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Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:07:52Z No. of bitstreams: 1 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) Made available in DSpace on 2013-08-22T19:07:53Z (GMT). No. of bitstreams: 1 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) Previous issue date: 2012-02-01 Made available in DSpace on 2013-09-30T20:12:37Z (GMT). No. of bitstreams: 2 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) S1516-35982012000200023.pdf.txt: 26582 bytes, checksum: 58a4225e0eb7844e6898ca66458e29f7 (MD5) Previous issue date: 2012-02-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:18:22Z No. of bitstreams: 2 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) S1516-35982012000200023.pdf.txt: 26582 bytes, checksum: 58a4225e0eb7844e6898ca66458e29f7 (MD5) Made available in DSpace on 2014-05-20T15:18:22Z (GMT). No. of bitstreams: 2 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) S1516-35982012000200023.pdf.txt: 26582 bytes, checksum: 58a4225e0eb7844e6898ca66458e29f7 (MD5) Previous issue date: 2012-02-01 The objective of this study was to determine requirements of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na) for grazing zebu bovines. The experiment area was composed of Brachiaria decumbens paddocks. Twenty-seven non-castrated animals, with initial live weight of 311.0 kg and at an average age of 14 months were used. Three animals were slaughtered, after adaptation period, so they were used as control for estimates of empty body weight and initial body composition of animals in the experiment. Out of the 24 remaining animals, four were sent to the maintenance group with restrict grazing time to limit energy intake close to the maintenance level. The other 20 animals were distributed in four treatments: mineral mixture, self-control intake and three-times-a-week-offer frequency (offered on Mondays, Wednesdays and Fridays) and daily. Concentrations of all studied macro elements in empty body and empty body gain decreased as live weight increased. The ratios obtained for g Ca/100 g of retained protein and g P/100 g of retained protein were 9.18 and 4.72, respectively. Total dietary requirement of calcium was lower than the one recommended by NRC (2000), but P requirement was very close to that. UFMT ICAA UFV DZO UNESP UNESP

Objetivou-se avaliar os efeitos da suplementação com compostos nitrogenados sobre o consumo e a digestibilidade em bovinos em pastejo durante o período seco do ano. Foram utilizados cinco novilhos mestiços Holandês × Zebu, com peso vivo (PV) médio inicial de 236 kg, mantidos individualmente em piquetes de Brachiaria decumbens Stapf. (0,34 ha). Utilizou-se delineamento em quadrado latino 5 × 5, com cinco níveis de suplementação (0; 0,35; 0,75; 1,05; e 1,40 g de proteína bruta (PB)/kg PV) e cinco períodos experimentais. Como fonte de compostos nitrogenados empregou-se mistura de ureia, sulfato de amônia e albumina (4,5:0,5:1,0, respectivamente). Os níveis médios de PB nas dietas foram de 7,39; 8,92; 10,98; 12,55 e 13,62%, com base na matéria seca (MS), para os respectivos níveis de suplementação. Verificou-se relação do tipo linear-response-plateau (LRP) entre as estimativas de consumo e os níveis de PB da dieta. O comportamento do tipo LRP permitiu evidenciar aumento no consumo até níveis próximos a 9% de PB, com base na MS, a partir do qual houve estabilidade das estimativas. Os coeficientes de digestibilidade total e ruminal da MS e da fibra em detergente neutro e o nível de nutrientes digestíveis totais na dieta apresentaram relação linear e positiva com os níveis de PB na dieta. A concentração de nitrogênio amoniacal ruminal (NAR) aumentou de forma linear e positiva de acordo com os níveis de PB na dieta, com valor estimado de 8,00 mg NAR/dL, equivalente à otimização do consumo voluntário. A suplementação com compostos nitrogenados em quantidades que permitam elevar o teor de PB da dieta a níveis próximos a 9% proporciona otimização na utilização de forragem de baixa qualidade por bovinos em pastejo. The objective of this work was to evaluate the effects of supplementation with nitrogenous compounds on intake and digestibility in cattle under grazing during dry season. It was used five Holstein × Zebu steers with average initial live weight of 236 kg, kept in five Brachiaria decumbens Stapf. paddocks (0.34 ha). The experiment was carried out according to a 5 × 5 Latin square design, with five supplementation levels and five experimental periods. The supplementation levels were the following: 0; 0.35; 0.70; 1.05, and 1.40 g of crude protein/kg live weight. A mixture of urea, ammonium sulfate and albumin (4.5:0.5:1.0, respectively) was used as nitrogen supplement. The average crude protein levels in the diet were 7.39; 8.92; 10.98; 12.55; and 13.62%, as dry matter basis, for the respective supplementation levels. Linear-response-plateau relationships were observed between intake estimates and diet crude protein levels. The linear-response-plateau pattern showed that intake was increased up to crude protein levels close to 9%, as dry matter basis. The estimates became unchangeable from this level. The total and ruminal digestibility coefficients of dry matter and neutral detergent fiber, and diet level of total digestible nutrients presented a positive linear pattern according to diet crude protein levels. The rumen ammonia nitrogen concentration was linearly increased by diet crude protein levels. This variable assumed the value of 8.00 mg/dL when the intake estimates reached the maximum values. Supplementation with nitrogen compounds in quantities that raise the crude protein content in the diet to levels close to 9% optimizes the use of low-quality forage by cattle under grazing.

Avaliaram-se as dinâmicas de trânsito e degradação da fibra em detergente neutro (FDN) em bovinos alimentados com forragem tropical de baixa qualidade e compostos nitrogenados. Foram utilizadas cinco novilhas Holandês x Zebu fistuladas no rúmen. A alimentação volumosa basal dos animais foi constituída por feno de capim-braquiária (Brachiaria decumbens Stapf.), com 5,08% de proteína bruta (PB), com base na matéria seca (MS), fornecido ad libitum. Os cinco tratamentos avaliados foram definidos de acordo com o nível de suplementação proteica (0, 3, 5, 7 e 9 pontos percentuais acima do nível de PB da forragem). Como fonte de compostos nitrogenados, empregou-se mistura de ureia:sulfato de amônia:albumina (4,5:0,5:1,0). O experimento foi estruturado segundo delineamento em quadrado latino 5 x 5. Os níveis médios de PB nas dietas foram de 5,28; 8,08; 9,82; 11,87 e 13,63%, com base na MS. Verificou-se elevação linear (P