Examination of risk and stocking rate decisions in the Mulga lands using simulation.

1990 ◽  
Vol 12 (1) ◽  
pp. 3 ◽  
Author(s):  
AJ Meppem ◽  
PW Johnston
Keyword(s):  
Daily Rainfall ◽  
Stocking Rate ◽  
Short Term ◽  
Pasture Production ◽  
Direct Benefits ◽  
Reduce Risk ◽  
Gross Margins ◽  
Stocking Rates ◽  
Benefits And Costs ◽  
Different Levels

A simulation model of a grazing enterprise was used to examine the economic risk associated with stocking rate decisions in the mulga lands. The model used historical daily rainfall records for Charleville (1890 - 1984) as input for determining annual pasture production. Stocking rates were set each year at the end of summer to utilize a portion of the available forage. Gross margins were determined for a total of six levels of pasture utilization (20% to 80%). The simulation results support the hypothesis that higher levels of pasture utilization lead to consistently lower pasture yields, and greater variability in income (high risk). To reduce risk, this simulation study suggests a more conservative use of the pasture. Optimum levels of pasture use therefore need to be determined; both from an individual graziers requirement to meet short term needs, and society's preference for long tern conservation of the pasture resource. This requires the ability to identify the direct benefits and costs of different levels of pasture use. This study has indicated the value of simulation in examining these costs and benefits.

The effects of stocking rate and nitrogen fertilizer on the productivity of irrigated perennial pasture grazed by dairy cows. 1. Pasture production, utilization and composition

1980 ◽  
Vol 20 (106) ◽  
pp. 529 ◽  
Author(s):  
CR Stockdale ◽  
KR King
Keyword(s):  
Dairy Cows ◽  
Nitrogen Fertilizer ◽  
Animal Health ◽  
Point Of View ◽  
N Fertilizer ◽  
Stocking Rate ◽  
Short Term ◽  
Pasture Production ◽  
Stocking Rates

The effects of stocking rate and nitrogen (N) fertilizer on the productivity of irrigated perennial pasture grazed by dairy cows was studied for 2 years at Kyabram, Victoria. There were ten treatments: five stocking rates ranging from 4.4 to 8.6 cows ha-l at both 0 and 224 kg N ha-1 year-1 . Although weeds did not invade the pasture, increases in stocking rate resulted in reduced daily pasture growth, and this was related to the level of residual pasture after grazing. Annual pasture production in both years declined by 0.394 t DM ha-1 for every additional cow per ha. The levels of the herbage minerals, N, P, K, Ca, Mg and Na were adequate from an animal health point of view at all stocking rates, at least in the short term. The response to N fertilizer declined from 17 to 3 kg DM kg-1 N applied, as stocking rate increased from 4.4 to 8.6 cows ha-1, and it appeared that this response was due mainly to an increase in the growth of the grasses. Apart from the stocking rate responses, which are specific to the Kyabram environment, a number of relations were found, which showed how residual pasture after grazing, pasture allocation and pasture utilization at a single grazing, influenced pasture intake. Providing allowances are made for pasture type and the level to which any particular pasture type can be grazed, these relations could be expected to give a reasonable assessment of pasture intake in other environments.

Seasonal relations between animal gain, pasture production and stocking rate on two tropical grass-legume pastures

1978 ◽  
Vol 29 (1) ◽  
pp. 103 ◽  
Author(s):  
LA Edye ◽  
WT Williams ◽  
WH Winter
Keyword(s):  
Response Surfaces ◽  
Stocking Rate ◽  
Wet Season ◽  
Pasture Production ◽  
Annual Basis ◽  
Seasonal Basis ◽  
Guinea Grass ◽  
Dry Seasons ◽  
Stocking Rates ◽  
The Relationship

The relationship between stocking rate and liveweight change per animal was examined over a period of 3 years for two continuously grazed pastures, one of Brachiaria and the other consisting of guinea grass with Endeavour stylo and Siratro. On an annual basis there was no significant effect of stocking rate over the last 2 years, but on a seasonal basis there were highly significant effects in all seasons. In the dry seasons, animal gain rose as the stocking rate fell, but in the last two wet seasons gains fell with the lower stocking rates. On an annual basis the two effects cancelled out. Response surfaces for gain versus pasture yield and stocking rate were curvilinear (quadratic) during the wet season and linear during the dry. Optimum stocking rates (for maximum gain per hectare) were determined for the wet and dry seasons; the rate was greatly affected by the yield of green material during the dry season but less so during the wet. The possible causes of this reversed wetseason effect are discussed.

