|
2002 Annual Report Grassland Section |
Dickinson
Research Extension Center
1089 State Avenue Dickinson, ND 58601 |
Pasture
Costs-Returns of Grazing Management Strategies for Range Cows
and Calves during the Lactation Production Period
Llewellyn L. Manske PhD
Range Scientist
North Dakota
State University
Dickinson Research
Extension Center
Introduction
The beef production industry
in the Northern Plains has a low profit margin. A logical response to this situation
is the scientific evaluation of management-practice effectiveness in reducing
production costs by reducing pasture and forage costs, which constitute the
greatest portion of the total annual production costs for a beef cow and calf.
Because the daily requirements for cows differ with production period, proper
evaluation of management strategies requires two steps: evaluation of pasture
and forage costs related to each production period and evaluation of the management
strategies for livestock production periods as components within a complete
12-month pasture-forage management system. Achieving reductions in livestock
production costs for range cows during the lactation production period requires
knowledge of the biological processes of grass plants and of grassland ecosystems
and an understanding of the production costs of common traditional practices
and the costs of alternative management practices. The most biologically effective
pasture management strategy will have the lowest production costs.
An effective grazing management
strategy for the Northern Plains must meet the biological requirements of the
plants, facilitate the functioning of ecological processes at potential levels,
and counterbalance problematic biological conditions inherent in the grassland
ecosystems. The grazing management strategy producing the most biological advantages
and the fewest biological disadvantages is the most biologically effective.
Evaluating the success of a grazing management strategy is difficult because
numerous complex interrelated factors of plant growth and livestock performance
are involved. However, since cost per pound of accumulated calf weight is the
culmination of a grazing management strategy's positive and negative effects
on grass plant and livestock performance, this value functions as a reliable
indicator of a grazing strategy's overall effectiveness.
Grazing management practices
affect plant biological mechanisms and rates of ecological processes, and, in
turn, the quantity and quality of herbage produced. These factors of herbage
production affect the cow-calf weight performance quantified as stocking rates,
total acres allotted per cow-calf pair, average daily gain, and gain per acre.
Differences in livestock performance among grazing management treatments are
reflected in total pasture costs per cow-calf pair, gross value of the accumulated
weight per calf, and net return per cow-calf pair and per acre when pasture
rent value and calf weight economic value are the same for all treatments. Total
pasture costs and calf weight gain determine cost per pound of accumulated calf
weight. In this report, cow performance, calf performance, and cost per pound
of accumulated calf weight are compared to evaluate the relative effectiveness
of grazing management strategies. The management strategy costs evaluated during
this study were pasture rent per acre, production costs per acre, costs per
unit of forage dry matter, costs per unit of nutrient, land area per animal
unit, and forage feed costs per day or per month. The management strategies
are identified by the type of grazing system used during the native rangeland
period: 6.0-month seasonlong, 4.5-month seasonlong, 4.0-month deferred, and
4.5-month twice-over rotation.
Procedure
This study was conducted
at the NDSU Dickinson Research Extension Center, located in western North Dakota.
Average annual precipitation is 16.0 inches, with 13.6 inches (84.6%) falling
as rain between April and October. Mean annual temperature is 40.7oF.
January is the coldest month, with a mean temperature of 10.9oF.
July and August are the warmest months, with mean temperatures of 68.6oF
and 66.9oF, respectively. The native rangeland vegetation is the
Wheatgrass-Needlegrass Type (Barker and Whitman 1988) of the mixed grass prairie.
The dominant native range species are western wheatgrass, needle and thread,
blue grama, and threadleaved sedge. Crested wheatgrass and Altai wildrye pastures
were seeded as monocultures, but a small assortment of forb and other grass
species developed as minor components.
Commercial Angus-Hereford
cows with Charolais-sired calves were allocated to treatments each spring on
the basis of cow age and calf age and sex. The average calf birth date was 16
March, and the average birth weight was 95 pounds. Individual animals were weighed
on and off each treatment, at 15-day intervals during the early portion of the
season, and at 30-day intervals during the later portion of the season. Weight
performance of cows and of calves was calculated for each treatment, and differences
between means were analyzed by a standard paired plot t-test (Mosteller and
Rourke 1973). Pasture rent values used were the mean of reported rent paid in
the 15 counties of southwestern North Dakota: rent per acre was $8.76 for native
rangeland and domesticated grass pastures. One treatment of crested wheatgrass
was fertilized annually with 50 pounds of nitrogen per acre, at an average cost
of $12.50 per acre. An assumed price of $0.70 per pound was used to determine
the economic value of calf accumulated weight.
