Abstract:Visual scores for precocity Visual scores for terminal carcass Predição da precocidade sexual em bovinos da raça Nelore por meio de componentes principais Prediction of sexual precocity in Nellore heifers using principal component analysis RESUMO: A eficiência reprodutiva e melhoria no desenvolvimento ponderal são as principais metas na pecuária de corte. O objetivo deste trabalho foi selecionar novilhas sexualmente mais precoces por meio de escores visuais de carcaça, peso e musculosidade. Dados de 283 fêmeas… Show more
“…Acta Scientiarum. Animal Sciences, v. 44, e53847, 2022 Other studies working with Nellore matrices (Semmelmann, Lobato, & Rocha, 2001;Freitas et al, 2011) have also reported positive association between weight at the beginning of reproduction and likelihood of pregnancy in heifers mated between 15 and 18 months, and heifers with greater weight at the beginning of the breeding season had better chances of becoming pregnant.…”
Section: Resultsmentioning
confidence: 97%
“…One of the main causes of low economic results of cattle farming systems in tropical regions is due to the advanced age at first calving (AFC) in Zebu heifers (Freitas, Souza, & Moreira, 2011). Thus, the selection of matrices able to start breeding early is one of the requirements for increasing the profitability of the cattle, as it allows the production of an extra calf throughout its lifetime productivity.…”
This study evaluated the influence of the quantitative traits measured by real-time ultrasound (adjusted longissimus muscle area [AdjLMA], adjusted rump fat thickness [AdjRFT], and adjusted marbling [AdjMAR]) as well as age at first breeding [AFB] and adjusted weight [AdjWeight], on the probability of occurrence of early pregnancy (EP) in 55 Nellore heifers, and also performed an economic analysis. All calves received supplementation in creep-feeding (ad libitum), and at weaning (average age= 210 ± 30 days; average weight= 241 ± 33 kg) until first breeding by artificial insemination (May to November) all heifers were managed in the same group (two paddocks of 25 ha each evenly covered with Urochloa Marandu Grass) and received protein-energy supplementation (1% of average BW per animal/day). The quantitative variables were collected immediately after timed artificial insemination (average age= 392 ± 27 days; average weight= 431.90 kg), and the pregnancy diagnosis was completed at 30 days following insemination. For economic analysis, two systems were compared (age at first breeding at 13 and 24 months). The greater adjusted weight on the first breeding increased the probability of occurrence of early pregnancy, while the greater adjusted longissimus muscle area reduced. In addition, intensive meat production systems provide greater economic return throughout cow-calf operation.
“…Acta Scientiarum. Animal Sciences, v. 44, e53847, 2022 Other studies working with Nellore matrices (Semmelmann, Lobato, & Rocha, 2001;Freitas et al, 2011) have also reported positive association between weight at the beginning of reproduction and likelihood of pregnancy in heifers mated between 15 and 18 months, and heifers with greater weight at the beginning of the breeding season had better chances of becoming pregnant.…”
Section: Resultsmentioning
confidence: 97%
“…One of the main causes of low economic results of cattle farming systems in tropical regions is due to the advanced age at first calving (AFC) in Zebu heifers (Freitas, Souza, & Moreira, 2011). Thus, the selection of matrices able to start breeding early is one of the requirements for increasing the profitability of the cattle, as it allows the production of an extra calf throughout its lifetime productivity.…”
This study evaluated the influence of the quantitative traits measured by real-time ultrasound (adjusted longissimus muscle area [AdjLMA], adjusted rump fat thickness [AdjRFT], and adjusted marbling [AdjMAR]) as well as age at first breeding [AFB] and adjusted weight [AdjWeight], on the probability of occurrence of early pregnancy (EP) in 55 Nellore heifers, and also performed an economic analysis. All calves received supplementation in creep-feeding (ad libitum), and at weaning (average age= 210 ± 30 days; average weight= 241 ± 33 kg) until first breeding by artificial insemination (May to November) all heifers were managed in the same group (two paddocks of 25 ha each evenly covered with Urochloa Marandu Grass) and received protein-energy supplementation (1% of average BW per animal/day). The quantitative variables were collected immediately after timed artificial insemination (average age= 392 ± 27 days; average weight= 431.90 kg), and the pregnancy diagnosis was completed at 30 days following insemination. For economic analysis, two systems were compared (age at first breeding at 13 and 24 months). The greater adjusted weight on the first breeding increased the probability of occurrence of early pregnancy, while the greater adjusted longissimus muscle area reduced. In addition, intensive meat production systems provide greater economic return throughout cow-calf operation.
“…A falha na reprodução é um dos mais importantes fatores que limita o desempenho da pecuária de corte brasileira. O baixo índice de desfrute do rebanho brasileiro, nos últimos anos, é resultado principalmente da elevada idade no que se refere ao primeiro parto e à baixa taxa de gestação das matrizes (FREITAS et al, 2011).…”
Por muito tempo a precocidade para a raça Nelore foi uma questão-paradigma para os criadores de bovinos de corte. No entanto, nos últimos anos, muitas dessas questões vêm sendo esclarecidas, e agora, sem tantos receios como em tempos passados, pode-se dizer com segurança que a raça Nelore possui animais precoces, e a utilização e multiplicação desses genes voltados à precocidade em um rebanho são essenciais para a manutenção de uma pecuária cada vez mais rentável. Para que essa precocidade possa ser utilizada de uma forma adequada é preciso entender que ela não pode ser tratada como um fator isolado, é necessário compreender que a nutrição, o melhoramento genético e a sanidade são fundamentais para que se alcance os objetivos traçados, reduzindo assim o período de inatividade dos animais no rebanho. Diante do exposto, este trabalho tem como objetivo realizar uma revisão bibliográfica acerca dos principais fatores que influenciam a puberdade de novilhas Nelores, assim como caracterizar o sistema de produção precoce.
“…Dependendo das características envolvidas na avaliação genética e da estrutura dos dados, diferentes modelos são utilizados para a predição dos valores genéticos dos indivíduos (MARTINS et al, 1997). Henderson (1963) (MORRISON, 1976;MEYER e KIRKPATRICK, 2004;MEYER, 2005;YAMAKI et al, 2009;FREITAS, et al, 2011).…”
Dedico aos meus pais José Walder Menezes (Zeca) e Sônia Julieta Rocha Menezes (Jujú), por todo o incentivo e força, e por serem a minha base em tudo. Ao meu esposo Klayton Vinicius Nozawa, que não mediu esforços para que eu concluísse esse trabalho. Aos meus irmãos Ione Rocha Menezes Leal e Vinícius Rocha Menezes, por todo apoio e incentivo. À todos os meus familiares e amigos que direta e indiretamente me ajudaram nessa trajetória. "O que vale na vida não é o ponto de partida e sim a caminhada. Caminhando e semeando, no fim terás o que colher"
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