Modelling the risk of different joining times and lamb sale policies

2014 ◽  
Vol 54 (10) ◽  
pp. 1694 ◽  
Author(s):  
S. M. Robertson ◽  
A. F. Southwell ◽  
M. A. Friend
Keyword(s):  
Carrying Capacity ◽  
Simulation Modelling ◽  
Management Systems ◽  
Stocking Rate ◽  
Gross Margin ◽  
Feed Resources ◽  
Systems Simulation ◽  
Gross Margins ◽  
The Impact ◽  
Stocking Rates

Month of joining and lamb sale strategy influence both the quantity and so value of lamb produced, and the feed required, so are important management decisions contributing to the profitability of sheep systems. Simulation modelling was used to evaluate the impact on gross margins of three lamb sale strategies for different months of joining and varying stocking rates. A flock of purchased Merino ewes producing crossbred lambs in southern Australia was modelled between 1971 and 2011. April joining produced higher gross margins than November or January only if the number of ewes per hectare was increased to potential carrying capacity. At the optimum stocking rate for each month of joining, three sale policies – a flexible lamb sale policy (where lambs were sold depending on seasonal conditions); selling lambs in December; or selling at 45-kg liveweight, all produced a similar mean gross margin, but the feed resources required were least using the flexible strategy (April-joined mean 195 ± 253 s.d. kg/ha for flexible compared with 219 ± 270 kg/ha if selling December or 1085 ± 459 kg/ha if sold at 45 kg). Mean gross margin differed between sale strategies by up to AU$66/ha if the optimal stocking rate was not used. These results suggest that the most advantageous lamb sale strategy will vary with both month of joining and stocking rate used, and should be considered when optimising sheep management systems.

Superphosphate and stocking rate effects on a native pasture oversown with Stylosanthes humilis in central coastal Queensland. 1. Pasture production

1978 ◽  
Vol 18 (95) ◽  
pp. 788 ◽  
Author(s):  
NH Shaw
Keyword(s):  
Soil Phosphorus ◽  
Total Yield ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Pasture Production ◽  
Average Percentage ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Nitrogen Concentrations ◽  
Stocking Rates

Changes in the yield, botanical composition and chemical composition of a native pasture (Heteropogon contortus dominant) oversown with S. humilis (T.S.) were measured in a grazing experiment from 1966 to 1973. The 24 treatments were factorial combinations of two sowing methods for T.S. (ground sowing into spaced cultivated strips, or aerial sowing), three levels of molybdenized superphosphate (F0 = nil ; F1 = 125 kg ha-1 annually; F2 = 250 kg ha-1 annually plus an extra 250 kg ha-1 initially) and four stocking rates. Stocking rates were gradually increased during the experiment and for the last three years overlapping ranges were used for the three fertilizer levels; the overall range was then from 0.55 to 1.65 beasts ha 1 T.S. establishment by ground sowing was much more reliable than from aerial sowing, giving twice the average percentage frequency, and this proportion was maintained over years. High fertilizer improved establishment and the best legume stands were in the high fertilizer high stocking rate treatments. Total presentation yield of pasture was increased by fertilizer and reduced by high stocking rates. Over the last two years the means for March, adjusted by regression to the overall average stocking rate of 0.98 beasts ha-1, were 31 20,4020 and 5370 kg ha-1 for F0, F1 and F2 respectively, but these yields were reduced by ca 25 per cent for an increase of 0.5 beasts ha-1. H. contortus remained dominant and its mean contribution to total yield increased from 48 per cent in 1969 to 67 per cent in 1973. This proportion was reduced by 12.8 per cent over the range from 0.55 to 1.65 beasts ha-1, but high fertilizer had the opposite effect so that differences between the extremes low stocked F0 and high stocked F2 were small. The DM percentage yield of T.S. was strongly increased by fertilizer, and, most importantly, also by high stocking rates in the presence of fertilizer. Values for F0 treatments remained below 10 per cent, but in the final year values for F1 and F2 at the highest stocking rates were 36 and 27 per cent, respectively. Despite these large changes in T.S., there was overall stability of botanical composition. Phosphorus and nitrogen concentrations in T.S. and H. contortus were increased by superphosphate but there was an overall decline in potassium concentration. Soil phosphorus levels were greatly increased

Steer gains, pasture yield and pasture composition on native pasture and on native pasture oversown with Indian couch (Bothriochloa pertusa) at three stocking rates

1997 ◽  
Vol 37 (7) ◽  
pp. 755 ◽  
Author(s):  
R. J. Jones
Keyword(s):  
Perennial Grasses ◽  
Grass Species ◽  
Stocking Rate ◽  
Pasture Grass ◽  
Pasture Production ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Unit Increase ◽  
Stocking Rates ◽  
Pasture Yield