Pasture and forage costs
of feed to meet livestock dry matter and crude protein requirements were determined
during this study. Production costs per acre were determined from the average
land rent per acre. Costs per ton of forage dry matter (DM) were determined
by dividing production costs per acre by pounds of forage dry matter yield per
acre and multiplying the quotient by 2000 pounds. Costs per pound of crude protein
(CP) were determined in two stages: first, pounds of forage dry matter per acre
were multiplied by percentage of forage crude protein to derive pounds of crude
protein per acre; then, production costs per acre were divided by pounds of
crude protein per acre. Pasture land area per animal unit per month was determined
in two stages: first, pounds of forage dry matter per acre were divided by pounds
of forage dry matter required per animal unit per day to derive number of grazing
days per acre; then, the average number of days per month was divided by the
number of grazing days per acre. Harvested-forage land area per animal unit
per month or per production period was determined in two stages: first, pounds
of crude protein required per animal per day during a production period were
divided by percentage of crude protein of forage type to derive pounds of forage
dry matter to provide as feed per animal unit per day; then, pounds of forage
dry matter to feed per day were divided by pounds of forage dry matter per acre,
and the quotient was multiplied by 30 days per month, 30.5 days per month, or
the number of days per production period. Forage feed costs per animal per day,
per month, or per production period were determined in three stages: first,
production costs per acre were divided by pounds of forage dry matter per acre,
and that quotient was divided by percentage of forage crude protein to derive
cost per pound of crude protein; next, the cost per pound of crude protein was
multiplied by pounds of crude protein required per animal per day during a production
period; then, the feed costs per day were multiplied by 30 days per month, 30.5
days per month, or the number of days per production period. Costs per pound
of calf weight gain were determined in two stages: first, accumulated calf weight
gain was determined by subtracting calf live weight at the beginning of a growth
period from calf live weight at the end of a growth period; then, total pasture
costs or forage production costs for a calf growth period were divided by the
accumulated calf weight for the growth period.
Grazing Treatments
The grazing portion of
the 6.0-month seasonlong (6.0M SL) management strategy started on 16 May. Livestock
were moved to a single native range pasture stocked at 0.25 animal unit months
(AUMs)/acre. Livestock grazed on the pasture for 183 days, until 15 November,
when the calves were weaned.
The grazing portion of
the 4.5-month seasonlong (4.5M SL) management strategy started on 1 May. For
the first 46 days livestock grazed an unfertilized crested wheatgrass pasture
stocked at 0.55 AUMs/acre. On 15 June livestock were moved to one native range
pasture stocked at 0.35 AUMs/acre. Livestock grazed on this pasture for 137
days, until 30 October, when the calves were weaned.
The grazing portion of
the 4.0-month deferred (4.0M Def) management strategy started on 1 May. For
the first 76 days livestock grazed an unfertilized crested wheatgrass pasture
stocked at 0.60 AUMs/acre. On 15 July the livestock were moved to one native
range pasture stocked at 0.45 AUMs/acre. Livestock grazed on this pasture for
122 days, until 15 November, when the calves were weaned.
The grazing portion of
the 4.5-month twice-over rotation (4.5M TOR) management strategy started on
1 May. For the first 31 days livestock grazed a fertilized (50 lbs N/acre on
1 April) crested wheatgrass pasture stocked at 1.33 AUMs/acre. The livestock
were then moved to one of three native range pastures stocked at 0.49 AUMs/acre.
Livestock remained on native range for 137 days, grazing each pasture for two
periods, one 15-day period between 1 June and 15 July (when lead tillers of
grasses were between the third-leaf stage and flowering stage) and one 30-day
period after 15 July (after secondary tillers of grasses reached the third-leaf
stage) and prior to mid October. The first pasture grazed in the sequence was
the last pasture grazed the previous year. On 15 October the livestock were
moved to an Altai wildrye pasture stocked at 0.72 AUMs/acre. Livestock grazed
on this pasture for 30 days, until 15 November, when the calves were weaned.
