The design and interpretation of experiments to study animal production from grazed pasture

1968 ◽  
Vol 71 (3) ◽  
pp. 327-335 ◽  
Author(s):  
J. B. Owen ◽  
W. J. Ridgman

SUMMARYExperiments designed to assess differences between treatments in pasture productivity as measured by the production of animals are complicated by the stocking rates chosen. The paper attempts toderive a simple model relating production per animal and production per unit area to stocking rate for meat animals, based on biological considerations.A method is proposed which would allow meaningful grazing experiments to be carried out employing only one stocking rate, thus considerably reducing the expense of this type of experimentation.The model is applied to some recent data obtained by Hodgson (1966) and Appleton (1967, personal communication).

1966 ◽  
Vol 67 (2) ◽  
pp. 217-221 ◽  
Author(s):  
A. G. Campbell

1. Pasture parameters have been correlated with animal production parameters from a trial in which two management systems (‘controlled’ and ‘uncontrolled’ grazing), each at two stocking rates (0.95 and 1.19 cows/acre), were compared.2. Per acre butterfat production was positively related to percentage utilization of available D.M., but negatively related to yield of available D.M.3. Per cow butterfat production was significantly and positively correlated with yield of available D.M. in the two months after calving (August and September) and in the penultimate month of lacta-tion (April), but this correlation was not significant in other months.4. It is concluded that management system was as important as stocking rate in increasing the utilization of pasture and animal production from pasture.


2007 ◽  
Vol 58 (3) ◽  
pp. 203 ◽  
Author(s):  
Fernando A. Lattanzi ◽  
the late Arturo Mazzanti ◽  
Michael H. Wade

In temperate regions, tall fescue (Festuca arundinacea Schreb.) cultivars derived from Mediterranean germplasm out-perform cultivars of temperate origin during autumn and winter, but the opposite occurs in spring and summer. This study assessed whether such seasonal differences are expressed under grazing and can thus be translated into animal production. Swards of ‘El Palenque’, a temperate cultivar, and of ‘Maris Kasba’, a cultivar developed from Mediterranean germplasm, were grazed under continuous stocking with frequent adjustment of the stocking rate to maintain similar sward state, in temperate Argentina. Liveweight gain per animal (LWGA) and per unit area was determined over 4 consecutive 1-year-long fattening cycles of Angus steers. Close control of sward state resulted in swards of similar height (82 ± 2.5 v. 83 ± 4.5 mm for El Palenque and Maris Kasba, respectively) and herbage mass (96 ± 13 v. 108 ± 8 g DM/m2). Thus, animals grazed structurally very similar swards in both cultivars, throughout the trial. Both cultivars showed similar seasonal trends in LWGA, but markedly contrasting seasonal patterns of carrying capacity. During autumn–winter, LWGA was 507 g/animal.day, but the temperate and Mediterranean cultivar supported, on average, 1.9 and 2.9 animals/ha, respectively. In spring, LWGA was 843 g/animal.day, but the temperate and Mediterranean cultivar supported, on average, 4.3 and 2.9 animals/ha, respectively. Thus, the established cultivar × season interaction in primary productivity was confirmed in terms of animal production. Mediterranean germplasm is certainly an option for increasing the carrying capacity of temperate-humid systems based on direct grazing during the critical period of low temperatures, helping to smooth annual forage supply.


1993 ◽  
Vol 33 (5) ◽  
pp. 561 ◽  
Author(s):  
CJ Gardener ◽  
MR McCaskill ◽  
JG McIvor