Summary. Pasture production and steer liveweight gain were compared on native pasture (Bothriochloa decipiens, Heteropogon contortus, Themeda triandra and Chrysopogon fallax) and on native pasture oversown with Indian couch or Indian bluegrass (Bothriochloa pertusa). This grass was not a planned introduction to the area but is spreading in Central and North Queensland and its value as a pasture species is questioned by graziers. There were 3 nominal stocking rates of 0.3, 0.6 and 0.9 steers/ha. Each paddock was stocked with 3 steers of stratified ages. The experiment was sown in March 1988 and terminated in June 1993. The experiment, sited 50 km south of Townsville in eucalypt woodland on a solodic-solodised-solonetz soil, was sown in March 1988 and terminated in June 1993. Increases in stocking rate resulted in a linear decline in both pasture yield (by 3–5 t/unit increase in stocking rate) and steer gains (by more than 100 kg/unit increase in stocking rate). Differences between pastures were apparent only at the medium and high stocking rates where, over time, Indian couch gave higher pasture yields and steer gains. Younger steers gained far more weight than older steers. Mean gains over 3 years were weaners 125 kg/year, yearlings 93 kg/year and 2-year-old steers 46 kg/year. Native pasture remained fairly stable botanically at the low stocking rate, but the tufted perennial grass species declined at both the medium and high stocking rates. Sowing Indian couch hastened the botanical changes due to stocking rate, and it became the dominant species at these higher stocking rates. At the low stocking rate, the contribution of Indian couch declined from initial values indicating that this is not an invasive species in the area at a low stocking rate. Contribution of Indian couch to pasture yield was linearly related to stocking rate. Nutritional quality of the Indian couch was similar to the other native perennial grasses though calcium concentration was higher. Increased steer gains were related to higher yield on Indian couch pastures at the higher stocking rates rather than to improved quality. Maximum liveweight gain/ha was achieved at about 0.6 steers/ha. Stocking at 0.9 steers/ha was not sustainable. Even at the low stocking rate, steers would need to spend about 2.8 years on the pastures after weaning to reach 500 kg liveweight. It was concluded that B. pertusa is a useful pasture grass in this environment giving steer gains equal to, or higher than, the gains from the native pasture which it replaced.

Stocking intensity and pastoral production: I. Changes in the soil and vegetation of a sown pasture grazed by sheep at different stocking rates

1973 ◽  
Vol 81 (2) ◽  
pp. 193-204 ◽  
Author(s):  
J. P. Langlands ◽  
I. L. Bennett
Keyword(s):  
Soil Moisture ◽  
Bulk Density ◽  
Pore Space ◽  
Water Infiltration ◽  
Root Weight ◽  
Stocking Rate ◽  
Pasture Production ◽  
Basal Cover ◽  
Soil Pore Space ◽  
Stocking Rates

SummaryA Phalaris tuberosa and Trifolium repens pasture was grazed continuously at stocking rates varying from 2·5 to 37·1 sheep per ha between 1964 and 1969. During this period herbage availability and composition, basal cover, root weight, water infiltration, soil moisture content, bulk density and chemical composition of the soil were measured at intervals.As stocking rate was increased, herbage availability, root weight, basal cover, soil pore space and the rate of water infiltration declined, and bulk density and the nitrogen and calcium contents of the herbage on offer increased. In periods of below-average rainfall, soil moisture and nitrate levels were greater when herbage was of low availability.Herbage production was calculated from estimates of herbage consumption and of litter decomposition, and averaged 8·45 t dry matter/ha/year; it was insensitive to changes in stocking rate over the range from 2 to 22 sheep/ha. The ratio, herbage consumption/ pasture production increased by 0'045 per unit increase in stocking rate.

Production and gross margins for sheep and cattle grazed separately and together

1975 ◽  
Vol 15 (72) ◽  
pp. 38 ◽  
Author(s):  
D Hamilton
Keyword(s):  
First Grade ◽  
Stocking Rate ◽  
Gross Margin ◽  
Supplementary Feed ◽  
Gross Margins ◽  
Stocking Rates

On annual pasture, ewes lambing in autumn and young steers grazed separately each at five stocking rates, and grazed together in a ratio of 4 : 1 at each of three stocking rates. Gross margin per hectare (GMH) from the sheep was greatest at the heaviest stocking rate that could be carried safely without supplementary feed, and from steers was greatest at the heaviest stocking rate at which a high proportion of carcases were first-grade, even in a year of poor pasture. Maximum GMH from the steers was obtained at a lighter equivalent stocking rate than that required for maximum GMH from the sheep. When the sheep and steers grazed together at a stocking rate where first-grade steer carcases were produced consistently, the loss in potential sheep GMH from reducing the sheep stocking rate to this level was greater than the value of any benefit from mixed stocking. This finding is discussed in relation to results from another environment where no difference was found between sheep and cattle in the stocking rate required for maximum GMH.

