Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2004
Publication Date: 11/8/2004
Citation: Sanderson, M.A., Soder, K.J., Klement, K.D., Brzezinski, N., Taube, F. 2004. Sward structure of simple and complex forage mixtures under grazing[abstract]. Agronomy Abstracts. Paper No. C06-4385. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Diet selection of grazing animals is influenced by the sward composition and the vertical sward structure. We conducted a grazing study to examine how selective grazing affected the sward structure of simple and complex mixtures of forages. Replicated 1-ha pastures were planted to either orchardgrass- (Dactylis glomerata L.) white clover (Trifolium repens L.) or a complex mixture of nine temperate forages (including chicory, Cichorium intybus> L.). Pastures were grazed by lactating dairy cows. The vertical structure was measured pre- and post-grazing by stratifying the canopy into six layers (5 to 7 cm each) and separating herbage into grass, legume, or forb. Forage samples of the different layers were analyzed for nutritive value via calibrated near infrared reflectance spectroscopy. The measurements were conducted during four grazing periods in 2002 and 2003. The nine-species mixture out yielded the two-species mixture. The deep rooting chicory was particularly productive due to the very hot dry weather conditions in the experiment. Nutritive value of the sward declined from the upper to lower layers and between pre- and post-grazing. The results of the stratified samples showed more selection for certain forages among the upper layers of the canopy than among the bottom layers. There was a clear preference by the cows for legumes than for grass or chicory.