For many years profitable farming in the southern wheat belt of NSW has been associated with subterranean clover pastures during the ley phase. This plant is of enormous agricultural importance through its contribution to nitrogen accretion and soil fertility and the provision of a high quality diet and enhanced wool and meat production. There is unequivocal evidence to show that animal production increases as the percentage of clover in the diet also increases.

However, even subclover has its shortcomings, namely relatively low dry matter production in the winter and cessation of growth during the summer. Livestock grazing subclover pastures will gain weight slowly over the winter, more rapidly in the spring and then lose weight during the summer. Three approaches can be taken to increase livestock production. Firstly, to improve dry matter production in the winter; secondly, to extend the growing season; or, thirdly, to improve the quality of the dry residues. Some of the most dramatic benefits to animal production have been shown through the provision of green feed over summer. Several of these options can be achieved with lucerne and it is the purpose of this paper to outline the benefits that can be obtained through the use of lucerne-based pastures.

Grazing Management

Lucerne is probably our most widely adapted forage plant. It spans the length and breadth of our continent and was first recorded in NSW in 1806. Incidentally, subclover was first identified in NSW in 1896 from a plant forwarded by a Mr P.W. Lorimer who found it growing near the Wagga saleyards. However, early writings of lucerne growing in Australia relate that the plant was highly valued as a forage but had inherent problems as a pasture. Our early settlers found that it was not conducive to continuous defoliation, a factor probably worsened by the lack of subdivision at that time. It was not until the late 1960s and early 1970s that serious attention was given to the grazing management of lucerne-based pastures and principles evolved for its persistence and high levels of animal production. Several systems of rotational grazing were developed, varying in the intensity and length of grazing, but the critical factor was found to be the length of the rest period between grazings. This should be a minimum of approximately 6 weeks during the period of active growth. There is also a suggestion that extended rest periods during periods of slow growth may improve plant reserves and enhance production during a period of active growth. The grazing period should be controlled to the extent that minimum regrowth is removed before spelling. It has also been shown that if lucerne plants flower at least twice a year, the resilience is improved. To obtain maximum benefit from lucerne- based pastures a system of rotational grazing is necessary. However, smaller benefits can be derived from paddock sowings without subdivision provided adequate rest periods are maintained. If managed appropriately lucerne can

make a significant contribution to the production of grazing animals through its ability to exploit soil moisture to considerable depths and produce green feed when other annuals are dormant. This effect is shown in Figure 1, during an average year at Wagga in which good summer rain was received followed consecutively by a very dry year.

Figure 1. Growth of lucerne/subterranean clover and clover pastures in two years at Wagga (adapted from Wolfe et al., 1980)

Increased growth rates during the summer and early autumn were attributable solely to lucerne and this resulted in a 16% and 175% increase in the production of high quality green feed and a 12 and 27% increase in animal production for the two years respectively. The major gain from lucerne occurred in the drier year owing to the ability of lucerne to respond to summer rain. The relatively smaller response in the second year was due to a reduced availability of total green feed, it being approximately half that of the previous average year.

On suitable country using correct sowing technology (Cregan, this Conference) lucerne can be readily established as a pasture mix with subterranean clover either on its own or by undersowing in the last year of the cropping cycle. To justify the added-expense of seed and possibly further subdivision it is necessary that profitable gross margins are obtained in comparison with the more conventional subclover, annual grass pastures.

Sheep Production

We do not have to go far afield to obtain information on the superiority of lucerne-based pastures for animal production. A considerable volume of local evidence directly applicable to our Region is available from experiments carried out at the Agricultural Research Institute at Wagga and the Rutherglen Research Institute.

FitzGerald (1979) at Wagga found that wethers on pasture containing lucerne were an average 2.4 kg heavier than sheep on subclover with phalaris or annual grass. The difference increased to as much as 7 kg in summer and was usually maintained over the winter. The composition of the winter-growing component was most important to production. Lucerne-based pastures consistently produced about 10% more wool per hectare than clover-based pastures over the four years of the experiment (Table 1). In addition, in 1973 the sheep on the lucerne-based pastures produced as much wool as sheep on the subclover pastures which had been hand-fed from ‘February to April.

