Suplementação de bovinos de corte em pastagens : forragem, época do ano e tipo de suplemento

• Ano de defesa: 2008
• Autor(a) principal: Tonello, Cleiton Luiz
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Programa de Pós-Graduação em Zootecnia; UEM; Maringá, Pr; Centro de Ciências Agrárias
• Palavras-chave em Português: Plantas forrageiras tropicais; Plantas forrageiras temperadas; Bovinos; Suplementos protéicos; Suplementos energéticos; Águas; Secas; Efeito Substituição, Meta-análise; Brasil.; Tropical forage plants; Temperate forage plants; Cattle; Protein supplements; Energy supplements; Waters; Droughts; Substitution Effect, Meta-analysis; Brazil.; Ciências Agrárias; Zootecnia
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/1831

The present study used meta-analysis to assess the effects of supplementation on beef cattle performance in pastures in Brazil, classifying data by forage type, period of the year and supplement type. There were reviewed articles published in journals indexed by "Scielo" using internet searching tools, from 1999 to 2007. There were used 70 articles and information from material and methods and results sections, of each article, were set to a database. Data were grouped according to forage type (Tropical and Temperate), period of the year (Rainy, Drought, Transition Rainy/Drought and Transition Drought/Rainy) and supplement type (Energy/Protein, Protein Salt, Protein and Energy). It was done comparisons between animals without supplement (control) and supplemented animals, to determine the real effect of supplementation on performance and to find the corrected daily gain in each study. A meta-analysis was performed using three sequential analyses: graphic, correlation and variance. The regression equations were obtained through the covariance, and correlation and significance level, between dependent and independent variables were obtained using the SAS statistical program PROC CORR, with a significance level of 1%, and the final selection of variables was based on R2 value. It was observed that 27.4% of animals grazing forage growing in Brazil, showed a corrected daily gain between 0.11 and 0.20 kg/d, and 85.2 % of corrected gain are positive, with a range between 0.02 and 0.40 kg/d. Animals grazing tropical grasses showed a gain positively correlated (P<0.01) with crude protein intake from supplement, with supplement intake based on dry matter and with TDN/CP ratio as well as it was negatively correlated with forage crude protein percentage. In tropical pastures, animals showed a corrected daily gain of 0.31 kg/d, with TDN intake from supplement equal to 0.43 % of LW/d. Temperate pastures showed a corrected daily gain of 0.165 kg/d and intake of TDN from supplement was 0.765% of LW/d. It was observed that in grasses from Brachiaria gender, supplementation guaranteed a positive corrected daily gain, with an average of 0.336 kg/d and TDN intake of 0.389 % of LW/day. In the mixed culture between Oats and Ryegrass, the animals showed values of corrected daily gain of 0.133 kg/day and a consumption of TDN of 0.809% of LW/day. Supplements used in tropical forages, showed an average of 29 % CP, with animals having a corrected daily gain of 0.25 kg/d and in temperate forage, crude protein was 17.4%, with data concentration between 10 and 20% CP and animals gained 0.19 kg/d. In rainy period (n=49) 45.8% of corrected daily gain ranged between 0.11 and 0.20 kg/day and for drought period (n = 54) it was observed that 21.2% of the data were under 0.02 kg/d and 21.2 % above 0.40 kg/day. During the period rainy/drought 33.3 % of data for corrected daily gain was above 0.40 kg/d and there were no negative values. During the period drought/rainy 33.3 % of data were between 0.31 and 0.40 kg/day, and 20% showed lost of weight. Correlation between corrected daily gain during drought and consumption of protein supplement was 0.598 (P <0.01), and in relation to TDN/PB ratio of forage this correlation was 0.61 (P<0.01). In the rainy period TDN consumption from supplement was 0.42 % of LW/d, resulting in a corrected daily gain of 0.15 kg/d, with a range between 0.06 and 0.31 kg/d. During drought period animals showed a corrected daily gain of 0.244 kg/d, with TDN consumption from supplement equal to 0.63 % of LW/d. In the rainy period, crude protein level in supplements was 25 % and animals showed a corrected daily gain of 0.14 kg/d. In the drought period, crude protein in supplements was 32.9 %, and animals gained 0.28 kg/d. Energy/protein supplements (n = 52) showed 30% of corrected daily gain over 0.40 kg/day. For Protein Salt, 29.6 % of data for corrected daily gain were between 0.11 and 0.20 kg/day, and 22.2 % were below 0.02 kg/day. Protein supplement showed 44 % of the corrected daily gain between 0.11 and 0.20 kg/d. Energy supplements showed 27.3 % of the corrected daily gain between 0.11 and 0.20 kg/d, and the highest percentage (27.3 %) of data with corrected gain below 0.02 kg/d was found here. For animals fed energy/protein supplements the corrected daily gain was correlated with crude protein level of supplement (R=-0.562; P<0.01) and with TDN/CP ratio of forage (R=0.540; P<0.01). Animals receiving energy/protein supplements showed a corrected daily gain of 0.37 kg/d with a TDN consumption from supplement equal to 0.61% of LW/d. Protein salt and protein supplement showed corrected daily gain of 0.12 and 0.22 kg/d, respectively, but for protein supplement the TND consumption was 0.225% of LW/d, while for protein salt was only 0.03 % of LW/d. Animals receiving energy supplements showed a corrected daily gain of 0.13 kg/d and a TDN consumption from supplement equal to 0,71 % of LW/d. CP in energy/protein supplements was 19.8 % and animals showed a corrected daily gain of 0.37 kg/day. These data showed that all supplements evaluated produced additive effect on corrected daily gain of the animals.