M.L. Mohler+, S.L. Boyles*, and B.W. Stoll++
+Ohio State University Extension,
*Department of Animal Sciences, and
++Natural Resources Conservation Service
There are 346,050 acres of Ohio farmland enrolled in the CRP (Loux et al., 1995). As contracts approach their expiration date, participants are faced with the decision of what to do with CRP acres. Anyone wishing to participate in other USDA programs must meet Conservation Compliance provisions. Agricultural commodities cannot be produced on highly erodible land (HEL) unless soil erosion prevention measures are initiated or installed that maintain soil loss to USDA acceptable standards. Maintaining CRP cover and using it for pasture or hay production should meet the Conservation Compliance demands. The objectives of this project were to monitor the performance and economics of cattle grazed on CRP land and to determine if intensive grazing is compatible with water quality and can economically compete with corn and soybean production.
An intensive grazing project was initiated at the Indian Lake Water Shed Project at the farm of Russ and Miriam Forsythe near Belle Center, Ohio. The 2-to-5-year project will evaluate intensive grazing of cattle instead of a cropping system.
Land Description. A 40-acre parcel of land was allocated for the grazing project. Permission was granted from the Consolidated Farm Service Agency (CFSA) to conduct the experiment. The land was seeded to orchardgrass, timothy, and clover 8 years ago when it went into CRP. Red clover was frost seeded in March, 1995, at a rate of 10 pounds per acre. The grazing site prior to the onset of the project was mowed once per year during the time the land was in CRP.
The soil was a Napponee St. Clair silt/loam with 6 to 12% slopes, which is typical of Logan County, Ohio. A soil test was done on December 22, 1994. Nitrogen applications (ammonium nitrate, ammonium sulfate, and urea) were made at various times throughout the grazing season to enhance forage quantity (Table 1). A soil nitrate nitrogen test was done on each section on July 13 after all nitrogen applications.
| Table 1. Nitrogen applications at Indian Lake Watershed stocker cattle intensive grazing project. | ||||
| Land sections | ||||
| Date | A | B | C | D |
| (Pounds N)1 | ||||
| (11.3 acres) | (6.1 acres) | |||
| April 17 | Cattle | 21 | 21 | |
| April 27 | 55 | |||
| May 22 | 78 | 40 | 40 | |
| May 31 | 51 | |||
| Total | 133 | 61 | 72 | 40 |
| 1 Actual nitrogen. | ||||
The Ohio Water Quality Standards (Ohio Administrative Code 3745-1-04) specify that all surface water of the state must be free from pollutants as a result of human activity. Longitudinally-cut plastic barrels were placed in holes in the ground at natural drainage spots in proximity of the grazing site. Two plastic barrels (Site 1 and Site 2) were placed at the grazing project to collect surface water runoff for nitrate testing, and one barrel (Site 3) was placed adjacent to the project area on CRP land and used as a control. Site 1 was a surface water collection point for Sections A and B. Site 2 was surface water collection point for Section C.
Fence Design. The pasture was divided into four sections. The perimeter fence consisted of high tensile fence (5 strands, 3 electrified). One strand of electric fence was used internally to divide the sections. However, paddock A and an arrival area were completely enclosed in high tensile fence to acquaint cattle to the electric fence. Three sections (A, B, and C) contained 11.3 acres per section, and the fourth section (D) comprised 6.1 acres. Each section was subdivided with movable electric tap so the paddocks were 1.4 acres in size (28 cells). The cattle were moved daily in the mornings within the 40 acres.
Water and electric were provided from a nearby barn. Black, plastic pipe (0.75 inch, 200 pound test) was laid along the fence, and a portable water trough was moved to the paddock that calves were currently grazing.
Cattle Description. The cattle were fed on a contract basis. The grazing charge was $0.25 per pound of gain. One-hundred cattle arrived at the site from Kentucky on April 15, 1995. Weight prior to shipment was 598.3 pounds. Arrival weight at the project site was 582.4 pounds, with the resulting shrink being 2.65%. Cattle received a body condition score (Boyles et al., 1992) at the beginning, mid-point, and conclusion of the trial. Prior to arrival, the calves were implanted with Ralgroª (Mallinckrodt Veterinary, Inc., Mundelein, IL) in March, had free choice hay and pasture, and 1 to 3 pounds of a grain supplement per head/day. A 10% magnesium mineral supplement (BioZyme, Inc., St. Joeseph, MO) was available ad libitum during the grazing trial. Cattle were given fly tags and implants on June 14. Internal parasites were determined to be negligible based on worm egg flotation tests done on June 14 and August 9. The cattle were individually graded (USDA, 1980) on June 14, 1995.
