by Dennis Cash, Ron Carlstrom, and Gene Surber, MSU Extension Service (retired)

 

2002 is winding down, and across central and western Montana, late summer rains have improved the dryland pasture and forage situation. Since 1999, severe drought conditions in this region have forced many producers to use some different forage strategies, such as planting alternative annual forage crops. The acreages of hay barley and other cereals and warm-season crops such as millet, sudangrass, sorghum x sudangrass hybrids and corn has risen in many counties. These helped offset the forage deficit of dryland alfalfa and perennial grasses for the past three years. Many of these annual crops have performed so well, it is likely more Montana ranchers will opt to use them in conjunction with perennial hay crops in the future. Aside from good tonnage and energy yields during a drought, the annual forages provide an excellent crop rotation break when renovating perennial stands of alfalfa or grass.

Current issues with standing annual forages and alfalfa hay:

  1. Late crops of cereals, millet, sorghum x sudangrass, and other warm - season crops due to cool, dry early summer followed by late rains (including grain crops, now to be salvaged as feed): Across the state, MSU Extension Service county agents have done several thousand nitrate tests for producers, and many of these crops grown under stress contained toxic levels of nitrate. For the sorghum or sorghum x sudangrass hybrids, there is the additional concern of prussic acid (HCN), and we are now dealing with that problem. Particularly with the impending "killing freeze" - be cautious with both nitrate and prussic acid.
  2. Regrowth of cereal or warm - season forages - with August rains, these crops have produced an abundance of high quality forage, but again be aware of potential nitrate and prussic acid.
  3. Poor hay curing weather for second or third - cut alfalfa fields. Our best recommendation for stand longevity of alfalfa and many cool - season grasses is to avoid cutting during the fall hardening period (30 - 45 days prior to "first frost" or early August UNTIL a "killing frost" or mid - October). Unfortunately, October is a challenging time to be making dry hay, especially in damp, cool years.

Swath or windrow grazing is a good forage option, and depending on upcoming weather, may be an excellent strategy for 2002. Swath grazing provides an excellent source of nutritious forage, and can result in a cost savings of over $30 per acre. At this time of year, swathed forages provide an excellent maintenance diet for bred cows, and with supplemental grain can provide a high - growth diet for bulls or replacement heifers. The mechanics of swath grazing involve swathing and early raking to minimize leaf loss, some inexpensive and timely movement of electric fencing, and a reliable and possibly mobile livestock water source. Swath grazing is superior to direct grazing in the fall because it eliminates leaf shatter and trampling losses, and the bloat potential of alfalfa after frost is minimized. Specifically for fall 2002, grazing wind rowed forages may help salvage forage crops if wet, cold weather prevent good haying.

For late (or regrowth) cereal, millet or sudangrass forages, monitor now for nitrate levels (if high, the level will likely stay high at freezing and the crop may not be useable). For sudangrass and sorghum - sudangrass, also be cautious of prussic acid which can be high in young tissue such as regrowth leaves. There is no quick test for prussic acid, and freezing (or fermenting during shipment to a lab) can change the lev el. Our recommendation is to leave the crop standing until a hard freeze, allow the crop to dry down, then send a representative sample to a lab for analysis (allow one week). These crops have minimal loss in palatability and quality in the fall, so a sl ight delay for the prussic acid test is a good safeguard. Swath grazing should be timed on perennial crops (soon) to reduce future stand damage. For alfalfa or grass - alfalfa mixtures, wait for the "killing frost" in your area (two or three consecutive da ys in the mid 20 - degrees), then cut. If the windrows are light, rake two or three together to make a dense, entwined swath that will withstand winds. Long - term comparisons of swath grazing vs. direct grazing on alfalfa stand life are not available, but b e cautious with newer stands and "experiment" with older stands.