Results
Native Rangeland
Cow and calf weight performance
generally did not differ among native range treatments during the early grazing
period of June and July, but during the later portion of the grazing period,
after early August, animal weight performance was greater on the twice-over
rotation treatment than on the seasonlong and deferred treatments.
Cow average daily gain
on the seasonlong and deferred treatments steadily decreased as the grazing
period progressed. Cows gained weight during the early portion of the grazing
period but lost weight during the later portion. Weight loss during the later
portion of the grazing season occurred at a greater rate on the deferred treatment.
Cows on the twice-over rotation treatment gained weight at a greater rate than
did cows on the seasonlong and deferred treatments. Cows on the twice-over rotation
treatment gained weight during the early and middle portions of the grazing
period and lost a small amount of weight at the end of the grazing period. Cow
daily gain, accumulated weight, and gain per acre were greater on the twice-over
rotation treatment than on the seasonlong and deferred treatments.
The greatest differences
in calf performance on the native range treatments occurred during the later
portions of the grazing period. Calf average daily gain on the seasonlong and
deferred treatments decreased as the grazing season progressed. The decrease
in calf average daily gain was greater on the deferred treatment than on the
4.5-month seasonlong treatment. Calf accumulated weight was greater on the 4.5-month
seasonlong treatment than on the deferred treatment. The decrease in calf daily
gain during the later portion of the grazing period was smaller on the twice-over
rotation treatment than on the seasonlong and deferred treatments. Calf accumulated
weight gain was greater on the twice-over rotation treatment than on the 4.5-month
seasonlong and deferred treatments.
Crested Wheatgrass
Cow and calf performance
was strong on unfertilized crested wheatgrass during May and June but decreased
considerably when grazing continued until mid July. Fertilization on crested
wheatgrass pastures during the first week of April increased the amount of herbage
produced but shortened by several weeks the period during which livestock performed
well. Weight performance for cows and calves during May and early June was greater
on fertilized crested wheatgrass pastures than on unfertilized pastures, but
livestock performance on fertilized crested wheatgrass pastures decreased earlier,
in mid June.
Altai Wildrye
Cow and calf weight performance
on Altai wildrye pastures between mid October and mid November was favorable,
but not as impressive as livestock weight performance on fertilized crested
wheatgrass during May. Weight gains of cows and calves grazing Altai wildrye
were considerably greater than those of livestock grazing native range or crop
aftermath during the same period. Lactating cows on 6.0-month seasonlong and
deferred native range grazing treatments and on crop aftermath treatments of
annual cereal stubble lost weight during the period between mid October and
mid November, and calves with those cows gained little weight.
Calf performance and cow
performance on grazing management strategies are shown in tables
1 and 2, respectively. Pasture costs and returns for grazing management
strategies are shown in table 3. Costs per pound of calf weight
gain are shown in table 3. Pasture and forage costs of pasture
management strategies for range cows during the lactation production period
are shown in table 4.
6.0-Month Seasonlong
The native range period
of the 6.0-month seasonlong treatment was 183 days. Cow weight gain was 0.12
lbs per day and 0.91 lbs per acre; accumulated weight gain was 21.96 lbs. Calf
weight gain was 1.80 lbs per day and 13.59 lbs per acre; accumulated weight
gain was 329.40 lbs. Each cow-calf pair was allotted 24.24 acres, at a cost
of $212.34. When calf accumulated weight was assumed to have a value of $0.70
per pound, the gross return was $230.58 per calf, and the net returns after
pasture costs were $18.24 per cow-calf pair and $0.75 per acre. Grazing for
6.0 months on the 6.0-month seasonlong strategy, a lactating cow and her calf
used 4.04 acres per month, at a cost of $1.16 per day, or $34.86 per month.
Each accumulated pound of calf weight cost $0.64 on the 6.0-month seasonlong
strategy.
4.5-Month Seasonlong
The native range period
of the 4.5-month seasonlong treatment was 137 days. Cow weight gain was 0.34
lbs per day and 3.67 lbs per acre; accumulated weight gain was 46.58 lbs. Calf
weight gain was 2.09 lbs per day and 22.55 lbs per acre; accumulated weight
gain was 286.33 lbs. Each cow-calf pair was allotted 12.70 acres, at a cost
of $111.25. When calf accumulated weight was assumed to have a value of $0.70
per pound, the gross return was $200.43 per calf, and the net returns after
pasture costs were $89.18 per cow-calf pair and $7.02 per acre on native range.
