chapter 8: considerations concerning stocking rate · table 8. yearling cattle production and...

Chapter 8: Considerations Concerning Stocking rate1. The concept of grazing capacity.2. What we have learned from stocking rate

studies. 3. Grazing intensity versus grazing timing.4. Components of stocking rate. a. Distance from water and slopeb. Forage demand by grazing animalsc. The harvest coefficientd. Stocking rate calculation5. Benefits of conservative stocking.6. Stocking rate economics.

Cornerstones of Grazing Management

1. Proper stocking rate2. Proper distribution3. Proper kinds of animals4. Proper grazing system

• ***Proper stocking rate is most important

Conservative versus Heavy stocking

0102030405060708090

1stQtr

2ndQtr

3rdQtr

4thQtr

EastWestNorth

0102030405060708090

1stQtr

2ndQtr

3rdQtr

4thQtr

EastWestNorth

Stocking vs. Specialized grazing systems

Range research shows stocking rate has had a much bigger impact on range vegetation and financial returns than specialized grazing systems.

Specialized grazing systems will not overcome the impacts of excessive stocking.

Stocking rate vs season of use

• Stocking rate has had much more effect on rangeland vegetation than season of use

Table 20. Effects of grazing management on semi-desert grass-shrub rangeland in southeastern Arizona.__________________________________

Continuous Summer WinterCharacteristics yearlong grazing grazing grazing_________________________________________________________________________________________________________________________________________________________________

Duration of study10 10 10

Annual precipitation (in) 12.53 12.53 12.53% Grazing use 47.2 46.0 41.6Forage production (lb/ac) 220.5 155.1 169.4Perennial grass prod. (lb/ ac) 89.4 27.5 42.4Calf weight (lbs) 414 396 396Range Trend up stable-down stable-down

Table 20b. Perennial grass yields and cover showed the greatest increases where percent use was lowest. Both vegetation and cattle performances was higher under year-long than seasonal grazing. The authors recommended that grazing use on the perennial grasses not exceed 40%. Stocking these ranges for about 35% use of forage with some destocking in dry years was considered the best strategy.

Source: Martin, S.C. 1975; Martin, S.C. and D.R. Cable, 1974.Source: Martin, S.C. 1975; Martin, S.C. and D.R. Cable, 1974.

Definitions of some grazing terms

Heavy grazing- a degree of herbage utilization that does not permit desirable forage species to maintain themselves.

Moderate grazing- a degree of herbage utilization that allows palatable species to maintain themselves.

Light grazing – a degree of herbage utilization that allows palatable species to maximize their herbage producing ability.

Definitions continued

Conservative grazing – a degree of herbage utilization between light and moderate, generally involving about 35% use of forage.

Severe grazing – a degree of herbage utilization generally above 60% use of forage that results in long term damage to the range.

Stocking Rate and Forage Production

Heavy stocking has greatest effects on forage production in drought years.

Table 12. Forage Production (lbs/acre) on Heavily and Moderately Stocked Pastures in Drought Compared to 10-years Average on the Fort Stanton Experimental Range in New Mexico.

Drought 10 years Drought yearYears Average as percent

Grazing intensity 1974 (1970-1979) of average

Heavy(50-55% use) 103 607 17%Moderate(40-45% use) 235 740 32%

Source: Pieper et al. 1991, Holechek, 1994.

Table 13. Forage Production (lbs/acre) on Moderately and Conservatively Stocked Pastures in Drought Compared to 6-years average on the Chihuahuan Desert Rangeland Research Center.

Drought 6 year Drought yearyears Average as percent

Grazing intensity 1994 & 1995 1993-1998 of Average

Moderate(40-45% use) 44 194 23%

Conservative (30-35% use) 89 273 33%

Source Molinar 1999, Molinar et al, 2002.

Table 6. Influences of grazing intensity on cattle production (yearlings) on ponderosa pine bunchgrass in Colorado1____________________________________________________

_______________________________________Study duration years 6 6 6Length of grazing months 5 5 5Period of grazing Jun-Oct Jun-Oct Jun-OctAcres/ yearling 12 13 24% use of forage 58 33 16Forage prod (lb/ ac) 1,256 1,565 2,037Gain/ head (lbs) 172 211 231Net return ($ ac) 0.74 1.35 0.98

Source Johnson W.M. 1953, USDA. Circ. 929

HeavyHeavy ModerateModerate LightLight

Stocking vs. Specialized grazing systems

Range research shows stocking rate has had a much bigger impact on range vegetation and financial returns than specialized grazing systems.

Specialized grazing systems will not overcome the impacts of excessive stocking.

Grazing capacity and stocking rate

Grazing capacity - maximum animal numbers which can graze each year on a given area of range, for a specific number of days without inducing a downward trend in range condition. It is based on vegetation weight, not cover.

Stocking rate – the actual number of animals assigned to a rangeland unit for a given time period.

