Addition of straw with ensiling of wet crops ensiling and feeding experiments with italian ryegrass and beet top ensiled with and without application of straw and ensiling and feeding experiments with maize and sunflower
Andersen, P.E.; Skovborg, E.B.
Beretning fra Faellesudvalget for Statens Planteavls- og Husdyrbrugsforsog 10: 1-28
Ensiling wet crops with a dry matter content below 20% could be a difficult task, because of the high effluent losses. It can also cause pollution problems. Such crops as Italian rye grass and beet top harvested in the autumn often have a low dry matter content. Barley straw can be used as an additive to increase dry matter content in the silage. It can be prepared as a bottom layer in the silo, or it can be mixed with the green crop in the silo. In both cases the straw absorbs a great part of the effluent from the green crops in the silo. Two experiments were conducted with Italian rye grass with and without addition of straw (10%). The results were an increase of 4% units in dry matter, 6% units in crude fibre and a reduction in crude protein and of the digestibility, but not more than expected, with the addition of straw. The quality of the mixed silage was not significantly lower than of the grass silage alone. There was some variation in the level of the losses in the silo, measured on grass alone. In the experiments with ensiling beet top with or without straw, the absorption and effluent into the straw was measured as 2.39 kg per kg barley straw. The best result was obtained, when careful mixing was applied. The absorption was more uneven in a bottom layer of straw, when this was the method of selecting effluent. The quality of the silage in these experiment was somewhat lower than was seen in experiments carried out on laboratory scale. It was also difficult to avoid after fermentation, when the silage was taken out for feeding. In this context it must be emphasized that a careful mixing of straw and beet top is essential to obtain good silage quality. Feed intake experiments with dairy cows were also conducted. In the experiments with Italian rye grass the silage was in complete rations together with concentrates. The same proportion of straw at feeding time as in the mixed silage was added to the pure grass silage. No significant difference was seen regarding feed intake, milk yield and daily gain between the two groups of cows. The advantage of adding straw should be to absorb the effluent from the green crop, and the straw can absorb 2.0 to 2.5 kg effluent per kg straw. Feeding such wet straw from the bottom layer in a silo was done in one experiment together with sugar beets and concentrates to dairy cows. The feed intake was fair, but the persistency of the cows milk yield was lower than normal. In two feed intake experiments the mixture of beet top + straw silage was compared with silage of maize- and sunflower. The feed intake of the mixture was somewhat lower than for the two other silages. In the last experiment the beet top was ensiled alone (1), mixed with normal barley straw (2) and mixed (NaOH) sodiumhydroxid-treated barley straw (10%). A group experiment was conducted with dairy cows. The feed intake increased, when straw was mixed into the beet top and the increase was highest for cows eating beet top + NaOH straw. The milk yield increased accordingly. The higher dry matter content in the mixed silage increased the feed intake as was seen from earlier feeding experiments with increasing dry matter content in the silages. The production of FCM by the dairy cows fell per kg organic matter in mixed silage. But the minimal reduction still indicated that the organic matter from the effluent was utilized well.