Use of roughage (silages, ryegrass, Jerusalem artichoke, and turnip) during vegetation course in year round free range production of fattening pigs

Publications

Sappok, Mascha; Pellikaan, Wilbert; Schenkel, Hans und Sundrum, Albert (2008) Einsatz von Raufuttermitteln (Silage, Weidelgras, Topinambur und Stoppelrüben) im Vegetationsverlauf in der ganzjährigen Freilandhaltung von Mastschweinen. [Use of roughage (silages, ryegrass, Jerusalem artichoke, and turnip) during vegetation course in year round free range production of fattening pigs.] Universität Kassel, D-Witzenhausen, FB 11 Ökologische Agrarwissenschaften.

Abstract

The research project was conducted to assess intake of different roughages by fattening pigs in free range systems by using titan dioxide as marker and in vitro methods to determine the apparent digestibility. In four fattening periods pigs of the experimental treatments had free access to the field crops while concentrate was reduced by 15% (starting period) resp. 30% (finishing period) compared to the control treatments.
Mean daily live-weight gains (dlwg) in the different fattening periods varied markedly between and within treatments. Pigs with access to Jerusalem artichoke gained clearly higher dlwg compared to the control treatments while access to the other roughages was only partly suited to compensate for the reduced concentrate. In general, carcasses were characterized by a high lean meat percentage.
Investigations on the digestibility of roughages by using three different in vitro methods (enzymatic incubation, fermentation, and pre-treatment before fermentation) gained similar results. Hence, all methods seem to be appropriate tools to assess roughages.
With a mean value of 41.2% ± 5.1% faeces contained a very high concentration of crude ash. High correspondence of the noble earth element patterns between faeces and soil samples indicate that the concentration of crude ash in faeces originated nearly exclusively from the incorporated soil. Analysis of titan dioxide in faeces after Kjeldahl-disintegration did not led to valid results. These were obtained after a repeated disintegration of samples after exposure to pressure and measuring with ICP-OES.
Due to the high amounts of incorporated soil elements and the interference with titan dioxide it is concluded that the use of titan dioxide does not allow drawing valid conclusions with regard to feed intake and that titan dioxide is not an appropriate marker under free range conditions. Potential risks with respect to the food safety issue when pigs are kept on soils possibly loaded with residues need further investigations.

Final Report