Stocking rate trials in Ankole, Uganda: I. Weight gain of Ankole steers at intermediate and heavy stocking rates under different managements

1974 ◽  
Vol 82 (3) ◽  
pp. 497-506 ◽  
Author(s):  
G. N. Harrington ◽  
D. Pratchett

SUMMARYA series of stocking rate trials running for differing periods between 1961 and 1972 are summarized. Weight gains of steers grazed at 2·4, 1·2, 0·8 and 0·6 ha/300 kg animal on Cymbopogon/Hyparrhenia/Themeda pasture are detailed. Subtreatments included continuous and rotational grazing and the removal of the unpalatable Cymbopogon afronardus.Weight gains at 0·6 ha/animal were higher than a linear relationship between stocking rate expressed as animals/ha and weight gain would predict. This was ascribed to the dominance of the high quality grass Brachiaria decumbens at this grazing pressure.Rotational grazing was less productive than continuous grazing, because C. afronardus increased more rapidly under this management, but there was less soil erosion. Removal of C. afronardus increased cattle growth rates and gains/ha by over 40% at 0·6 ha/animal. The cost of clearing this weed should be recovered in 2 years from a commercial cattle ranch. A grazing pressure of ca. 0·8 ha/animal is expected to maximize long-term profits on C. afronardus-free Ankole rangeland and in 3 years in this trial average gains of 0·29 kg/day/animal were achieved. This was an annual production level of 131 kg/ha/annum, which compared with 53 kg/ha at 2·4 ha/animal and 143 kg/ha at 0·6 ha/animal.

1974 ◽  
Vol 82 (3) ◽  
pp. 507-516
Author(s):  
G. N. Harrington ◽  
D. Pratchett

SUMMARYBotanical analyses of trials grazed at 3·6, 2·4, 1·2, 0·8 and 0·6 ha/300 kg animal for 4 years are detailed. The two heaviest grazing pressures encouraged Brachiaria decumbens, a high quality grass, at the expense of Themeda triandra and Hyparrhenia filipendula. Rotational grazing allowed the weed grass Cymbopogon afronardus to regenerate after clearing more rapidly than did continuous grazing.Bullocks with oesophageal fistulas sampled pastures grazed at 2·4, 1·2 and 0·6 ha/animal at 4-weekly intervals for 12 months. The 0·6 ha/animal treatment was repeated on pasture cleared of the weed grass Cymbopogon afronardus. Cattle growth rates, both long term and at the time of sampling, were recorded.Cattle growth rates were greatest at 2·4 ha/animal but fistula sampling demonstrated that the diet was significantly lower in CP and higher in CF than the more heavily stocked treatments, which is contrary to the normal pattern. It is concluded that the differences in cattle growth rates at the different stocking rates were due to differences in dry-matter intake rather than the recorded differences in diet quality. The higher CP in the diet at the heavier stocking rates is ascribed to the increase of B. decumbens in the diet.An unexplained ceiling to cattle growth rates of ca. 0·5 kg/day, and a calculated drymatter intake of < 2·1% body weight/day, in the presence of unlimited forage of 10% CP and 55% apparent digestibility, makes it more economic to stock for maximum production per ha than per animal.


1966 ◽  
Vol 66 (1) ◽  
pp. 49-57
Author(s):  
C. A. Smith

The effect of stocking-rate was measured on growth of indigenous oxen grazing Hyparrhenia veld and dambo. Stocking-rate had a relatively small effect on weight gain per ox in the rainy season when veld was relatively nutritious, but had a significant linear effect and a lesser quadratic effect on weight loss per ox in the dry season. Oxen stocked leniently on veld in the dry season lost less weight than heavily stocked oxen. Oxen fed a protein supplement, maintained or gained weight when grazing veld in the dry season even at high stocking-rates.In long-term trials, compensatory growth so affected cattle weight gains that heavily stocked oxen which had large weight losses in the dry season compared with leniently stocked oxen, had greater weight gains in the following rainy season. Stocking-rate had a highly significant, linear effect on cumulative weight gain per ox, which was more evident on dambo grazing than on Hyparrhenia veld.


1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.