The spring crested wheatgrass complementary pasture period was 46 days. Cow
accumulated weight gain was 89.70 lbs. Calf accumulated weight gain was 87.86
lbs and cost $23.92 per calf. The combined pasture-forage types for the entire
4.5-month seasonlong strategy yielded an accumulated cow weight gain of 136.28
lbs and an accumulated calf weight gain of 374.19 lbs on 15.43 acres in 183
days, at a cost of $135.17 per cow-calf pair. When calf accumulated weight was
assumed to have a value of $0.70 per pound, the net returns after pasture costs
were $126.76 per cow-calf pair and $8.22 per acre for all portions of the grazing
season. Grazing for 6.0 months on the 4.5-month seasonlong strategy, a lactating
cow and her calf used 2.57 acres per month, at a cost of $0.74 per day, or $22.16
per month. Each accumulated pound of calf weight cost $0.36 on the 4.5-month
seasonlong strategy.
4.0-Month Deferred
The native range period
of the 4.0-month deferred treatment was 122 days. Cow weight gain was 0.32 lbs
per day and 4.40 lbs per acre; accumulated weight gain was 39.04 lbs. Calf weight
gain was 1.80 lbs per day and 24.73 lbs per acre; accumulated weight gain was
219.60 lbs. Each cow-calf pair was allotted 8.88 acres, at a cost of $77.79.
When calf accumulated weight was assumed to have a value of $0.70 per pound,
the gross return was $153.72 per calf, and the net returns after pasture costs
were $75.93 per cow-calf pair and $8.55 per acre on native range. The spring
crested wheatgrass complementary pasture period was 76 days. Cow accumulated
weight gain was 69.16 lbs. Calf accumulated weight was 136.04 lbs and cost $36.44
per calf. The combined pasture-forage types for the entire 4.0-month deferred
strategy yielded an accumulated cow weight gain of 108.20 lbs and an accumulated
calf weight gain of 355.64 lbs on 13.04 acres in 198 days, at a cost of $114.23
per cow-calf pair. When calf accumulated weight was assumed to have a value
of $0.70 per pound, the net returns after pasture costs were $134.72 per cow-calf
pair and $10.33 per acre for all portions of the grazing season. Grazing for
6.5 months on the 4.0-month deferred strategy, a lactating cow and her calf
used 2.01 acres per month, at a cost of $0.58 per day, or $17.31 per month.
Each accumulated pound of calf weight cost $0.32 on the 4.0-month deferred strategy.
4.5-Month Twice-Over
Rotation
The native range period
of the 4.5-month twice-over rotation treatment was 137 days. Cow weight gain
was 0.62 lbs per day and 9.44 lbs per acre; accumulated weight gain was 84.94
lbs. Calf weight gain was 2.21 lbs per day and 33.64 lbs per acre; accumulated
weight gain was 302.77 lbs. Each cow-calf pair was allotted 9.00 acres, at a
cost of $78.84. When calf accumulated weight was assumed to have a value of
$0.70 per pound, the gross return was $211.94 per calf, and the net returns
after pasture costs were $133.10 per cow-calf pair and $14.79 per acre on native
range. The spring crested wheatgrass complementary pasture period was 31 days.
Cow accumulated weight gain was 83.08 lbs. Calf accumulated weight was 67.58
lbs and cost $15.95 per calf. The fall Altai wildrye complementary pasture period
was 30 days. Cow accumulated weight was 16.50 lbs. Calf accumulated weight was
52.77 lbs and cost $12.18 per calf. The combined pasture-forage types for the
entire 4.5-month twice-over rotation strategy yielded an accumulated cow weight
gain of 184.52 lbs and an accumulated calf weight gain of 423.12 lbs on 11.14
acres in 198 days, at a cost of $106.97 per cow-calf pair. When calf accumulated
weight was assumed to have a value of $0.70 per pound, the net returns after
pasture costs were $189.21 per cow-calf pair and $16.98 per acre for all portions
of the grazing season. Grazing for 6.5 months on the 4.5-month twice-over rotation
strategy, a lactating cow and her calf used 1.72 acres per month, at a cost
of $0.54 per day, or $16.21 per month. Each accumulated pound of calf weight
cost $0.25 on the 4.5-month twice-over rotation strategy.
