It doesn't take a rocket scientist to figure out that, as a society, we are getting busier. The feelings aren't just anecdotal, because it seems every morning when I watch television there is someone saying, "according to statistics of some new study, Americans are busier." Therefore, there are very few things that you can "set your watch by" anymore. Personally, I start feeling a twitch in the fall and again in the spring to pick up a gun (or a bow) and go hunting (legally) for something, unless I am too busy.
Similar twitches are felt by cattlemen and are evidenced by the type of questions they ask throughout the year. In the spring, about the middle of April, you can bet that the questions will pertain to purchasing bulls. This scenario repeats itself in late fall and early winter regarding the purchase of replacement females. However, I think the biggest twitch (seizures, in some cases) occurs about the time we turn our clocks back in the fall and manifests into the question "What do I feed my cows this winter?"
For instance, I just received an e-mail from a friend of mine who wants to know whether he should be contracting 20 percent or 38 percent cubes. He has fed "twenties" in the past, but feels as though the "thirty-eights" should be considered. He outlined a few of his concerns, but I think his biggest hesitation in making the switch was unveiled when he said, "We have been feeding the twenties for years and have never had one starve to death, so why should we switch?" I get that one a lot!
For a few obvious (and some not so obvious) reasons, this same question gets asked frequently. As with most questions involving agriculture, the answer is "it depends" and it primarily depends upon the following key areas: Product Specifics, Availability and Price.
Probably the single biggest factor in answering the question is can you get thirty-eights, and if you can, what is the energy content and price compared to 20 percent cubes. Most folks think that because "high energy" is on the label of the twenties, there is a big difference in the energy content of the two. However, if the thirty-eights contain cottonseed and/or soybean meal, then in fact there should be very little difference in energy content between the two feeds. It is always a good idea to ask your feed dealer what the total digestible nutrients (TDN) are for all feeds (this information is not required on the tag) you expect to purchase. This information will help you compare products and is important in formulating a feeding program.
Forage and/or Hay Characteristics
Assuming you can purchase both, the decision then primarily boils down to forage availability. Forage quality is important, but you can get through the winter with decent quality roughage (i.e., hay, stockpiled introduced pasture and/or dormant native grass) if you have enough of it and your cattle (mature cows) are in the right physiological stage and condition. In general, if roughage quantity is inadequate or limiting, then a 20 percent cube (i.e., Range Cube) can be used to "substitute" this inadequacy, if it is fed in relatively high amounts and is not cost prohibitive. However, if forage quantity is not a concern, then an all-natural 38 percent cube will be most effective at meeting nutrient deficiencies, as well as stimulating forage intake. Far too often, we try to make up for a lack of forage management with a feed sack it is always better to have too much forage than not enough.
Stage of Production
I have heard the statement "Feed them thirty-eights until they calve, and then start feeding them twenties because they need more energy after they calve." This is true. However, their protein needs also increase after parturition. In fact, according to what is considered the bible for beef cattle nutrition, Nutrient Requirements of Beef Cattle (NRC 1996), energy requirements increase by about 30 percent for an average milking cow after she calves, and protein requirements increase by 50 percent. Therefore, a good quality 38 percent cube (assuming price is factored in) can be used throughout the feeding season, if it makes sense to do so.
If you check your cattle every day, then both types of cubes are options. If you only see them once or twice a week and you have adequate pasture, generally speaking, a good thirty-eight will fit your situation better. In all fairness, this topic goes beyond the scope of this article. More in-depth questions need to be asked and answered before a definitive answer can be reached for your particular situation. With that said, it has been my experience that if animal condition, forage quantity and labor are not limiting factors, a high-quality 38 percent cube is going to make more economic sense, more of the time. This is primarily due to protein being the first limiting nutrient in most of the scenarios that I have dealt with. If indeed a lack of protein is the problem, then it stands to reason that unless 20 percent cubes are almost half the cost of thirty-eights (which I have never seen) and the energy content is similar, then the thirty-eights are going to be the most economical choice.
In most cases, either of the two feeds can be used under "normal" circumstances, so whatever you have fed in the past was not necessarily the wrong thing to do. Only in extreme cases, when forage quantity and/or quality is very low and/or animal condition is very poor, does it become difficult to make the twenties work due to the amount the cattle have to consume in order to meet their protein deficiency. However, in these situations, what to feed becomes secondary to alleviating what caused the situation. I have heard the comment numerous times "You can't starve a cow to make a profit," which is very true and an important concept to keep in mind. An equally important concept to remember, however, is not to drain profit out of an operation by implementing a poorly-thought-out feeding program.