Effects of grass species on ruminal degradability of silages and prediction of dry matter effective degradability

Abstract

Forty samples of grass silages, made from the five most widely used grass species in ruminant nutrition (Dactylis glomerata L., Phleum pratense L., Lolium perenne L., Festuca arundinacea L. and hybrid Felina) were tested in the present study. These grass species conserved by an ensiling process were compared among each other according to dry matter (DM) rumen degradability parameters (a = portion of DM solubilized at initiation of incubation, b = fraction of DM potentially degradable in the rumen, c = rate constant of disappearance of fraction b and ED DM = effective degradability of DM, estimated for each ingredient assuming the rumen solid outflow rates of 0.02 (ED DM2 ), 0.05 (ED DM5 ) and 0.08 (ED DM8 ) h -1 ). Based on the chemical composition of grass silages the regression equations for prediction of ED DM were evaluated. The influence of the ensiling process on dry matter degradability parameters was also assessed. The best values of ED DM were determined for Lolium perenne (ED DM2 = 753.2, ED DM5 = 631.1 and ED DM8 = 567.7 g/kg DM). The best predictor was NDF (R 2 -values of 0.757 (ED DM2 ), 0.863 (ED DM5 ) and 0.906 (ED DM8 )). Using two predictors the accuracy level increased. The combination of CF and NDF gave R 2 -values 0.892, 0.920 and 0.929 for ED DM2 , ED DM5 and ED DM8 , respectively. The regression equations based on the most important grass species harvested in different vegetation periods seem to be a useful tool for practical use. No significant (P < 0.05) effect of the ensiling process in relation to dry matter rumen degradability parameters was proved.

Anaerobic degradability of organic matter of cattle faeces and a possibility of its utilization

“…Degradability of organic matter in other disciplines is investigated particularly from the aspect of resistance in acid hydrolysis (Rovira and Vallejo, 2002;Shirato and Yokozava, 2006) or in oxidation (Blair et al, 1995;Chan et al, 2001). Because it determines the reaction time of organic matter transformations, it plays an important role in many practical applications (Frelich et al, 2009;Jančík et al, 2009;Hanuš et al, 2010;Jurajda et al, 2010;Váradyová et al, 2010).…”

Ruminal degradability of dry matter and neutral detergent fibre of grasses

“…ED DM was best predicted by NDF (R 2 = 0.878), although all presented equations gave satisfactory predictions. NDF was also detected as the best ED DM predictor for grass silages by Jančík et al (2009). Nousiainen et al (2003a) found ADF as the best single predictor of organic matter digestibility of grass silages.…”

“…Prediction equations based on chemical composition have been successfully applied for different feeds and nutrients (Nousiainen et al, 2003a;Yan and Agnew, 2004;Andrés et al, 2005;Jančík et al, 2009;Villamide et al, 2009). However, adequate equations to predict DM and NDF rumen degradation parameters of grasses from chemical composition are lacking.…”

The effects of wilting and biological and chemical additives on the fermentation process in field pea silage

“…The in sacco analysis, which has been applied in the present study, is the most frequently used method for determination of degradability of DM, organic matter (OM), protein, fibre, minerals and other nutrients of feeds (Jančík et al, 2009).…”