Stocking rate effects on liveweight gain of ewes and their twin lambs when grazing subterranean clover-perennial grass pastures

2014 ◽  
Vol 70 (3) ◽  
pp. 418-427 ◽  
Author(s):  
S. Ates ◽  
R. J. Lucas ◽  
G. R. Edwards
2007 ◽  
Vol 60 ◽  
pp. 164-167 ◽  
Author(s):  
K.N. Tozer ◽  
R.J. Lucas ◽  
G.R. Edwards

The effect of endophyte infection of tall fescue (with and without AR542 endophyte Neotyphodium coenophialum) plant competition (white versus Caucasian clover with and without subterranean clover overdrilled) and spring stocking rate (10 versus 20 ewes/ha) on the population size of annual grass weeds was monitored in a pasture on dry stony soils in Canterbury Barley grass (Critesion murinum) cover and seedhead production were lower in AR542 than endophyte free pastures and where subterranean clover was overdrilled than where it was not Vulpia hair grass (Vulpia spp) seedhead production and cover were lower where subterranean clover was overdrilled and where Caucasian rather than white clover was sown Ewe stocking rate did not affect annual grass weed cover or seedhead density The results indicate that sowing tall fescue with AR542 endophyte may be a useful management tool to enhance growth of the perennial grass and reduce invasion of barley grass into dryland pastures


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.


2006 ◽  
Vol 53 (1) ◽  
Author(s):  
J.A. Winder ◽  
C.C. Bailey ◽  
M. Thomas ◽  
J. Holechek

1971 ◽  
Vol 22 (1) ◽  
pp. 81 ◽  
Author(s):  
PG Ozanne ◽  
KMW Howes

The applied phosphorus requirement of a pasture sown to subterranean clover was measured with and without grazing. Under moderate grazing pressure, in the year of establishment, the pasture required about 50 % more phosphorus than when ungrazed. In the following season, at a higher stocking rate, the grazed areas needed twice as much phosphorus as the ungrazed to make 90% of their maximum growth. In both years this difference in requirement between stocked and unstocked treatments was present throughout the growing season. Increased phosphorus requirement under grazing is associated with the need for greater uptake of phosphorus under conditions where redistribution of absorbed phosphorus within the plant is prevented by defoliation. It does not appear to be due to effects of defoliation on root size. Nor does it depend on differential light interception or on changes in botanical composition.


2000 ◽  
Vol 53 (1) ◽  
pp. 32 ◽  
Author(s):  
John A. Winder ◽  
Calvin C. Bailey ◽  
Milton Thomas ◽  
Jerry Holechek

2000 ◽  
Vol 51 (3) ◽  
pp. 377 ◽  
Author(s):  
G. M. Lodge

Seedlings of 3 perennial grasses, Danthonia linkii Kunthcv. Bunderra, D. richardsonii Cashmore cv. Taranna(wallaby grasses), and Phalaris aquatica L. cv. Sirosa,were each grown in replacement series mixtures with seedlings ofTrifolium repens L. (white clover),Trifolium subterraneum L. var. brachycalycinum (Katzn.et Morley) Zorahy & Heller cv. Clare (subterraneanclover), and Lolium rigidum L. (annual ryegrass). Plantswere sown 5 cm apart in boxes (45 by 29 by 20 cm) at a density of 307plants/m2. Maximum likelihood estimates were usedto derive parameters of a non-linear competition model using the dry matterweights of perennial grasses and competitors at 3 harvests, approximately 168,216, and 271 days after sowing. Intra-plant competition was examined inmonocultures of each species, grown at plant spacings of 2, 5, and 8 cm apartwith plants harvested at the above times.Competition occurred in all perennial grass–competitor mixtures, exceptin those of each perennial grass with white clover and thephalaris–subterranean clover mixture (Harvest 1) and those withD. richardsonii and phalaris grown with white clover(Harvest 2). For D. richardsonii (Harvests 1 and 2) andD. linkii (Harvest 1 only) grown with white clover andthe phalaris–subterranean clover (Harvest 1), the two species in themixture were not competing. In the phalaris–white clover mixture, eachspecies was equally competitive (Harvests 1 and 2). These differences incompetition and aggressiveness reflected differences in individual plantweights in monocultures where there was an effect (P < 0.05) of species ondry matter weight per box, but no significant effect of plant spacing.These data indicated that for successful establishment,D. richardsonii and D. linkiishould not be sown in swards with either subterranean clover or white clover,or where populations of annual ryegrass seedlings are likely to be high.Phalaris was more compatible with both white clover and subterranean clover,but aggressively competed with by annual ryegrass.


