During times of limited forage, crop residue is sometimes used to replace other hay sources. Crop residues could include cornstalks, grain sorghum stubble, straw from cereal grains (e.g., wheat, oats, etc.) and even soybean hay. When considering these potential options, it is important to understand any pros, cons or limitations of each. Some important things to consider include cost, nutrient content (especially total digestible nutrients [TDN] and adjusted crude protein [CP]), palatability, amount of potential waste and possible risk for nitrates or hydrogen cyanide (aka prussic acid). A more complete discussion on hydrogen cyanide will be left for another day – but yes, it can sometimes be an issue in hay.
In general, cornstalks or grain sorghum stubble are better options for most producers. Straw from cereal grains is very low in palatability and difficult to get cattle to consume unless it is ground and mixed in a complete ration. Additionally, it is generally lower in TDN and adjusted CP than other options. Due to stem size and how fragile leaves can be, soybean hay can be difficult to make hay from without losing a lot of leaves. The stems are lower in quality and palatability than leaves.
Regardless of source, all hay should be purchased by the ton whenever possible – if priced by the bale, it is important to convert bale prices to a price per ton so different sources can be evenly compared. The Texas A&M AgriLife Extension publication “Bale weight: How important is it?” illustrates the importance of this.
Because of aflatoxin, spoilage and other risks that come from grain included in the bale, corn or sorghum stalks are generally a better option than corn or sorghum hay. (Stalks don’t include grain.) Based on results from 2011 and other years, cornstalk hay is generally a little higher in TDN and palatability and has less waste than grain sorghum stubble. However, cornstalks can vary tremendously depending on how the hay was made.
Removing the spreader from the back of the combine and just baling the windrow will result in the highest-quality cornstalks. Hay produced like this has tested from 55% to 63% TDN with 5% to 6% protein. If the stalks are cut, moderately raked and then baled, the quality will be lower, often 43% to 48% TDN. With more aggressive raking, the TDN may be from 32% to 40% TDN. Aggressive raking leads to increased soil contamination, which reduces both TDN and palatability.