Native pastures dominated by Heteropogon contortus (speargrass) were sown to Stylosanthes hanzata cv. Verano in 1972, and herbage production and steer growth rates were compared with those of native pastures from 1973 to 1985. The native pastures also contained naturalised Stylosanthes humilis, but its contribution to pasture yield diminished rapidly, after infection by Colletotrichum gloeospoirioides (anthracnose) in 1973. The experiment was a factorial design of 2 pasture types (native, native plus Verano) x 2 stocking rates (0.6, 1.2 steers/ha) x 2 superphosphate treatments (nil, 300 kg/ha.year) x 2 replicates. Fertiliser application decreased the proportion of legume but had no significant effect on herbage or animal production on this comparatively fertile site (extractable P, 18 mg/kg). Annual liveweight gains at the high and low stocking rates, respectively, on the native pasture averaged 100 and 120 kg/steer. Sowing to Verano did not affect herbage yields but increased annual liveweight gains by 28 and 36 kg/steer at low and high stocking rates. The high stocking rate of 1.2 steers/ha was sustainable for the first 9 years of the experiment, when above-average rainfall was received. However, in the following 3 below-average years, there was a shift to less-desirable species, and a decline in pasture productivity. Relative to the low stocking rate, herbage production on the native pasture in the final season was reduced by 60% and on the Verano pasture by 26%. The highest annual herbage utilisation rate that appeared sustainable in the long term was about 45%, which corresponded to a utilisation rate of 30% during the growing season (about November-May). When oversown with Verano, speargrass tended to decline in favour of annual grasses, weeds, and the introduced grass Urochloa mosanzhicensis, which had been sown on an adjacent experiment. Urochloa appeared to be a more suitable companion species than speargrass for Verano.


1976 ◽  
Vol 27 (6) ◽  
pp. 881 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe ◽  
M Freer ◽  
WR McManus

The production of young crossbred wethers grazing oat, barley and wheat stubbles was measured in each of three years at stocking rates ranging from 15 to 30/ha. In one year, production on 'weedy' stubbles was compared with that of 'clean' (weed-free) stubbles, and also the effect of a wheat–urea–mineral supplement on the production of sheep was measured on oat stubble. Liveweight change and wool production were significantly influenced by the availability of green plant material and by stocking rate, but not by supplementation. The maximum liveweight loss in any year was 7.5 kg and the maximum gain 6.0 kg, both recorded over 11 weeks' grazing. Mean daily clean wool production was 9.9 g/sheep at the lower stocking rate and 6.6 g/sheep at the higher rate, but production per hectare was 10–60% higher at the heavier stocking rate. The ranking of the crop stubbles with respect to animal production was not consistent from year to year. Intense selection for green plant material by sheep resulted in the proportion of green in the diet being nearly always greater than 80%, when the weight of this material on the plots was more than 40 kg dry matter/ha. It appeared that a low intake of nitrogen was not the main limitation to animal production. A maximum of only 36% of the crop residue which disappeared during the experiment could be accounted for as animal intake. Thus it is unlikely that the potential of cereal residues as a source of food for animal production will be realized with grazing sheep.


1970 ◽  
Vol 11 ◽  
pp. 63-70
Author(s):  
NR Devkota ◽  
MR Kolachhapati

A study of the representing rangelands of Taplejung district was carried out during summer of 2009 to estimate the herbage mass yield of different slope categories, and to calculate the carrying capacity (CC) of the representing rangelands based on 60 days re-growth period so that optimum number of livestock unit (LU) per unit area would be possible to allow for grazing. The findings revealed that plain slope had higher herbage mass produced, but was comparatively over-grazed as revealed by higher stocking rate. Existing carrying capacity reasonably supports the grazers, but irrespective of the quality herbage. In deed there was a lower CC for higher slope area with higher CC for plain slope. Nevertheless, the CC values for different slope categories indicated that rangelands in Taplejung district has wider scope of improvement, both for herbage mass productivity, and grazing management through precise stocking rates to match with the prevailing carrying capacity. A major challenge, however, lies to convince herders about the benefits of reducing stocking rates and improving production efficiencies, with the increased income and less degradation of the present available rangelands. Detail study on herbage mass production based on total herbage mass harvest days of a year along with stocking rate for the respective period would be important to consider in generating concrete and site specific information. Key words: herbage mass; carrying capacity; stocking rate; rangelands; herders; Taplejung district DOI: 10.3126/njst.v11i0.4125Nepal Journal of Science and Technology 11 (2010) 63-70