The results from the study
show that cows and calves do not gain weight at the same rate during the entire
grazing season and that different grazing treatments cause differences in cow
and calf weight performance. The cost per pound of accumulated calf weight was
$0.64, $0.36, $0.32, and $0.25 on the 6.0-month seasonlong, 4.5-month seasonlong,
4.0-month deferred, and 4.5-month twice-over rotation strategies, respectively.
The 4.5-month twice-over management strategy had the lowest cost per pound of
accumulated calf weight, at 61%, 31%, and 22% lower than the cost per pound
on the 6.0M SL, 4.5M SL, and 4.0M Def strategies, respectively. The twice-over
rotation treatment is the most biologically effective grazing management strategy.
Implementation of a biologically effective grazing management strategy reduces
annual pasture costs, reduces cost per pound of accumulated calf weight, and
improves net returns after pasture costs per cow-calf pair and per acre.
Discussion
The twice-over rotation
grazing management system on native rangeland with complementary domesticated
grass spring and fall pastures was developed specifically for the Northern Plains.
The use of complementary domesticated grass spring and fall pastures extends
the grazing season both early and late by exploiting the biological growth characteristics
of the perennial grasses that grow well in the region. The twice-over management
strategy coordinates grazing on crested wheatgrass, native rangeland, and Altai
wildrye pastures so that the nutritional quality of the various forage types
and the nutritional requirements of the livestock match over the entire grazing
season; this coordination of nutrient supply and demand improves individual
animal performance.
The number of sets of tillers
developed by native grasses each year determines the number of times each pasture
in a rotation system can be grazed. Two sets of tillers can be developed annually
by grasses in the Northern Plains when the grass plants are properly manipulated.
This production of two sets of tillers permits two rotation grazing periods
in each of three to six native range pastures of the twice-over rotation grazing
management system. The twice-over rotation system on native rangeland is biologically
effective because grazing periods are coordinated with grass growth stages and
a small amount of leaf material is removed between the third-leaf stage and
the flowering stage. This timed defoliation activates secondary tiller development
from axillary buds, activates plant physiological mechanisms, and stimulates
rhizosphere organism activity that increases nutrient flow and plant growth
(Manske 1999): the result is increased plant basal cover, increased aboveground
herbage biomass, and improved nutritional quality of herbage. The increases
in herbage quantity and quality permit increased stocking rates, reduced acreage
required to carry a cow-calf pair for the season, increased total accumulated
weight gain, reduced cost per pound of accumulated calf weight, increased net
return after pasture costs per cow-calf pair, and increased net return after
pasture costs per acre (Manske et al. 1988, Manske 1994, Manske 1996).
The twice-over management
strategy does not start grazing on any forage type until the grass plants have
reached the third-leaf stage because grazing before grass is ready affects plant
biological processes negatively and in turn reduces herbage biomass production
(Manske 2000). Delaying grazing on native rangeland until grass plants have
reached the third-leaf stage, in early June, requires the use of another forage
type for earlier grazing. Some domesticated perennial cool-season grasses reach
the third-leaf stage three to five weeks earlier than native cool-season grasses
and are dependable as spring pastures from early May until early June. Crested
wheatgrass is an excellent early season spring pasture forage. The start of
the grazing season on domesticated grass pastures is restricted to very late
April or early May, because no perennial grass in the Northern Plains reaches
the third-leaf stage before late April.
Manipulation of secondary
tiller growth of grasses on native rangeland can improve livestock performance
for two to two and a half months, until late September or mid October, but the
biology of native grass plants does not permit extending this improved performance
longer. Nutritional quality of herbage on native rangeland grazed after mid
October is below the requirements of lactating cows. Forages that meet the nutritional
requirements of lactating cows after mid October include Altai and Russian wildryes.
The wildryes are excellent fall pastures because they retain nutrient quality
in the aboveground portions of the plant until about mid November, much later
than other types of perennial grasses, which translocate aboveground cell components
relatively early in the grazing season. No perennial grass in the Northern Plains
retains sufficient nutritional quality to dependably meet the nutritional requirements
of lactating cows later than mid November.
