Made available in DSpace on 2014-06-11T19:26:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-10-23Bitstream added on 2014-06-13T20:14:38Z : No. of bitstreams: 1 barrozo_d_me_jabo.pdf: 515290 bytes, checksum: 672a5fd2bc13656f7e2aa5b2c9cfe9ba (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo foi estudar a influência da idade da vaca ao parto (IVP), da idade do animal ao sobreano (IS) e do peso ao sobreano (PS) sobre os escores de conformação (C), precocidade (P), musculatura (M) e temperamento (T) ao sobreano de animais Nelore; estimar a herdabilidade (h²) destas características, empregando-se diferentes modelos estatísticos e estimar as co-variâncias e correlações entre T e as características reprodutivas perímetro escrotal (PE), idade ao primeiro parto (IPP) e idade ao segundo parto (ISP), de bovinos Nelore. A base de dados utilizada pertence ao PAINT®, CRV Lagoa LTDA. Foram realizadas análises de regressão após a absorção do efeito de grupo de contemporâneos (GC). As estimativas de h² foram obtidas por máximaverossimilhança restrita sob um modelo animal, considerando-se o efeito genético aditivo de animal como aleatório, incluindo diferentes efeitos fixos. IVP apresentou efeito quadrático sobre P e M, segmentado quadrático-quadrático sobre C e linear sobre T. A característica C comportou-se de modo similar ao PS e P e M foram semelhantes ao ganho de peso neste período. IS e PS apresentaram efeitos quadráticos sobre C, P e M e efeito cúbico e linear, respectivamente, sobre T. Estimativas de h² foram encontradas entre 0,13 á 0,38 (C, P e M) de acordo com o modelo utilizado, enquanto para PE, IPP e ISP, as estimativas foram iguais a 0,52; 0,13 e 0,03. As correlações genéticas entre T e PE, T e IPP e T e ISP foram de 0,16; -0,04 e -0,32. As correlações estimadas entre T e as características reprodutivas foram de pequena magnitude. A seleção para os escores visuais pode trazer ganhos genéticos moderados nas características de carcaça / The aims of this study were to study the effect of age at calving (IVP), age of yearling (IS) and yearling weight (PS) on the scores of conformation (C), precocity (P), muscle (M) and temperament (T) of yearling Nellore, to estimate heritability (h ²) of these traits, using different statistical models and to estimate the covariance and correlation between T and the reproductive traits scrotal circumference (SC), age at first calf (IPP) and age at second calf (ISP). The database used belongs to the breeding program PAINT ® of CRV Lagoa LTDA. Regression analysis were performed after the absorption of the effect of contemporary group (CG). Estimates of h² were obtained by restricted maximum likelihood method under an animal model, considering the genetic effect of animal as random, with different fixed effects. IVP showed a quadratic effect on P and M, segmented quadratic-quadratic and linear on C on T, respectively. C showed similar patter as PS while P and M were similar to weight gain in this period. IS and PS showed a quadratic effect on C, P and M and cubic and linear effects, respectively, on T. The estimates of h ² ranged from 0.13 to 0.38 (C, P and M) according to the model used, whereas for PE, IPP and ISP, the estimates were equal to 0.52, 0.13 and 0, 03. Genetic correlations between T and PE, T and IPP and T and ISP were 0.16, -0.04 and -0.32. The estimated correlations between T and the reproductive traits were small. Selection applied on visual scores could bring moderate genetic gains to the carcass traits

Made available in DSpace on 2014-07-29T15:07:56Z (GMT). No. of bitstreams: 1 Lucas Jacomini.pdf: 1839805 bytes, checksum: 1969be815165b4eb0a4afeeae7f84141 (MD5) Previous issue date: 2010-02-22 / The objective of this study was to characterize the age, weight and body morphometric measurements of Nellore heifers reared in Cerrado biome. Fifty-six heifers were experimentally exposed with bulls for determining the onset of their reproductive life. Body weight, condition and measurements of the heifers were evaluated every 60 days between 16 and 32 months of age. The following body measurements were registered: withers height, rump height, body length, head length, rump length, ear length, distance between ribs, distance from dorsal spine to belly, distance from ground to belly, head width, rump width, width between ischiums, ear width, cannon bone perimeter, tail implantation