1992 ◽  
Vol 32 (6) ◽  
pp. 693 ◽  
Author(s):  
TR Evans ◽  
JB Hacker

The response of 3 setaria cultivars, the setaria variety splendida, kikuyu grass, and pangola grass to stocking rates of 4-6 steers/ha under continuous grazing was evaluated over a 3-year period. On a year-round basis, averaged over stocking rates, liveweight gain per ha ranged from 822 kg on Narok (164 kg/steer) to 568 kg on Kazungula (114 kg/steer). Narok produced the highest weight gains in summer and winter (142 and 23 kg/steer, respectively). The greatest winter weight loss was from steers grazing Nandi and Kazungula (both -15 kg/steer). Animal production in a year of above-average rainfall, in both summer and winter periods, was markedly reduced overall, even though the quantity of feed on offer was increased. The year x grass interaction was statistically significant in summer, but year x stocking rate and grass x stocking rate were not. Species response to stocking rate showed a linear relationship between stocking rate and liveweight gain per steer, declining with increasing stocking rate, except for Narok setaria where the reverse occurred over the range of 4-6 steers/ha. The results of this experiment support those previously published on these 6 grasses and demonstrate the species potential for good levels of animal production per ha and their ability to withstand high grazing pressures and to maintain weed-free pastures.


1980 ◽  
Vol 20 (106) ◽  
pp. 537 ◽  
Author(s):  
KR King ◽  
CR Stockdale

The relation between the stocking rate of dairy cows and their production from irrigated perennial pasture, with and without nitrogen (N) fertilizer, was studied over 2 years at Kyabram, Victoria. Pastures were rotationally grazed at stocking rates ranging from 4.4 to 8.6 cows ha-1. In each year, N treatments were topdressed four times at a rate of 56 kg N ha-1. For every additional cow per ha, production per ha decreased by 260 and 329 kg of milk, 12.3 and 15.5 kg of butterfat, and 10.7 and 14.5 kg of protein for years 1 and 2, respectively. In year one, the highest production of milk and butterfat (17,900 and 847 kg ha-1, respectively) was from cows stocked at 8.6 cows ha-1, and for protein (597 kg ha-1) from 7.6 cows ha-1. In year 2, production per ha of all milk products maximized and then declined. Maximum production of milk and butterfat (14,180 and 675 kg ha-1, respectively) was at 6.6 cows ha-1, and protein (508 kg ha-1) at 5.9 cows ha-1. Increasing stocking rate also reduced the liveweight of cows at all times. Topdressing with N fertilizer had no effect on total milk or butterfat production per cow, but consistently increased protein production. The range in response increased from 2 to 7 kg protein per cow at 4.4 and 8.6 cows ha-1, respectively. Application of N fertilizer increased liveweight per cow, with greater increases occurring at high stocking rates. In year 2, the efficiency of butterfat production over the whole year was 29.9, 29.3 and 37.0 kg of DM (pasture and supplements) per kg of butterfat produced for 4.4, 6.6 and 8.6 cows ha-1, respectively.


1981 ◽  
Vol 97 (2) ◽  
pp. 353-364 ◽  
Author(s):  
S. E. Watson ◽  
P. C. Whiteman