Forage Nutrient Content. Forage samples were collected on weekly intervals after cattle began on the demonstration area. Samples were taken from a paddock just prior to the steers entering that particular grazing cell. The procedure was to walk diagonally across the field, take small samples, and place the collected forage in a sealable plastic bag. The samples were frozen and then sent to the OSU Research Extension Analytical Laboratory at Wooster for analysis (Table 3).
Stocking Rate. The initial stocking rate was 100 steers on 40 rotationally grazed acres (Table 2). The stocking rate of 2.5 steers per acre was selected because it was thought that this was the maximum tolerable rate for 450- to 500-pound steers on this land area. However, the steers were actually 100 pounds heavier than anticipated.
| Table 2. Stocking rate changes over time at Indian Lake Watershed Intensive Grazing Project. | ||
| Date | Situation | Number of cattle |
| April 17 | Cattle arrive.
Cattle 100 pounds heavier than expected. Rainfall for April 17 to 30 = 1.8 inches. |
100 |
| April 29 | Removed 20 head. | 80 |
| May 4 | 1) Four round bales fed/day for 4 days.
2) Added an ionophore to the mineral supplement. Rainfall for May = 6.05 inches. Rainfall for June = 6.0 inches. |
80 |
| June 28 | Grass short, removed 20 head | 60 |
| July 1 | Supplemented pasture with hay for 15 days.
Rainfall for July 1 to 19 = 0.3 inches. |
60 |
| August 10 | Supplemented with hay until project ended.
Rainfall for August = 2.7 inches Rainfall for September 1 to 13 = 1.45 inches. |
60 |
| Sept. 13 | End of project | 60 |
A major difference between CRP land and pasture that previously had been grazed was the number of plants per square foot or per acre. The forage was adequate in quality on this CRP land, but there were fewer plants and more bare spots compared to a previously grazed pasture. An initial stocking rate of less than two steers per acre may be more prudent.
Animal Performance. The final 60 steers departed on September 13, 1995, resulting in a 149-day grazing period. The weighted average daily gain for the 60 steers remaining in the project and the 20 steers that were removed in June was 1.4 pounds/day. The yield of beef per acre was 351.1 pounds. Gross returns per acre were $87.77 based on a charge of $0.25/pound of gain.
Animal Requirements (Energy and Protein). Protein levels ranged from 18 to 30% on a dry matter basis (Table 3). Rotational grazing is keeping the forage in a vegetative state and maintaining high protein levels. Net energy values were adequate for maintaining approximately 1.5 pounds of body weight gain/day (NRC, 1984).
Animal Requirements (Minerals). In general, the forage appeared to be adequate in most of the minerals required to meet cattle requirements (Table 3). However, supplementation of minerals could be recommended, because sodium requirements approach 800 ppm and the forage only supplied 100 to 200 ppm.
The current phosphorus levels in the forage (0.35 to 0.40%) were adequate to borderline in meeting NRC requirements (0.30 to 0.40%). Although phosphorus levels appeared to be numerically adequate, it should not be assumed that all phosphorus present was actually available to the animal. Therefore, a mineral supplement fed free-choice should contain phosphorus for stocker cattle (Bock et al., 1991). The mineral supplement in our study contained 2.6% phosphorus.
