Effect of chemical removal of grasses from pasture leys on pasture and sheep production

1987 ◽  
Vol 27 (3) ◽  
pp. 349 ◽  
Author(s):  
CW Thorn ◽  
MW Perry

Pasture production, pasture composition and quality, and liveweight, body condition and wool growth of Merino weaner wethers were monitored over 2 seasons and at 2 stocking rates (4 and 8 sheep/ha) on a mixed annual grass-legume pasture sprayed with propyzamide to control grasses. Propyzamide virtually eliminated annual grasses from the pasture (less than 5 kg/ha of grass dry matter in spring v. 403 kg/ha on untreated pasture in 1981) and this carried over into the second season (61 kg/ha v. 647 kg/ha in spring 1982). Propyzamide treated pastures had less total dry matter (P = 0.05) throughout 1981: however, except for a single sample date, there was no effect of propyzamide on total available pasture in the second season. Increased growth of clover and capeweed compensated for the absence of the grasses. The higher stocking rate reduced available clover, capeweed and total dry matter (P = 0.05) throughout both years. Sheep grazing grass-free pastures had lower liveweights during winter in both years, but made compensatory gains during late spring and summer consistent with the higher quality (1.6 v. 1.07% nitrogen when sampled in January) of propyzamide treated pastures. In 198 1, wool growth rates were reduced at the higher stocking rate and total clean wool production was reduced from 4.55 kg/sheep at 4/ha to 3.65 kg/sheep at 8/ha. Pasture treatment had no effect on wool production in either year. The implications of using selective herbicides to remove the annual grass component of legume-based annual pastures in south-western Australia are dis cussed in relation to pasture and sheep production.

1986 ◽  
Vol 8 (1) ◽  
pp. 46 ◽  
Author(s):  
RD Graetz

Measurements were made of the wool growth, body weight gain and diet of sheep grazing a saltbush pasture near Broken Hill, N.S.W. The experiment utilized a fenceline contrast in saltbush (Atriplex vesrcarra) density that was visible on Landsat imagery. It ran for five years (1976-1981) with a design of two pasture types by two stocking rates. Fleece weights varied from 3.9-6.0 kg/head and wool production from 0.6-2.9 kg/ha. Neither wool production per head nor bodyweight were substantially affected by stocking rate or pasture type. The composition and quality of the diets selected by sheep on both pastures were identical and of high nutritional value indicating their capability to accommodate differences in pasture composition. Pasture quality was not limiting between stocking rates or determined by the abundance of saltbush. Changes in pasture composition resulting from grazing and exclosure were small and of no significance.


1964 ◽  
Vol 4 (15) ◽  
pp. 392 ◽  
Author(s):  
GW Arnold ◽  
WR McManus ◽  
IG Bush

A four year experiment is described in which Merino wethers were continuously grazed on Phalaris- subterranean clover pasture containing some annual grasses, at three rates for a year and at four rates in subsequent years. For the first year of the experiment a pasture of annual grasses and subterranean clover was also studied at three stocking rates. From the time that the eco-systems that were established reached an equilibrium there was rarely less than 2500 lb of herbage dry-matter an acre available on the lowest stocking rate and rarely more than 1000 lb an acre on the highest stocking rate. There was a significant difference in wool cut per head only in the first year ; over the last three years of the experiment it was slightly lower on the highest and lowest stocking rates than on the intermediate stocking rate. Wool production per acre was proportional to stocking rate. Large seasonal fluctuations were recorded in estimated digestible organic matter intake, liveweight, and wool production. Peaks of intake, liveweight gain, and wool production occurred in autumn and spring but at different dates at different stocking rates. At all but the highest stocking rate, wool production per unit time was lower in summer than in winter. Estimated herbage intake increased with decreasing availability of pasture. Digestibility of the diet, availability of pasture, and body condition of the sheep appeared to affect intake. Despite a higher estimated herbage intake on the higher stocking rate treatments, wool production was no higher.


2007 ◽  
Vol 13 ◽  
pp. 259-262
Author(s):  
K.N. Tozer ◽  
S. Ates ◽  
N.R. Mapp ◽  
M.C. Smith ◽  
R.J. Lucas ◽  
...  

