Submitted to: Extension Fact Sheets
Publication Type: Other
Publication Acceptance Date: February 15, 2009
Publication Date: March 4, 2009
Citation: Soder, K.J. 2009. Does Sward Structure Affect Bite Mass of Grazing Cattle? - Fact Sheet. Northeast Pasture Consortium Fact Sheets. p. 1.
Interpretive Summary: An interpretive summary is not required.
A study was conducted to evaluate the effect of forage species and sward structure of dairy cows grazing micro-swards. Cows were offered one of the four grasses planted in experimental micro-sward boxes over two years. Grass species consisted of: orchardgrass (Dactylis glomerata L.), meadow fescue (Festuca pratensis Hud.), quackgrass (Elytrigia repens), or reed canarygrass (Phalaris arundinacea L.). In 2006, the seeding rate was high to mimic previous work, while in 2007 the seeding rate was reduced to more closely mimic pastures in the Northeast. Boxes were weighed before and after each grazing session. The number of bites taken was recorded. Bite mass was calculated by dividing the number of bites taken by the total weight loss of the box. Sward measurements (herbage mass, bulk density, tiller length, tiller density) were collected to evaluate sward structure. Bite mass was not affected by forage species, indicating that, within the scope of this experiment, forage species had little influence on the decision-making process. The cattle were able to adjust their bite patterns to maintain a similar bite mass across forage species, despite differences in sward structure (sward height and density). Bite mass was affected by year; taller, denser swards in 2006 resulted in greater bite masses than in 2007. This fact sheet summarizes this research project at the USDA-ARS Pasture Systems and Watershed Management Research Unit in University Park, PA.