Effects of varying dietary ratios of corn silage to alfalfa silage on digestion of neutral detergent fiber in lactating dairy cows

Abstract

An in vivo study was performed to test an in vitro procedure and model that predicts total-tract neutral detergent fiber (NDF) digestibility for lactating dairy cattle. Corn silage (CS) and alfalfa silage (AS) were used as forages for this study. These forages had similar NDF composition, but fiber in the CS contained less indigestible NDF compared with AS (35.5 and 47.8% of indigestible NDF, respectively). The in vitro method estimated rate of digestion of alfalfa potentially digestible NDF to be approximately 2 times faster than CS fiber (6.11 and 3.21%/h, respectively). Four diets were formulated containing different proportions of CS to AS: 100CS:0AS, 67CS:33AS, 33CS:67AS, and 0CS:100AS, as percentage of diet DM basis. The objective was to construct diets that contained approximately similar levels of NDF but with different pool sizes and rates of digestion of potentially digestible NDF. Diets were fed to 8 ruminally cannulated, multiparous, lactating dairy cows in a replicated 4×4 Latin square with 21-d periods. Total-tract fiber digestibility and fiber digestion kinetic parameters observed in vivo were compared with the values predicted by the in vitro assay and model. Total-tract NDF digestibility coefficients were similar (41.8 and 40.6% of total NDF) for the in vitro and in vivo methods, respectively. As the proportion of dietary alfalfa increased, the digestibility of NDF increased. The rate of digestion of potentially digestible NDF predicted from the in vitro assay was also similar to what was observed in vivo. Results suggest that the in vitro total-tract NDF digestibility model could be used to predict rate of fiber digestion and NDF digestibility for lactating dairy cattle.

Effects of the addition of essential oils cumimaldehyde, eugenol, and thymol on the in vitro gas production and digestibility of alfalfa ( Medicago sativa L. ) silage

“…The nutrient contents of the silage used in this research are given in Table 1. The results of the present study were similar to those of many studies in terms of CP (19)(20)(21), ADL (19,21,22), ash (21,23,24), EE (25), NDF (19,21), and ADF (19,21,23). The mean cumulative gas production of 100-ppm, 200-ppm, and 300-ppm concentrations from each cuminaldehyde, eugenol, and thymol addition to alfalfa silage at 2, 4, 8, 16, 24, 48, 72, and 96 h incubation were significantly lower than those of the control group (P < 0.05).…”

Effect of Additives on In Vitro Intestinal Utilizable Crude Protein in Dairy Cows and Mobile Bag Nutrient Digestibility of Corn, Alfalfa and Whole Barley Silages

“…The lowest postruminal digestibility of ruminal-undegraded protein in silage prepared with urea may have resulted from the greater protein degradability in rumen [46]. Post-ruminal NDF disappearance was similar for three silages than their untreated controls and was approximately 5-9% in the intestine which is fairly similar with the study of Lopes et al [52] and estimation of Cornell Net Carbohydrate and Protein System Model [53] which reported that hindgut digestion of NDF is assumed to be 10% of total NDF digestion. Throughout the present study, total tract protein disappearance was not significantly affected by the silage additives (P>0.05).…”

Lactation response to soybean meal and rumen-protected methionine supplementation of corn silage-based diets

“…Moreover, Faciola and Broderick (2014) observed NDF and ADF digestibilities of 44 and 49%, respectively, when cows were fed the control diet (i.e., with no added lipid) with a 10:50 ratio of corn silage: alfalfa silage DM. Although Lopes et al (2015) found greater indigestible NDF in alfalfa silage versus corn silage, apparent total-tract NDF digestibility increased as the dietary proportion of alfalfa silage increased. This result was explained by a rate of ruminal digestion of digestible NDF in alfalfa silage that was twice as rapid as that for corn silage.…”