Sustainable Agriculture in North Dakota:

Farm and Family Economics Extending the Grazing Season in North Dakota by Grazing the Beef Herd on Oats Chaff and Field Corn

Extension Report 53, April 1999
Tim Semler, Extension Agent/Bottineau County

Introduction

Rangelands and pastures in northern North Dakota are dominated by cool season grasses. While the cooler northern climate allows for moderate to good forage production from these grasses, nutritional value for beef cattle decreases substantially by mid summer. Access to higher nutrition warm season grass pastures for beef herds is very limited to nonexistent.

As a result of lower beef herd nutrition during late summer into fall, milk production in the herd cow and potential calf weaning weights fall short of genetic potential. In addition, cow body condition declines.

Without additional supplementation of nutrient dense feeds, cows going into the winter with low body condition score run the risk of producing low birth weight calves that are prone to stress-related diseases of pneumonia and scours. Also, low body condition score beef cows produce less milk at calving and are slow to re-breed and calve within a 365-day period, which is one of the main goals for the beef cow/calf operator.

Situation

Beef cow/calf enterprises in north central North Dakota are predominantly small grain farms diversified into beef cow/calf operations to utilize marginal farmland. Declining efficiency of beef herd production in the fall is seldom noticed by grain farmers as their attention is focused on harvesting the crop.

Crop aftermath grazing is a standard practice but rarely provides any better nutritional value than a maintenance level diet. A tremendous untapped resource for most diversified grain and cattle operations is the use of small grain chaff for extending the grazing season and providing a higher level of nutrition.

Studies in Saskatchewan and Manitoba have shown that beef cows provided free access to small grain chaff piles in the field will readily consume the chaff, as a main part of their fall diet. Nutritional value of small grain chaff as indicated by feed tests, is adequate for fall beef herd nutrition due to light grain kernels, hulls and weed seeds which make up the chaff.

Oats Chaff and Straw Grazing Phase

A 22-acre field was seeded into Paul hulless oats in mid May. Nitrogen and phosphorus fertilizers were applied for a yield goal of 80 bushels per acre. Rainfall during the grazing season was plentiful and the potential yield goal was attained.

A local operator was hired to custom harvest the field with a Redekop chaff saver apparatus on a John Deere combine on August 26. Chaff piles were dumped at random on the field and the straw was chopped and spread by the combine.

Estimated grain yield came to 60 bushels per acre (32 lb/bushel) hulless oats. This yield equates to a 90 bu/A whole oat yield. Based on a straw yield of 80-100 pounds per 60-pound bushel of wheat, straw production was estimated at 4000 pounds per acre. The 22 acres yielded 16 600-pound piles of chaff for a yield of 436 pounds per acre.

Dry matter intake (DMI) based on wet chemistry analysis should be 1.88% of body weight. For a 1200-pound cow, this equates to 22.5 pounds/cow/day consumption. Total chaff production of 9600 pounds divided by 22.5 pounds per day would equal 426 daily cow rations.

Fifty-two beef cows with calves and two bulls were turned into the field on Oct. 18. Although these cattle had never consumed chaff before, the herd readily accepted the chaff and straw. The herd also grazed the oat regrowth and chopped straw residue. The herd was satisfied for seven days. At the end of the grazing period a 2-3 inch mat remained in the location of the chaff piles.

Fifty-four adult cattle times seven days equals 378 grazing days provided by 22 acres of oats chaff and straw. Nutrient composition of the oats chaff dry basis was 10.1% protein, 54.9% TDN, 26.3 Mcal/cwt. NEg and 51.7 Mcal/cwt. NEm.

Field Corn Grazing Phase

A 16 acre field of 85-day silage blend corn was seeded in mid May. Nitrogen and phosphorus fertilizers were applied for a corn grain yield of 75 bushels per acre. Corn emergence and population was at the expected 20,000 plants per acre. Due to excessive rains in June, some stand loss was experienced in low lying areas of the field.

By October 9, corn grain was well-dented as no frost damage occurred. On this date, Kent McKay, Northwest Area Extension Agronomist, estimated the grain yield at 68 bushels per acre at 15.5% moisture. Silage yield at 33% dry matter was estimated at 13.66 tons per acre for total silage production of 218 tons on this field.

Prior to grazing by the beef herd, the corn field was divided into three equal size paddocks with electric fence to facilitate efficient utilization. Just prior to allowing access to the corn, John Dhuyvetter, Northwest Area Extension Livestock Specialist, came to view the chaff and corn grazing systems. He also randomly selected 11 cows from the herd and gave body condition scores which ranged from BCS 4 to BCS 6 with the average being BCS 4.8.

On October 25, 52 adult beef cows with calves and two bulls were allowed access to the first corn paddock. This carried the herd for 12 days until Nov. 6, when the herd was turned into the second paddock.

