Don Johnson, the television actor who played one of the lead roles in "Miami Vice," used to talk about the hazards of working with the trained alligator that was supposed to be his pet on the series. As he would say, the term "trained alligator" is actually a contradiction in terms; like "military intelligence," or "Postal Service." Likewise, the term stockpiled hay is actually a misnomer.
What we're talking about is leaving grass unharvested in the field at the end of the season. Instead of cutting hay for wintering cattle, it's "stockpiled" in the field. Whenever it's needed, cattle are simply turned into the field. Said to be a new concept, I've been surprised to hear that some Extension services have been promoting it.
Actually, the concept is not totally new. It's common to hear old timers talk about the "cure" on winter grass. Specifically, many ranchers winter stocker cattle on native pasture, and whether the calves did or did not gain well during the winter ... is usually explained or blamed on whether the grass did or did not cure well that winter.
Grass Vs. Hay Grass does not cure. Hay cures but grass does not. When grass is left in the field it goes dormant or vernalizes. So, the term stockpiled hay is not correct. The correct term would be stockpiled grass.
If hay is cut and stored properly, it's a different commodity than stockpiled grass. If you open up a bale of hay, the interior will be green. Unharvested grass in a hayfield will not be green (during the winter). What's the difference? About 10-15 cents/head/day.
I'll be the first to acknowledge that there's an enormous amount of hay that is neither cut at the right maturity, nor stored correctly. However, if it's cut and stored properly, grass hay will run about 8-12% crude protein. If you take a sample of stockpiled grass, it will run about 5-6% crude protein. Good grass hay will contain a significant amount of carotene, which can be converted to vitamin A. The stockpiled grass will have none. Good hay will have about 11/43 more phosphorous, and 50-100% more trace minerals.
When warm-season grasses go into winter, the physiology of the plant changes dramatically. The plant is no longer growing, so minerals and nitrogen are no longer absorbed; and chlorophyll and carotene are no longer manufactured.
The bottom line is that good quality grass hay needs very little supplementation; stockpiled grass needs a great deal. Good quality hay typically needs only salt, a modest amount of trace minerals, and/or a little phosphorous. Stockpiled grass, on the other hand, will need a lot more phosphorous and trace minerals, a full dosage of vitamin A, and 0.75-1 lb. of a protein supplement.
It's Nitrogen, Not Protein It's important to realize that 5-6% crude protein is not just 50% less than 10-12%. In terms of what's useful to the animal, it's 70-80% less. The reason being that below 5% crude protein, virtually none is digestible. What is showing up as crude protein is the nitrogen complexed with the lignon (the indigestible portion of the fiber). So, the analysis for crude protein is not an analysis for protein at all. It's merely an analysis for nitrogen. The amount of nitrogen is simply multiplied by 6.25 and the result is called crude protein (CP).
If you're interested, take a sample of stockpiled hay, send it to a laboratory capable of running a sophisticated forage analysis known as a "pepsin digestion test" (not every laboratory can do this test). Ask them to run both crude protein as well as the pepsin protein test. The results will be 5-6% CP and 0-2% apparent digestible protein (from the pepsin test). What you will find is that you do not have stockpiled hay. What you have is dormant grass.
Don't get me wrong, dormant grass can be a valuable feed. But it's not as valuable as hay. Certainly it will save on harvesting and labor costs, but it's not a free lunch. It will have to be supplemented, whereas hay needs little or no supplementation.
David P. Price is a consulting nutritionist specializing in feedlot and range cattle. A number of his books and a subscription newsletter are available through BEEF magazine by contacting Marilyn Anderson at 800/722-5334, ext. #710.
For more information on the Coulter Scrotal Tape, contact Trueman Mfg. of Edmonton, Alberta at 800/363-4085.