The Advantage of Brassicas
Brassicas are popular products in the cover crop and food plot arenas. However, these broadleaf cool-season annuals can be valuable in livestock grazing operations. They have excellent cold tolerance, surviving temps below 20 degrees F. Forage quality is excellent. Brassica foliage often exceeds 20% protein and is a great companion to high-sugar grasses. Dry matter digestibility can be comparable to alfalfa.
Brassicas forages are most often mixed with cool-season annual forages (annual ryegrass or winter cereals). When established early in the fall planting season and given a mild dose of nitrogen, brassicas can produce exceptionally large leaves that can remain green and upright well into the coldest months. A common practice is to allow the mixed brassica field to reach full size (when cold temperatures begin to limit growth), and then release cattle onto the field. In the Central and Southern Plains, where brassicas are often mixed into winter pastures, fields can be saved for late fall or winter grazing.
Farmers often claim their winter pastures with the highest grazing yields are cool-season annual grasses mixed with brassicas. Some varieties, if temperatures are not too cold, show moderate regrowth after grazing. Brassicas have a strong taproot and are fairly drought tolerant.
There are several categories of forage brassicas.
Forage Turnips: Forage turnips are similar to purple top turnips, except they have been developed to provide more top growth for grazing. Like purple top turnips, forage turnips produce a palatable tuber (bulb) that animals can pull up and eat after foliage is grazed off. The tuber is very nutritious. Forage turnips can provide grazing earlier than rape.
Forage Rape: Forage rape is improved rape or hybrid brassicas (crosses between forage rape and forage turnips). Above the ground, forage rape looks very similar to forage turnips. However, forage rape does not produce a tuber. Forage rape may produce foliage faster than forage turnips because less energy is used to grow a tuber. Rape often produce higher foliage yields than forage turnips.