Seeds threaten top season

Great seasonal conditions across much of the state are likely to increase the seedset of problem species, including silver grass, brome grass, barley grass and geranium.

Rural Solutions South Australia livestock industry development consultant Anne Collins said it was important to now prepare grass seed-free paddocks for weaners, including spraying along fencelines, creeks and gullies.

Attention should also be paid to laneways and yards used by lambs.

There was also still time for last-minute winter-cleaning of lucerne and annual pastures.

"While grass seeds infest livestock for only a few months of the year, managing a seed problem needs to have a year-round focus," she said. "Forward planning and advance preparation is the key to taking timely action against grass seeds."

"If you only start thinking about seeds when they appear in the paddock, it is too late."

Spraytopping during spring with appropriate grazing management was a good way to reduce seedset but required careful planning, and producers should speak to their agronomists about it.

"The whole farm does not need to be seed-free, but it is important to have enough clean paddocks to get lambs through to turn-off or to carry them through to stubbles or other clean feed," she said.

"If grass seed-free paddocks are not possible, then consideration should be given to short-term containment-feeding in a feedlot."

Grass seeds could hit producers hip pockets hard, with downgrades at slaughter, but there were also significant productivity losses on-farm associated with reduced growth rates and weaner ill-thrift.

"Lambs contaminated with seeds can become too sore to move and suffer damage to their eyes, ears, feet and mouths," she said.

"As few as 25 seeds in a lamb can reduce post-weaning daily liveweight gain by up to 50 per cent."

* Full report in Stock Journal, August 29 issue, 2013.