R. Bras. Zootec.01/Jun/2006;35(3 Sup..):1239-41.

Ruminal metabolism, plasma urea concentration, and urinary excretion of nitrogen of dairy cows fed concentrate processed in different forms

Humberto Luiz Wernersbach Filho, José Maurício de Souza Campos, Anderson Jorge de Assis, Sebastião de Campos Valadares Filho, Augusto César de Queiroz, Rilene Ferreira Diniz Valadares, Rogério de Paula Lana

DOI: 10.1590/S1516-35982006000400039

The objective of this trial was to study the effects of different forms of concentrate processing on ruminal pH and ammonia as well as on plasma concentration of urea. Sixteen dairy cows, pure Holstein and crossbred, were blocked by production level (30.0 and 20.0 kg/day) and randomly assigned to two Latin squares with four periods of 15 days each. Diets were isonitrogenous and contained the following forage (corn silage):concentrate ratios: 50:50 and 60:40 (% of DM) for cows yielding 30.0 and 20.0 kg of milk/day, respectively. Ruminal pH and ammonia (N-NH3) did not differ at 0 h (pre-feeding) and at 3 h after the morning feeding in the different production levels. However, it was observed lower ruminal ammonia concentration at 3 h post-feeding on cows fed diets contained extruded concentrate. Plasma urea did not differ across diets while for urinary excretion of nitrogen a significant difference was observed only for the diet containing the partially processed high-energy concentrate.

Ruminal metabolism, plasma urea concentration, and urinary excretion of nitrogen of dairy cows fed concentrate processed in different forms

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