UNDERESTIMATION OF FORAGE DIGESTIBILITY COEFFICIENTS DUE TO THE EFFECT OF OMITTING DETERGENT EXTRACTION OF IN SITU RESIDUES.

Accurate determination of ruminal degradability is essential for evaluating the nutritional value of forages.The in situ technique is widely used for such assessments; however, microbial contamination (MC) can significantly underestimate digestibility parameters.This study evaluated the extent of underestimation caused by omitting detergent extraction during mechanical washing of in situ residues.Samples of four chemically distinct forages (alfalfa hay, corn stover, oat hay, and cactus silage) were incubated in the rumen of two cannulated bovines for 48 hours.After incubation, residues were mechanically washed either with or without sodium lauryl sulfate and analyzed for digestibility of dry matter (DMD), organic matter (OMD), and crude protein (CPD).The omission of detergent led to underestimations of DMD and OMD by 2.8 and 2.3 percentage units, respectively, while CPD was markedly affected-up to 17.9 percentage units in corn stover.These findings emphasize the importance of incorporating detergent-based microbial correction in in situ protocols to ensure accurate forage evaluation.