Last stubble season saw many cases of lupinosis in Eyre Peninsula sheep with a high rate of severe cases.
Severe lupinosis and associated liver damage causes stock deaths, while less severe lupinosis may reduce appetite and body condition, with liver damage likely.
Lupinosis is caused by a toxin produced by a fungus, known as phomopsis.
Phomopsis can infect all lupin plant parts but is more common on dry stems at maturity and on pods, making stubbles the greatest risk.
In severe cases seed can be affected, so stock that are feeding on infected lupin grain can also suffer.
Late rain or humidity favouring fungal growth increases the lupinosis risk, even in so-called resistant lupin varieties.
Be aware that infected grain or stubble remains toxic and cannot be re-grazed when dried out.
Where the stubble infection status is unknown, lupin stems are the highest risk.
Having enough lupin grain on the ground with other fodder available in the paddock means livestock are less likely to graze the potentially more dangerous lupin stem.
By carefully monitoring seed quantity and grazing habits, stock can be removed before they consume stem.
Sheep on a lupin stubble need at least 50 kilograms per hectare of grain available on the ground, while cattle need at least 100kg/Ha.
- Grain and stubble can be tested for phomopsis prior to grazing.
- Graze lupin stubbles as soon as possible after harvest. The more rain events that occur on an infected crop or stubble, the higher the risk.
- Monitor the grain and other feed available in stubble paddocks to prevent stock from eating lupin stubble stems.
- Avoid moving hungry stock onto lupin stubbles as they are more likely to consume stems than take the time to find grain.
- Weaners need to learn to eat lupin grain before they are moved onto lupin stubble. Weaners are more susceptible possibly because they feed less selectively.
- Graze paddocks sown with clean seed, with a minimum four-year crop rotation.
- Avoid grazing last year’s lupin stubble or sowing fodder crops into lupin stubble. Check for ‘leopard spotting’.
- Graze sheep in mobs of 600 or less for ease of checking, and less than 10 head per hectare.
- Be vigilant in monitoring stock. It is vital to move the mob a short distance, check for stragglers or weak or hollow looking animals and jaundice. Check them daily and move the entire mob if they show any signs.
Contact Primary Industries and Regions South Australia Port Lincoln animal health officer Pat Lawler for queries on 0408 539 060.