Max gave us an update on mimosine toxicity.
The young tips of leucaena can contain up to 10% of the alkaloid mimosine which depresses animal appetites and growth.
It’s been known for many years that cattle can be inoculated with rumen bacteria (Synergisti jonesii) that can overcome the problems of mimosine toxicity, but part of the pathway is new to me.
The old story was that in the rumen, minosine was broken down to the real villain known as DHP (3, 4 di hydro pyridoxine), and it is this that the special bacteria render harmless.
What was new to me was that the 3,4 DHP was broken down first to 2,3 DHP and then to harmless compounds.
The UQ work looked at 44 herds in six districts in Queensland to see what proportion of stock eating leucaena were protected by inoculated bacteria.
They took urine and dung samples to test for the presence of DHP and for how much leucaena the stock were eating.
On average, leucaena was providing 40% of the steer’s diet, nearly half the 44 herds were protected but the DHP story was unusual.
Some herds with poor protection had high levels of 3,4 DHP and 2,3 DHP as expected, others had low 3,4 DHP showing some bacterial degradation but high 2,3 DHP suggesting something was missing.
These animals had been inoculated with the bacteria bred in vitro by the Inoculating with Rhizobia Leucaena plants need to be inoculated with Rhizobia bacteria to fix the nitrogen that makes the leaf so high in protein. 4 TGS News & Views The current recommendation has been to inoculate leucaena seed with the CB3060 Rhizobia, but this is no longer available commercially.
Fortunately, it has been found that strain CB 3162 is just as good.
Since CB 3162 is recommended for Desmanthus, it is still commercially available. Cutting back leucaena Leucaena has many forms in the wild of central America.
Some lines are multibranching shrubs – from which have come the cultivars Peru and Cunningham, others are more erect and tree-like.
Tarramba, selected for its high production, faster establishment and degree of cool tolerance, is an arboreal line.
Without good management, all cultivars can grow out of reach of stock and Tarramba is even more vigorous in this regard.
So there may come a time when the leucaena stems need to be cut back or knocked down.
Some growers put in a herd of lactating cows to pull down the tall stems, some have pushed the tall stems down with grader type blades, others use slashers.
In the recent issue of this newsletter, there was a picture of a giant circular saw as used for citrus and other orchards being used on Tagasaste, and earlier issue showed Peter Larsen’s flail mower based on the heavy duty Critter.
Rod and Kevin Linke of Biloela showed their trimmer based on multiple horizontal circular saws.
It’s still in the developmental stage with Rod reckoning that 20 hp is insufficient with 40 hp being preferable for heavier growth.
That is still much less that the big machines use.
The unit is mounted on the deck of a LandCruiser and can be driven between properties as Rod and Kevin offer contract trimming as Leucaena Maintenance Pty Ltd out of Biloela. Planting leucaena Planting leucaena is an expensive business but the legume becomes cheap if a stand lasts for 20 or more years.
Poor establishment is doubly expensive and may have to be ploughed out for another go.
As a result many growers use precision planters.
The Norseman Techni-Plant unit was on display at Jambin and has given excellent and even strikes.
Another issue of TGS News and Views showed the Gyral planter.
I took this photo of Peter Larsen’s planter set up based on old Chamberalin precision planter units to show what (Above) The Norseman Techican be done without buying Plant is a precision seeder for the latest.
This unit has planted leucaena.
Thousands of hectares. (below) Peter Larsen’s homemodiﬁed seeder has planted thousands of hecatres. Rod and Kevin Linke of Biloela have designed this leucaena trimmer. TGS News & Views 5 Wynn cassia – eaten or rejected? OK in the drier subtropics Wynn cassia can be a useful legume when sown into native pasture.
It has been shown to improve steers weight gains in south-east Queensland, but it’s not very palatable.
In summer and then stops raining abruptly—because tall ungrazed Wynn cassia plants don’t like drought.
The leaves turn red, then brown, then drop off, leaving a hard inedible stalk. — TGS News & Views 9 Practical Abstracts Tropical Grasslands, Vol. 39, 2 June 2005 The impact of fire on population density and canopy area of currant bush (Carissa ovata) in central Queensland and its implications for grazed woodland management—by Paul Back, on pages 65–74.
Currant bush has been thickening up in grazed eucalypt woodlands in central Queensland.
It is not highly competitive but cattle cannot reach grass growing under the canopy.
However, this allows enough grassy fuel to accumulate.
Although currant bush is quite resistant to fire, burning in spring will halt its spread.
Currant bush needs to be burnt at least every five years, and the area needs to have at least one-year ’s growth of grass available for a hot enough fire.
This reduction in the shrub canopy cover leads to a proportional increase in pasture available for grazing.
Fertilisation of creeping signalgrass and bahiagrass under grazing in Florida—by R.S.
Ezenwa and F.G.
Martin, on pages 75–87.
Bahiagrass provides much of the minimal-input pasture in Florida, but is susceptible to mole crickets.
