Ureia de liberação lenta em substituição ao farelo de soja na terminação de bovinos confinados

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito da substituição da proteína bruta do farelo de soja pela ureia de liberação lenta sobre o desempenho, as características de carcaça e o custo alimentar de bovinos Nelore terminados em confinamento. Foram utilizados 48 machos inteiros da raça Nelore, com idade média de 22 meses e peso inicial de 367,95+18,52 kg. Utilizou-se o delineamento inteiramente casualizado com quatro tratamentos: FS, 8,91% de farelo de soja e 0% de ureia de liberação lenta (ULL); OP33, 6,01% de farelo de soja e 0,46% de ULL; OP67, 2,94% de farelo de soja e 0,94% de ULL; e OP100, 0% de farelo de soja e 1,41% de ULL. Não houve diferença entre os tratamentos para as variáveis peso inicial, peso final, ganho médio diário, ganho de carcaça, consumo de matéria seca, conversão alimentar, eficiência biológica, peso de carcaça quente, rendimento de carcaça e custo alimentar da arroba produzida. A ureia de liberação lenta, usada em substituição parcial ou total à proteína do farelo de soja na dieta, não altera o desempenho, as características de carcaça e a eficiência econômica de bovinos de corte confinados.Termos para indexação: ganho de peso vivo, nitrogênio não proteico, proteína degradável no rúmen, ureia protegida. Slow-release urea to replace soybean meal in finishing feedlot cattleAbstract -The objective of this work was to evaluate the effect of replacing crude protein of soybean meal by slow-release urea on the performance, carcass traits, and feeding costs of feedlot Nelore steers. Forty-eight Nelore steers were used, with an average age of 22 months and weight of 367.95+18.52 kg. A completely randomized design was used with four treatments: SM, 8.91% soybean meal and 0% slow-release urea (SRU); OP33, 6.01% soybean meal and 0.46% SRU; OP67, 2.94% soybean meal and 0.94% SRU; and OP100, 0% soybean meal and 1.41% SRU. No difference was observed between treatments for the variables initial weight, final weight, average daily gain, carcass gain, dry matter intake, feed conversion, biological efficiency, hot carcass weight, carcass yield, and feed cost of produced arroba. Slow-release urea, used to partially or totally replace protein of soybean meal in the diet, does not modify the performance, carcass traits, and economic efficiency of feedlot cattle.Index terms: live weight gain, non-protein nitrogen, rumen degradable protein, protected urea.

<b>Nitrogen sources associated with different physical forms of corn grain in the diet for steers in feedlot

“…As the proportion between weight gain and dry matter intake was maintained, and both increased for steers fed with soybean meal, there was no significant difference in feed conversion. This result is in agreement with Fernandes et al (2009) and Azevedo et al (2015), who evaluated, respectively, the substitution of soybean meal with common and protected urea, without differences in feed conversion. The physical forms of corn also presented similarity for feed conversion (p > 0.05), as observed by Vargas Junior et al (2008).…”

“…According to Oliveira and Millen (2014), soybean meal was the main protein ingredient used by cattle nutritionists, but it has lost ground to other sources. This reduction is due to the increase in the acquisition costs of this ingredient, since it is widely used in poultry and pork production, with prices varying in the harvest and off-season periods and with international market demands (Azevedo et al, 2015).…”

Substitution of soybean meal for urea in diets based on deferred buffelgrass hay for feedlot sheep

“…These findings corroborate Paixão et al (2006), who stated that dry matter intake will not be influenced by urea inclusion in the diet, provided that the protein requirement is met. This effect was also observed by Azevedo et al (2015), who used slow-release urea substituting soybean meal in the finishing of feedlot cattle and did not observe alterations in their dry matter intake.…”

Comportamento ingestivo de bovinos holandeses x zebu alimentados com diferentes formas físicas do milho e uréia

“…Uma alta taxa de hidrolise associado a não disponibilização de energia proporcionará acúmulo e escape de amônia no rúmen. Com base no apresentado, a uréia será melhor utilizada como fonte de nitrogênio para síntese protéica, quando houver sincronismo entre liberação de energia e nitrogênio (Azevedo et al 2015). Nos últimos anos foram desenvolvidos produtos que visam o controle da liberação de nitrogênio não protéico no rúmen, com intuito de reduzir os custos das dietas e melhorar a conversão do nitrogênio em proteína microbiana, caso da ureia de liberação lenta ou protegida.…”