1997 ◽  
Vol 128 (3) ◽  
pp. 339-346 ◽  
Author(s):  
D. T. CHONG ◽  
I. TAJUDDIN ◽  
Abd. M. S. SAMAT ◽  
W. W. STÜR ◽  
H. M. SHELTON

The productivity of grazing sheep was assessed under 7-year-old rubber at the Rubber Research Institute of the Malaysia Experimental Station at Sungai Buloh near Kuala Lumpur between October 1988 and May 1990. The sheep were Dorset × Marlin crossbred lambs and they grazed planted leguminous cover crops and naturally occurring species at a range of stocking rates.In the immature rubber trial, presentation yields of forage declined with time regardless of stocking rate. In the mature rubber trial, presentation yields of forage were low (<1000 kg/ha) due to low light transmission. High stocking rates (>6 sheep/ha) resulted in a decrease in the proportion of palatable species, namely Pueraria phaseoloides, Paspalum conjugatum, Asystasia gangetica and Mikania micrantha and an increase in the proportion of the less palatable species such as Calopogonium caeruleum and Cyrtococcum oxyphyllum.Daily liveweight gains ranged from 100 g/lamb per day at 4 sheep/ha to 70 g/lamb per day at 14 sheep/ha in the immature rubber trial. Only the lowest stocking rate of 2 sheep/ha was continuously sustainable in the mature rubber trial. The estimated maximum liveweight gain that could be achieved under immature rubber was 266 kg/ha per year at a stocking rate of 13·2 sheep/ha.


2011 ◽  
Vol 51 (11) ◽  
pp. 982 ◽  
Author(s):  
Geoffrey Saul ◽  
Gavin Kearney ◽  
Dion Borg

Two pasture systems (Typical, Upgraded) were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The Typical pasture treatment mimicked the pastures common in the region, with volunteer annual-based species fertilised with ~5 kg/ha.year phosphorus (P). The Upgraded pasture treatment was sown to phalaris, perennial ryegrass and subterranean clover using cultivars recommended for the particular area. Higher rates of fertiliser (13–25 kg/ha.year P) plus other nutrients were applied. Both pastures were set-stocked with breeding ewes. The stocking rate on the Typical treatments was based on normal farm practice. Initially, the stocking rate of the Upgraded pastures was 15% higher than the Typical pastures and increased over time depending if the ewes in the Upgraded pastures were heavier than those in the Typical pastures. Measurements included pasture growth, composition and persistence, ewe stocking rates, ewe and lamb liveweights and condition scores, lambing, marking and weaning percentages, fleece characteristics and supplementary feeding. Over the 6 years, the average carrying capacity of the Upgraded pastures was 18.0 DSE (Dry Sheep Equivalents)/ha compared with 10.2 DSE/ha on the Typical pastures (P < 0.001). As well, the ewes on the Upgraded pastures were 2–3 kg heavier (P < 0.001) and 0.3 condition score higher (P < 0.001) than those on the Typical pastures. Ewes grazing the Upgraded pastures cut significantly more wool per head (4.8 versus 4.5 kg) of higher micron wool (23.1 versus 22.6 um, P < 0.001) but with similar yield and strength. There was no difference in the supplementary feeding required on the treatments. Ewes grazing Upgraded pastures had significantly higher lambing (116 versus 102%), marking (86 versus 81%) and weaning percentages (84 versus 79%) and weaned significantly heavier lambs (23.6 versus 22.6 kg) than those on Typical pastures. There was less feed on offer (P < 0.05) in the Upgraded pastures compared with the Typical pastures in autumn–winter but similar or higher levels in spring and summer. Gross margins using current costs and prices were $20 and $24/DSE for the Typical and Upgraded pastures, respectively. These values were used in a discounted cash flow analysis to determine the long-term benefits of the treatments. Assuming a 12-year life for the pasture, the internal rate of return was 27% with the breakeven point in Year 7. Treatment and ewe condition score significantly influenced lambing percentage with ewes in condition score 3.0 at joining having a lambing percentage of 111% compared with 95% if at condition score 2.3. Irrespective of condition score, ewes grazing Upgraded pastures had a 7% higher lambing percentage than those grazing the Typical pastures. Ewe condition score and lambing time significantly affected weaning weight. Lambs born to ewes in condition score 2.3 during pregnancy and lambing in autumn, reached only 32% of mature ewe liveweight at weaning whereas lambs from ewes at condition score 3.0 achieved 51% of mature weight by weaning.