Components of weight estimate-key area grazing capacity (Holechek 1988)1. Land area

determination2. Adjustment for

ungrazable range3. Determination of forage

production4. Selection of utilization

Coefficient 5. Determination of forage

demand by livestock and game animals

6. Adjustment for distance form water

7. Adjustment for slope8. Computation of grazing

capacity9. Interpretation of grazing

capacity relative to recent precipitation

10. Use of stubble heights to cross-check actual use.

Stocking ranges

How many days? How many animals?500 lbs forage per acre (dry)200 acres100,000 lbs total100,000 lbs X 0.35 (harvest coefficient)=35,000 lbs

grazable forage325 lbs forage per acre needed to protect the site 200 acres65, 000 lbs forage that must be left on the site for

protection

100,000 – 65000= 35, 000 lbs (can be consumed)

Stocking ranges cont.

You have the following animals10 cows (average weight = 800 lbs) = 8000 lbs1 bull ( average weight = 1100 lbs) = 1,100 lbs9 calves ( average weight = 200 lbs) = 1,800 lbs

10, 900 lbs

Stocking ranges cont.

• Ruminant animal will eat 2% of body weight/day

• (ranges from 2.6 on high quality forage to 1.4 on mature forage)

10, 900 x .02 = 218 lbs. forage consumed/day35,000/218 = 160 days of grazing, however this

is only a guideline.

Uses of grazing capacity information

1. Forage allocation to livestock and wildlife. 2. Quantification of forage resources on a

pasture, ranch, or allotment. 3. Assignment of stocking rate when data are

lacking on trend and grazing intensity.4. Assignment of stocking rate when data are

lacking or uncertain on past stocking rates.

Uses of grazing capacity information cont.5. Determines ranch monetary value.

* Grazing capacity is the most expensive of the 4 types of grazing surveys (trend, intensity, capacity, condition).

** Sound grazing capacity data requires at least 3 years of data collection.

Problems with stocking at grazing capacity1. Major reductions in livestock numbers will

be needed in one half the years to avoid rangeland degradation.

2. Difficulty in accurately estimating forage crops.

3. Stocking at capacity generally does not permit rangeland improvement.

4. Stocking at capacity gives lower financial returns than conservative stocking ( 80-90% of capacity)

Problems with stocking at grazing capacity cont.5. Severe financial losses can occur under

drought conditions.6. Multiple use values are difficult to maintain.

* Stocking at capacity involves about 40% use forage on New Mexico rangelands.

** Considerable research shows the financially most effective stocking rate is well below what the rangeland vegetation will sustain.

Table 6. Influences of grazing intensity on cattle production (yearlings) on ponderosa pine bunchgrass in Colorado1____________________________________________________

_______________________________________Study duration years 6 6 6Length of grazing months 5 5 5Period of grazing Jun-Oct Jun-Oct Jun-OctAcres/ yearling 12 13 24% use of forage 58 33 16Forage prod (lb/ ac) 1,256 1,565 2,037Gain/ head (lbs) 172 211 231Net return ($ ac) 0.74 1.35 0.98

Source Johnson W.M. 1953, USDA. Circ. 929

HeavyHeavy ModerateModerate LightLight

Table 8. Yearling cattle production and financial return characteristics at the Central Great Plains Experimental Range, Colorado

Grazing IntensityExcessive Moderate

Forage production (lbs/acre) 536 689Forage utilization (%) 54 37Weight again per animal (lbs) 218 268Weight again per unit area (lbs/acre) 22 34Death loss (%) 1.43 0.33Gross income/acre ($) 1.54 1.93Gross income/yearling ($) 81.22 96.02

Source; Kipple, G.E., and D.F. Costello. (1960). Vegetation and cattle to different intensities of grazing on shortgrass range of the central Great Plains. U.S. Dept. Agric. Tech. Bull. 1216.

Stocking plans recommended for New Mexico and other western rangelands.1. Stock for about 30%

use of long term average forage production.

2. Apply flexible stocking in drought.

3. In dry years sell older cows

4. Always sell livestock to level forage resources will support;

avoid expensive feeding programs.

5. Rest or lightly graze for 2 growing seasons after severe drought.

6. Restock with about one half normal herd first year after severe drought.

Benefits of conservative grazing (30-35% use of forage)

1. Maximized long term (and often short term) financial returns from ranching

2. Permits improvement in forage productivity. 3. Reduces risk of damage to range from heavy

grazing in drought.4. Facilitates multiple use concept on public

lands. 5. Strongly and broadly recommended by

researchers conducting long term razing studies.

Guidelines to proper useHeavy use- Range has a “clipped” or mowed

appearance. Over half of the fair and poor forage-value plants are used. All accessible parts of the range show use, and key areas are closely cropped. They may appear stripped if grazing is severe. There is evidence of livestock trailing to forage.

Moderate use (proper use)- About one-half of the good and fair forage value plants are used. There is little evidence of livestock trailing. Most of the accessible range shows some use.

Guidelines to proper use cont.

Light use- Only choice plants and areas are used. There is no use of poor forage plants. The range appears practically undisturbed. On key areas average stubble heights of

12 to 14 inches for tall grasses, 6 to 8 inches for mid grasses and 2 to 3 inches for short grasses are recommended minimums for proper use.

Guidelines on management changes

• If grazing intensity is heavy on 30% or more of a pasture two years in a row or in 2 years out of 5 management changes are need

• If grazing intensity becomes severe on one third or more of the pasture in any year, management changes should be implemented