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February May 20102013 Mob: 0418 928 222

In this issue… • Leucaena toxicity research in Indonesia • Leucaena’s value in dry conditions • Pros and cons of burning • Date claimers • Selection for psyllid resistance

TLN contacts TLN Executive President – Robin Cruikshank 07 4995 1236 Vice President – Craig Antonio 0427 954 208 Treasurer – Kathy Alsop 07 4992 1448 Minutes Secretary and Accel. Adoption of Leucaena Stuart Buck (07) 4992 9187 Research and Training – Andrew Richardson 0428 711 246 Executive Officer – Berry Reynolds 0418 928 222 TLN Regional representatives Craig Antonio, Millmerran 0427 954 208 Greg Brown, Mt Garnet 07 4097 1443 Luke Comiskey, Dingo 07 4985 8156 Robin Cruikshank, Thangool 07 4995 1236 Don Heatley, Home Hill 07 4784 9168 Tony Hindman, Jackson 07 4627 6398 Peter Larsen, Banana 07 4995 7228 Stuart Maunder, Wallumbilla 07 4623 4328 Laurie Peake, Wandoan 07 4627 4157 Steve Williams, Dalby 07 4663 3506

The Leucaena Network News

Leucaena toxicity research in eastern Indonesia

by Michael Halliday, Max Shelton, Jacob Nulik, Deborah Nulik, Charles Pakerang

The University of Queensland (UQ), in partnership with the Australian Centre for International Agricultural Research (ACIAR) and Indonesian government agricultural research departments is continuing to investigate the ongoing issue of leucaena toxicity, under the direction of Associate Professor Max Shelton (UQ). Leucaena is a highly nutritious legume and is used widely as an important source of protein in both Indonesia and northern Australia. It makes a vital contribution to the fattening of animals in both countries. As we know, it has the toxin mimosine present in its leaves. Although acutely toxic and potentially deadly, mimosine toxicity is rarely an issue as it is quickly converted to a less toxic compound known as dihydroxypyridine (DHP). It is toxicity due to DHP that we believe many ruminants worldwide are suffering from, often without the knowledge of the farmers. The effects of this are less dramatic than mimosine poisoning yet ultimately result in poor animal performance due to reduced intake and decreased liveweight gain. The ‘leucaena bug’ (Synergistes jonesii), which is capable of degrading DHP to harmless by-products, was originally found in the islands of Indonesia and Hawaii, and is now being produced, and made available to graziers in Australia, in an artificial fermenter from bugs brought back from Hawaii in 1982.

Collecting rumen fluid from a Bali cow before inocultion in the village of Bone, West Timor.

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There is some concern however, that growing bugs outside the rumen for long periods of time e.g. in a fermenter, may result in changes in their ability to fully degrade DHP. This concern has led to several ACIAR funded experiments, in an attempt to better understand the effects of DHP toxicity on animal performance, and further develop methods to ameliorate the toxic effects of feeding leucaena. On a survey trip conducted in 2011 through 4 eastern islands of Indonesia, rumen fluid samples were collected from ruminants consuming large amounts of leucaena and excreting no toxin. The samples were analysed at CSIRO Livestock Industries laboratories for presence or absence of the ‘bug’ using the latest advances in molecular DNA analysis; many of these animals were found to have the bug present in the rumen. The most notable animals were the buffalos in the village of Merlolo in the island of Sumba. These animals have been earmarked as potential donors of inoculum using direct transfer of rumen fluid for animals found to be unprotected in Indonesia. In the weeks preceding Christmas last year, a small scale study was undertaken in the islands of Timor and Sumba to measure the effectiveness of cross species rumen fluid transfer from these buffalo to cows and goats previously found to be unprotected from DHP toxicity. Unexpectedly, in contrast to the early work, there was no rapid protection from toxicity following transfer of the rumen fluid. From this and other work, it seems that the leucaena bug is difficult to transfer successfully, perhaps as it exists in very small numbers within protected animals, or perhaps it does not adapt easily or quickly to the new rumen environment of other animals. It seems that it can take many weeks to develop a foothold in the recipient animals. This research is still ongoing with continuous samples being collected for future analysis. The findings are especially relevant to the Australian practice of transferring the artificially produced rumen inoculum ‘bug’.

