|This article appeared
in the November 2001 issue of the "West Virginia Farm Bureau News, WVU Update."
Extending the grazing season is one way to reduce winter feed cost since pasture costs one-half to one-third as much to produce as harvested feeds. Managing a meadow by accumulating forage produced during late summer for use in late fall or winter is called "stockpiling" or "deferred grazing."
In the fall, stockpiled tall fescue is leafy, palatable, and high in protein and sugars. It is highly digestible because it is low in fiber. Other perennial grasses have fall growth and forage quality similar to tall fescue until they are killed by freezing weather and damaged by rain and snow.
The quality of stockpiled tall fescue depends on the date of deferral, rate of nitrogen (N) fertilization, fall growing conditions, and how late in the winter the forage is used. Stockpiling in August or September produces higher quality but lower fall yields than stockpiling in June or July.
Tall fescue deferred in August and fertilized with 50 to 100 pounds of N per acre will yield 2,000 to 4,000 pounds of dry matter (DM) per acre containing I I to 16 percent crude protein (CP) and having 60 to 65 percent total digestible nutrients.
After killing frosts, forage quality declines as freezing weather kills the leaves and rains leach nutrients from the forage. Nitrogen fertilization increases the sugar and CP content of fescue and decreases the rate of leaf death caused by frost. Green leaves contain 12 to 20 percent CP, compared to dead leaves' 8 to 10 percent.
When N fertilization is delayed to late summer, the CP content of the forage increases in December. Weather conditions favorable for high yields tend to decrease CP in December, apparently by diluting the CP with fiber and sugars. As winter progresses, the CP content of deferred tall fescue decreases; CP content increases in the spring as new forage growth begins. In early fall, CP levels can be as high as 29 percent, but they decline in February to 8 to 16 percent.
Nutrition deficiencies occurring on winter pastures can be avoided by sampling the pastures for laboratory analysis. Then, the proper mineral, energy, or protein supplements can be given, based on the production status of the animals.
The quality of stockpiled tall fescue is more than adequate for dry cows. A study at the Jackson Branch of the Ohio Agricultural Research and Development Center evaluated the weight gain of beef cows grazing deferred tall fescue. Over the four- year study, three-month fall weight gains averaged 1.71 pounds per head per day and body condition increased 0.71 units. There was a significant reduction in the number of cows in condition score 4 or lower.
The forage quality of stockpiled fescue may not be optimal for growing or lactating animals, which may require energy or protein supplements. Quality hay or fibrous grain by-products such as soybean hulls can be used. They are less likely to reduce forage digestibility than corn and other high-starch supplements will.
If protein is low because of a low rate of nitrogen fertilization or good growing conditions causing high forage yields, animals may respond to protein supplements. The amount of supplement fed should be based on the pasture's protein quality and the animal's requirement. For dry cows, urea-based supplements usually will be adequate. For growing calves, supplements supplying degradable protein to stimulate rumen bacterial fiber digestion and some undegradable protein may produce the highest gain.