Degradación ruminal en bovinos de la proteína bruta de paspalum notatum a diferentes edades de rebrote y estaciones del año

Abstract

To evaluate parameters of ruminal degradation of crude protein (CP) in Paspalum notatum, samples of 15, 30 and 45 days of re-growth were cut at 5 cm height at each season of the year. Rumen-cannulated steers of 550 kg body weight were used to run in situ procedure. Incubation times were: 0, 3, 6, 12, 24, 48, 72 and 120 h. Samples were analyzed for CP and data were fitted to Orskov y McDonald model. Resulting degradation parameters as well as effective CP degradation were analyzed by the GLM procedure of SAS package. Only the soluble fraction differed among seasons. Potentially degradable fraction, degradation rate and effective ruminal degradation were different only at 45 days of re-growth. Other CP ruminal degradation parameters were not affected by days of re-growth or season of the year, suggesting that the method may not be adequate for detecting effect of re-growth and season.