Influence of Chemical Drying Agent and Surfactant on Drying Time and Ruminal Nutrient Digestion of First-Cutting Alfalfa Hay
- James E. Nocek ,
- James B. Russell and
- Janet B. Fallon
Drying agents and surfactants have been used to decrease field drying time of hay; however, little is known about their influence on ruminal digestion. This study was conducted to determine the effect of chemical drying agents (alkaline carbonates, 30 g L−1) or surfactant (actylphenoxypolyethoxyethanol, 0 to 0.164 ml L−1), or both, on field drying time and extent and rate of ruminal nutrient digestibility of alfalfa (Medicago sativa L.) hay. Untreated controls had longer drying times than treatments containing drying agent. Drying agent alone did not influence in situ dry matter (DM) or neutral detergent fiber (NDF) digestibility. Surfactant addition decreased the rate of DM and NDF digestion. Bacterial-N contamination (fraction of residue N of bacterial origin) increased with time in the rumen for treatments receiving the highest surfactant concentrations. The rate of N digestion was faster when treatments contained drying agent plus surfactant. When examined with in vitro fermentation, surfactant concentrations greater than 0.0005 mL L−1 resulted in a greater than 80% reduction in digestion of filter paper. Surfactant had little effect on soluble starch fermentation, but there was an approximately 50% reduction both of ammonia production and cell protein, if protein hydrolyzate was the substrate. Amylolytic bacteria were less sensitive to the surfactant than cellulolytic species. The surfactant used in this study was inhibitory to rumen microorganisms and decreased the NDF digestion rate of alfalfa hay.
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