title: Effects of partial substitution of concentrates with maize silage in organic dairy cow rations on performance and feed efficiency.
abstract: BACKGROUND
  The general goal of organic dairy farming is to minimize purchased concentrate use and focus on milk production from forages. The aim of the present paper is to examine the influence of a partial substitution of purchased concentrates with home-grown maize silage on feed intake, milk production and feed efficiency in rations for organic dairy cows. In the experimental treatment group (E), two-thirds of average herd concentrate intake was replaced with 2.7 kg maize silage on a dry matter (DM) basis.
  
  
  RESULTS
  In treatment E, total DM, energy and protein intake were significantly reduced compared to the control treatment group (C). Daily milk yield decreased in E by 11% and milk urea content was significantly lower. Calculated milk production from forage was significantly higher (91 versus 71%) in treatment E. Efficiency of dietary nitrogen (N) utilization (calculated as milk N as a percentage of N intake) was slightly improved in E and protein and energy balance (calculated as intake as a percentage of requirements) were closer to zero than in C.
  
  
  CONCLUSIONS
  The present study indicates a potential to reduce levels of concentrates and substitute them with maize silage in organic dairy cow rations at least in the second half of lactation. Copyright © 2007 Society of Chemical Industry.
authors.affiliation: Department of Sustainable Agricultural Systems, Division of Livestock Sciences, BOKU-University of Natural Resources and Applied Life Sciences, Gregor Mendel Straße 33, A-1180 Vienna, Austria.
authors.forename: Margit
authors.initials: M
authors.lastname: Velik
authors.forename: Roswitha
authors.initials: R
authors.lastname: Baumung
authors.forename: Werner
authors.initials: W
authors.lastname: Zollitsch
authors.forename: Wilhelm F
authors.initials: WF
authors.lastname: Knaus