1963 ◽  
Vol 61 (2) ◽  
pp. 147-166 ◽  
Author(s):  
C. P. McMeekan ◽  
M. J. Walshe

1. A large-scale grazing management study comparing rotational grazing and continuous grazing with dairy cows at two stocking rates over four complete production seasons is described.2. The four treatments were: (i) controlled grazing, light stocking rate; (ii) controlled grazing, heavy stocking rate; (iii) uncontrolled grazing, light stocking rate; (iv) uncontrolled grazing, heavy stocking rate.Each treatment involved 40 cows for a first 2-year phase and 42 cows for the following 2 years. Each herd had a normal age distribution pattern and seven 2-year-old first lactation heifers (17% of total herd) were introduced each year to maintain this pattern.3. Stocking rate was the more important factor affecting the efficiency of pasture utilization as measured by per acre output of milk and butterfat. In general, high stocking was associated with higher outputs per acre despite lower yields per animal.4. Grazing method was of less importance. In general, controlled rotational grazing was superior to uncontrolled continuous grazing, both per animal and per acre, but the average influence even of these extremes of management was only half that of stocking rate.5. Significant interactions between stocking rate and grazing method existed. Under continuous grazing a point was reached where production per acre declined to the vanishing point with increased stocking rate due to excessive depression of per cow yield: this point was not reached under rotational grazing at the same high stocking levels.6. The results suggest that optimum stocking rate under rotational grazing occurs at a level some 5–10% higher than under continuous grazing. A depression of 10–12% in per cow yield, compared with more lenient grazing, corresponds with optimum stocking level irrespective of the grazing system. This estimate is suggested as a guide line in applying the principles involved.


1985 ◽  
Vol 104 (1) ◽  
pp. 173-180 ◽  
Author(s):  
M. A. Smith ◽  
P. C. Whiteman

SummaryA continuously grazed trial on natural and sown pastures under coconuts was reported by Watson & Whiteman (1981). This has been continued for another 3 years as a rotationally grazed trial. The paddocks were divided down the centre and three animals grazed for 28 days in one half and were transferred to the other half for 28days. The same three stocking rates of 1·5, 2·5 and 3·5 steers/ha were maintained. In the sown pasture paddocks Brachiaria decumbensand Brachiaria miliiformis were planted in rows from rooted cuttings, while Centrosema pubescens (centro) and Pueraria phaseoloides (puero) were sown, with seed at 4 and 3 kg/ha, respectively. Naturalized pastures were maintained by grazing at 2·5 steers/ha during the establishment of the sown pasture. Light transmission was 62 %. Sown grasses were lost after 4 months from the start of rotational grazing. In the sown pastures puero became dominant. Animal live-weight gain (LWG) on puero was poor in the first 140 days of grazing in each year, but after this time it increased. Centro was the dominant species in the natural pasture of 2·5 and 3·5 steers/ha. However, there was little difference in yearly LWG except in year 3 when the 2·5 steers/ha had higher gains in the natural (363 kg/ha) than in the sown pasture (250 kg/ha). Th9 mean live-weight gain (kg/ha) in the first 2 years of the rotationally grazed trial (315 kg/ha) was lower than in the continuously grazed trial (364 kg/ha) at 3·5 steers/ha. The time and efficiency of collecting fallen coconuts was lower at 1·5 steers/ha in both pastures, but not different between 2·5 and 3·5 steers/ha. In continuous and rotational grazing there is little point in planting Brachiaria species. Productive pastures in plantations oan be obtained by conti oiling weeds and sowing centro and puero into the naturalized Axonopus compressus and stocking at 2–5–3–0 steers/ha. Further research on other grasses such as Ischaemum aristatum and Stenotaphrumsecundatum may lead to better grass persistence.


