WITH spring shaping up to deliver top feed-growing conditions in many cattle regions, experts are urging producers not to let pasture volumes get out of control.
Improved tropical pastures like Premier digit, Bambatsi panic and Rhodes grass should continue to be managed for good stock growth rates.
Above-average rainfall to date has meant that many tropical grass pastures currently have excellent levels of legumes, annual ryegrass and other valuable species.
Cattle weight gains on these pastures are likely to be in excess of 1 kilogram per day well into the spring.
As these annual species decline over summer, the tropical grasses will dominate, especially if the La Nina rains eventuate, and this effect will be magnified because herds are smaller than pre-drought numbers.
In order to manage the potential for large amounts of lower-quality feed, producers should consider tactics such as crash grazing to open up the canopy for new growth, conserving feed to restore depleted hay stocks, or resting those paddocks hardest hit during the drought to maintain higher stocking rates on other paddocks.
NSW Department of Primary Industries Beef Development Officer based at Armidale Todd Andrews said producers who run breeders often employed minimal pasture management.
Now that that they were running more replacement heifers or other younger stock, they might need to manage pastures to maintain good animal weight gain because the best pastures for breeding females were not always the best choice for younger animals, he said.
Young growing stock require a more nutritious feed to maintain optimum growth rates - more energy but particularly higher protein.
Growing out young cattle generally means there are weight targets. "For prime stock or feeder steers this often means a carcase or live weight target while they have 0-2 teeth (up to two-and-a-half years old) while for replacement heifers this might be target weights and fat scores at joining and calving," Mr Andrews said.
"Where producers are planning to join yearling heifers to calve at two years old, we would recommend that these heifers are at least 65 per cent of their expected mature weight by joining.
"For sale stock, the sooner these targets are achieved, the sooner they can be sold and the pasture used for other purposes. This is especially relevant as most industry forecasts expect livestock prices to fall in the new year and this has already begun in some market sectors."
Climatic trends of hotter summers, combined with large amounts of irregular, heavy rainfall followed by long dry spells, is driving a trend in many livestock regions towards tropical pastures.
They have proven to be drought tolerant and persistent, producing good feed from rain that falls in most months of the year.
"Producers at a recent NSW Local Land Services/DPI Tamworth field day noted that tropical grasses were 'mental health boosters' as it was such a relief to look out at the desperately-needed green feed produced during and after the drought," Mr Andrews said.
"The shift to tropicals has been at the expense of temperate pastures, even in areas where they have traditionally been favoured, as the trend for hotter drier summers has damaged these pastures, even Mediterranean types that go dormant during summer."
The massive growth potential of tropical pastures, producing up to 100kg of dry matter per hectare per day under ideal conditions, can bring its own set of challenges in some seasons.
There is the potential for these pastures to produce an overwhelming amount of feed, if the predicted wet spring and summer conditions materialise.
That can result in a couple of issues, Mr Andrews explained.
First is the challenge of maintaining legume component in these pastures.
"Because of the tremendous growth potential of these tropical species they have a high nitrogen requirement, but because of this growth, high ground cover and efficient water extraction, maintaining the legume component requires management," Mr Andrews said.
NSW DPI pasture researcher Sue Boschma is researching a number of legume varieties and management options to maintain satisfactory legume levels in tropical grass based pastures.
Secondly, rank tropical pasture without any fresh growth coming through at the base, can mean that livestock performance can suffer.
While feed quality declines when pastures get rank, cows can still do well with the addition of cheap urea based supplements to boost protein, especially when calves are weaned off them, Mr Andrews said.
Cows require a year-round feed supply but the quality is not as important.
"While it is important for producers to target specific fat scores to maximise reproductive rates in breeders, once this is reached there is no benefit in exceeding this. In fact, some producers have concerns about their cows being too fat in the current season," Mr Andrews said.
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