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Made available in DSpace on 2018-12-11T17:25:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-31. Added 1 bitstream(s) on 2021-07-15T15:03:45Z : No. of bitstreams: 1 S1413-70542015000400355.pdf: 888034 bytes, checksum: 8cfad4d3ef27ff6658f9b1202346a40c (MD5) Genetic breeding programs of beef cattle in Brazil are including new features, mainly related to reproductive efficiency. Thus, it is necessary to study the effectiveness of selection and quantify genetic gain for these traits in herds. This study estimated genetic and phenotypic parameters and genetic trends for reproductive traits used in breeding programs for Nelore beef cattle. The traits studied were the scrotal circumference (SC) at 365 and 450 days of age (SC365 and SC450), age at first calving (AFC) and gestation length, as a cow trait (GLcow) and a calf trait (GLcalf). The (co)variance components were obtained with the Restricted Maximum Likelihood Methodology in a single and double-trait analysis of the animal model. For scrotal circumference (SC365 and SC450), positive and favorable genetic gains were observed. For AFC, GLcow and GLcalf, the trends were favorable for selection, but without significant genetic gain. Selection for large SC may reduce AFC and improve female reproductive efficiency. The selection for reproductive traits (SC365, SC450, AFC and GL) may improve reproductive and productive efficiency of Nelore cattle, if used as a selection criterion. Agência Paulista de Tecnologia dos Agronegócios/APTA Instituto de Zootecnia, Highway: Carlos Tonanni – km 94 – Setor Industrial Água Vermelha Universidade Estadual Paulista Júlio de Mesquita Filho/UNESP Veterinárias de Jaboticabal Agência Paulista de Tecnologia dos Agronegócios/APTA Instituto de Zootecnia Universidade de São Paulo/USP Departamento de Genética Universidade Estadual Paulista Júlio de Mesquita Filho/UNESP Veterinárias de Jaboticabal

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:29:53Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:37:42Z : No. of bitstreams: 1 2-s2.0-84883413497.pdf: 86160 bytes, checksum: c1accf628bd20b6ed87ab073daca6b5e (MD5) Made available in DSpace on 2014-05-27T11:29:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In central Brazil after soybean or other annual agricultural species is harvested, sorghum hybrids are planted in the fall in order to establish pastures for grazing animals. This study conducted for two consecutive years aimed at quantifying the contents of hydrocyanic acid in the leaves and determining plant height, forage dry matter yield and the leaf/stem ratio for sorghum hybrid 1P400 at different ages. Statistical analysis was performed by regression analysis based on plant age. Leaf HCN content decreased with plant growth, ranging from 205.0 and 230.3 mg HCN/100 g leaf DM at two weeks old to 5.9 and 6.1 mg HCN/100 g leaf DM at five weeks old in the first and second year, respectively. The average heights measured varied from 60 and 56 cm, in the 4th week, to 117 and 151 cm, in the 8th week, during the first and second experimental year, respectively. Forage mass increased linearly with age and displayed average of 1.411 and 1.637 kg DM/ha in the first year and, 2.905 and 3.640 kg DM/ha in the second year, during the 7th and 8th week, respectively. Leaf proportion decreased while stem increased linearly with plant age. The leaf/stem ratio decreased with plant growth, elongation and increasing stem weight. The sorghum hybrid should be grazed only after five weeks or when the plant height is above 80 cm, in order to avoid the risk of cyanide poisoning. Agência Paulista de Tecnologia dos Agronogócios/APTA Secretaria de Agricultura e Abastecimento/SAA, Avenida Bandeirantes, Ribeirão Preto 14.030-670. São Paulo - SP Agência Paulista de Tecnologia dos Agronogócios/APTA Secretaria de Agricultura e Abastecimento/SAA, Ribeirão Preto - São Paulo - SP Instituto de tecnologia de Alimentos/ITAL Agência Paulista de Tecnologia dos Agronogócios/APTA Secretaria de Agricultura e Abastecimento/SAA, Campinas - SP Universidade Estadual Paulista 'Julio de Mesquita Filho'/UNESP Campus de Jaboticabal, Jaboticabal - SP Universidade Estadual Paulista 'Julio de Mesquita Filho'/UNESP Campus de Jaboticabal, Jaboticabal - SP FAPESP: 04/13427-3