Effects of Combining Feed Grade Urea and a Slow-release Urea Product on Characteristics of Digestion, Microbial Protein Synthesis and Digestible Energy in Steers Fed Diets with Different Starch:ADF Ratios

Autor: M. A. López-Soto, C. R. Rivera-Méndez, J. A. Aguilar-Hernández, A. Barreras, J. F. Calderón-Cortés, A. Plascencia, H. Dávila-Ramos, A. Estrada-Angulo, Y. S. Valdes-García
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: Asian-Australasian Journal of Animal Sciences, Vol 27, Iss 2, Pp 187-193 (2014)
Druh dokumentu: article
ISSN: 1011-2367
1976-5517
DOI: 10.5713/ajas.2013.13395
Popis: As a result of the cost of grains, the replacement of grains by co-products (i.e. DDGS) in feedlot diets is a common practice. This change produces diets that contain a lower amount of starch and greater amount of fibre. Hypothetically, combining feed grade urea (U) with slow release urea (Optigen) in this type of diet should elicit a better synchrony between starch (high-rate of digestion) and fibre (low-rate of digestion) promoting a better microbial protein synthesis and ruminal digestion with increasing the digestible energy of the diet. Four cannulated Holstein steers (213±4 kg) were used in a 4×4 Latin square design to examine the combination of Optigen and U in a finishing diet containing different starch:acid detergent fibre ratios (S:F) on the characteristics of digestive function. Three S:F ratios (3.0, 4.5, and 6.0) were tested using a combination of U (0.80%) and Optigen (1.0%). Additionally, a treatment of 4.5 S:F ratio with urea (0.80% in ration) as the sole source of non-protein nitrogen was used to compare the effect of urea combination at same S:F ratio. The S:F ratio of the diet was manipulated by replacing the corn grain by dried distillers grain with solubles and roughage. Urea combination did not affect ruminal pH. The S:F ratio did not affect ruminal pH at 0 and 2 h post-feeding but, at 4 and 6 h, the ruminal pH decreased as the S:F ratio increased (linear, p
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