03 July 2015
By Geoff Casburn
DPI Sheep Development Officer
Wagga Wagga NSW
At this time of year the main focus is getting the best out of grazing crops and short, slow growing pastures, and many producers are not thinking five months ahead on the potential problem of seed contamination on animal welfare, lamb growth rates and wool, skin and carcase value.
However, given the potential impacts, it is important to start planning practical ways to keep lambs and sale sheep free of seed and breeders as free from seed as possible.
The first step is to identify the problem plant species, when they set seed and how they can be managed. MLA's publication Winning Against Seeds provides valuable information.
The next step is to identify suitable weaning paddocks and commence a management program to ensure they will be free of problem seeds, free of worms and contain a good quantity of high quality pasture.
Lucerne paddocks are ideal as they provide quality feed late in the season when grasses are maturing. They can also be effectively winter cleaned to remove problem grass species. However, careful paddock selection is required as winter cleaning significantly reduces biomass production, potentially leaving a large feed deficit if too many paddocks are treated at once.
Allocating 'seedy' paddocks now will ensure pasture growth will be well utilised before the seed becomes a problem. Concentrating on these paddocks will also give the paddocks to be winter cleaned a chance to build up dry matter. Graze seedy paddocks with a westerly aspect first as these are likely to become moisture stressed and set seed early.
Erodium, commonly known as Corkscrew or Crowfoot, is one of the earliest plants to set seed. These paddocks need to be carefully monitored to ensure stock are removed before the large seed head opens. The seeds are sharp and contain a corkscrew-like awn that quickly burrows through the wool to penetrate the skin and muscle. These seeds can also pose significant impacts and cost on meat processing.
Chemical control of Erodium is most effective early in the season when plants are small.
Spray topping paddocks containing barley grass and silver grass is a long term strategy aimed at reducing, not eradicating, problem plants in the years following application. The chemical is applied late in the season allowing the pasture growth to fill the feed gap resulting if other paddocks have been winter cleaned. These paddocks are ideally suited to mature, non-sale sheep as they are more likely to avoid any seedy areas.
Shearing prior to maturity of seeds significantly reduces seed contamination and may be an option when lambs need to graze paddocks with small amounts of seed. This strategy needs careful thought when considering premature shearing of adults.
Producers need to remain focused to avoid grass seeds. Meat processors are sending a clear message to producers that any seed contamination of sheep or lamb will not be tolerated, and this is supported by the sheep industry nationally. The cost of seed contamination will flow through to the producer.
Information: Geoff Casburn E: geoff.casburn@dpi.nsw.gov.au
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