Substitution of soybeanmeal for urea in diets high in citrus pulp for growing or finishing bulls / Substituição de uréia por farelo de soja em rações com polpa cítrica para bovinos em crescimento ou em terminação

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Two trials were conducted at the Animal Sciences Department, ESALQ/USP. Trial 1: The objective was to evaluate the increase in metabolizable protein supply (urea vs soybean meal) for feedlot growing bulls, fed diets high in citrus pulp. Twenty-eight Nellore bulls, averaging 293 kg of body weight and 14 months of age, were grouped in randomized blocks. Animals were housed in 14 pens (4x7m), and experimental period lasted 93 days, divided in three 31 days sub periods. Diets were isonitrogenous and contained 16.5% Tifton hay and 83.5% concentrate (%DM), formulated using NRC (1996) Level 1. Treatment U contained 2.3% urea in ration dry matter, with positive RDP (rumen degradable protein) balance and negative MP (metabolizable protein) balance. Treatment FS contained 6.61% soybean meal and 1.32% urea in ration dry matter, with positive RDP and MP balances. Average daily gain (1.42 x 1.22 kg) was highest (P<0.05) for animals in the FS treatment. There was a tendency (P = 0.051) for highest daily dry matter intake (8.32 x 8.07 kg) and a tendency (P= 0.058) for highest feed efficiency (ADG/DMI) (0.172 x 0.153) for animals in the FS treatment. Trial 2: The objective was to evaluate the increase in metabolizable protein supply (urea vs soybean meal) for feedlot finishing bulls, fed diets high in citrus pulp. Twenty-six finishing Canchim bulls, averaging 351 kg of body weight and 14 months of age, were grouped in randomized incomplete blocks. Animals were housed in 13 pens (4x7m), and experimental period lasted 93 days, divided in three 31 days sub periods. Diets were isonitrogenous and contained 16.5% Tifton hay and 83.5% concentrate (%DM), formulated using NRC (1996) Level 1. Treatment U contained 2.3% urea in ration dry matter, with positive RDP (rumen degradable protein) and MP (metabolizable protein) balances. Treatment FS contained 6.61% soybean meal and 1.32% urea in ration dry matter, with null RDP balance and positive MP balance. Daily dry matter intake (8.76 x 8.64 kg), average daily gain (1.39 x 1.42 kg) and feed efficiency (ADG/DMI) (0.160 x 0.167) were not different (P>0.05) for FS and U treatment respectively. There were significant interactions (P<0.05) between treatments and periods for average daily gain and for feed efficiency. In the first sub period, animals in treatment FS gained more weight (1.56 x 1.29 kg) with greater feed efficiency (0.179 x 0.156) than animals in treatment U. On the other hand, in the third sub period, animals in treatment U gained more weight (1.31 x 1.00 kg) with greater feed efficiency (0.143 x 0.110) than animals in treatment FS.

ASSUNTO(S)

bovino de corte animal feed supplement animal nutrition suplemento protéico para animal beef cattle confinamento animal animal protein supplement feedlots aditivo alimentar para animal nutrição animal

ACESSO AO ARTIGO

Documentos Relacionados