The effect of intensity of rotational grazing with breeding ewes on phalaris-subterranean clover pastures

1969 ◽  
Vol 9 (36) ◽  
pp. 74 ◽  
Author(s):  
FHW Morley ◽  
D Bennett ◽  
GT McKinney

Animal production and pasture amount and composition are presented from an experiment at Canberra in which one-, three-, and nine- subdivisions were rotationally grazed throughout the year in 1963, from December to September 1964, and from March to September in 1965, 1966, and 1967, at 20, 25, or 30 Merino ewes per hectare for three years, and at 17 ewes per hectare for a further two years. Intense subdivision resulted in pastures in which perennials, rather than the annual components, predominated. Moderate subdivision produced a pasture in which both perennials and annuals contributed substantially. Under a one-paddock (set stocked) system the annuals yielded more in spring than did perennials. Intensive subdivision favoured winter production, but resulted in less growth from pastures during spring, less dry feed in summer, and hence an increased need for supplementary feeding in years with dry autumns. The three-paddock system resulted in more winter production than the one-paddock, and about the same production in spring. Intensity of subdivision had little effect on animal production, except in increased frequency of deaths from Phalaris poisoning, some reduction in pre-lambing mortality, and increased requirement for supplementary feeding for survival. These results indicate that intensive subdivision of such pastures is unlikely to be worthwhile in environments such as that at Canberra. A moderate amount of subdivision as exemplified in a three paddock rotation, may give worthwhile increases in winter production, without the penalty of decreased spring growth.

1975 ◽  
Vol 26 (4) ◽  
pp. 751 ◽  
Author(s):  
M Statham ◽  
AC Bray

Congenital goitre was first recorded in Tasmanian sheep In 1945. Severe but sporadic outbreaks have since occurred in 1956, 1964 and 1968. The disease seemed to be associated with particular farms and its incidence often differed markedly between ewe flocks on the one farm. A survey indicated that the condition was mainly confined to the Derwent Valley and the northern Midlands. Studies involved a grazing trial near Bothwell, where goitre was endemic, and included supporting animal house tnals and plant growth studies. Soil type was shown to be a major factor in the disease: ewes grazing pasture on a sandy soil produced many more goitrous lambs than ewes grazing pasture on clay soil. Analyses of the two pastures revealed that those on sandy so11 contained less iodine than those on clay soil but neither contained the minimum level necessary to prevent goitre. Observations revealed that outbreaks of the disease followed wet autumns with subsequent lush pasture during pregnancy. This correlation could be explained if pasture grown under moist conditions contained less iodine than pasture grown under moisture stress. However, experiments with the two main pasture species (perennial ryegrass and subterranean clover) showed that plant iodine levels were not affected by the water supply. Two goitrogenic agents, nitrate and thiocyanate, were present in the pastures, but they were not considered to be Important in the aetiology of the disease. Similarly, the drinking water was found to be unimportant, even though the two sources available contained widely different amounts of iodine. Apparently, between-year variation in the incidence of goitre and the effect of soil type can best be explained by a varying iodine intake dependent on soil ingestion which varies with pasture availability. This hypothesis is discussed in the light of the results.


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.


1965 ◽  
Vol 5 (19) ◽  
pp. 500
Author(s):  
DJ Connor

Amsinckia is a serious weed in the wheat growing areas of north-western Victoria. It is successful in the inter-crop pastures, based upon barrel medic, because it grows faster than barrel medic in the cooler months of May to August. In addition, the rapid growth in height associated with the change from rosette to elongating phases ensures a height advantage over the pasture species when the flush of pasture growth does commence. Seed production by each Amsinckia plant is very high, and for this reason any competitive restriction obtained in one year is not necessarily reflected in the establishment phase of the next. Subterranean clover c.v. Clare is more competitive than barrel medic and was able to eliminate Amsinckia from the sward in two years. However it has only limited application in the pastures of north-western Victoria. A mowing treatment was carried out at the commencement of Amsinckia flowering, for this coincides with the beginning of rapid pasture growth. Regrowth produced a reversal of height relationships within the pasture and enabled barrel medic to shade Amsinckia BJ this treatment growth and seed production of Amsinckia were reduced by 99 per cent within the one season.