If you are concerned about DHP toxicity, the University of Queensland currently offers a DHP testing service for graziers with cattle on leucaena. A colorimetric method is used to determine DHP levels in cattle urine, allowing management strategies to be improved to get the most out of leucaena pastures. If you would like more information or a collection kit sent out please contact Michael Halliday (MPhil Candidate at UQ) at or 0408 870 462.

Leucaena’s value in dry conditions by Stuart Buck

The ability of leucaena to grow and produce valuable feed during dry spells has never been more evident this spring and early summer across many parts of Queensland. With its deep tap root, leucaena is able to extract moisture from deep in the soil profile than most (or all) grasses can efficiently draw water from. An example of this is at Robin and Jenny Cruikshank’s property near Thangool in the Callide valley. Winter was cold with numerous frosts. A total of 108 mm rainfall during winter that was stored deep in the soil profile. Like most places, spring has been hot and dry however 97 mm rain fell (over a number of falls) early in the season, months before the photo below was taken. Leucaena has been able to extract deep moisture providing valuable feed at a time when the grasses are still dormant due to the lack of rain. The Cruikshanks have a number of paddocks that are fed in rotation, and this provides the opportunity for the leucaena to rest, re-grow and produce forage, enabling cattle to still gain weight despite the dry conditions. The paddock where the photo was taken had been spelled for 3 months and cattle reentered around Christmas time. These cattle are putting on weight whereas others on grass-only are holding at best.

Whilst the interest in these buffalo in Sumba extends to several neighboring islands in Indonesia, they may even prove to be a potential future source of inoculum for Australian animals.

Leucaena growing on deep soil moisture whereas the grass is dry and dormant.

Collecting rumen fluid from a buffalo in Merlolo, Sumba.

Robin’s details: • Cattle were out of the paddock for 3 mths prior to photo • Cattle in now Christmas time • Rainfall: Dec 19th dec onwards 80 mm; Nov nil; Oct 69 mm in 3 falls; Sept 28 mm; Aug 43 mm in 1 fall; July 19 mm; June 46 mm in 3 falls; May 18 mm.

Pros and cons of burning leucaena–grass pastures by Stuart Buck


• Re-set the grass if tall and rank with little nutritive quality • Cheap method of height control for tall leucaena • To control woody weeds that might be, or are about to dominate


• Loss of organic matter that could otherwise be cycled back into the ground • Reduction in ground cover, increasing the risk of soil erosion if heavy storms occur soon after burning • Weaken or kill leucaena plants, particularly if the fire is hot • Encourage the germination and growth of native grass species that are not as desirable as improved grasses (from a production point of view) • If soil moisture and follow-up rainfall is limited, leucaena could potentially out-compete the grass (due to its tap root) leading to future height control issues and grazing management difficulties • Extended time to rest the pasture after burning, resulting in lost production

Therefore, I wouldn’t be advocating burning of leucaena– grass pastures, unless there is a specific need such as woody weed control.

TLN Key dates—not to be missed! The Leucaena Network Conference & AGM You are invited to The Leucaena Network 2013 Annual Conference and AGM, 21–22 March at University of Queensland’s Redland Research Station, Brisbane.

DAY 1 – Conference Key speakers include: • Professor Jim Brewbaker (University of Hawaii) • Mr Don Heatley (Past MLA Chair) • Mr Greg Brown (Past Cattle Council Chair) • Mr Kevin Smith – AbacusBio Pty Ltd – Findings of feasibility study of sterile variety • Latest research and development from UQ, Santos and DAFF projects

DAY 2 – AGM Retiring Executive: President, Robin Cruikshank; Vice President, Craig Antonio; Treasurer, Kathy Alsop. We urge anyone who would like to take one of these positions to put nominations forward to Berry Reynolds at These positions truly do not take a lot of your time. To register online — conference.htm or contact Berry Reynolds on 0418 928 222.

Regional Representative Information days The next round of Information days are coming to an area near you. These days are a great opportunity for both new and established growers to meet, discuss leucaena and exchange ideas. A representative from The Leucaena Network will be in attendance. Leucaena re-sprouting after fire.

