Cubes are a common supplement for protein, energy or both because there are several options available, and cubes offer the flexibility of feeding on the ground or in troughs. The most appropriate option will vary depending on forage or hay quality, nutrient needs and body condition of the cows, and cost of the cubes.
If only protein supplementation is needed, then a 40% protein cube is a good option. A “40% cube” is a generic term that is often used to describe a cube that will be from about 38% to 41% crude protein on the feed tag. These cubes may be the most expensive per sack or ton of feed, but they will price out cheaper per pound of protein than other cube options.
If both protein and energy supplementation are needed, then a 20% protein cube is a good option. Most feed companies make more than one version of a 20% cube. To compare these different options, look at the maximum crude fiber amount listed on the feed tag. The lower the crude fiber content, the better. As the crude fiber content decreases, the energy (e.g., total digestible nutrient [TDN]) content of the cube increases. When selecting 20% cubes for supplementation, look for options that contain 11% crude fiber or less. The ones with less crude fiber might appear to cost a little more per bag or ton, but they will be cheaper per unit of TDN. Unfortunately, TDN is not listed on the feed tag, so crude fiber should be used to compare cubes from an energy standpoint.
For a recent program, I calculated the difference in the amount of cubes and cost per day of a 10% crude fiber cube compared with a 15% crude fiber cube. To provide the same amount of energy per day it only took 5 pounds ($1.46 per day) of the lower fiber cube compared with 6.4 pounds ($1.61 per day) of the higher crude fiber.
If only energy supplementation is needed, then cubes that contain 11%-14% crude protein are good options. As discussed above, focus on the crude fiber content when comparing these cubes. Lower crude fiber is better.
Availability of distillers grain cubes from ethanol plants has increased in recent years. These cubes are a good source of both protein and energy. They will typically contain about 28% crude protein on the tag and will be higher in energy than other cubes.
