In situ rumen degradation kinetics as affected by type of pasture and date of harvest

  • Juan Pablo Keim Universidad Austral de Chile; Faculty of Agricultural Sciences
  • Ximena Valderrama Universidad Austral de Chile; Faculty of Agricultural Sciences
  • Daniel Alomar Universidad Austral de Chile; Faculty of Agricultural Sciences
  • Ignacio Fernando López Universidad Austral de Chile; Faculty of Agricultural Sciences

Abstract

Botanical composition affects the nutritive value and nutrient degradation kinetics of pastures. However, there is little information about pastures composed of various species. The present study was conducted to evaluate in situ degradation kinetics of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of a naturalized non fertilized pasture (NNF), naturalized fertilized pasture (NF), sown pasture with Lolium perenne L. and Trifolium repens L. (RGWC), and sown pasture with Bromus valdivianus Phil., Dactylis glomerata L., Holcus lanatus L., L. perenne and T. repens (MIXED); at three dates of harvest (early-spring, mid-spring and autumn). Duplicate bags were incubated in the rumen of three cannulated cows for 2, 4, 8, 12, 24 or 48 h. Zero-hour bags were washed with water. Ruminal degradation was evaluated according to exponential models with or without lag phase. Pasture chemical composition showed on average low DM, high CP and digestible organic matter (DOMD). Degradation parameters of DM, CP and NDF exhibited strong pasture type*date of harvest interactions. In general, high potential degradability and fractional degradation rates of DM, CP and NDF were observed. Nutrient supply was generally higher for RGWC and NF, especially compared with NNF during autumn. Naturalized fertilized pastures supply similar amounts of nutrients to grazing cattle as sown pastures. However, it is necessary to consider other variables that determine the productive performance such as DM intake and rumen fermentation products.

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Published
2013-12-01
How to Cite
Keim, J., Valderrama, X., Alomar, D., & López, I. (2013). In situ rumen degradation kinetics as affected by type of pasture and date of harvest . Scientia Agricola, 70(6), 405-414. https://doi.org/10.1590/S0103-90162013000600005
Section
Animal Science and Pastures