Table 1. Clean wool production for four pasture types from 1970 to 1973, meaned over two stocking rates of 8.9 and 13.3 sheep/ha (FitzGerald, 1979).

PASTURE	CLEAN WOOL PRODUCTION (kg/head/year)
	1970*	1971	1972	1973
Subclover	3.7	3.8	3.7	2.3
Subclover/Phalaris	4.1	4.1	3.8	2.2
Lucerne/Subclover	4.6	4.3	3.6	2.4
Lucerne /Subclover / Phalaris	4.7	4.4	3.7	2.4

* Greasy wool 10 months growth

The effect of establishing lucerne on 30% of the available grazing area on prime lamb and wool production from an autumn and spring lambing was studied by Reeve and Sharkey (1980) at Rutherglen for pasture based on either Woogenellup or Mt Barker clovers and barley grass and Vulpia sp. They found that the growth of annuals increased through the presence of lucerne, perhaps as a result of selective grazing of the lucerne, and that both pasture productivity and botanical composition declined as stocking rates exceeded 9.9 ewes per hectare coupled with a spring lambing. Excessive stocking intensity when the clover was flowering may have affected seed set and subsequent germination and pasture establishment. It should be noted, however, that the stocking intensities which were found to be detrimental to pastures were more than twice the average stocking rate for the Wagga and surrounding districts. Ewe fleece weights averaged over four years for stocking rates ranging from 7.4 to 14.8 ewes/ha for a spring lambing were 10% higher where lucerne was available. A direct comparison with autumn lambing is not possible as lucerne was not part of these treatments. The output of prime lamb is shown in Table 2.

Table 2. Production of prime lamb carcase (kg/ha) averaged over four years from a spring lambing (Reeve and Sharkey, 1980).

STOCKING RATE (Ewes/ha)	CARCASE PRODUCTION (kg/ha)
	Subclover	Lucerne/Subclover
7.4	114	127
9.9	132	149
12.4	144	166
14.8	154	180

Overall, there was a 14.7% higher output of lamb from the lucerne/ subclover pasture, even though in one year there was no difference in production between the two pasture systems. They also noted that a spring lambing system with lucerne was equal in production to a winter lambing system for north-eastern Victoria and suggested that winter lambing could also be increased by the inclusion of lucerne.

The possible competitive effect of lucerne and subclover noted by Reeve and Sharkey (1980) was investigated by Hall, Wolfe and Cullis (1985). Lucerne and subclover will at times compete for moisture and this may affect germination and early growth of subclover in the autumn and seed set and senescence in the late spring. These workers compared lucerne at four densities (0.75, 1.0, 1.5 and 3.0 kg/ha) with Woogenellup clover (5 kg/ha) at two stocking rates (9.6 and 12.7 ewes/ha) and its effect on pasture production and animal production of Border Leicester x Merino ewes and lambs over three years. Levels of animal production were not affected by lucerne density. While the denser lucerne stands produced more pasture and bigger liveweight gains in the summer, these trends were reversed in the winter when the clover contributed more of the total green herbage. The average yearly production of clean wool and live lamb (34 and 310 kg/ha) give some indication of the potential production from lucerne/subclover pasture. Lucerne density declined over the three years by about 45%. Reserves of clover seed fell in the same period from about 1000 kg/ha to 100-200 kg/ha. The use of an earlier maturing subclover variety mightaid persistence.

Problems were also encountered with rotationally grazing pregnant ewes during the winter. This resulted in rapid changes in both the amount and quality of the diet and led to outbreaks of pregnancy toxaemia and a large incidence of tender fleeces. To avoid this the authors suggested that if ewes are in late pregnancy over winter then lucerne pastures should be grazed continuously. Overall their work showed that high levels of animal production can be achieved with a lucerne density of 10 plants/in² or a sowing rate of 1.0 kg/ha.

