R-1006; This circular focuses on designing twice-over rotation grazin

Barker, William T.

Sedivec, Kevin K.

English

NDSU Libraries Institutional Repository

R·1006 111111[I~iIIII11111~rllllm~rl ~[I'lr~~~1'1111111111 3 ()109 00919 1704 Design and Characteristics of the Twice-Over Rotation Grazing System Kevin K. Sedivec Rangeland Management Specialist NDSU Extension Service Dr. William T. Barker, Prof. Animal and Range Sciences Dept. North Dakota State University NDSU LIBRARIES IIIIIIIIIIII!IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII!III!IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII11I111111111111111111111111111111111111111111111111111III 111111111111111111111111111111111111111111111111111111111111111111111111111111I11I111111111111111111111111111111I111111111111111111111111111111111111111111111111IIII NDSU EXTENSION SERVICE JUNE 1991 North Dakota State University, Fargo, ND 58105 Twice-over rotation grazing is a variation of the deferred-rotation grazing system, which involves graz-ing three or more native pastures in rotation based on the growth stages of key species. In twice-over rota-tion grazing, livestock are rotated through the system faster than a once-over rQtati~n grazing system, allow-ing for periods of regrowth ofvegetation and resulting in more acceptable forage for livestock throughout the grazing season. A higher quality vegetative re-growth forage is available for livestock use during the second grazing cycle. Twice-over rotation grazing in-volves more management of the range resource than season long or continuous grazing and will require more attention to the livestock herd. The manage-ment recommendations for this grazing system are based on data collected at the Central Grasslands Research Center from 1983 through 1990. System Design Number of Pastures The twice-over rotation grazing system can be im-plemented with three, four or five pastures. Generally, four pastures are recommended to maximize forage and livestock production while minimizing fencing and water development costs. Four pastures allow for greater flexibility of use than three pastures while still providing desirable amounts of forage and good live-stock responses. Pasture Size Size of each pasture should be considered on the basis of potential forage productivity from the land, numbers of acres involved in the system, herd size, and number of herds. Maximum or minimum size of individual pastures is determined by the number of animals desired in one herd. A minimum of 40 acres per pasture is suggested to eliminate overcrowding, but smaller pastures may be desired if total land or animal numbers are limited. Each pasture should be similar in herbage produc-tion potential, making some pastures larger than others if dominated with low producing range sites (such as shallow-to-gravel and thin-upland sites). An evaluation of your rangeland should be performed before fencing the pastures. Knowledge of range sites (see Circular R-580, Range Site Identification) and their herbage potential will aid in determining correct pasture sizes. Technical help to determine your range production and carrying capacity is avail-able from your county agent and local Soil Conserva-tion Service office. .. . 2 Pasture Layout The twice-over rotation grazing system is relative-ly simple to design and, generally, can be modified from the producer's current grazing operation. Since many livestock producers already have multi-pas-tures, designing a twice-over rotation grazing sys-tem may mean just adding one or two new fences, or simply changing the rotation of the livestock herd. Pasture layout will generally be determined on water availability, range site productivity, and distance from home base. The layout can range from develop-ment of separate pastu res (Figu re 1), a centrally located pasture center (Figure 2), or fan-shaped radi-ated fences from a pasture center (Figure 3). The fan-shaped design has been used successfully at the Central Grasslands Research Center near Streeter. Separate pastures must have a sufficient amount of water in each pasture to maintain the livestock 1 2 3 4 Figure 1. A four-pasture grazing system with pastures not sharing a central point. Three or five pastures may also be designed. 