In addition to improving
livestock performance, the enhanced performance of native grass plants on the
twice-over rotation grazing management system strengthens ecosystem health.
The increase in basal cover and herbage biomass reduces the number and size
of bare soil areas and increases the quantity of residual vegetation. These
changes in the grassland ecosystem produce conditions favorable to the limitation
of grasshopper pest species populations (Manske and Onsager 1998, Onsager 2000,
Belovsky et al. 2000). The increased plant density, herbage production, and
residual vegetation, and the stronger ecosystem health conditions improve the
grassland habitat for prairie grouse, ducks, waterfowl, and ground nesting birds
(Manske and Barker 1988, Manske et al. 1988).
The low cost per pound
of accumulated calf weight on the twice-over rotation grazing management strategy
reflects the combined biological advantages and disadvantages of the strategy
and demonstrates that it is biologically effective. The beneficial effects of
improved vegetation condition, livestock performance, wildlife habitat, and
grasshopper population reduction show that the twice-over rotation grazing management
strategy can be successfully implemented in the Northern Plains region.
Acknowledgment
I am grateful to Amy M. Kraus for assistance in the preparation of this manuscript. I am grateful to Sheri Schneider for assistance in production of this manuscript and for development of the tables.
Literature
Cited
Barker, W.T., and
W.C. Whitman. 1988. Vegetation of the Northern Great Plains. Rangelands
10:266-272.
Belovsky, G.E.,
M.A. Brusven, D.J. Fielding, and L. Manske. 2000. Grasshopper habitat
manipulation. United States Department of Agriculture, Animal and Plant Health
Inspection Service, Grasshopper Integrated Pest Management User Handbook Technical
Bulletin No. 1809, Washington, D.C. p.VII.15-1-VII.15-5.
Manske, L.L., and
W.T. Barker. 1988. Habitat usage by prairie grouse on the Sheyenne
National Grasslands. U.S.D.A. Forest Service. General Technical Report RM-159.
p. 8-20.
Manske, L.L., W.T.
Barker, and M.E. Biondini. 1988. Effects of grazing management treatments
on grassland plant communities and prairie grouse habitat. U.S.D.A. Forest Service.
General Technical Report RM-159. p. 58-72.
Manske, L.L., M.E.
Biondini, D.R. Kirby, J.L. Nelson, D.G. Landblom, and P.J. Sjursen. 1988.
Cow and calf performance on seasonlong and twice over rotation grazing treatments
in western North Dakota. Proceedings of the North Dakota Cow-Calf Conference.
Bismarck, ND. p. 5-17.
Manske, L.L., and
J.A. Onsager. 1998. Cultural management practices as tools to help
reduce grasshopper populations. Proceedings of the 1998 Annual Meeting of the
NationalGrasshopper Management Board. Denver, CO. p. 5-6.
Manske, L.L. 1994.
Ecological management of grasslands defoliation. p. 130-136. in F.K. Taha, Z.
Abouguendia, and P.R. Horton (eds.). Managing Canadian rangelands for sustainability
and profitability. Grazing and Pasture Technology Program. Regina, Saskatchewan.
Manske, L.L. 1996.
Economic returns as affected by grazing strategies. p. 43-55. in Z. Abouguendia
(ed.). Total ranch management in the Northern Great Plains. Grazing and Pasture
Technology Program, Saskatchewan Agriculture and Food. Regina, Saskatchewan.
Manske, L.L. 1999.
Can native prairie be sustained under livestock grazing? p. 99-108.
in J. Thorpe, T.A. Steeves, and M. Gollop (eds.). Proceedings of the fifth Prairie
Conservation and Endangered Species Conference. Provincial Museum of Alberta.
Natural History Occasional Paper No. 24. Edmonton, Alberta.
Manske, L.L. 2000.
Grazing before grass is ready. NDSU Dickinson Research Extension Center.
Range Management Report DREC 00-1032. Dickinson, ND. 6p.
Mosteller, F.,
and R.E.K. Rourke. 1973. Sturdy Statistics. Addison-Wesley Publishing
Co., MA. 395p.
Onsager, J.A. 2000. Suppression of grasshoppers in the Great Plains through grazing management. Journal of Range Management 53:592-602.
Tables and Graphs
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