as zebu?nas Gir e Guzer?, pertencentes ? Empresa de Pesquisa Agropecu?ria do Rio Grande do Norte (EMPARN). Para as an?lises estat?sticas, as vacas foram previamente agrupadas em classes para o estagio fisiol?gico, per?odo de lacta??o, contagem de c?lulas som?ticas (CCS) e ECC, inclu?das como efeitos fixos no modelo. As an?lises foram realizadas utilizando-se os procedimentos dispon?veis no pacote computacional SAS? (SAS, 2009). O ECC influenciou (P<0,05) o teor de gordura do leite, com um aumento 0,25 unidades percentuais no teor de gordura a cada aumento de 0,5 no ECC. As m?dias dos constituintes do leite foram maiores na primeira classe (I) de dias em lacta??o (P<0,05). O segundo cap?tulo teve como objetivo verificar as tend?ncias gen?tica e fenot?pica dos animais Gir e Guzer? pertencentes ? Empresa de Pesquisa Agropecu?ria do Rio Grande do Norte. Para isso, foram utilizadas as estimativas de DEP (diferen?a esperada na prog?nie) para as caracter?sticas de produ??o e constituintes do leite (gordura e prote?na) dos animais avaliados pelo Programa Nacional de Melhoramento do Guzer? para Leite, a partir dos dados de controles leiteiros mensais. As an?lises descritivas e as regress?es das diferentes caracter?sticas foram realizadas empregando os procedimentos estat?sticos dispon?veis no pacote computacional SAS? (Statistical Analysis System). Observou-se tend?ncia gen?tica e fenot?pica positiva para a produ??o de leite e constituintes nos rebanhos Gir e Guzer? avaliados, ? exce??o da tend?ncia fenot?pica para gordura e prote?na na ra?a Guzer?. / In dairy cattle, the economic performance of the production system is closely related to the productive performance of the herd. Thus, in the first chapter of this work, the objective was to verify the influence of body condition score (ECC) on productive traits of zebu cows. Data from 98 zebu cows of Gir and Guzer? breeds, belonging to the Agricultural Research Center of Rio Grande do Norte (EMPARN). For the statistical analysis, cows were previously grouped into classes of physiological stage, lactation period, somatic cell counting (CCS) and ECC, included in the model as fixed effects. Analyses were performed using the procedures available in SAS? computational package (SAS, 2009). ECC influenced (P <0.05) the milk fat content, with an increase of 0.25 percentage units in fat content for each increase of 0.5 in the ECC. The average milk constituents were higher in the first class (I) of days in milk (P <0.05). The second chapter aimed at determining the genetic and phenotypic trends of Gir and Guzer? herds belonging to that research center. For this, estimates of DEP (predicted transmitting ability) for milk production traits and components (fat and protein) obtained in the genetic evaluations of the National Breeding Program for the Improvement of Guzer? Dairy Cattle, using data of monthly milk records. Descriptive analyzes and regressions of different characteristics were performed using the statistical procedures available in the computational package SAS? (Statistical Analysis System). Positive genetic and phenotypic trends for milk production and constituents were observed in the Gir and Guzer? herds, except for the phenotypic trend for fat and protein in that of Guzer? breed.