The foregoing discussion has raised two further issues, namely weaner nutrition and the use of winter active varieties of lucerne. It is well known that young stock produce poorly on dry annual pastures. Apart from the necessity and economic gain of survival feeding, the answer to this problem at current costs and returns is not supplementary feeding. The answer is the establishment of summer growing species like lucerne. Weaners require a minimum of 14% protein and a highly digestible source of energy to maintain a satisfactory level of liveweight gain and wool growth. Among the best and cheaper ways of ensuring adequate weaner health and nutrition during the summer/autumn period is by the use of lucerne-based pastures. This effect was amply demonstrated by Morley and Axelsen (1965) when 5 months old crossbred weaners gained 13.2 kg on lucerne and only 1.2 kg or a rye/ subclover pasture from early January to early April. Intermediate results were obtained by rationing lucerne for 3 days followed by rye/subclover for 4 days. In addition, experiments have shown that potential animal production from hayed-off lucerne is higher than from either subcl.over or Wimmera ryegrass at a similar level of digestibility (Table 3).

Table 3. Intake and digestibility values for some temperate pasture species during the summer using sheep (Davies, 1972)

SPECIES	DIGESTIBILITY (%)	INTAKE OF DIGESTIBLE DRY MATTER (g)
Lucerne	52	538
Mt Barker subclover	54	367
Phalaris tuberosa	47	395
Wimmera ryegrass	56	221

All of the grazing experiments mentioned so far have involved Hunter River lucerne. The question arises how good are the new varieties for animal production, particularly the winter active varieties These could be expected to boost the availability of herbage during the winter period thereby enhancing animal production and maybe allowing an increase in stocking rate.

The only published information is that of Axelsen, Nadin and Forrester (1986) at Canberra who compared the growth rates of spring-born Dorset-cross carryover lambs on Sirosa phalaris, Hunter River lucerne and four aphid- resistant lucerne varieties (Nova, WL318, Cuf 101, Siriver) in different seasons over approximately four years. Both Cuf 101 and Siriver are winter active types. All plots were oversown with Woogenellup clover and stocked at either 10.2 or 14.8 lambs/ha. Since aphids were almost absent throughout the experiment Hunter River lucerne was at its full potential. Overall the production ratings on lucerne pastures were Siriver, WL 318, Nova, Cuf 101 and Hunter River. Siriver produced 9% more gain than Hunter River with the largest differences occurring in the autumn-winter period. This result suggests that production from lucerne pastures based on winter active varieties should exceed that achieved with Hunter River lucerne. The production from phalaris in the above experiment was 21% less than that from lucerne. The authors estimated that 1 ha of lucerne was required for every 25 lambs to be fattened.

For the higher rainfall districts lucerne sown with eithel- a mixture of ryegrass (Wimmera or perennial) and phalaris cv. Australian was found to be superior to subclover cv. Marrar plus ryegrass or subclover and phalaris (Reed, Snaydon and Axelsen, 1972) (Table 4).

Table 4. Liveweight gain, wool production, mortality and supplementary feeding of wether weaners from December 30, 1966 to October 4, 1967 at stocking rates of 16 and 23/ha (Reed et al., 1972).

Treatment Legume Species	Liveweight Gain (Kg/Head)	Greasy Fleece Wt (Kg/Head)	Mortality (%)	Wheat Fed (Kg/Head)
lucerne	6.3	2.0	13	6.4
subclover	1.5	1.7	23	12.3
Grass species
phalaris	4.1	1.9	31	12.3
ryegrass	4.3	1.8	4	6.3

A significantly higher liveweight gain and wool production, reduced mortality and a reduction in supplementary feed were recorded in favour of lucerne as the sown legume. Once again the biggest responses were during the summer-autumn period. They also noted that the lucerne-based pastures were more effective in preventing the invasion of grass weeds. Often the subclover plots were dominated by other annual grasses. This effect on botanical composition has been recorded in several experiments and could be significant for disease control in following crops.

Beef Production

The most comprehensive and relevant data on beef production from lucerne- based pastures is that of Wolfe et al. (1980). These workers compared the growth and carcase composition of eight month old Poll Hereford steers on Hunter River lucerne sown with Woogenellup clover and Woogenellup clover pasture over three years from 1975 to 1977, including the drought year of 1976. They found that the annual gains on lucerne exceeded those on clover by 20-30 kg/head in 1975 and 1977 and by 70 kg/head in 1976. Carcases from animals on lucerne were heavier, with a greater depth of fat, and overall.had better eye muscle development (Table 5). A combination of above average summer rainfall and below average winter rainfall contributed to the marked superiority of lucerne in 1976. Most of the advantages of lucerne were restricted to the summer-autumn period and were associated with a greater availability of green herbage. In most cases the weight advantage over summer-autumn was maintained during winter. The main contributor to animal prodvction in the winter was clover and this highlights the importance of maintaining a balanced pasture with an adequate proportion of clover. The results also indicated that lucerne pastures were capable of supporting a higher stocking rate than clover pasture and that a stocking rate between 2 and 3 steers/ha was possible on lucerne subclover.