| Table 3. Forage analyses for Indian Lake Watershed Intensive Grazing Project (100% dry matter basis). | |||||||
| Nutrient | April1 | May | June | July | August | September2 | SE3 |
| Dry matter, % | 16.6 | 15.9 | 21.9 | 24.5 | 22.9 | 40.8 | 1.79 |
| Crude protein, % | 22.2 | 27.5 | 22.9 | 23.1 | 24.7 | 24.4 | 0.77 |
| NDF4, % | 49.8 | 46.4 | 45.7 | 50.5 | 45.8 | 45.6 | 1.40 |
| Lignin5, % | 6.0 | 6.5 | 6.0 | 7.0 | 6.6 | 9.0 | 0.55 |
| NEm6, % | 0.59 | 0.59 | 0.59 | 0.56 | 0.58 | 0.54 | 0.01 |
| NEg7, % | 0.28 | 0.27 | 0.29 | 0.25 | 0.28 | 0.22 | 0.02 |
| Phosphorus, % | 0.37 | 0.39 | 0.42 | 0.46 | 0.57 | 0.51 | 0.02 |
| Potassium, % | 2.93 | 4.00 | 4.11 | 3.61 | 4.06 | 3.61 | 0.13 |
| Calcium, % | 0.78 | 0.84 | 0.76 | 0.85 | 0.93 | 1.11 | 0.06 |
| Magnesium, % | 0.26 | 0.34 | 0.37 | 0.38 | 0.43 | 0.47 | 0.02 |
| Sulfur, % | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | . . . |
| Sodium8 , ppm | 118 | 168 | 212 | 87 | 224 | 130 | 25.60 |
| Manganese, ppm | 125 | 109 | 126 | 100 | 95 | 58 | 6.90 |
| Iron, ppm | 289 | 254 | 483 | 216 | 311 | 130 | 45.30 |
| Copper, ppm | 10 | 12 | 10 | 11 | 15 | 12 | 0.60 |
| Zinc, ppm | 37 | 38 | 32 | 41 | 58 | 41 | 2.70 |
| K/ (Ca+Mg)9 | 2.83 | 3.47 | 3.73 | 3.05 | 3.12 | 2.30 | 0.76 |
| 1 First forage collection occurred on April 16, 1995.
2 Last forage collection occured on September 7, 1995. 3 Standard error. 4 Neutral detergent fiber. 5 Values for lignin were estimated. 6 NEm = Net energy maintenance. 7 NEg = Net energy gain. 8 Parts per million. 9 K = potassium, Ca = calcium, Mg = magnesium; a value of 2.2 has been correlated with an increase in frequency of tetany. | |||||||
Grass Tetany Potential (High Potassium). No symptoms of grass tetany were observed in the cattle. The average magnesium content of the forage in this trial was more than 0.2% (Table 3). Minimum needs of sheep and cattle for growth generally can be met by pastures or diets containing 0.10% magnesium, but 0.18 to 0.20% magnesium is considered necessary for lactating cows (McDowell et al., 1993). A value of in excess of 2.2 for K/(Ca+Mg) has been correlated with an increase in the frequency of grass tetany (Kemp and t'Hart, 1957). The values for the forage alone were in excess of 2.2 and did not change over time (P = 0.52). However, Seekles, as cited by Grunes et al. (1970), questioned the accuracy of the equation K/(Ca+Mg) for predict-ing the incidence of grass tetany. The mineral supplement for the steers contained 6.8% magne-sium and an ionophore. Ionophores may increase the absorption of magnesium (Bock et al., 1991).
Soil test results were a pH of 7.1, phosphorus at 36 pounds/acre, potassium at 366 pounds/acre, magnesium at 904 pounds/acre, calcium at 2160 pounds/acre, and a cation exchange capacity of 24. It is not necessary to include potassium in starter fertilizers unless the soil test potassium levels are less than 75 ppm (Vitosh et al., 1995). Potassium fertilization was not needed based on the current levels of soil potassium and cation exchange capacity.
Frame and Muscle Score. Of the 80 steers in this trial, 52 steers (65%) were classified as large-frame cattle; 28 steers (35%) were classified as medium-frame. The proportion of muscle scores were similar across frame, with 80% of the steers having a number 1 muscle score (highest score, more muscle) and 20% having a number 2 muscle score. No thinly-muscled or number 3 muscle score (lowest score, less muscle) cattle were observed.
Body Condition. All of the medium-frame cattle had average body condition (BCS = 5) in June except one steer that had a BCS of 4. Seven of the large-frame steers had body condition scores of 4, and the rest of the large-frame steers had body condition scores of 5. All cattle appeared to gain weight and condition, given that the majority of cattle in April had a BCS of 4 and a few were even thinner. It generally is preferred to have growing cattle in average body condition (BCS = 5) or slightly thin (BCS = 4). Gains will be more efficient when cattle are slightly thin but healthy. Seventy-five percent of the 60 remaining steers in September had an average body condition score of 5, while 25% averaged a body condition score of 4.
Nitrates. Soil nitrate analyses were conducted in July after all the nitrogen applications had been made to the forage. This was done to evaluate the nitrogen previously applied and to evaluate potential nitrogen utilization. Sections A, B, C, and D had soil nitrate nitrogen contents of 2, 0, 4, and 4 ppm, respectively. These are considered to be low soil nitrate levels.