Creeping signalgrass (Brachiaria humidicola) could be an alternative pasture grass for these low fertility and poorly drained conditions; however, it is more difficult to manage because it produces less herbage than bahiagrass in spring and much more in summer.
P and K fertiliser is needed, but nitrogen should not be applied until the beginning of the rainy season (late May-early June).
Without extra nitrogen, protein levels might be too low for lactating cows.
Emergence and seedling survival of leucaena on poorly drained soil and management practices to mitigate negative effects—I.V.
Ezenwa and R.S.
Kalmbacher, on pages 88–98.
Leucaena has potential in Florida but poorly drained soils make establishment difficult.
Since leucaena can handle dry conditions better than flooding, sowing before or after the rainy season may give better establishment.
Leucaena K636 and K340 survived better and might be better for southern Florida and offer more flexible establishment options.
Raised beds did not improve survival of seedlings during high rainfall periods.
So far, large scale commercial plantings of leucaena have not established uniformly and larger trials are needed to confirm the applicability of the research findings.
Brachiaria species in north-east Thailand: dry matter yields and seed production—by Mike Hare, P .
Lunpha and K.
Wongpichet, on pages 99–106.
Marandu and CIAT 6387 (both B.
Brizantha) and common signal grass all yielded about 50% more dry matter than ruzi grass with the brizanthas also having 30% more leaf.
CIAT 26297 (B.
Decumbens) had the highest leaf protein levels.common signal grass and CIAT 6387 produced as many inflorescences as ruzi but negligible amounts of seed while Marandu and CIAT 26297 had few flowers.
Only ruzi grass produced reasonable yields of viable seed (30 and 80 kg/ha in the two years).
This seed failure in the flowering accessions was attributed poor seed set and caryopsis maturation.
Seed yield and quality of buffel grass (Cenchrus ciliaris) as influenced by row spacing and fertiliser level—by D.
Dwivedi and S.N.
Singh, on pages 107–111.
On an infertile soil, seed yield increased with wider row spacing (75 cm) and up to the highest level of fertiliser (60 kg N, 26 kg P/ha).
Seed quality increased with wider row spacing but not with fertiliser. 10 TGS News & Views Effects of a fibrolytic enzyme supplement on the performance of Holstein Friesian cows grazing kikuyu—by B.C.
Granzin, on pages 112-116.
The low digestibility of tropical grasses reduces herbage intake and cow productivity.
Fibrolytic enzymes (FE), such as cellulases and hemicellulases, help the digestion of structural carbohydrate and can increase milk yield when fed with grain-based concentrates.
Feeding up to 4 g of FE (as Promote®) increased yield of milk and milk protein in first-calving heifers but not in older cows—maybe because the effective dose was higher in the lighter animals.
There were no effects of FE on the digestibility of organic matter or fibre.
The nutritive value of laboratory ensiled lablab (Lablab purpureus) and pearl millet (Pennisetum americanum)—by J.T.
Adeyinka, J.P .
Alawa and J.O.
Jegede, on pages 117–123.
Various proportions of lablab were added to millet to see whether it improved the quality of the silage.
All silage mixtures fermented well but adding lablab increased crude protein, crude fibre and nitrogen-free extract.
However, all mixtures would barely supply enough protein to maintain cattle, and would need extra sulphur and sodium for lactating cows.
Effect of different seed treatment options on dormancy breaking, germination and emergence of Ziziphus mucronata (buffalo thorn) seed: research note by—Abubeker Hassen, N.F.G.
Rethman and W.A.
Van Niekerk, on pages 124–128.
Buffalo thorn is a valuable fodder tree for livestock and game animals in the drier parts of Africa.
The leaves are high in protein and digestible.
Establishment has been constrained by poor germination and seedling emergence due to an impermeable seed coat.
Scarification with sandpaper gives the best germination but is labour-intensive; immersing seed in concentrated sulphuric acid for 20 minutes, followed by soaking in water for 24 hours resulted in the best germination and emergence.
Editor’s note: Z.
Mauritiana (Chinee apple) is classified as a declared weed of grazing land in northern Australia. New rules for 21st Century Farming Is this how you see yourself? 1.
Become a business, not a way of life 2.
Do not blame other countries; play a different game. 3.
Grow what the market wants, not what has always been grown. 4.
Do not pray for rain, make sure there is a supply of water. 5.
Outsource activities, such as ploughing, seeding, harvesting and shearing, that can bd done cheaper and better by others. 6.
Do not own land, buildings, equipment, stock or debtors. 7.
Work the brain (intellectual property) harder than the body. 8.
Add value at the farm, not the factory (ie high-quality fresh food is often better than processed). 9.
Have long-term contracts and relationships, not spot markets. 10.
Franchise or be a franchisee wherever possible. (from BRW) TGS News & Views 11 If not delivered, please return to SURFACE MAIL AUSTRALIA 12 TGS News & Views POSTAGE PAID 1 2 3 4 6 7 8 10
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