Table 5. Performance of steers on lucerne-clover and clover pastures at Wagga (Wolfe et al., 1980)

Treatment Lucerne-Clover	Yearly Gain (Kg)	Carcase Weight (Kg)	Fat Thickness (Mm)
1975	238	242	13.2
Clover	202	216	9.7
1976
Lucerne-clover	132	173	3.4
Clover	61	136	1.9
1977
Lucerne-clover	191	182	7.7
Clover	171	164	7.5

In this experiment the pastures were set stocked from late June to early October to avoid the possible effect of sudden changes in feed supply on the occurrence of bloat. This management system had little effect on lucerne density and suggests that the need for a system of rotational grazing to ensure lucerne persistence may be less critical with cattle than it is with sheep. Further support for lucerne-based grazing systems is evidenced by the work of Hamilton (1974) at Rutherglen,where the annual gain of 7 months old weaner steers on lucerne was 51 kg higher than those on Wimmera ryegrass and clover and of Christian and Shaw (1952) in Queensland who recorded an extra 79 kg gain over 22 months with the inclusion of lucerne with Rhodes grass even though the lucerne density was only 3 to 5 plants/in².

Bloat

Probably the major limitation to the more widespread use of lucerne on properties which run cattle is the fear of bloat. In temperate Australia, bloat is a serious problem limiting the production of beef cattle on high quality legume-dominant pastures and occurs most frequently in late winter and early spring. The likelihood of bloat may be worsened by the use of a twin legume pasture, such as lucerne/clover. FitzGerald et al. (1980) found that ratings of rumen distention were consistently more frequent and more severe on lucerne/clover than on clover and that 7 steers died as a result of bloat on lucerne/clover and 3 on clover. There was only one death in steers that had been treated with an anti-bloat capsule. However, no lethal or sub-lethal bloat was observed from December to May inclusive. This is of considerable practical importance, for it is at this time that production gains are most likely to come from the lucerne component of a lucerne/subclover pasture. Thus, it would appear that, apart from the use of anti-bloating compounds such as licks and oils, management methods are available which can maximise the gain from lucerne/clover pastures and at the same time reduce the likelihood of bloat.

Gross Margins

A farm survey in 1966 indicated that only 24% of farms in the Wagga district were growing lucerne and only 6% had more than 50 ha (Southwood and Robards, 1975). A more recent survey is unknown. A number of reasons have beenadvocated by various writers for the low adoption of lucerne- based pastures. Factors listed include the extra cost of subdivision and watering; the conflict between smaller paddock size and farming operations; a reluctance to take on more intensive management; and insufficient benefits for the cost and management inputs necessary with lucerne.

Previously it has been noted that the benefits from lucerne are maximised through rotational grazing, but are not dependent on it. Benefits can be gained through the establishment of a single paddock of lucerne-based pasture.

Probably what is most lacking is a clear economic index of the benefits from lucerne pastures and unfortunately this has not been calculated, as far as is known, for the Wagga region. However, since responses to lucerne pastures have been highly consistent across Regions and States it is reasonable to use, as an example, gross margins obtained in a grazing systems experiment at Hamilton, Victoria (Saul, 1986). This involved autumn- and spring-born merino weaners grazed on perennial ryegrass/subclover or lucerne/subclover pastures from 1983-86. A supplement of oats was fed to weaners in the summer/autumn when one-third of any mob had a condition score of 1.7 or less and ewes were fed in autumn when the condition score of any mob fell below 2. The gross margins are shown in Table 6.

Table 6. Gross margins per hectare for lucerne/subclover and rye/subclover pastures at Hamilton, Victoria (Saul, 1986).