1972 ◽  
Vol 12 (56) ◽  
pp. 240 ◽  
Author(s):  
KFM Reed ◽  
RW Snaydon ◽  
A Axelsen

Young sheep were rotationally grazed, at two stocking rates, on pasture sown to combinations of two legume species (lucerne or subterranean clover) and two grass species (a mixture of annual and biennial ryegrass or phalaris) at Canberra. Liveweight gains were 45 per cent greater, and wool production was 10 per cent greater, on the lucerne dominant pasture (87 per cent lucerne) than on the grass dominant subterranean clover pasture (8 per cent subterranean clover). The differences were maximum during summer, but also occurred during spring. Mortality and supplementary feed requirement on grass dominant pasture was double that on lucerne pasture. Liveweight gains were 13 per cent greater on pasture sown to ryegrass than on pasture sown to phalaris. Sheep mortality was eight times greater on the phalaris than on the ryegrass pasture, and survival feed requirements at least double. The superior animal production from lucerne pasture was due mainly to the ability of lucerne to grow during periods of low rainfall and to maintain a high production of legume in the pasture.


2016 ◽  
Vol 12 (7) ◽  
pp. 2024-2035 ◽  
Author(s):  
A. Marco-Ramell ◽  
A. M. de Almeida ◽  
S. Cristobal ◽  
P. Rodrigues ◽  
P. Roncada ◽  
...  

Stress and welfare are important factors in animal production in the context of growing production optimization and scrutiny by the general public.


2003 ◽  
Vol 43 (6) ◽  
pp. 539 ◽  
Author(s):  
G. M. Lodge ◽  
S. R. Murphy ◽  
S. Harden

An experimental site was established in 1997 on the North-West Slopes of New South Wales to further investigate the use of strategic grazing management to improve the persistence of phalaris (Phalaris aquatica cv.�Sirosa) and subsequent effects on animal production and soil water content. The pasture was sown in 1992 to Sirosa phalaris, subterranean clover (Trifolium subterraneum var. subterraneum cv. Seaton Park) and lucerne (Medicago sativa cv. Aurora). Four grazing treatments were applied in a randomised 3-replicate design. Treatments consisted of continuous grazing at 12.3 sheep/ha (C12 or control); continuous grazing at 6 sheep/ha (C6), and 2� spring and autumn strategies of either resting from grazing for 6 weeks in each season (SAR0), or reducing stocking rate from 12.3 to 4.0 sheep/ha (SAR4). Despite annual applications of fertiliser and high clover content, Sirosa phalaris herbage mass in plots continuously grazed at 12.3 sheep/ha declined from a mean of 3300 kg DM/ha in spring 1997 to < 700 kg DM/ha by May 1998. At the end of the study (February 2001), Sirosa mean herbage mass in these plots was 670 kg DM/ha and lower (P < 0.05) than for the other treatments (mean value 5400 kg DM/ha). These marked changes in herbage mass, and the degradation of the Sirosa-based pasture to an annual pasture by continuous grazing at 12.3 sheep/ha, were not generally reflected in either short-term animal production or substantial differences in soil water content. Wool production (kg/head) was not significantly different among treatments each year. Compared with continuous grazing at 12.3 sheep/ha, sheep liveweights were higher (P < 0.05) in plots continuously grazed at 6.1 sheep/ha from November 1997 to February 1999. However, from February 1999 to 2001, sheep liveweights in the 2 treatments with the highest Sirosa phalaris content were lower (P < 0.05) than those continuously grazed at 12.3 sheep/ha. Only the soil water content for the C6 and SAR4 treatments at 0–30�cm was significantly different to the control treatment, but the differences were predicted to be < 2.5 mm/year. In the root zone (0–90 cm), mean soil water content ranged from 159 to 309 mm (mean 220 mm), while plant available water (soil water content – soil water content at –1500 kPa) was a mean of 79 mm, ranging from 11 to 168 mm.


