Currently up to 5% of feed offered in organic farming is allowed to be conventionally produced feed stuffs as temporary regulation. In general, a 100% organic feeding of fattening pigs is possible. In practice, this goal has currently not been reached. Alfalfa, clover and their dried meals can be used aside from hay, straw, silage and root vegetables. Alfalfa (Medicago sativa) shows a methionine content of 1.5 g/100 g crude protein, when harvested at early stages. This corresponds to the level of soya protein, and exceeds the average contents of peas (0.28 g/100 g crude protein) and fava beans (0.24 g/100 g crude protein), which are often used as home-grown protein sources. Therefore, alfalfa conserved as silage, could be used as a protein source as well as roughage. Additionally, the European guidelines for organic livestock include a daily offer of roughage for pigs. The supply of protein for the organic pig production so far has not been achieved, therefore, the potential of alfalfa silage as feedstuff was examined in a feeding trial: 3 feeding groups x 2 gender x 6 repetitions (2 animals/repetition) with 36 fattening pigs crossbred: (Duroc x Pietrain) x (German Landrace x Large White), initial body weight: 29 kg. The control group (A) was fed with a complete feed mixture and the silage groups (B and C) were fed with a supplementary feed mixture (adjusted to the alfalfa silage). Group B and C received alfalfa silage as chopped (B) and as extruded (C) ad libitum. Animals were slaughtered at 100–105 kg live weight. Feed intake, fattening performance and carcass characteristics were determined. The proportion of alfalfa silage in the total daily DM ration of the experimental groups was ~ 20% in the starter phase, ~ 40% in the grower phase and up to 50% in the finishing phase. In this way, approximately 100 kg of concentrated feed per pig and fattening period could be saved in comparison to the control group.
Fattening performance and carcass characteristics of the silage groups (groups B and C) did not significantly differ from those of the pigs in control group (A), which was served concentrated feed only. However, the daily gain of all feeding groups (an average of 600 g) was at a relatively low level. Young harvested alfalfa can be an appropriate regional protein source and additionally possible roughage for organically fattening pigs.
Wüstholz, J., Carrasco, S., Berger, U., Sundrum, A., and Bellof, G. (2017). Fattening and slaughtering performance of growing pigs consuming high levels of alfalfa silage (Medicago sativa) in organic pig production. Livestock Science. https://doi.org/10.1016/j.livsci.2017.04.004