1981 ◽  
Vol 97 (3) ◽  
pp. 669-676 ◽  
Author(s):  
S. E. Watson ◽  
P. C. Whiteman

SUMMARYA grazing study, comparing a naturalized and a sown pasture at three stocking rates, was conducted under a uniform stand of 65-year-old coconuts on a fertile soil in the Russell Islands. In a plot trial on this site there was no significant response to application of up to 400 kg N/ha/year over 2 years to Brachiaria decumbens. Average daily transmission of photosynthetically active radiation through the coconut canopy was 60% of full sunlight. The sown pasture consisted initially of para (Brachiaria mutica), signal (B. decumbens) and koronivia (B. humidicola) with the legumes Centrosema pubescens, Pueraria phaseoloides and Stylosanthes guianensis. The main species in the naturalized pasture were Axonopus compressus, Mimosa pudica, C. pubescens and Colopogonium mucunoides. Pastures were set stocked in two replicates over 3 years at 1·5, 2·5 and 3·5 animals/ha. There was no significant difference in live-weight gain between pastures in any year. Live-weight gain per head declined linearly with increasing stocking rate. Highest live-weight gain was 437 kg/ha/year in the 1st year at 3·5 animals/ha. The planted grasses declined from 60% at the start of grazing to 6% 8 months later. A. compressus increased from 2 to 24% over 3 years in the sown pasture, and from 12 to 34% of yield in the natural pasture. M. pudica increased from 27 to 44% in the sown, and remained approximately constant at 37% in the natural pasture. G. pubescens increased at 2·5 animals/ha, but was replaced by P. phaseoloides at 1·5 animals/ha and by A. compressus and M. pudica at 3·5 animals/ha. There were no significant effects of pasture treatments or stocking rate on copra yields. Where there is a cover of naturalized grasses and legumes under coconuts, cultivation and planting of exotic species cannot be recommended. Major improvement will come from thorough weed control and maintaining stocking rates between 1·5 and 2·5 animals/ha.


1993 ◽  
Vol 15 (2) ◽  
pp. 302 ◽  
Author(s):  
R Roe ◽  
GH Allen

Pasture productivity and wool production on the Warrego Mitchell grass (Astrebla spp.) rangeland in south-westem Queensland were studied over a period of 13 years under continuous or rotational grazing, each at three stocking rates. The stocking rates were one sheep to three, two or one hectares and the rotational grazing was a six- monthly system of summer or winter grazing. The grazing treatments were applied over two five- year terms with a nil-grazing period at the conclusion of each. The latter periods provided a means of measuring the cumulative effects of the grazing treatments. Drought conditions prevailed during the first term so that supplementary feeding was necessary, but the second experienced above average rainfall. Quarterly measurements were made of the pasture dry matter on offer and its botanical and chemical composition. Monthly sheep liveweights, annual wool production and sheep size development in each term were also measured and monetary returns from wool calculated. Rainfall had a major influence on the results recorded and tended to nullify the effects of grazing treatments. Its unpredictability precludes the reliable use of complex techniques in management planning. The overall results suggested that the optimum grazing management of this Mitchell grass rangeland would be continuous grazing at a stocking rate of one sheep to two hectares. Supplementary feeding during drought would be obligatory and should be budgeted for in long-term planning. There was a 50% higher monetary return from this grazing treatment than from the lighter stocking rate and pasture stability (maintenance of Astrebla spp.) was sustained. Pasture stability was adversely affected by the heavier stocking rate. There was no srlstained advantage from rotational grazing compared with continuous grazing.


2002 ◽  
Vol 53 (2) ◽  
pp. 115 ◽  
Author(s):  
J. W. D. Cayley ◽  
M. R. McCaskill ◽  
G. A. Kearney

