Will it work? I'm trying to find out
I have been known to do egregious things. One I did recently was to mention Sericea lespedeza and not follow with how much Remedy to use to kill it. So let me clarify. Good Sericea lespedeza is dead Sericea Lespedeza.
Now that I have offended nearly everyone, except perhaps the Missouri highway department that introduced Sericea, I am pursuing another agronomic adventure.
I am trying to find information on grazing rice as a late-summer annual pasture. I was speaking with a Missouri cattle raiser who is looking at using rice as a pasture crop, seeding it down like any other small grain crop and grazing it as we would rye or wheat. The interest in rice is acute in that it has a growth habit that covers a part of the year when we tend to be forage short-the mid- to late-summer time of year.
When I look through the literature, I find data on feeding rice straw. Usually the reports are from Asia, and draft animals are fed the rice straw (people eat the grain). To the American ruminant nutritionist, this can be an emotional hurdle. I overcame it some years ago in Central America. I was looking at some skinny lop-eared milk cows. The farm manager solicited my opinion. I was the wise guy from the States. Trying to make a point, I said, "Hey! Do you know what corn is?"
The farm manager said, "Of course, we eat corn, all the tortillas on this morning's table were from slaked corn, and your point is?"
So, I said, "I, uh... I guess we won't be feeding corn to the cows; they get the stalks, cobs and husks, right?"
Rice straw is tough stuff, notorious for silica, it dulls knives about like chopping sand. It has fiber levels as high as cottonseed hulls.
Years ago I scrounged around looking for rice forage, because some high end Waggie recip cows were supposed to be fed rice straw and barley. I wanted to feed the cows Iowa brand corn silage, but the honorable Japanese owners wanted to feed the cattle rice forage, and since the honorable Japanese were paying the bills, we went to Arkansas for rice forage.
This was a tremendous experience. Most of the rice straw was plowed under, and the rest, which was baled, was most frequently used for erosion control. We did find some unheaded material that was baled, and it did not feed too bad-much better than straw would have.
For rice straw, figure these averages: about 60 to 65 percent neutral detergent fiber (of which 30 percent is digestible); 40 to 45 percent acid detergent fiber and 5 percent crude protein-roughly similar to corn stalks, although corn stover NDF will tend to be of higher digestibility than 30 percent. Given that whole-plant corn silage can have substantially more energy and protein than the subsequent corn stover, I would expect that younger rice plants have substantially higher nutrient content than rice straw. A research team from Korea, lead by Ki et al, in the April 2009 issue of Asian-Australasian Journal of Animal Sciences, reported that whole-plant rice silage could be used to replace corn silage in milking cow diets without reducing milk production. Ishida and the Korean Rural Development Administration have also done work on using whole-plant rice silage for dairy feed. I would suspect if a forage can be used as dairy feed, it would certainly be a beef feed alternative.
I would expect that higher protein content would tend to improve digestibility, as would lower silica contents. UC Davis did work across a wide variety of rice cultivars and the California work did not show a correlation between silica concentration and digestibility. This is encouraging in that the silica might not be directly reducing the digestibility.
When I went and asked colleagues about grazing rice, the most common response was, "I have no idea." Other common responses told me that rice is a grain crop-and one of the most costly crops to establish. It is too costly for cow feed with the exception of the by-products: bran, mill feed and hulls.
Agronomists I talked to were particularly concerned with the amount of silica. Rice may have a silica requirement, but cows do not. A clever emeritus professor said that it should work, but doubted the likelihood of getting funding for such a project.
So, at this juncture, I am soliciting the experience or advice of anyone who has tried grazing ruminants on rice as we would graze other small grains such as wheat, rye, barley, oats or triticale.
Dr. Jim White is ruminant nutritionist for MFA Incorporated.