Pasture growth, botanical composition and sheep grazing preference were measured over 20 months in tall fescue (cultivar Advance), without endophyte (Nil) or infected with AR542 (MaxPTM) endophyte, and clover pastures sown into a dryland soil, Canterbury, New Zealand. Pastures were rotationally grazed with sheep, with grazing preference for the two endophyte treatments measured in late autumn and early spring. Annual dry matter production from April 2004 to April 2005 was not significantly different between AR542 (6293 kg DM/ha) and Nil (5864 kg DM/ha) tall fescue. The number of tall fescue plants/m2 and their basal diameter was greater for AR542 (35 plants/m2, 7.5 cm diameter) than Nil endophyte tall fescue (28 plants/m2, 6.8 cm diameter). AR542 endophyte tall fescue pastures had fewer weeds, mainly annual grasses, than Nil endophyte pastures throughout the trial. Grazing preference, measured by the number of sheep grazing each plot, and decline in pasture height did not differ between Nil and AR542 tall fescue. Keywords: tall fescue, novel endophyte, AR542, botanical composition, weed, grazing preference


1975 ◽  
Vol 15 (73) ◽  
pp. 159 ◽  
Author(s):  
PA Kenney ◽  
IF Davis

A study was made during a three year period (1 968-1 970) of wool production by a flock of 540 ewes grazing annual pasture at Werribee, Victoria. The ewes were stocked at three rates (5, 7 1/2 and 10 ewes ha-1) and lambed between July 6 and August 20 or between September 10 and October 29 each year. Fibre diameter and length of wool samples were measured in 1968, 1969 and 1970 ; in 1970 growth of greasy wool was calculated from staples of dye-banded wool. Wool growth was reduced in all ewes during late pregnancy and early lactation but was not affected during late lactation in ewes lambing in September. The proportion of tender fleeces from all ewes was greater in 1970 and the weight of fleeces from only those ewes bearing single lambs was less in all years for ewes lambing in July than for ewes lambing in September. More ewes were barren and fewer ewes had twins in July and consequently the mean fleece weights of all ewes from both groups were similar. Fleeces from ewes stocked at 10 ha-1 were lighter, shorter and finer than fleeces from ewes stocked at 5 and 7 1/2 ha-1, but the proportion of tender fleeces did not differ between the groups. Wool production of ewes stocked at 5 and 7 1/2 ha-1 increased from 1968 to 1970, whereas that of ewes at 10 ha-1 did not. This was associated with differences in pasture availability and composition. At 10 ewes ha-1 less pasture was present in winter and spring in 1970 than in 1968, whereas at the other stocking rates it was greater. In 1970 the density of weeds in autumn was greater and in spring more silver grass (Vulpia spp.) and less brome grass (Bromus spp.) was available at the high stocking rate.


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.


1982 ◽  
Vol 33 (4) ◽  
pp. 705 ◽  
Author(s):  
BA Rowe

A simple relation between the annual wool production per animal (y) and the amount of pasture dry matter produced per animal (x) was derived and tested using the results from a grazing experiment in which the effects of superphosphate and stocking rate on wool and pasture dry matter production were measured from pastures which were continuously grazed by Merino wethers for 3 years. The linear relation, y = a + b/x, accounted for 63% of the variance in wool production per animal in the first year, 82 % in the second and 97 % in the third. Exclusion of an outlier from the first year results increased the variance accounted for to 85 %. This model is simpler and more precise than some others that have been published. It is also consistent with the curvilinear relation between production per animal (y) and pasture production per animal (x).


2003 ◽  
Vol 11 ◽  
pp. 109-115
Author(s):  
T.N. Barry ◽  
P.D. Kemp ◽  
C.A. Ramirez-Restrepo ◽  
N. Lopezvillalobos

Lotus corniculatus (lotus) contains condensed tannins (CT; 25-35 g/kg DM), which reduce the microbial degradation of forage protein in the rumen and increase amino acid absorption from the small intestine. In grazing experiments at Palmerston North during the 1990s, sheep grazing L. corniculatus had superior wool production, body growth and ovulation rates (OR) relative to sheep grazing lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne)/white clover (Tritolium repens) pasture. Polyethylene glycol (PEG) drenching studies showed that action of CT was responsible for a component of the increases in wool growth and OR, but not body growth, and increased milk yield in lactating ewes. The 'Massey lotus' programme moved in 2000 to Riverside farm in the Wairarapa, where L. corniculatus is more agronomically suited, and its integration into dryland farming systems is being studied. We aim to develop systems that increase animal productivity whilst also reducing chemical input, notably of anthelmintic drenches. In two experiments conducted over 12 weeks in spring, ewes and lambs grazing L. corniculatus without pre-lamb drenching had lower faecal egg counts (FEC) and lower dag scores than ewes and lambs grazing pasture. Also, liveweight gain (+44%), weaning weight (+26%) and wool production (+32%) were greater for lambs grazing lotus. Weaned lambs grazing L. corniculatus over 14 weeks in summer grew faster than those grazing pasture (298 cf. 201 g/day) when regularly drenched. Reduction of anthelmintic drenching reduced the growth rates of lambs grazing L. corniculatus, but at 228 g/day this was still much faster than those grazing pasture (187 g/day). Lambs grazing L. corniculatus with restricted anthelmintic grew slightly faster than regularly drenched lambs grazing pasture. In addition, ewes mated on L. corniculatus had greater ovulation rates, lambing % and weaning % (approximately 25%) than ewes mated on pasture. Lamb weaning weight was unaffected by the ewes grazing L. corniculatus during mating, but mortality rate during the period from birth to weaning was lower for lambs that were conceived when their dams were grazing lotus. Annual (dry matter) production under grazing averaged over two years (2000-2001), was 9.5 t/ha for L. corniculatus and 8.6 t/ha for pasture. The percentages of annual production that occurred in spring, summer, autumn and winter were 49, 40, 8 and 4%, respectively, for L. corniculatus and 55, 30, 9 and 6%, respectively, for pasture. L. corniculatus has potential as a specialist feed in dryland farming systems for use during mating to increase subsequent lambing percentage and to increase lamb growth while reducing anthelmintic use. The result is more lambs being drafted at an earlier age. Key words: agronomy, body growth, condensed tannins, dry matter yield, Lotus corniculatus, reproduction, sheep, withdrawing anthelmintic, wool growth