TIME OF LAMBING	AUTUMN		SPRING
PASTURE TYPE	Rye / Subclover	Lucerne / Subclover	Rye / Subclover	Lucerne./ Subclover
INCOME	$	$	$	$
Wool @ 40O~/kg	232	252	224	235
COSTS
Pasture Estab.	6	13	6	13
Supp. feed
oats @ $100/t
- weaners	18	7	35	10
- ewes	18	18	7	7
Shearing, Medicines,
Fertiliser, etc.	70	70	70	70
GROSS MARGIN/ha	120	144	106	135

The inclusion of lucerne increased gross margins by 29 and 30% respectively for the autumn and spring lambings mainly through a higher wool cut and a reduction in the requirement for supplementary feeds. Although the cost of subdivision was not included a quick calculation would show that if it had been included a substantial economic benefit would still be shown for lucerne.

Conclusion

Lucerne, as a component of subterranean clover pastures, can be established on a large proportion of the southern cereal growing area. While rotational grazing will ensure high levels of animal production and persistence of lucerne pastures, other grazing systems are available which can be used to advantage.

In general the production of sheep and cattle grazing lucerne/subclover pasture will be 10 to 20% higher than for subclover pastures and gross margins will be of a similar magnitude. It makes good economic sense to consider the place of lucerne in our pasture systems.

Although bloat in cattle can be a problem on legume-dominant pasture, grazing management can be used to avoid bloat and gain the benefits from lucerne.

References

1. Axelsen, A., Nadin, J.B. and Forrester, R.I. (1986). Growth of weaned lambs on some aphid-resistant lucerne varieties. Proc. Aust. Soc. Anim. Prod. 16: 135-138.

2. Christian, C.S. and Shaw, N.H. (1952). A study of two strains of Rhodes grass (Chloris gayana Kunth) and of lucerne (Medicago sativa L.) as components of a mixed pasture at Lawes in South-East Queensland. Aust. J.Agric. Res. 3: 277-299.

3. Davies, H. Lloyd (1972). Beef production from temperate pastures. AMRC Review No. 5, 1-12.

4. FitzGerald, R.D. (1979). A comparison of four pasture types for the wheat belt of southern New South Wales. Aust. J. Exp. Agric. Anim. Husb. 19: 216-224.

5. FitzGerald, R.D., Wolfe, E.C., Laby, R.H. and Hall, D.G. (1980). Beef production from lucerne and subterranean clover pastures. 2. Bloat occurrence and effect of anti-bloat capsules. Aust. J. Exp. Agric. Anim. Hush. 20: 688-694.

6. Hall, D.G., Wolfe, E.C. and Cullis, B.R. (1985). Performance of breeding ewes on lucerne-subterranean clover pastures. Aust. J. Exp. Agric. 25: 758-765.

7. Hamilton, D. (1974). Alternativesto dry annual pasture for steers over summer and later effects on liveweight gain during winter. Proc. Aust. Soc. Anim. Prod. 10: 99-102.

8. Morley, F.H.W. and Axelsen, A. (1965). The role of lucerne for summer grazing. Field Station Record 4, 13-18.

9. Saul, G. (1986). Gross margins for weaner sheep grazing perennial ryegrass/ subclover or lucerne/subclover pastures. Proc. Victorian Grassi. Soc. p.69.

10. Southwood, O.R. and Robards, G.E. (1975). Lucerne persistence and the productivity of ewes and lambs grazed at two stocking rates within different management systems. Aust. J. Exp. Agric. Anim. Husb. 15: 747-752.

11. Reed, K.F.M., Snaydon, R.W. and Alexsen, A. (1972). The performance of young sheep grazing pastures sown to combinations of lucerne or subterranean clover with ryegrass or phalaris. Aust. J. Exp. Agric. Anim. Hush. 12: 240-246.

12. Reeve, J.L. and Sharkey, M.J. (1980). Effect of stocking rate, time of lambing and inclusion of lucerne on prime lamb production in north-east Victoria. Aust. J. Exp. Agric. Anim. Hush. 20: 637-653.

13. Wolfe, E.C., FitzGerald, R.D., Hall, D.G. and Southwood, O.R. (1980). Beef production from lucerne and subterranean clover pastures. 1. The effects of pasture, stocking rate and supplementary feeding. Aust. J.Exp. Agric. anim. Hush. 20: 678-687.