Optimal management of fertiliser and stocking rate in temperate grazing systems

2010 ◽  
Vol 50 (1) ◽  
pp. 6 ◽  
Author(s):  
Karel Mokany ◽  
Andrew D. Moore ◽  
Phillip Graham ◽  
Richard J. Simpson
Keyword(s):  
Cash Flow ◽  
Application Rate ◽  
Optimal Management ◽  
Stocking Rate ◽  
Eastern Australia ◽  
Grazing Systems ◽  
Fertiliser Application ◽  
Gross Margins ◽  
Stocking Rates

Phosphorus (P) fertilisers are one of the key tools available for increasing pasture production and the profitability of grazing enterprises. However, recent rapid changes in fertiliser price have increased the importance of developing optimal management strategies for applying P fertiliser and setting stocking rates. We applied a novel combination of process-based grazing systems modelling and randomised cash flow analyses to examine how changes in fertiliser price affect optimal fertiliser application rates and stocking rates for sheep grazing systems in south-eastern Australia, simultaneously taking into account long-term economic viability and environmental sustainability. We used ‘GrassGro’, a grazing systems decision support tool, to simulate three sheep enterprise types (Merino wethers, Merino ewes, crossbred ewes) at two locations (Hamilton, Victoria; Bookham, New South Wales). Gross margins from each year simulated in GrassGro (1966–2007) were randomised 500 times and input to a cash flow analysis that identified the financially optimal stocking rate for a range of fertiliser applications and the financial risk frontiers (combinations of stocking rate and fertiliser input for which the enterprise becomes financially unviable). For all enterprises examined at both locations, the optimal combinations of stocking rate and fertiliser application rate did not vary markedly as fertiliser price changed. Regardless of enterprise type or location, the fertiliser application rate at which the highest gross margins were achieved provided the greatest range of stocking rates that were both financially viable and environmentally sustainable. Increases in fertiliser price reduced the combinations of stocking rate and fertiliser application rate that were viable in the long term, emphasising the importance of well informed grazing management decisions.

scholarly journals Evaluation of nitrogen fertiliser in a beef production system

1990 ◽  
pp. 89-92
Author(s):  
S.T. Morris ◽  
A.F. Mcfrae
Keyword(s):  
Beef Cattle ◽  
Production System ◽  
Individual Animal ◽  
Stocking Rate ◽  
Beef Production ◽  
Pasture Production ◽  
Nitrogen Fertiliser ◽  
Stocking Rates ◽  
Objective Being ◽  
Clover Content

This paper reports and discusses the results of 4 years of trials (1985-1988) involving 2 farmlets, one receiving 3 nitrogen applications (50 kg /ha) in autumn, winter and spring (+N) and one receiving no N fertiliser (-N). Stocking rags were 3.3 animals/ha on -N farmlet and 4.3 animals/ha on the +N farmlet for the first 3 years, with the objective being to utilise the extra N-boosted grass with extra animals/ha but not to sacrifice individual animal performance. In the fourth year the stocking rates were kept the same on each farmlet (3.3 animals/ha) in an endeavour to utilise the extra grass grown on the +N farmlet by way of increased per head performance. In 2 of the 3 years (1985 and 1987) where the +N farmlet supported the higher stocking rate, liveweight gain (LWG) did not differ between animals. In 1986 the extra animals on the -l-N farmlet had a lower LWG, whereas in 1988 the LWGs were similar for the 2 farmlets stocked at the same rate. The apparent DM responses (kg DM/kg N applied) ranged from 2 to 12. The rates of N fertiliser used in this trial do not appear to result in economic increases in pasture production for the beef production system reported here. Nitrogen fertiliser did not reduce the clover content of pastures rotationally grazed by beef cattle. Keywords beef production, nitrogen fertiliser, pasture composition, livewieght gain, economics.

scholarly journals POTENTIAL OF HILL COUNTRY FARMING IN THE KING COUNTRY

1973 ◽  
pp. 44-51
Author(s):  
P.G. Yeoman
Keyword(s):  
Carrying Capacity ◽  
Economic Conditions ◽  
Stocking Rate ◽  
Pasture Production ◽  
Hill Country ◽  
Management Techniques ◽  
Stocking Rates

The evidence available on pasture production in the King Country is reviewed and compared with stock requirements. A potential carrying capacity of 19 stock units/ha in the Waitomo County is estimated. It is shown that, when product prices are high, the economic optimum stocking rate is near the point beyond which stock will be seriously underfed. Management techniques aimed at producing and utilizing pasture feed efficiently and also allowing flexibility in stocking rates to meet varying economic conditions are outlined.

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