Run-off. Ohio EPA must notify the area residents when the water nitrate nitrogen level is greater than 10 ppm. In only one instance were water run-off levels greater than 10 ppm (May 26; 22 ppm). On May 22, 78 pounds of actual nitrogen was applied to Section A, and 40 pounds of actual nitrogen was applied to Section B. A substantial rain (greater than 1 inch) occurred on May 23, and sampling was done on May 24. Surface run-off samples were collected if there was a 1 inch or greater rainfall (Table 4).
Break-even Prices. The profitability of grazing partially will depend on initial prices of the cattle and the cost of gain. The analyses assumed three purchase prices for the cattle ($60, $65, and $70/cwt) and two different costs of gain ($25 and $35/cwt). Table 5 contains the results for those various break-even calculations. The break-even price spread was approximately $9/cwt.
| Table 4. Run-off water testing at Indian Lake Watershed stocker cattle intensive grazing project for nitrate nitrogen.1 | |||
| Date | Site 12 | Site 23 | Site3/control |
| (ppm) | |||
| May 26 | 22 | 2 | 3 |
| May 31 | 3 | 3 | 4 |
| June 5 | 4 | 3 | 4 |
| June 10 | 3 | 3 | 2 |
| June 22 | 5 | 3 | 2 |
| June 30 | 4 | 2 | 2 |
| 1 Quick test.
2 Sections A and B. 3 Section C. | |||
| Table 5. Break-even prices for stocker cattle at various initial prices and at two different costs of gain. | |||||
| Initial price
($/pound) |
Beginning weight
(pounds) |
Total gain
(pounds) |
Final weight
(pounds) |
Cost of gain
($/pound) |
Break-even price
($/pound) |
| 0.60 | 598 | 208 | 806 | 0.25 | 0.51 |
| 0.60 | 598 | 208 | 806 | 0.35 | 0.54 |
| 0.65 | 598 | 208 | 806 | 0.25 | 0.55 |
| 0.65 | 598 | 208 | 806 | 0.35 | 0.57 |
| 0.70 | 598 | 208 | 806 | 0.25 | 0.58 |
| 0.70 | 598 | 208 | 806 | 0.35 | 0.61 |
Other participants in the project are: OSU Extension: Gene McCluer, Mark Bennett, John Smith, Tammy Dobbels, and Cindy Folck; Logan and Hardin County Soil and Water Conservation District; Merck AgVet Division: Carol Robertson; Logan County Cattle Association: Jim Warne; Champaign Landmark, Inc.: Eric Johnson; Mallinckrodt Veterinary: Ken Anderson; Evans Fence Company: Richard Evans; Dailey Fence & Supply: Dave Dailey; North Side Vet Clinic: Don Kerns; H.B.D. Industries: Ron Swonguer; Carter Lumber: Mike Alstaetter; Indian Lake HUA: Frank Phelps; Agri-Pro Seeds: Larry Brake; Vita Ferm: John Heitbrink; Vigro: William Hammond; C.F.S.A.: Chris Foust; Y-Tex: Fred Luman; Tractor Supply Co.
Bock, B.J., S.M Hannah, F.K. Brazle, L.R. Corah, and G.L. Kuhl. 1991. Stocker cattle management and nutrition. Kansas State University Cooperative Extension Service, Manhattan. C-723.
Boyles, S., T. Flakoll, and K. Ringwall. 1992. Cow nutrition and body condition. North Dakota State University, NDSU Extension Service, Fargo. AS-1026.
Grunes, D.L., P.R. Stout, and J.R. Bronell. 1970. Grass tetany of ruminants. Advan. Agron. 22:331.
Kemp, A., and M.L. t'Hart. 1957. Grass tetany in grazing milking cows. Neth. J. Agric. Sci. 5:4.
Loux, M.M., R.M. Sulc, P. Thomison, J.E. Beuerlein, and J. Johnson. 1995. Converting CRP land to cropland or pasture/hayland: Agronomic and weed control considerations. Ohio State University Extension, Columbus. Extension Fact Sheet AGF-024.
McDowell, L.R., J.H. Conrad, and F.G. Hembry. 1993. Minerals for grazing ruminants in tropical regions. 2nd Ed., Animal Science Dept., University of Florida, Gainesville.
NRC. 1984. Nutrient Requirements of Beef Cattle. 6th Ed., National Academy Press, Washington, D.C.
U.S. Department of Agriculture. 1980. U.S. standards for feeder cattle. Agriculture Marketing Service. AMS-586.
Vitosh, M.L., J.W. Johnson, and D.B. Mengel. 1995. Tri-state fertilizer recommendations for corn, soybeans, wheat and alfalfa. Michigan State University Extension, East Lansing. E-2567.