1982 ◽  
Vol 22 (116) ◽  
pp. 182 ◽  
Author(s):  
WK Anderson ◽  
RJ Parkin ◽  
MD Dovey

The effects of weather on clover scorch disease caused by Kabatiella caulivora, the effects of the disease on pasture and sheep production, and the effect of sheep stocking rate (6, 8, 10 and 12 sheep/ha) on the disease were studied in a field experiment over three seasons near Albany, Western Australia. Spraying with benlate was used to control clover scorch on some treatments. Mean temperatures during the period when symptoms of the disease increased were in the range 11-17�C. Rainfall was frequent each year during the same period. The rapid increase in disease symptoms was observed when pasture dry matter on offer was approximately 2500 kg/ha. Disease symptoms decreased during a period of water stress of the pasture. Clover scorch disease had no consistent effect on pasture or animal production except that pasture dry matter on offer in spring was reduced in the unsprayed treatments at the lower stocking rates in the second two years. Higher stocking rates (10 and 12 sheep/ha) reduced the level of clover scorch symptoms without the use of chemical control with benlate. At the period of peak scorch symptoms a stocking rate of 10 sheep/ha reduced disease incidence by 20-35% compared with 6 sheep/ha in unsprayed plots. Increased sheep stocking rates are suggested as a possible alternative to chemical control or replacement of susceptible strains of subterranean clover in grazed pasture.


1973 ◽  
Vol 13 (62) ◽  
pp. 238
Author(s):  
RJ Campbell ◽  
DG Saville ◽  
GE Robards

Natural annual pasture at Trangie, New South Wales, was set stocked from August, 1967 to December 1970 at rates of 2.5, 3.7, and 4.9 merino wethers per ha to determine an optimum stocking rate for the pasture type. All stocking rates were supported without the necessity to hand feed any sheep. Wool production per head was reduced significantly by increased stocking rate in 1968, but not in 1969 and 1970. The suppression of barley grass at the higher stocking rates appeared to benefit animal production in 1969. Substitution of portion of the natural annual pasture with areas of lucerne or natural perennial pasture was also investigated and found to be ineffective in increasing wool production per head above that of wethers at similar rates of stocking on natural annual pasture alone. Possible reasons for the apparent failure of the grazing supplements, particularly lucerne, are discussed in terms of grazing pressure and management strategies.


1974 ◽  
Vol 14 (70) ◽  
pp. 613
Author(s):  
MJ Sharkey ◽  
JP Murphy ◽  
RG Ward ◽  
CG Winfield

At Werribee in southern Victoria changes in liveweight, wool growth and carcase weights were measured over a 96 day period in summer during which two-year-old Corriedale and Merino ewes grazed various combinations of irrigated perennial and non-irrigated annual pasture. To provide the different combinations of grazing, groups of each breed grazed the two pasture types for different periods of time in 8 or 32 day grazing cycles. Groups with an eight day grazing cycle spent 1, 2, 3, 4, 5, 6, or 7 days (the 32 day grazing cycle groups 4, 8, 12, 16, 20, 24 or 28 days) on the irrigated pasture before completing the grazing cycle on the non-irrigated pasture. Two other groups grazed on either irrigated or non-irrigated pasture throughout the 96 days and a further group was slaughtered on day 1 of the experiment to measure the effect of treatments on carcases. The results were examined by regression analysis and showed that both breeds declined in liveweight, carcase weight, and wool growth on non-irrigated pasture. Production improved with time spent on irrigation. Corriedales (initial liveweight 47.0 kg) fattened when grazed on irrigated pasture for 50 per cent or more of the time but Peppin Merinos (initial liveweight 40.1 kg) could not be fattened beyond their initia carcase weights on any treatment. Wool production increased linearly with time spent on irrigation and was greater in Corriedales than in Merinos. The sheep grazing pastures in consecutive 8 day cycles did not differ significantly in production from sheep on similar treatments in the 32 day cycle.


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