1 2 I I I r 3 4 Figure 2. A four-pasture grazing system with a centrally located pasture center. Figure 3. A four·pasture fan·shaped radiating cell design with centrally located watering supply. herd. The fan·shaped or centrally located designs mayor may not need a central watering supply, depending on availability of water in each pasture. Water Water is a critical component when designing the pasture layout. Sufficient water must be supplied to meet the daily needs of the livestock herd plus an emergency supply in case of drought or inadequate water levels. A separate pasture layout design can meet the needs of a grazing system if water is not limited. When water supplies do not meet the minimum reo quirements for the livestock herd in each pasture, a central watering facility may be desired. Wells may be developed in pastures with insufficient water or located where two or more pastures meet so that one tank can serve several pastures. In some cases, water can be piped from a well to pastures with in-sufficient water. Stockponds can also serve as per· manent water sources, either in individual pasture or as a centrally located water source for all pastures. Fencing Permanent or temporary fences can be used in the design of the twice-over rotation grazing system. Boundary fences should be conventional four- or five-strand barb wire or their equivalent. Three- or four·strand barb wire fences have provided adequate control of cattle as interior and boundary fences. Woven fences control sheep, but five-strand barb wire fences have been adequate if the bottom wire is about five to six inches above ground level. Electric fenCing is commonly used when imple· menting grazing systems, particular when interior cross fences are used (ex. fan-shaped design). All cross fences need not be charged, only those pas-tures controlling livestock need to be electrified. 3 Two-wire cross fencing will control cattle. The top wire, approximately 28 to 30 inches from the ground, is charged while the bottom wire is grounded. Elec-tric fences controlling sheep need at least three wires with four being optimum (two hot, two ground). Fiberglass posts are commonly used in electric fences, but steel and wooden posts can be substitu· ted. Fences should be designed for maximum ease of handling and minimum stress on the livestock and vegetation. Fencing design consideration should be given to creeks, topography, range sites, potholes, roads, etc. to maximize forage production potential among pastures. Operations Rotation Cycle Rotation dates will vary with forage production potential in each pasture, plant growth, and plant speCies. Initially, rotation dates should be based on calendar dates, then, after considerable experience with the grazing system, on the growth stage of the vegetation. The rotational schedule of the twice-over rotation grazing system being studied at the Central Grass· lands Research Center is set up on calendar dates. The cattle graze one pasture for 20 days and are then rotated to the next pasture. Each of four pastures is grazed for 20 days, twice throughout the grazing sea· son for a total of 40 days per grazing season (Table 1). This system allows for 60 days of rest between each rotation. A productive native mixed grass prairie is com-posed of both cool and warm season species. If a pasture is grazed at the same time each year or is overgrazed in a given year, the balance of cool and warm season speCies can be upset, resulting in a less productive system. Alternating the first pasture grazed each year is essential to maintaining the Table 1. A four year grazing schedule for a four·pasture twice-over rotation grazing system based on 20 day grazing periods per cycle per pasture. Days Pastures Date Grazed 1 2 3 4 May 28-Jun 16 20 1990 1991 1992 1993 Jun 17-Jul 6 20 1993 1990 1991 1992 Jul 7-Jul 26 20 1992 1993 1990 1991 Jul 26-Aug 15 20 1991 1992 1993 1990 Aug 16-Sep 4 20 1990 1991 1992 1993 Sep 5-Sep 24 20 1993 1990 1991 1992 Sep 25·0ct 14 20 1992 1993 1990 1991 Oct 15-Nov 3 20 1991 1992 1993 1990 balance of cool and warm season grass species. Start the grazing season in pasture one the first year and in pasture two the second year, leaving pasture one to be grazed last in each rotation cycle in year two. The third year grazing should begin in pasture three and on the final y~ar of the cycle grazing begi~s in pasture four. On the fifth year the cycle will start over again in pasture one. Range Readiness Range readiness for grazing can never be over-em-phasized in proper grazing management. No grazing system can improve the productivity of the range resource if native range is grazed too early. Grazing should not begin until about May 20 in southcentral North Dakota and late May in northern North Dakota for proper management of the range resource. Gen-erally, the three- to four-leaf stage on native grasses is a recommended guideline for range readiness. The use of complementary pastures seeded to in-troduced domestic grasses is recommended if ear· lier spring pastures are required. Crested wheat-grass and smooth bromegrass are the two most common grasses utilized for spring pastures in North Dakota. Grazing can begin on crested