Effect of stocking rate, time of lambing and inclusion of lucerne on prime lamb production in north-east Victoria

1980 ◽  
Vol 20 (107) ◽  
pp. 637 ◽  
Author(s):  
JL Reeve ◽  
MJ Sharkey

Results of a grazing study involving Border Leicester x Merino ewes and their progeny are reported for a 4-year period 1969 to 1972. The study was conducted at Rutherglen in north-east Victoria. The 1260 ewes observed throughout the study were allotted to 42 treatment plots with 30 ewes per plot. Thirty of the plots were located on annual pasture (subterranean clover, barley grass) involving three replicates of ewes stocked at 7.4,9.9 and 12.4 ewes ha-l for ewes joined over 7-week periods to commence lambing about May 5, June 23 or August 8. Additionally, an extra three plots with spring lambing were grazed at 14.8 ewes ha-1. A further 12 plots contained lucerne on one third of the plot area. The ewes on these plots also lambed for a 7-week period commencing August 8, and provided three replicates of 7.4 9.9, 12.4 and 14.8 ewes ha-1. First services were concentrated early in the joining period in the spring-lambing ewes, there were few returns to services and few ewes failed to mate. On the other hand, among ewes joined to lamb in autumn, first services were distributed over the entire joining period, and many ewes returned to service or failed to mate. The mating pattern of ewes joined to lamb in winter were intermediate between the autumn and spring lambing groups. Although the liveweight of spring-lambing ewes was lighter at mating, the number of lambs born per 100 ewes joined was greater than for winter lambing, and these in turn were greater than for autumn lambing ewes. The response to an additional 1 kg liveweight at mating was 1.7, 2.0 and 2.8 additional lambs born per 100 ewes joined for autumn, winter and spring lambing, respectively. Wool production per hectare increased linearly with increase in stocking rate; it was marginally affected by time of lambing and was greatest where lucerne was provided. The number of lambs reared per ha increased linearly with increase in stocking rate, albeit there was some decline in carcase weight and a small decline in numbers of lambs reared per ewe. Lambs born in autumn and winter were generally slaughtered in prime condition at 31 kg liveweight, except in the drought year of 1972, but more lambs were produced from a winter lambing than from autumn lambing. When lambing was in August-September there was a slight increase in the numbers of lambs reared above that of winter lambing, but the proportion of lambs marketed at less than 31 kg was greatly increased. Where lucerne was provided to spring-lambing ewes the greatest weight of meat per hectare was produced, and few lambs were less than 31 kg. In descending order of magnitude, the major factors affecting carrying capacity were season, year, stocking rate and time of lambing. Seasonal shortcomings in nutrition were alleviated by the provision of supplementary feed. At the lighter stocking rates of 7.4 and 9.9 ewes ha-1 the amounts of supplements fed were very low, even in the drought year of 1972. These two lowest stocking rates could be maintained indefinitely without excessive use of supplementary feed. Discernible changes in botanical composition with partial loss of productive grass and clover species, reduction in pasture growth rate, increased use of supplementary feed and lowered wool production of ewes, occurred with spring lambing without lucerne, particularly at 12.4 and 14.8 ewes ha-1. Pasture composition and growth details were very similar with either autumn or winter lambing.

1983 ◽  
Vol 34 (5) ◽  
pp. 537 ◽  
Author(s):  
JR Donnelly ◽  
FHW Morley ◽  
GT McKinney

