Maize silage is acknowledged to be a good energy source for high-production dairy cows, but it is protein deficient. Many farmers therefore add large amounts of protein concentrate to rations to give the animals a balanced feed. This makes for high production performance but at the same time makes feeding considerably more expensive. Unlike maize, the lupin is a protein-rich plant generally harvested at maturity for its seeds. Like all legumes, the lupin is difficult to ensile due to excess humidity prior to maturity, often causing the silage to deteriorate in storage. The idea developed in this study is mixing maize and lupin in the same silage in order firstly to improve its keeping properties and, secondly, to produce forage with a more balanced nutritional value in relation to the animal’s requirements.
Objectives
A late variety of lupin (Lupinus albus, var. Energy) was planted alongside an early maize variety (Zea maïs, var. Pernel), in two adjacent plots with the same area with a view to harvesting simultaneously in mid-September. The cutter-blower moved from one plot to the other with no adjustment to the settings in order to obtain a homogeneous mix which was then ensiled without any additive. The aim of the research was to compare the effect of two rations of the same nutritional value, containing either 50 % maize silage or 50 % mixed lupin/maize silage, on the performance of two homogeneous batches of nine high-production dairy cows.
Results obtained
Yields were in the region of 55T/ha in the case of maize (34.9% DM) and 32 T/ha with lupin (21.5% DM). The mixed silage was richer in protein than the maize silage (11.8 as opposed to 6.9%) with an OEB of 0.8 g/kg, indicating a perfect balance between the rumen fermentable energy content and degradable N content. Milk production, measured in the Department of Animal Production and Nutrition’s herd, exceeded 1.65 L/head/day on the mixed silage ration. The latter also permitted the concentrate added to the ration to be cut by 500 g/d compared to the maize silage ration. Milk quality (fat and protein content) and animal weight were not affected by the type of silage. The results therefore indicate tangible benefits from combining lupin and maize in the same silage. In the future, it should be interesting to investigate the proportions of lupin and maize in the mix, the complementary varieties and the economic benefits of this method, notably to promote the utilization of forages with a lower environmental impact than the maize crop alone.