perimeter and thoracic perimeter. The average age at the onset of their reproductive life and the mean body weight were 28,74±2,81 months and 333,83±39,13 kg, respectively. Significant difference were observed for the following measurements: withers height, rump height, body length, rump length, head width, rump width, width between ischiums, tail implantation perimeter, thoracic perimeter and body condition score. Higher morphometric measurement values were observed in pregnant animals. The age in which the animals achieved the onset of their reproductive life in this study was similar to the ones described for Zebu females in the literature. In this case, more studies on genetic improvement and management alternatives are needed to anticipate the onset of the heifers´ reproductive life. The body morphometric mensuraments were higher in the pregnant heifers, indicating that the morphometric records can be an important tool to identify precocious Nellore females. The objective of this study was to characterize the age, weight and body morphometric measurements of Nellore heifers reared in Cerrado biome. Fifty-six heifers were experimentally exposed with bulls for determining the onset of their reproductive life. Body weight, condition and measurements of the heifers were evaluated every 60 days between 16 and 32 months of age. The following body measurements were registered: withers height, rump height, body length, head length, rump length, ear length, distance between ribs, distance from dorsal spine to belly, distance from ground to belly, head width, rump width, width between ischiums, ear width, cannon bone perimeter, tail implantation perimeter and thoracic perimeter. The average age at the onset of their reproductive life and the mean body weight were 28,74±2,81 months and 333,83±39,13 kg, respectively. Significant difference were observed for the following measurements: withers height, rump height, body length, rump length, head width, rump width, width between ischiums, tail implantation perimeter, thoracic perimeter and body condition score. Higher morphometric measurement values were observed in pregnant animals. The age in which the animals achieved the onset of their reproductive life in this study was similar to the ones described for Zebu females in the literature. In this case, more studies on genetic improvement and management alternatives are needed to anticipate the onset of the heifers´ reproductive life. The body morphometric mensuraments were higher in the pregnant heifers, indicating that the morphometric records can be an important tool to identify precocious Nellore females. / Este trabalho teve como objetivo caracterizar o peso, as medidas morfométricas do corpo e prenhez em novilhas Nelore dos 16 aos 32 meses criadas no bioma Cerrado. Foram utilizadas 56 novilhas da raça Nelore, expostas com touros para a determinação da idade a primeira prenhez. As novilhas foram avaliadas quanto ao peso, condição corporal e morfometria corporal a cada dois meses dos 16 aos 32 meses de idade. Tomaram-se as seguintes medidas corporais: altura da cernelha, altura do posterior, comprimento do corpo, comprimento da cabeça, comprimento da garupa, comprimento da orelha, distância entre costelas, distância dorso ventre, distância ventre solo, largura da cabeça, largura da garupa, largura entre ísquios, largura da orelha, perímetro da canela, perímetro da rabada, perímetro torácico. Os resultados evidenciaram idade aproximada a primeira prenhez de 28,74±2,81 meses com peso médio de 333,83±39,13 kg. Com relação às medidas morfométricas observaram-se diferenças significativas na altura da cernelha, altura do posterior, comprimento do corpo, comprimento da garupa, largura da cabeça, largura da garupa, largura entre ísquios, perímetro da rabada e perímetro torácico, sendo estas maiores nos animais gestantes. Concluiu-se que a idade a primeira gestação das novilhas Nelore observada neste experimento encontra-se próxima ao descrito na literatura para fêmeas zebuínas. Este fato indica haver a necessidade de maiores estudos, relacionados ao melhoramento genético e/ou alternativas de manejo, a fim de antecipar o início da vida reprodutiva. As medidas morfométricas foram maiores nas novilhas gestantes, sugerindo que esta abordagem de mensuração corporal pode ser uma ferramenta auxiliar na identificação de animais precoces.