Changes in soil pH from a long-term experiment at Hamilton, Vic., associated with time, fertiliser application, and stocking rate were assessed. The pH was measured in a 1 :5 suspension of soil in water (pHW) from 1980 onwards and in a 1:5 suspension of soil in 0.01 M CaCl2 (pHCa) from 1984 onwards. Topsoils (0–10 cm) were sampled regularly from 1980 to 1999, and the soil profile to a depth of 80 cm in 1994. The site was sown to perennial ryegrass, phalaris, and subterranean clover in 1977. Treatments fertilised with different amounts of superphosphate were grazed by sheep at stocking rates of 7–19 dry sheep equivalents (DSE)/ha. Average applications of phosphorus (P) ranged from 0.5 to 38.7 kg P/ha.year. The pHCa of the topsoil in 1984 was 4.9. It decreased at an average rate of 0.005 pHCa or 0.008 pHW units/year, with little variation due to fertiliser or stocking rate. Measurements in 1994 revealed subtle but statistically significant (P < 0.01) trends in soil pHCa that were associated with grazing pressure, inputs of fertiliser, and whether or not areas sampled were used by the sheep for camping. The top 0–5 cm of soil was slightly less acidic (+0.07 pHCa units) in the camp areas compared with non-camp areas. Below 5 cm to a depth of 80 cm, camp areas were more acidic (–0.19 pHCa units). At the highest stocking rates, heavier applications of superphosphate were associated with greater subsoil acidity: –0.06 pHCa units per 100 kg phosphorus (P) applied. There was no relationship at medium stocking rates. At low stocking rates, higher P applications were associated with more alkaline subsoils. Net removal of product from 1979 to 1994 (wool and meat removed from plots and excreta transferred to camps) was estimated to be equivalent to 140–380 kg/ha of lime over this 15-year period. The organic carbon (OC) content of the topsoil did not change over 20 years of records from 1979, and was unaffected by inputs of P. In 1994, the OC content of the 0–5 cm layer of topsoil was greater than the 5–10 cm layer (mean values 5.5% and 3.8% respectively; P < 0.001). The OC content of camp areas was higher than that of non-camp areas, this difference being more pronounced in the 0–5 cm layer (P < 0.01). It was concluded that the rate of change of pH was slow because of the high pH buffering capacity of the soil, the small amount of alkalinity removed in product, and the generally high perennial grass content of the pastures. Soils shown to be at greatest risk of acidification from this study were those under camp areas, and where high fertiliser rates were applied to pastures with a low perennial grass content. Rotational grazing should diminish these problems by reducing the concentration of excreta in camp areas, and favouring perennials over annuals in both camp and non-camp areas. Inputs of lime may eventually be needed to compensate for the acidifying effect of product removal.


1971 ◽  
Vol 76 (1) ◽  
pp. 97-106 ◽  
Author(s):  
D. D. Thornton ◽  
G. N. Harrington

SUMMARYStocking rates of 3, 6 and 9 acres per 2- to 3-year old steer on Acacia-Cymbopogonj Themeda complex pasture in Ankole, Uganda, demonstrated that 3 acres per head gave significantly lower individual live-weight gains, but that there was little difference between 6 and 9 acres over a 6-year period. Although cattle grazed at 3 acres averaged only 175 lb per head per annum, compared with 207 lb at 6 acres per head, the income was Sh. 34 per acre compared to only Sh. 20–50 at 6 acres per head. At 9 acres/head the return was Sh. 13–50 an acre.A comparison of a 2 paddock/1 herd system with continuous grazing revealed no differences in production, despite the heavier capital investment involved in the former system. Growth rates at all three stocking rates were similar for most of the year, but in the dry season when all the cattle lost weight those stocked at 3 acres per head suffered the greatest losses (50–60 lb) and those at 9 acres per head the least (20–30 lb).


1977 ◽  
Vol 17 (84) ◽  
pp. 66 ◽  
Author(s):  
WH Winter ◽  
LA Edye ◽  
RG Megarrity ◽  
WT Williams

The seasonal changes in the yield, botanical composition and chemical composition (nitrogen, phosphorus and sulphur) of the pasture plants were measured in a grazing experiment over three years. The 48 treatments were factorial combinations of two different grasses with a common legume mixture, three annual maintenance rates of phosphorus fertilizer, four stocking rates of continuous grazing and two rates of phosphorus fed directly to the cattle. The pastures consisted of Brachiaria decumbens cv. Basilisk or Panicum maximum (common guinea grass) sown with Stylosanthes guyanensis cv. Endeavour and Macroptilium atropurpureum cv. Siratro. Brachiaria decumbens was more persistent than Panicum maximum when heavily stocked at low fertilizer phosphorus rates and in the latter half of each wet season the legume content of the Brachiaria pastures was lower. Of the two grasses, Panicum maximum contained the higher N, P and S contents. In the third year 20 kg ha-1 of phosphorus gave higher yields than 10 kg ha-1 without affecting the chemical or botanical composition of the pastures but 40 kg ha-1 decreased the legume content of the pastures and raised the phosphorus levels in stylo. Pasture yield decreased with increasing stocking rate with only minor effects on the botanical composition of the pastures. However, there was a concomitant increase in pasture quality, particularly in phosphorus content, with increasing stocking rate.


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