RESEARCHERS have found that molasses supplements can be used to increase cattle liveweight that are rotationally grazing leucaena-pangola pastures in WA’s Ord River irrigation area (ORIA).
Over 106 days between August and November, researchers evaluated the liveweight gain of 70 12-month old Bos indicus cross heifers grazing only leucaena-grass pasture or supplemented with varying amounts of molasses or maize.
The cattle were allocated to seven treatments and two replicates of each treatment with a stocking rate of 6.25 head per hectare.
Each replicate paddock of 0.4ha was rotationally grazed with 10 animals with a seven-day grazing period and a 21-day regrowth period for each rotation.
The results demonstrated that molasses significantly increases cattle liveweight with an optimum gain of 1.08kg/head a day at a supplement level of 2.65kg molasses/head a day.
However, there was no significant response to the level of maize supplement.
University of Queensland researchers Dr Steve Petty and Professor Dennis Poppi say molasses supplements, which had been used in systems throughout Queensland, is a viable solution for pastoralists needing to increase cattle liveweight during dry seasons.
“High levels of molasses supplementation results in substitution: the animal eats less pasture when supplemented but overall pasture and molasses intake is greater than just pasture alone, hence the animal grows faster.”
“Such a phenomenon means that when pasture is short, or in this case you have limited leucaena-pangola pasture, then you can still maintain stocking rates by this supplementation.
“Leucaena systems have a lot of protein and so molasses with no protein can be used with a diet so that the rumen functions better.”
Prof Poppi says despite maize supplements not resulting in increased liveweight in this experiment, previous research has suggested maize has the same effect on liveweight gain as molasses.
“We were surprised that it did not do as well this time,” he says.
“I would be confident that maize would give a response but of course it is usually more expensive than molasses.”
This experiment was a State Government initiative to assess how to manage and improve production from leucaena systems.
“Leucaena systems have been a big part of the Ord cattle fattening operation with potential for other areas in the north and the ORIA leucaena systems are amongst the highest beef production areas in the world.”
“Furthermore, if local meatworks develop then these systems will be required for cattle to meet market specifications.”