Prediction of the relative intake potential of grass silage by dairy cows

摘要: Data based on the mean treatment values from production studies in lactating dairy cows were used to estimate relationships between silage composition and dry matter intake (SDMI). 21 D-value (g digestible organic kg (DM)) crude protein (CP) content, SDMI. The silages harvested at different maturities but using same ensiling techniques within study. Relationships fermentation characteristics SDMI estimated data 47 studies. time sward various additives. When factorial designs used, each (subexperiment) recorded separately. sets included 125 234 observations. parameters analyzed mixed model regression analyses with experiment as a fixed factor subexperiment random factor. ranges for CP concentration 111 238 (S.D. 25.2) 589 756 48.5) g/kg DM, respectively. was much better predictor of than (R2 0.71 vs. 0.26). effect diminished increasing level concentrate supplementation (interaction P<0.001). had greater when total DM high. negatively correlated concentrations ammonia N, lactic acid, individual volatile fatty acids positively residual water soluble carbohydrates. Total acid best 0.41) followed by N. Use quadratic regressions generally increased variation accounted model. multiple 0.51 experiment. To facilitate interpretation data, theoretical is presented. An interplay physical load capacity use energy determines well-fermented over whole range D-values. With extent constrained nutrient imbalance, most probably amino ratio tissue level, resulting reduced microbial synthesis rumen. Low palatability can further constrain intake. For advisory evaluation following predicting relative proposed: index=100+0.151×(D-value−690)−0.000531×(TA2−6400)−4.7650 [Ln(Ammonia N) −Ln(50)], where (TA) are expressed N Regression coefficients scaled 10 DM/day. 690, 80 50 standard (g/kg DM), DM) high quality restrictively fermented silages. limited those which currently available Finnish farm analyses, i.e., near infra-red reflectance spectra (D-value) electrometric titration (fermentation parameters).