Spring-lambing Merino and crossbred ewes grazing on dryland lucerne pastures were generally heavier throughout the year than ewes grazing on phalaris and subterranean clover pastures, even though they experienced greater weight losses during winter. These losses were mostly eliminated by compensatory gains in spring. Annual fleece weights of the Merino ewes grazing on lucerne or phalaris and subterranean clover pastures declined linearly by 146 and 64 g respectively for each additional ewe carried over a range of stocking rates from 9 to 18 ha-1. Corresponding figures for crossbred ewes were 114 and 46 g. In each case the difference between pasture species was significant (P < 0.02). Only at the lowest stocking rates were fleeces from ewes on lucerne heavier (by c. 500 g) than those from ewes on phalaris. At the highest stocking rates, there were no advantages in terms of wool production from grazing breeding ewes on lucerne. Not only was there a greater need for supplementary feed during late pregnancy to avoid losses from pregnancy toxaemia, but the lucerne pastures at all stocking rates proved more sensitive to unfavourable physical and chemical characteristics of soils than did phalaris and subterranean clover pastures. The fleece weights of Merino and crossbred ewes declined, on average, by 70 and 50 g per year for ewes aged between 1+ and 6+ years. Pregnancy reduced fleece weights by 5-10% in Merinos and 5-21% in crossbred ewes, depending on seasonal conditions which varied from year to year. For Merinos only, dry ewes grew about 4% more wool than lactating ewes. No other effects of reproduction on fleece weights were observed.


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.


1978 ◽  
Vol 18 (91) ◽  
pp. 202 ◽  
Author(s):  
DJ Cannon ◽  
MJ Sharkey ◽  
PT Stewart

Oat yields and wool production of Merino wethers were measured at five stocking rates in five systems of land use in each of two years, 1971 and 1972, in north-east Victoria. Nominal stocking rates were 6.8, 8.6, 10.5, 12.4 and 14.2 sheep ha-1. The production at each stocking rate was compared in the following systems: 1, all pasture; 2, and 3. pasture grazed year long with oats grazed in winter and oat stubbles in summer on 15 per cent (system 2) or 30 per cent of the plot area (system 3) ; 4. and 5. pasture grazed throughout with oat stubbles grazed in summer but crops not grazed during the growing season and crops comprised either 15 per cent (system 4) or 30 per cent of the plot area (system 5). In 1971 the rainfall of 540 mm was sufficient to produce a harvestable oat crop and to maintain sheep on all plots without supplements. The mean oat yield of 2.04 � 0.01 t ha-1 for system 3 far exceeded that of the more heavily grazed crops in system 2 (1.44-0.05) or of ungrazed crops in systems 4 and 5 (1.44i-0.07). Clean wool production per head from each system was compared in terms of an 'average' stocking rate S which accounted for variation in grazing intensity throughout the year inherent in systems 2, 3, 4, 5. In 1971 clean wool production kg-1 declined with increase in average stocking rate in all systems but the mean of the four dual land use systems did not differ from the all pasture system (1). 1972 was a drought year with only 330 mm of rain, oat crops failed to produce grain and were grazed from October. The wool production of sheep on systems 2 to 5 was greater than that of sheep at equivalent average stocking rates on the all pasture system. Growing oats for grazing and grain in association with wool production would appear to be more profitable than wool production alone. Light grazing of oats in winter may increase oat yield but more information is needed in relation to seasonal variation and oat variety.


1966 ◽  
Vol 6 (20) ◽  
pp. 101 ◽  
Author(s):  
GW Arnold ◽  
WR McManus ◽  
IG Bush

Merino wethers were grazed for four years on Phalaris-subterranean clover pastures at four stocking rates. Measurements over two years showed that wear of incisor teeth increased substantially with stocking rate. This wear was closely associated with intake of silica by the sheep. After the experiment marked carry-over effects in wool production and live weight were observed in adult wethers. Significantly more wool was produced by sheep previously grazing at high stocking rates. Possible reasons for this effect are discussed.


