Proteins sources in multiple supplements for steers at pasture / Fontes de proteína em suplementos múltiplos para bovinos em pastejo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

This work was carried out from three experiments with crossbreed and/or zebu steers on Brachiaria decumbens pastures. In the first experiment were evaluated supplements with different protein sources during the dry periods and transition phase between the dry and the rainy seasons. To evaluate the performance 20 animals were used (Holstein x zebu, or zebu) with 220 kg of live weight (LW) and 10 months old each, grazing in five paddocks (2 ha), in a completely randomized desing, with five treatments and four replicates. The supplements with 38% of crude protein (CP) in the dry matter (DM) basis were supplied daily at 0.5% of their weight. The treatments employed were supplements based on: soybean meal /wheat meal (FSFT), wheat/urea (FTU), cottonseed meal 38% of CP (FA38), cottonseed meal 28% of CP/urea (FA28), wheat meal, cottonseed meal 38% of CP/urea (FAFTU), and mineral salt was present in all the supplements. The treatment FA38 allowed superior animal performance compared with the treatments FSFT, FTU and FA28; and the treatment FAFTU was superior to the treatments FTU and FA28. Five Holstein-zebu steers 10 months old and initial weight of 170 kg, and fistulated in the esophagus and rumen, were used to evaluate the nutritional parameters. These animals were grazing in five paddocks of 0.3 hectare each in design of randomized blocks where each experimental period was treated as a block. The protein sources did not effect the intake of DM in relation to LW but the intake of neutral detergent fiber (NDF) was superior in treatments of FTU and FA28 in relation to FA38 and FAFTU; and the digestibility of DM obtained in FSFT and FTU treatments were superior to those of FA38, FA28, and FAFTU, and the digestibility of CPs FTU was superior to those of FA38 and FA28. The treatments had effect on pH but all were within the favorable limits of digestion of forage. The protein sources effected the concentration of ruminated N-NH3 that was bigger than a FTU treatment, and it had a bigger content of urea in relation to other treatments, for treatments FSFT, FA28, and FAFTU in relation to FA38. It had no effect from the treatments on the fluxes of microbial protein and its efficiency. The less value of N-urea concentration in plasma was observed for FA38 treatment; and the biggest value was observed in products that contained urea (FAFTU, FTU, and FA28). In the second experiment were evaluated supplements with different protein sources during the rainy period. To evaluate the productive performance 20 animals were used with average live weight of 284Kg and approximate age of 14 months grazing in five paddocks (2 ha), in a completely randomized design, with five treatments and four replicates. The daily supplements (500g/day) had approximately 35% of CP in the DM. The following treatments were used: FSFT, FTU, FA38, FAFTU, and the control treatment mineral (CONTROL). The supply of multiple supplements during the rainy period allowed extra weight gains of 135 275 g/day. The treatment FAFTU and FTU showed gains over CONTROL. The nutritional parameters were evaluated in five animals with initial average weight and age of 219Kg and 14 months respectively, fistulated in the esophagus and in the rúmen, distributed in five paddocks of 0.3 hectares, in design of randomized blocks where each experiment period was treated as a block. There was no effect of supplementation or the protein sources under the intake of nutrients or intake of DM from pasture. The digestibility of DM and NDF obtained in FA38 was inferior to others. There was no effect in the treatments under the pH, which average value was 6.41. The ruminal concentration of N-NH3 was bigger to that of FTU treatment that had the bigger content of urea in relation to others, and to FSFT, FA38, and FAFTU in relation to CONTROL. There was no effect in the supplementation or protein sources on the fluxes of microbial protein and microbial efficiency. There was no effect in the treatments on the N-urea concentration in plasma that showed average value of 13.7mg/day, nor on the excretion of nitrogen compounds (N) in the urine. However, the supplementation allowed bigger nitrogens balance. In the third experiment were evaluated supplements with different protein sources during the transition phase between the rainy and the dry seasons. To evaluate the performance 20 animals were used with average live weight of 357Kg and approximately 17 months of age, grazing in five paddocks (2 ha), in a completely randomized design, with five treatments and four replicates. The supplements were supplied in base of 1.0kg per day. The following treatments were used: FSFT, FTU, FA38, FAFTU and CONTROL. No difference was found (P>0.10) in the daily weight gain. However, the supplemented animals showed 24.3% more in weight gain in relation to the control group. Considering only th supplements (FA38 and FAFTU) that contained cottonseeds meal with 38% CP, the daily weight gain was 0.223Kg/day or 41.8% more than the CONTROL. The nutritional parameters were evaluated in five animals with initial average weight and age of 249Kg and 17 months respectively, fistulated in the esophagus and in the rumen, distributed in five paddocks of 0.3 hectares each in design of randomized blocks, where each experimental period was treated as a block. The supplementation in general provided proportional increase in intake of DM in kg/day or in relation to LW not affecting the intake of DM from pasture or the intake of NDF. The digestibility of the DM found in the FSFT was superior to others that did not differ from each other. There was no effect in the treatments under the pH which average value were 6.42. The ruminal concentration of NNH3 was bigger that the FTU, FSFT and FAFTU treatments in relation to FA38 that was bigger than CONTROL. No effects were observed to treatments of the protein microbial fluxes and microbial efficiency. There was no effect of the protein sources on the concentration of N-urea in the plasma and the nitrogens balance, all being superior to the CONTROL.

ASSUNTO(S)

nutricao e alimentacao animal bovine suplementação pasture pastejo supplementation garrotes

ACESSO AO ARTIGO

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