The 22nd International Grasslands Congress Sydney | 15–19 September 2013. Theme: ‘Revitalising grasslands to sustain our communities’. One of the pre-congress tours of interest to The Leucaena Network will be the Northern Tour organised by Assoc. Prof. Max Shelton on 10–13 September. This tour will begin in Cairns, travelling through the Atherton Tableland and beef country to Townsville, visit CSIRO at Lansdowne and Don and Laurel Heatley’s irrigated leucaena operation at Home Hill. Visit the website for details:

Please contact one of the following to register your interest in attending: • March 4 at 278 Heckendorf Rd, Milmerran. Contact Craig Antonio, 0427 954 208 • March 5 at ‘Yathong’, Dalby. Contact Steve Williams, 0429 008 323 • April 3 at ‘Indiri’, 36302 Dawson Hway, Springsure. Contact Fred Nofke, 0427 843 166 • April 4 at ‘Yackadoo’, Kilcummin Rd, Clermont. Contact John Burnett, 4983 5175 • April 5 at ‘Lucky Creek Stn’, Middlemount. Contact Gerard Lyons, 4987 3003 • April 8 at ‘Braeside’, Thangool. Contact Robin Cruikshank, 4995 1236

L.M. Robertson Supervisor: H.M. Shelton School of Agriculture and Food Sciences, University of Queensland 4072 Brisbane, Australia

The Leucaena psyllid (Heteropsylla cubana) is a leaf sucking insect that feeds

Results All



on the growing tips of susceptible Leucaena species. Psyllids cause


varieties but had higher STDEV.


The mean PDR of the lines was ~3

A breeding program was initiated in 2002 to develop an inter-specific variety

with a pooled STDEV of 1.05,

between the susceptible species L. leucocephala and the resistant species L.

compared to ~7.5 and a STDEV of

pallida. Following three generations of mass selection, 2 generations of


backcrossing to L. leucocephala, and 2 generations of progeny testing of

(Figure 1).

backcrossed breeding lines, 40 superior lines of the psyllid-resistant leucaena were produced.




significant economic damage to leucaena pastures in tropical and subtropical




Figure 1: Mean PDR & pooled StDev of breeding vs commercial lines 10



PDR Rating



8 6 4 2 0


Comm. cvv.

lines were similar in leafiness, branchiness and floral development

ratings, while superior in yield to commercial cultivars, but they were not as


uniform (Figure 2).

The objectives of this study were to: a. compare the breeding lines with existing commercial cultivars, and b. select the superior and most uniform Leucaena lines based on the criteria: (1) psyllid resistance, (2) floral development, (3) branchiness, (4) leafiness, (5) yield and (6) digestibility.

Materials and Methods Six replications of the 40 breeding lines were compared to 4 commercial cultivars in a randomized block design at the DAFF Redlands Research Station. There were 12 plants per plot. Buffer rows of the highly susceptible cv. Peru were planted to ensure even psyllid pressure across the site. Psyllids

However, among the 14 lines analysed for DMD, only 2 exceeded the minimum digestibility standard of 65%, while the commercial cultivars were ~74% (Figure 3).

were sprayed regularly until the trees were fully established. The selection criteria were:



• Psyllid damage ratings of growing tips (PDR) (1=no damage, 9=dead). • Floral development rating (FDR) assessed twice (1=vegetative, 5=mature seed pods). • Leafiness and branchiness ratings (1= low, 5=high).

70 65 60 55

• Dry matter digestibility (DMD) of the first fully expanded leaves from 3 plants per plot. Fourteen superior lins were initially selected based on psyllid resistance and minimum standards for each agronomic trait. These were then subjected to in vitro DMD analysis. A two-way ANOVA was performed on all data using the statistics program ‘Minitab’ to remove variation due to replicates. The means for each of the breeding lines was used in conjunction with standard deviations (STDEV) to assess differences and uniformity in selection criteria.

Figure 3: In vitro dry matter digestibility













Breeding Lines







All lines showed superior psyllid-resistance but lower digestibility compared to commercial cultivars. While agronomic parameters (leafiness, branchiness, FDR) of most lines were similar to the commercial cultivars, only 2 varieties (33 and 36) had DMD >65%. Since line 33 has not produced seed, only line 36 appears to meet criteria for commercial release. Due to the DMD being lower than anticipated, a second round of DMD analysis is recommended for verification.


The invaluable guidance of Dr Max Shelton and previous work of Dr Scott Dalzell is acknowledged. The statistical assistance of Ms Delma Greenway and Mr Allan Lisle, and the laboratory assistance of Mr Peter Isherwood for DMD analysis were greatly appreciated. This project was funded jointly by UQ and MLA.

Leucaena Network News  

February 2013

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