GRAIN-LEGUME SILAGES FOR THE SWARTLAND

The Swartland area utilizes winter cereal crops and mostly relies on small grain cereals as silage in dairy cow diets. These crops are usually lower in crude protein (CP) and result in lower dry matter (DM) yields than either maize or lucerne, which implies that more CP concentrates at extra cost need to be supplemented to achieve the milk yields wanted. Therefore, it has become important to evaluate alternative forage sources to grain-only silages. This then forms the basis for the investigation cited.

Fourteen mixtures were planted at Langgewens Experimental Farm which included two mixtures of only grain (triticale and oats with either SVG13 barley or Moby barley); four mixtures of two grains (triticale and oats) with one legume (bitter lupines, vetch, faba beans, and field peas); four mixtures of one grain (triticale) with either bitter lupines, vetch, faba beans, or field peas; three mixtures of two grains (triticale and oats) and one legume (vetch) with either field peas, faba beans, or bitter lupines; and one mixture of triticale, oats, field peas and bitter lupines. Three samples of each mixture were cut at the soft-dough stage with a Ferraboli silage chopper, inoculated with Sil-All and ensiled into Weck glass flasks for six weeks and then chemically analysed. Dry matter was also determined.

The mixture of triticale and faba beans had the highest DM yield of 4 027kg per ton, which was higher than the DM yields of the only grain mixtures of 3 187 and 3 740kg per ton for SVG13 and Moby respectively. The predicted milk production for the triticale-faba bean mix was 1 299kg milk per ton silage. The predicted milk production of the mixture of triticale and vetch was significantly higher at 1 364kg milk per ton silage, although this mixture had the lowest DM yield of 2 040kg per ton. This is probably due to the fact that vetch requires a longer growth period than faba beans which should be taken into account.