SummaryAnimal production was compared on three pastures, Brachiaria mutica (para), B. decumbens (signal) and Panicum maximum cv. Hamil (hamil) each sown with a common legume mixture of Centrosemapubescens (centro), Macroptilium atropurpureum cv. Siratro, and Stylosanthes guianensis cv. Endeavour (stylo), at four stocking rates, 1·8, 21·87, 31·86, and 41·85 animals/ha, over 4 years on the GuadalcanalPlains, Solomon Islands.Mean live-weight gain per head over the four stocking rates and 4 years on para pastures was 01·847, on signal pastures 01·838, and on hamil pastures 01·828 kg/head/day. Mean production per hectare at the optimum stocking rates were: para at 3.6 animals/ha, 607 kg; signal at 31·86 animals/ha, 442 kg; hamil at 21·87 animals/ha, 362 kg/ha/year.The high stocking rates of 31·86 and 41·85 animals/ha caused the hamil pastures to decline to the stage where they were destocked in the 4th year of grazing.Superior production on para pastures was not simply related to green dry matter (GDM) on offer. In the 1st year of grazing, GDM was highest in hamil pastures, but in the 2nd year highest in para, and in the 3rd year mean yields were similar in all pastures, but were very low at the 31·86 and 41·85 animals/ha stocking rate in the hamil pastures.Para pastures maintained highest legume contents. The quadratic relationship between live-weight gain/head and legume content was significant over all pastures and stocking rates. Live-weight gain (LWG) per head increased up to 15% legume content, after which there was little change. Yield of green leaf, percentage green leaf, and sward bulk density did not appear to be related to LWG/head. Para pastures had lower values for all these components than the other pastures.Chemical factors contributed to the higher animal production from para pastures. Para leaf maintained consistently higher in vitro dry-matter digestibility values. Na content of para averaged 01·812%, whereas other species were 01·801 to 01·802%, and below the critical level (01·805%) for animal intake. N and S in leaf material, and Cu in total tops were also consistently higher in para grass.Results of this grazing trial suggest that selection of grass species on the basis of quality including dry-matter digestibility and mineral content, on ability to persist with increasing stocking rate, on compatibility with legumes, and on growth habit are more important than selection for dry-matter yield.


1967 ◽  
Vol 15 (3) ◽  
pp. 198-206
Author(s):  
J.P.H. Van der Veen

A trial was begun in 1963 at the Wadi al A'azib Range and Sheep Experiment Station to compare stocking rates of 9.0, 6.0 and 4.5 ha/sheep on animal production (liveweight of ram and ewe lambs, milk production and unwashed wool yield) and on the composition and density of the vegetation which was classified into 5 units: (a) valley stream-bed and floodplain on alluvial silt, (b) valley terrace on higher floodplain, (c) Artemisia herbaalba associations on marly soils, (d) Haloxylon articulation associations in small valleys and on hill-slopes, (e) Haloxylon articulatum/Noea mucronata associations on shallow, stony, grey desert soil on folded limestone hills. Fresh herbage yields in 1964 were 3129, 1126, 1312 and 859 kg/ha for areas (a), (b), (d) and (e), respectively. Average yields were lower at the higher stocking rate in the drought year 1966, but results were generally inconclusive. It was concluded that, pending further work, a stocking rate of 4.5 ha/adult ewe would not seriously deplete the grazable herbage.-M.G.W. (Abstract retrieved from CAB Abstracts by CABI’s permission)


1977 ◽  
Vol 17 (85) ◽  
pp. 187 ◽  
Author(s):  
WH Winter ◽  
LA Edye ◽  
WT Williams

The animal production from two grass/legume pastures was measured over three years. The pastures were grazed at four stocking rates and annually received one of three maintenance rates of phosphorus fertilizer. The animals were given a phosphorus supplement at two rates. The grasses were either Brachiaria decumbens cv. Basilisk or Panicum maximum (common guinea grass) each sown with Stylosanthesguyanensis cv. Endeavour and Macroptilium atropurpureum cv. Siratro. The grasses had little effect on animal production although three Panicum pastures at higher stocking rates became overgrazed and required destocking during the experiment. Even though 73.5 kg ha-1 of phosphorus was used to establish the pastures, the maintenance rate of 40 kg ha-1 gave higher production than the 10 kg ha-1 rate in the first two years. In the third year, production was similar for each fertilizer rate. There was a concomitant rise in faecal phosphorus level with fertilizer rate but no such effect with blood inorganic phosphorus levels. Over the three years of the experiment the liveweight gain per hectare was similar (mean of 0.54 kg per day) at 1.7 and 1.9 beasts ha-1 but was significantly less at lighter stocking rates. In the last two years stocking rate did not significantly affect liveweight gain per head. At the highest stocking rate, gains were greater during the wet season and losses greater during the dry season than those at the lowest stocking rate. The phosphorus supplement did not affect animal production but increased blood inorgainc phosphorus levels. The relationships of animal production with blood and faecal compositions and with the pasture measurements described in a previous paper are discussed.


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