In Vitro Dry Matter Disappearance of Three Different Forage Sources

Abstract

resh 7 day growth Bermudagrass-clipping lawn pellets (Cynodon dactylon L.), alfalfa hay, sun-cured, mid-bloom pellets (Medicago sativa L.), and Coastal hay, sun-cured, 43-56 days growth bermudagrass hay pellets (Cynodon dactylon L.) were used to study the effects of forage source on dry matter disappearance in an in-vitro ruminal culture system. Rumen fluid was collected from a cannulated steer receiving 100% bermudagrass hay diet and transported to the Texas Tech University Ruminant Nutrition Laboratory.  Tubes were prepared in triplicate with substrate and McDougall’s Buffer.  Incubation times of cultures with forage substrate were 12, 24, and 48 hours.  As expected, there was a linear increase (P < .0005) in dry matter disappearance for both the Coastal hay pellets and the alfalfa pellets over the 12h, 24h, and 48h time periods.  Furthermore, there was a significant (P < .05) quadratic increase in dry matter disappearance over the 12h, 24h, and 48h, time period for the Coastal hay pellets.  However, while the bermudagrass-clipping lawn pellets had adequate dry matter disappearance, there was no difference (P > .05) between the 12h, 24h, and 48h time period.   Differences amongst treatment diets at hour 12 and hour 24 were different (P < .05) between the alfalfa pellets, Coastal hay pellets, and the bermudagrass-clipping lawn pellets.  However, at hour 48, dry matter disappearance was higher for the alfalfa pellets, but was not significantly different for the Coastal hay diet or the bermudagrass-clipping lawn pellets.  Therefore, this study indicates that alfalfa pellets are most digestible in an in vitro culture system followed by the bermudagrass-clipping lawn pellets, and the Coastal hay pellets.