wheat-grass by late April or early May and on smooth bromegrass in early May in North Dakota. The three-leaf stage is the recommended guideline when these plant species are ready for grazing. Grazing Periods Range sites differ significantly in forage produc-tion potential and need to be considered when deter-mining pasture size and length of grazing periods. Each range site is associated with a soil type. The use of soil maps may help you determine range site composition. Determine forage potential of each area to be fenced and adjust fencing layout accord-ingly. Records Records are essential when implementing a rota-tional grazing system. Records provide the informa-tion to make wise, informed decisions and need to be kept in a manner that allows easy analysis and im-mediate access. A well kept grazing record form will provide the information necessary to make proper decisions. (A sample grazing record form is attached at the end of this circular.) 4 Vegetation and Livestock Responses Vegetation Plant vigor appears to be improved and forage pro-duction increased with twice-over rotation grazing when compared to season long grazing. Spot grazing is decreased but will still occur, especially at lower stocking densities. The density of brush species such as western snowberry did not change on the trials at the Central Grasslands Research Center. Livestock Producers may wish to increase the stocking rate to achieve the desired forage responses and pro-duce a return on the investment. Studies at the Central Grasslands Research Center showed an in-crease in stocking rate of 40 percent on the four-pasture twice-over rotation grazi ng system compared to u.S. Soil Conservation Service recom-mended rates for season long grazing (Table 3). Both treatments were stocked to utilize no more than 50 to 60 percent of the above ground fOliage. More beef was produced per acre with four-pasture twice-over rotation grazing due to an increased stocking rate acheived with the grazing system. Three- or five-pasture twice·over rotation grazing can also be im-plemented with increased stocking rates achieved. Any increases in stocking rate should be compared to the recommended U.S. Soil Conservation Service stocking rates for your region. If your pastures are already overstocked, a grazing system will not allow you to increase stocking rates. How much the stocking rate can be increased will vary according to the previous year's stocking rate and range condition. Stocking rate increases may be minimal or none if rangeland was overstocked before the system was implemented. Stocking rate increases from 15 to 40 percent of the present stock-ing rate may be acheived if the pastures were proper-ly stocked in previous years and if range condition is good to excellent. Probably the greatest benefit following the initia-tion of the twice-over rotation grazing system is im-provement of grazing distribution and rest to the plants after defoliation. Higher stocking densities encourage the use of more available forage by live-stock. An initial stocking rate increase on the grazing system shou Id be no more than 15 to 25 percent above the recommended rates by the U.S. Soil Con-servation Service for each range condition class. Therefore, if a pasture is judged in poor, fair, good, or excellent condition, a 15 to 25 percent increase Table 3. Forage production, utilization, and livestock performance on a three·pasture twice·over rotation grazing from 1983·1984, four·pasture twice·over rotation grazing system from 1985·1990 and seasonlong grazing from 1983·1990 on the Central Grasslands Research Center, Streeter, North Dakota. Year Forage Production (Ibs/ac) Utilization (%) Livestock Number Calves cow/calf Days ADG AG/Aa pairs grazed (Ibs) (Ib/a) ........................ Three·pasture twice·over rotation grazing (240 acres) ....................... . 1983 2159 56 40 153 1.75 47.6 1984 2104 45 45 153 2.08 49.3 Mean 2132 50 42.5 153 1.92 48.5 ......................... Four·pasture twice·over rotation grazing (320 acres) ........................ . 1985 2592 52 65 160 2.20 57.0 1986 3132 48 65 161 2.16 60.6 1987 3439 50 65 160 2.36 66.6 1988b 1382 55 65 105 2.16 46.1 1989 2354 63 65 160 2.73 78.3 1990 2426 60 65 160 2.55 72.5 Mean 2553 55 65 151 2.36 63.5 ........................................... Season long grazing (320 acres) .......................................... . 1983 2220 67 40 153 1.76 35.4 1984 2353 54 45 153 2.08 37.6 1985 2828 58 45 160 2.09 40.2 1986 3424 59 45 161 2.20 42.4 1987 4059 51 45 160 2.43 47.5 1988b 1538 47 45 105 2.22 33.6 1989 2468 53 46 160 2.81 58.6 1990 2604 55 46 160 2.59 52.1 Mean 2687 56 44.6 152 2.27 43.4 aADG - Average Daily Gain, AG/A - Average Gain per Acre. b1988 was a severe drought year, grazing season shortened by 55 days. Source: Barker and Nyren. 