2003 ◽  
Vol 43 (8) ◽  
pp. 785 ◽  
Author(s):  
D. F. Chapman ◽  
M. R. McCaskill ◽  
P. E. Quigley ◽  
A. N. Thompson ◽  
J. F. Graham ◽  
...  

The effects of combinations of different fertiliser rates and grazing methods applied to phalaris-based pastures on an acid, saline, yellow sodosol on the Dundas Tablelands of western Victoria (mean annual rainfall 623�mm) were measured from 1997 to 2000. The objective was to help identify management systems that improve phalaris growth and persistence, water use, and animal production, and thereby the productivity and sustainability of grazing systems. Pastures were either set stocked with low [mean 6.4 kg phosphorus (P)/ha.year] or high (mean 25 kg P/ha.year) fertiliser rates, or rotationally grazed with high fertiliser (mean 25 kg P/ha.year). Rotational grazing was implemented as either a simple '4-paddock' system (fixed rotation length), or a more intensive system where rotation length varied with pasture growth rate. Unreplicated paddocks of volunteer pasture (dominated by onion grass and annual grass weeds) receiving an average of 8 kg P/ha.year were also monitored. All treatments were stocked with spring-lambing Merino ewes. Stocking rate was an emergent property of each treatment, and was driven by pasture quality and availability. Total pasture herbage accumulation ranged from 7150 to 9750 kg DM/ha.year and was significantly lower on the set-stocked, low-fertility treatment than on all other treatments. A significant treatment.day effect in the spline analysis of herbage mass was explained by a trend toward higher pasture mass in the rotationally grazed treatments than set-stocked treatments from the break of season until mid-spring. Rotational grazing led to significantly higher phalaris herbage accumulation than set stocking (mean 3680 v. 2120 kg DM/ha.year), but significantly lower subterranean clover herbage accumulation (1440 v. 2490 kg DM/ha.year). Despite the stronger growth of deep-rooted phalaris in the rotationally grazed treatments, maximum soil water deficits at the end of summer differed only slightly between treatments, with the difference between driest and wettest treatments amounting to only 14 mm. Summer growth of phalaris was apparently insufficient to generate significant differences in soil water extraction at depth, even when phalaris content was increased by rotational grazing, and re-wetting of the soil profile occurred at a similar rate for all treatments. Rotationally grazed treatments supported higher stocking rates than set-stocked treatments at high fertiliser rates (mean 14.9 v. 13.7 ewes/ha), but apparent losses in pasture feeding value due to lower legume content under rotational grazing meant that there were few significant differences between treatments in lamb production per hectare. The experiment showed that grazing method can have a substantial and rapid effect on pasture botanical composition. There are clear opportunities for producers to use temporal and spatial combinations of set stocking and rotational grazing to manipulate herbage mass and pasture composition within broad target ranges for achieving both animal production (e.g. high per-head animal performance) and sustainability (e.g. persistence of perennial grasses) objectives. Rigid application of either set stocking or rotational grazing imposes limitations on both pasture and animal production, and neither grazing method will optimise system performance under all conditions. The experiment also demonstrated that management and land-use changes that have much greater potential to increase water use than those examined here will be needed to ensure the sustainability of pasture systems in the high rainfall zone of western Victoria.


2015 ◽  
Vol 68 (4) ◽  
pp. 332-340 ◽  
Author(s):  
Zalmen Henkin ◽  
Eugene D. Ungar ◽  
Avi Perevolotsky ◽  
Mario Gutman ◽  
Yehuda Yehuda ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document