During grazing of the second paddock, unusually heavy snowstorms for early November hit the area. The first arrived on November 9 and left 10 inches of snow in its wake. The second and third storms arrived on November 15 and 18, which left less snow but prevented the cattle herd from grazing for two days, so the herd was supplemented with hay. Following the storms, average snow depth in the corn field was measured at 11 inches.

Cattle readily grazed the corn ears, stalks and residue until the majority of the field was fully utilized, which was December 3, 1998. At this point, the herd was provided with full daily rations of hay but allowed access to the corn field.

Fifty-four adult cattle grazed the corn over a 40-day period. Calves were weaned from the cows on November 17, with substantial grazing from the corn occurring during the 24-day period they were on the cows.

The 11 randomly selected cows were again body condition scored by John Dhuyvetter on December 8. Average BCS increased to 5.3 after the 40 days of corn grazing. An increase of 1 BCS equates to an increase of 80 pounds in body weight for a 1200-pound cow. For this herd, the average weight gain per cow would be approximately 40 pounds.

Calves nursed the cows during this phase until weaning on November 17, just prior to the third snowstorm. If calves were weaned prior to the corn grazing phase, expected body weight gain on herd cows would have been greater.

Corn Grazing Costs

Herd feeding costs from grazing corn can be viewed from several aspects. From a direct expenses standpoint, the cost of feeding the cows for the period of use is the sum of costs incurred in growing and grazing the corn. This is represented by the following budget which includes costs of seed, fertilizer, herbicides and land rent.

From an opportunity cost standpoint, the cost of grazing standing corn is the lost income (less harvesting costs) of sacrificing the sale of the corn as a cash grain crop. In either case, the sum of the direct expenses or projected income from harvesting the corn divided by the days or units of grazing provided, puts costs on a basis to compare the alternatives of daily feeding costs or pasture rental.

Based on either production or opportunity costs, corn grazing was competitive to leased grazing or feeding harvested forage due to high production costs, relative to modest inputs and low market value of harvested corn.

Corn grazing in animal units (A.U.)

                  16 acres � 68 bu./A. corn
Herd in 10/25/98 � Calves weaned 11/17/98 � End of grazing 12/3/98
      52 cows    x  1.13 A.U.  x  40 days  =  2350 A.U. days
       2 bulls   x  1.50 A.U.  x  40 days  =   120 A.U. days
      48 calves  x   .30 A.U.  x  24 days  =   345 A.U. days
                                             ----------------
                        Total grazing A.U.    2815 A.U. days
      Less 2 days feed during storms         - 156 A.U. days
                                             ----------------
                        Net grazing A.U.      2659 A.U. days

   2659 grazing days
  ------------------- = 87 A.U.M.
    30.5 days/month

Field corn budget – 16 acres

Seed         4 bags Pioneer 85 day silage blend       $135.00
Fertilizer   Urea      @  120#/A. = 1920#  @  $195/T   187.20
             Phosphate @   70#/A. = 1120#  @  $245/T   137.20
Herbicide    Basis - 6.66 oz. package                  183.15
             +Banvel   @ 8 oz./A. = 1 gal.              44.75
Land charge  16 A x $25/A                              400.00
                                                    ----------
                                             Total   $1087.30

   $1087.30
  ---------- = $12.50/A.U.M.
   87 A.U.M.

$12.50 x 1.13 A.U.M./1250# cow � 30.5 days/A.U.M. = 46.3 cents/cow/day 

Cash grain opportunity

16 A. x 68 Bu./A.                       =  1088 Bu.
1088 Bu. x $1.75 (loan price)           =  $1904.00
Less harvesting at $15/A.                   -240.00
Less drying costs at $.50/Bu.(5% moisture)  -544.00
                                          ----------
                                 Returns   $1120.00

   $1120.00
  ----------- = $12.87/A.U.M.
   87 A.U.M.

$12.87 x 1.13 A.U.M./1250# cow � 30.5 days/A.U.M. = 47.7 cents/cow/day

Summary

• A beef herd will readily adapt to grazing oats chaff and straw.
• One acre of oats chaff and straw supported 17 1250-pound cows with nursing calves for one day.
• Nutrition in oats chaff will maintain the herd cow during fall grazing.
• Under managed grazing, the cattle herd will efficiently utilize standing corn.
• Beef cattle experienced no adverse digestive or health effects in grazing mature corn.
• Body condition on selected cows increased by � BCS while grazing mature corn during the fall.
• While grazing nursing cows on mature corn, provide a protein supplement such as alfalfa.
• A craving for mineral was observed while the herd was grazing the standing corn. Supplement by providing a high calcium mineral free choice.
• Moderate level costs in establishing field corn for grazing are very competitive to pasture rental rates.
• One acre of standing corn will support 60 1250-pound cows with nursing calves for one day or about 85 1250-pound dry cows for one day. (3.4 A.U.M./acre)
• Feed cost in November through early December for 1250-pound cows was 47.7 cents/cow/day, which is competitive with hay or other harvested feeds.

Extension Report 53, April 1999