1991. 1990 Grass and Beef Review. NDSU·Central Grasslands Research Center, Streeter, North Dakota. p 10. Wienhold. 1985. M.S. Thesis. North Dakota State Univ. Fargo, North Dakota. would be based on the assigned rate for each condi-tion class. Future stocking rate increases, or decreases, will be based on range improvements resulting from increased plant vigor, which will in-crease forage production and improved range condi-tion. Good record keeping should be maintained to help determine the adjustments in stocking rates. Records should include: 1) days grazed per pasture for each season, 2) forage usage (light, medium, heavy) for each pasture during each grazing period, 3) precipitation records, and 4) livestock production records. A sample grazing record form is provided. 5 Wildlife Benefits Studies at the Central Grasslands Research Cen-ter provided positive information on the effects of twice-over rotation grazing system on wildlife pro-duction. Upland nesting waterfowl production in-creased on the system because of improved nesting habitat (Table 4). Nesting habitat for sharp-tailed grouse and upland nesting nongame birds was also improved on the twice-over rotation grazing system when compared to seasonlong grazing at the Central Grasslands Research Center. The twice-over rotation grazing system provides temporarily undisturbed cover on areas of the sys-tem during the nesting season and also minimizes competition for forage with other grazing herbivores. Flexibility of use provided by the numerous pastures is a positive feature of any grazing system. The flex-ibility allows modifications in use to oenefit wildlife and should be included in the grazing plan. Table 4. Waterfowl nesting success and number of suc-cessful nests per 100 acres comparing twice-over rotation grazing and season long grazing at the Central Grasslands Research Center, Streeter, North Dakota from 1983-1989. Treatment Twice·over rotation Season long Mayfield Number nesting Acres of nests success Number of successful nests/100 ac. ........................................ percent ....................................... . 594 320 549 216 34.7 26.6 6.6 4.6 Source: Sedivec et al. 1990. In Proceedings: Can Livestock Be Used as a Tool to Enhance Wildlife Habitat. U.S.DA Forest Servo p 72·92. 6 Conclusion The twice-over rotation grazing system is an op-tion for livestock producers to eliminate seasonlong grazing on native rangelands. Implementing a graz-ing management plan in livestock operations to max-imize forage production and economic return from an acre of land is strongly suggested. Twice-over rotation grazing is just one of many grazing system that can be considered. The system will help max-imize forage production while maintaining or improv-ing the range condition. It allows flexibilty in a graz-ing operation without intensive management and high fencing costs. The system at the Central Grass-lands Research Center showed increased livestock production as well as increased wildlife production over season long grazing. GRAZING RECORDS year ____ _ Grazing System # ____ _ "-Number of Days Grazed Pasture Month 1 2 3 4 5 6 Precipitation January February March April May June July August September October November December Total days per pasture No. of acres per pasture Total acres of grazing system· ______________________________ ~ Number of livestock grazed Totalnumberofdaysgrazed ________________________________________________ _ Stocking rate ____________________________________ _ First pasture being grazedthisyear ______________________________ __ Rotation dates (date moved to next pasture) __________ _ Cont. Cont. Date of calf weaning ___________________________________ _ Yearly precipitation Average calf weights going on pasture Average calf weights coming off pasture Average weaning weights Forage usage (light, medium, heavy) ___________________________ _ (Make extra copies of grazing record forms for future years use.) 7 Helping You Put Knowledge To Work NDSU Extension Service, North Dakota State University of Agriculture and Applied Science, and U.S. Department of Agriculture cooperating. William H. Pietsch, Director, Fargo, North Dakota. Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. We offer our programs and facilities to all persons regardless of race, color, sex, religion, age, national origin, or handicap; and are an equal opportunity employer. 3M-5·91 

Design and characteristics of the twice-over rotation grazing system

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Design and characteristics of the twice-over rotation grazing system

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