This article was written collaboratively by David Casper and Xingyou Gu.
The fall forage harvest has started at South Dakota State University (SDSU) evaluating unique forage blends. Forage production continues to be an important part of South Dakota livestock production. The production of high quality forages are highly valuable crops. In addition, forages are the most economical nutrient sources for meeting the nutritional requirements of livestock. The greater the concentration and digestibility of forage nutrients, the greater the forage inclusion can be in the ration, which lowers feed costs and the cost of production. While improving forage quality and digestibility is economically valuable, the development of new forage crops and blends are being evaluated for meeting nutrient requirements of South Dakota Livestock.
The Plant and Dairy Science Departments are working on a novel approach to develop blend(s) of specific crops grown in combination for forage production. This approach offers livestock productions the opportunity of supplying additional nutrients in the ration in the form of forages. Forages are the most economical sources of nutrients on the farm for meeting the nutrient requirements of livestock. Thus, improved nutrient concentrations and digestibilities creates opportunity for further lowering the cost of producing meat and milk.
The Plant and Dairy Science Departments are currently evaluating an inter-cropping system between a new variety of soybean that grows like a vine and a new grazing corn hybrid. The vining soybean was developed by hybrid breeding of cultivated (Glycine max) with wild (G. soja) soybean. The soybean and corn seed were sown in alternative lines or mixed to sow so that the vining soybean grows by climbing and wrapping itself around the corn plant. The photograph highlights the vine type of soybean plants climbing corn plants. Since soybeans belongs to the legume family, the plants can actually fix nitrogen in the soil that would benefit the corn plant. In addition, soybean plants harvested as haylage are high in crude protein (~20%) and can be very digestible.
The grazing corn hybrid being evaluated is MasterGraze, which is a high sugar corn that will not produce an ear. MasterGraze will be higher in crude protein (~14%) than normal corn silage. MasterGraze is a high energy (high sugar) and protein corn plant that will readily ensile. Thus, the combination of soybeans and grazing corn could/will result in the production of a forage blend that is high in both protein and energy. This forage blend has the potential to reduce the cost of growing dairy and beef heifers, beef steers, beef cows, and dairy cows in the dry period by reducing or eliminating protein and energy supplementation, i.e. soybean meal and corn.
This demonstration project contains 3 corn hybrids (1 grazing and 2 normal corn hybrids) and 2 types of soybeans (regular and vine) for comparative purposes. The corn and soybeans have been grown individually and in combination to demonstrate concept feasibility. Currently, the crop material has been harvested as silage.
The ensiling process (Figure 1.) consisted of chopping the wilted material through a chipper, weighed, and mixed with a silage inoculant using a small cement mixer and then packed into 5 gallon mini-silo buckets. These buckets will be stored at room temperature for 90 days and then reweighed to measure weight loss and open and sampled for nutrient composition and digestibility.
Based on this information, plans will be formulated for spring planting to evaluate the different planting ratios of vine soybeans and corn that would optimize nutrient composition for livestock. The goal of this project is to develop new forage blends that will meet the nutrient requirements of beef and dairy cattle, while reducing the cost to grow animals for the production of meat and milk.