Replacement of soybean meal by conventional and coated urea in dairy cows: intake, digestibility, production and composition of milk/ Substituicao do farelo de soja por ureia convencional e protegida em vacas leiteiras: consumo, digestibilidade, producao e composicao do leite

• Published in: Acta scientiarum. Animal sciences Vol. 36; no. 1; p. 71
• Main Authors: Goncalves, Geogenes da Silva, Pedreira, Marcio dos Santos, Azevedo, Jose Augusto Gomes, Del Rei, Antonio Jorge, Silva, Heryma Giovane Oliveira, Silva, Fabiano Ferreira
• Format: Journal Article
• Language: Spanish
• Published: Universidade Estadual de Maringa 01-01-2014
• Subjects: Dairy cattle; Milk production; Soybeans; Urea
• ISSN: 1806-2636
• DOI: 10.4025/actascianimsci.v36i1.21314

This study evaluated the effect of dairy cows' diets containing two different sources of urea on dry matter intake, nutrient apparent digestibility, and milk production and composition. Eight crossbred cows (Holandes x Zebu) were confined and randomly assigned to four sequential diets distributed in two 4 x 4 Latin: SM = soybean meal; SRU 0 = conventional urea (CU) 100%/slow release urea (SRU) 0%; SRU 44 = CU 56%/SRU 44%; SRU 88 = CU 12%/SRU 88%. Experimental periods consisted of 21 days, with total duration of 84 days. Dry matter intake, neutral detergent fiber, organic matter, crude protein, and total digestible nutrients were not affected by experimental diets. Dry matter and neutral detergent fiber digestibility coefficient presented average values of 69.43 and 51.07%, respectively. Average digestibility of crude protein was 65.43%. Average milk production was 9.609 kg. The partial replacement of soybean meal by conventional urea and slow release urea, at 2.1% of the diet dry matter, showed that these sources of urea can be offered without production impairment for dairy cows. Keywords: conventional urea, dry matter intake, slow-release urea. Objetivou-se, avaliar o efeito de duas diferentes fontes de ureia em dietas de vacas lactantes sobre consumo, digestibilidade aparente, producao e composicao do leite. Utilizaram-se oito vacas mesticas Holandes x Zebu, sendo confinadas e distribuidas aleatoriamente, alocadas a uma sequencia de quatro dietas experimentais, em delineamento distribuido em dois quadrados latino 4 x 4. FS--farelo de soja; ULL 0 = ureia convencional (UC) 100% / ureia de liberacao lenta (ULL) 0%; ULL 44 = UC 56% / ULL 44%; ULL 88 = UC 12% / ULL 88%. Os periodos experimentais foram de 21 dias, com duracao total de 84 dias. Nao houve efeito significativo nas dietas experimentais, para os coeficientes de consumo de materia seca, fibra em detergente neutro, materia organica, proteina bruta e nutrientes digestiveis totais. O coeficiente de digestibilidade da materia seca apresentou valor 69,43% e o da fibra em detergente neutro de 51,07%. A digestibilidade da proteina bruta obteve media de 65,43%. A media de producao de leite foi de 9,609 kg. A substituicao parcial de farelo de soja por ureia em 2,1% da materia seca da dieta, mostra que as fontes de ureias utilizadas podem ser oferecidas, sem que haja prejuizos produtivos para as vacas lactantes. Palavras-chave: ureia convencional, consumo de materia seca, ureia encapsulada.