1971 ◽  
Vol 11 (52) ◽  
pp. 498
Author(s):  
GW Arnold ◽  
A Axelsen ◽  
HR Gharaybeh ◽  
HW Chapman

In an experiment at Canberra, A.C.T., extending over four years, crossbred and Merino ewes were grazed at three stocking rates on pastures of either phalaris (Phalaris tuberosa), phalaris combined with separate paddocks of brome grass (Bromus inermis), and cocksfoot (Dactyllis glomerata), or separate paddocks of brome grass and cocksfoot. Subterranean clover (Trifolium subterraneum) was present in all pastures. One-, two-, and three-paddock systems and two times of lambing were also compared. Pasture availability and animal productivity were measured. Early lambing resulted in more prime lambs although the later lambs had slightly higher rates of gain. At the highest crossbred stocking rate studied (seven ewes per acre) wool production per acre was still increasing, but number of prime lambs and lamb liveweight gain did not increase above stocking rates of five ewes per acre. More feed was available to ewes during late pregnancy on treatments allowing feed rationing in autumn and early winter, but neither rationing nor including brome grass and cocksfoot in the system increased animal productivity beyond that achieved by grazing phalaris continuously. At stocking rates up to six ewes per acre, animal production was greatest from phalaris grazed continuously. Stocking rates were designed to provide similar weights of either Merino or crossbred ewes per acre at each stocking level. Because more lambs were born to crossbred ewes they had less feed than Merinos in spring and summer at all stocking rates. Lambs from crossbred ewes were heavier at birth and grew faster than lambs from Merino ewes. More prime crossbred lambs were produced per acre at all stocking levels. The reproductive rate and lamb production of Merino ewes dropped sharply with increased stocking rate. Fleeceweights were similar for both breeds, particularly at low stocking rates. Wool production per acre increased with stocking rate and was higher from Merinos at each level.


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.


1977 ◽  
Vol 28 (1) ◽  
pp. 133 ◽  
Author(s):  
JP Langlands

Grass and milk consumption and liveweight changes of lambs grazed at stocking rates ranging from 9 to 35 sheep/ha were measured during a 105 day lactation. Grass consumption and wool production of their mothers and of similar ewes without lambs were also determined. The forage and total organic matter intakes of the lamb increased with time while milk consumption declined; all three variables were negatively correlated with stocking rate. The intake of the ewe and its liveweight gain were not sensitive to increasing stocking rate, but wool production declined at higher stocking rates. The maintenance requirement of the ewes was estimated to be 218 kJ metabolizable energy/kg liveweight, and the efficiency with which metabolizable energy was utilized for milk production was 66%. Lactation increased the intake of the ewe but reduced its wool production.


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.


1974 ◽  
Vol 14 (69) ◽  
pp. 454
Author(s):  
DJ Cannon

The wool production and liveweight of Corriedale wethers was measured when both stocking rate and the proportion of land to wheat and pasture varied. The nominal stocking rates (R) were 6.8, 8.6, 10.5, 12.4 and 14.2 wethers ha-1, and the proportion sown to wheat was 0, 15 or 30 per cent. Clean wool production per head declined linearly with increase in stocking rate and the proportion of land sown to crop. Generally both maxima and minima liveweights declined with increase in cropping and minima liveweights with increase in stocking rate. The effect of cropping on wool production was attributed to the increased stocking rate on the uncropped portion of land during the period when the cropped area was unavailable to grazing. 'Average' stocking rates per ha (S) were calculated on the basis of the proportion of land to crop and the fraction of the year stubbles were available for grazing. S was found to be a more useful measure of stocking rate than R, in a system of dual use of land.


1974 ◽  
Vol 14 (69) ◽  
pp. 454
Author(s):  
DJ Cannon

The wool production and liveweight of Corriedale wethers was measured when both stocking rate and the proportion of land to wheat and pasture varied. The nominal stocking rates (R) were 6.8, 8.6, 10.5, 12.4 and 14.2 wethers ha-1, and the proportion sown to wheat was 0, 15 or 30 per cent. Clean wool production per head declined linearly with increase in stocking rate and the proportion of land sown to crop. Generally both maxima and minima liveweights declined with increase in cropping and minima liveweights with increase in stocking rate. The effect of cropping on wool production was attributed to the increased stocking rate on the uncropped portion of land during the period when the cropped area was unavailable to grazing. 'Average' stocking rates per ha (S) were calculated on the basis of the proportion of land to crop and the fraction of the year stubbles were available for grazing. S was found to be a more useful measure of stocking rate than R, in a system of dual use of land.


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