Sincronização ruminal de energia e proteína em bovinos de corte criados em sistema pasto-suplemento
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2020-02-28
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Universidade Federal de Goiás
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Protein-energy supplementation was evaluated during 84 days on the consumption, digestibility, metabolism and performance of Nellore bulls kept in pasture of Brachiaria brizantha cv. Marandu,with two levels of rumen-undegradable protein (RUP) (72.5% and 48.8% of CP) and two levels of energy ( 1.5 and 3.0 kg / animal / day) and mineral supplementation (control treatment) in the transition period from the dry to the rainy season. To evaluate the performance, 30 animals with initial weight (IW) of 181.5 ± 6.3 kg were distributed in 15 paddocks with 0.66 ha in a completely randomized design. To evaluate the effects of the diet on metabolism, five bulls with IW of 183.34 ± 30.54 kg kept in individual paddocks of 0.33 ha, were used in a 5x5 Latin square design, each period lasted 15 days, with 7 days for adaptation and 8 days for sample collection. The concentrated supplement decreased the consumption of DM from pasture by 22% (P <0.10) and increased (P <0.10) the average daily consumption of CP proportionally to the energy level. The concentrated supplement improved the digestibility of organic matter, CP and NDF (P <0.10). The intake of N and the retained N suffered an effect (P <0.10) of the concentrated supplementation, with 32.05% lower values of retained N for the control diet compared to the other treatments. For animals supplemented with concentrate, those that received high energy obtained higher values for the retention of N. The ruminal pH did not differ between treatments (P>0.10). The blood plasma urea level was lower (P <0.10) in the control animals compared to concentrated supplementation. Furthermore, it was observed that the level of RUP influenced the plasma urea concentration, and treatments with high RUP resulted in lower values (P <0.10) of plasma urea compared to treatments with low RUP. Animals kept on pasture receiving only mineral mixture had an average daily gain (ADG) of 0.873 kg, being lower (P <0.10) than animals that received concentrated supplementation, whose averages were 1.095 and 1.328 kg for the supply of 1.5 and 3.0 kg, respectively. It was observed that animals supplemented with high RUP and high energy showed a drop in ADG (P <0.10) compared to those supplemented with low RUP and high energy. It is concluded that supplementation with different levels of RUP and energy affect the metabolism, mainly in the blood urea levels, of the animals, however, RUP does not affect the performance of animals kept on pasture during the transition period of the dry season. for rainy.
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SOCREPPA, L. M. Sincronização ruminal de energia e proteína em bovinos de corte criados em sistema pasto-suplemento. 2020. 51 f. Tese (Doutorado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2020.