Article ID Journal Published Year Pages File Type
2453987 The Professional Animal Scientist 2010 7 Pages PDF
Abstract
The objective of this study was to compare the nutritive value of forage selected by grazing cattle (masticate) with hand-collected forage samples from bahiagrass (Paspalum notatum Flüggé) pastures. Forage and masticate samples were collected monthly at 4 locations within the state of Florida. Chemical composition of forage and masticate samples was determined and selection indices (SI = {[(masticate - hand-sampled analyte concentration)/hand-sampled analyte concentration]  × 100} + 100) were calculated for in vitro digestible OM, CP, and ADF concentrations. Hand shears were used to collect hand-sampled forage, and masticate samples were collected using ruminally fistulated steers. Masticate samples had greater (P ≤ 0.001) in vitro digestible OM and CP concentrations and lower (P < 0.001) ADF concentration than hand-collected forage samples (60.0 vs. 48.7, 11.7 vs. 10.0, and 34.4 vs. 29.4%, respectively). A sampling type × month interaction (P ≤ 0.006) existed for IVOMD, CP, and ADF during the study. The SI was greatest (P < 0.001) in the winter months in January and February for IVOMD, whereas the SI was lowest in June. The SI for ADF was lowest (P < 0.001) in February, March, and November compared with other months. Selection of CP tended (P < 0.06) to be affected by month. Throughout the year, steers were able to selectively graze bahiagrass forage and consume a diet better than what would be predicted by collecting hand-sampled forage. Ultimately, understanding selection differences could influence supplementation decisions for cattle grazing subtropical forages.
Related Topics
Life Sciences Agricultural and Biological Sciences Animal Science and Zoology
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