Self-fed multiple supplements and supplementation frequency, in growing steers during rainny season and transition rainny season-dry season

Objetivando avaliar, no Experimento 1, o efeito de suplementos de auto controle de consumo sobre o desempenho e parâmetros da cinética ingestiva e digestiva de novilhos mestiços recriados em pastagem de Brachiaria decumbens durante o período das águas, utilizaram-se 24 animais mestiços não - castrados, com idade e peso médios iniciais de 12 meses e 172 kg, respectivamente, para o ensaio de desempenho; além de quatro novilhos mestiços fistulados no rúmen, abomaso e esôfago, para estudo dos parâmetros nutricionais. Forneceram-se sal mineral (SAL) e suplementos à base de: uréia, mistura mineral, milho grão triturado e farelo de soja (MFS); uréia, mistura mineral, farelo de soja e farelo de glúten de milho (FGFS); e, uréia, mistura mineral, farelo de trigo e farelo de soja (FTFS), com teor protéico médio de 53,60% de PB. Não se verificou efeito da suplementação sobre os ganhos médios diários (P>0,05), que foram de: 0,820; 0,950; 1,020 e 0,970 kg/animal/dia, respectivamente, para SAL, MFS, FGFS e FTFS. Não houve diferenças (P>0,05) entre os consumos de MS, MO, MS do pasto, MO do pasto, CT, FDN e CNF, que apresentaram valores médios de 9,66; 9,14; 8,19; 7,33; 6,18 e 1,24 kg/dia. Entretanto, verificaram-se efeitos significativos (P0,05). Verificou-se efeito da suplementação sobre a digestibilidade aparente da PB (P0,05) quanto aos parâmetros de cinética de trânsito de partículas, sendo os valores médios encontrados para L e TMRT de 0,018 h -1 e 106,93 horas, respectivamente. Verificou-se efeito da suplementação sobre a concentração de amônia ruminal (P0,05). Verificou-se efeito da suplementação sobre a digestibilidade aparente da PB (P0,05).Twenty four crossbred steers, with average initial age and weight of 12 months and 172 kg, respectively, grazing Brachiaria decumbens, in the rainy season, were used in the performance essay to evaluate, in the Experiment 1, the effect of supplements of self feed on the performace and parameters of ingestive kinetic, besides four crossbred steers, fistulated in the rumen, abomasum and esophagus were used for evaluating nutritional parameters. Mineral salt (SAL) and supplements based on: urea, mineral mix, grounded corn grain and soybean meal (MFS); urea, mineral mix, soybean meal and corn gluten meal (FGFS); and urea, mineral mix, wheat bran and soybean meal (FTFS), with average protein content of 53.60% CP, were fed. It was not observed effect (P>0.05) of supplementation on the average daily gain, of 0.820, 0.950, 1.020 and 0.970 kg/animal/day, respectively, for SAL, MFS, FGFS e FTFS. No differences (P>0.05) were observed for the intakes of DM, OM, DM of pasture, OM of pasture, TC, NDF and NFC, that presented average values of 9.66, 9.14, 8.19, 7.33, 6.18 and 1.24 kg/day. However, significant (P>0.05) effects were observed for CP intake, and the supplemented animals showed CP intake higher (51%) than the control animals (SAL). There was no effect of supplementation on the ruminal passage rate (L) and the average total retention time in the gastrointestinal tract (TMRT), with average values of L and TMRT of 0.0251 h -1 and 88.00 hours, respectively. There was effect (P> 0,05) of supplementation on the ruminal ammonia concentration (NH 3 ) and interaction treatment x time (P>0.05), and the supplementation presented higher NH 3 concentrations (27.71 mg NH 3 /dl) in relation to the control treatment (SAL). There was no xeffect (P>0,05) of supplementation on the total, ruminal and intestinal apparent digestibility of DM, OM, TC, NDF and NFC. There was effect (P>0,05) of supplementation on the CP apparent digestibility (P>0.05), and the diets with supplements showed higher values of CP appant digestibility than the control. The animals supplemented excreted higher N contents-urea in the urine (95.28 g/day) (P>0,05) than the control animals (46.90g/day). No effect of treatments on the efficiency of microbial protein synthesis express by different forms was observed. In the Experiment 2, twenty-eight four crossbred steers, with average initial age and weight of 14-15 months and 249 kg, respectively, grazing Brachiaria decumbens, in the rainy-dry season, were used in the performance essay to evaluate the effect of supplements of self feed on the performance and ingestive and digestive parameters, besides four crossbred steers, fistulated in the rumen, abomasum and esophagus were used for evaluating nutricional parameters. Mineral salt (SAL) and supplements based on: mineral mix, salt, and grounded corn grain (MGS); mineral mix, salt, and grounded corn grain (MGS); mineral mix, urea and grounded corn grain (UMG), and mineral mix, urea, grounded corn grain and soybean meal (UMGFS), with different protein contents, were fed. There was effect of supplementation (P>0.05) on the average daily gains of: 0.385, 0.380, 0.454 and 0.538 kg, respectively, for the treatments SAL, MGS, UMG and UMGFS. The supplements showed no significant differences for the intakes of DM, OM, DM of pasture, OM of pasture, TC, NDF and NFC, that showed average values of 9.01; 7.85; 8.09; 7.39; 6.86; 5.69 and 1.23 kg/day. However, significant (P>0.05) effects were observed for the CP intake, with greater values when the supplements UMGFS and UMG were used. No effect (P>0.05) of treatments were used for the parameters of particulate transit kinetic, with average values of L and TMRT of 0.018 h -1 and 106.93 hours, respectively. There was effect (P0.05) for supplements UMGFS (31.25 mg/dl) and UMG (24.22 mg/dl). There was no effect (P>0.05) of supplementation on the apparent total, ruminal and intestinal digestibility of DM, OM, TC, NFC. There was effect (P>0.05) of xisupplementation on the CP apparent digestibility (P0.05) of supplementation and frequencies of supplementation on the animal performance was observed.Conselho Nacional de Desenvolvimento Científico e Tecnológic