1997 ◽  
Vol 37 (5) ◽  
pp. 531
Author(s):  
S. G. Clark ◽  
J. Li ◽  
A. M. Johnson ◽  
G. N. Ward ◽  
J. F. Chin

Summary. The seed banks of 6 subterranean clover (Trifolium subterraneum L.) cultivars were sampled at 3 abandoned cultivar evaluation experiments in south-western Victoria (Hamilton, Macarthur and Timboon). Two were var. yanninicum (Trikkala and Larisa) and 4 were var. subterraneum (Denmark, Goulburn, Karridale and Leura). Seed was sampled in late summer–early autumn 1993, between 6 and 10 years after the sites were established and between 3 and 7 years after the sites were abandoned. The collected seed was separated into black and white seed, and a sample of the black seed was grown in a glasshouse and identified as either belonging to the sown cultivar or belonging to another cultivar/genotype. All white seed was assumed to belong to the sown cultivar. The aim was to determine if these widely used cultivars were persisting under farm management conditions and competition from perennial grass, other subterranean clover and annual weeds. With some variation between sites all cultivars were found to be persisting satisfactorily. Over the 3 sites, white-seeded cultivars averaged 460 kg/ha and 6640 seeds/m2; black-seeded cultivars averaged 260 kg/ha and 5590 seeds/m2. Contamination with other subterranean clover cultivars/ecotypes was generally low, except at Macarthur where the white-seeded cultivars were heavily contaminated (Trikkala 39% pure; Larisa 57% pure) with black seeds highlighting the poor adaptation of var. yanninicum to light soil types. Of the black seeds, over the 3 sites, average contamination level was 13% and ranged from 41% (Goulburn at Macarthur) to 1% (Leura at Timboon). The study indicates that in south-western Victoria, all the recently released cultivars are likely to persist and be productive, and that the small-plot evaluation techniques used to identify potential new cultivars are likely to be adequate if replicated in space and if the clovers are sown in mixed swards with perennial grass.


2009 ◽  
Vol 49 (8) ◽  
pp. 654 ◽  
Author(s):  
Geoffrey Saul ◽  
Gavin Kearney ◽  
Dion Borg

Two pasture systems were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The ‘typical’ pasture treatment mimicked the pasture and grazing management common in the region, with volunteer annual-based pastures fertilised with around 5 kg/ha phosphorus (P) each year. The ‘upgraded’ pasture treatments were resown to phalaris, perennial ryegrass and subterranean clover, and higher rates of fertiliser (13–25 kg P/ha.year) plus other nutrients were applied. Both pastures were set stocked with the participating farmers breeding ewes. Stocking rate was an emergent variable on each plot. The stocking rate on the typical treatments was based on normal farm practise. Initially, the stocking rate of the upgraded pastures was 15% higher than for the typical pastures and increased over time depending if the ewes in the upgraded pastures were heavier than those in the typical pastures. Measurements included soil fertility, pasture production, nutritive value and composition, and animal production. Net annual pasture production of the upgraded pastures was 10 500 kg/ha compared with 8700 kg/ha for the typical pastures. This average difference (18%) between the treatments was greatly influenced by the large advantage (40%) of the upgraded pasture in the wet year of 1992. Upgraded pastures had higher pasture production than typical pastures in spring but the reverse occurred in autumn. In a separate small plot experiment, the response of each pasture to higher P fertiliser applications was tested. In autumn and winter, there was a significant interaction between pasture type and P rate, with higher responses on the upgraded pastures. In spring, both pastures responded to increased P applications but the upgraded pastures were more responsive at all P rates. The upgraded pastures contained significantly higher legume content (30–50%) than the typical pastures (10–20%). The proportion of sown perennial grasses in the upgraded pasture declined from around 30 to 10% after 6 years displaced by annual grasses and broad-leaf weeds. Herbage from upgraded pastures had significantly higher crude protein content (2–7 units) and digestibility (1–10 units) than the typical pastures with the difference between the treatments increasing over time. The set stocking policy used in this experiment is likely to have exacerbated the decline in sown perennial grasses and implementation of some form of strategic or rotational grazing may have improved persistence. The experiment also highlights the importance of selecting perennial grasses able to cope with the local environment and grazing conditions. Despite the decline in perennials, these results show significant potential to improve pasture productivity and quality in south-western Victoria.


Sign in / Sign up

Export Citation Format

Share Document