WITH headers coming out of sheds across the Mallee in the next few weeks there are some big numbers involved which tend to escape people.
Such as stubbles, and what they are truly worth to mixed operations and graziers.
Across Australia crop stubbles can provide a staggering three billion ewe grazing days – that’s enough forage to feed the national flock for six weeks.
And in a season as tight as the current one, where fodder is in such high demand across the southeast agricultural zone, stubbles suddenly take on a lot more importance.
CSIRO researcher Dr Dean Thomas said producers should graze them because; Stubbles provide a substantial feed base component, with ewes in mixed farms typically spending 20 per cent of their time on stubbles each year; Stubbles provide a high-quality source of feed during summer; Removing spilt grain from paddocks reduces risk of pests such as mice or birds; Breaking down the stubbles makes the following cropping season easier as seeding into high volume stubbles can be difficult.
Dr Thomas has provided his five key tips for grazing sheep on stubbles.
1. Maintain a good source of nutrition.
Grazing stubbles is often done when ewes are pregnant so it’s important they’re kept in good condition.
Producers should aim for a condition score of three and have them on a rising plane of nutrition.
Stubbles are a feed source which starts as high quality but depletes quickly (as the sheep clean up the spilt grain) so producers need to keep this characteristic in mind to ensure a good source of nutrition is maintained.
Grains and young green plants have a higher proportion of digestible carbohydrates and protein, so they typically have a higher nutritive value. Leaf and fine stem components are low quality but generally edible, and make up roughly half of the energy for a typical diet from dry stubbles (where the remainder is grain and green material).
However, ripe wheat stems (that make up a large component of stubbles) have a high proportion of structural carbohydrates that are poorly digestible, making them lower in nutritive value and generally little of this material is eaten.
2. Prioritise stubbles for grazing
It’s important for producers to prioritise stubbles for grazing by providing ewes or finishing lambs with the highest quality stubbles, followed by pregnant ewes (or in preparation for joining). Allowing older ewes to graze on lower quality stubbles, such as wheat or canola stubbles, although provision of adequate nutrition is still key.
3. Keep an eye out for metabolic diseases
There are a few risks associated with grazing stubbles, such as acidosis.
Spread out any piles of grain left in the paddock after harvest to reduce this risk and acclimatise ewes by starting them on barley or lupin stubbles prior to grazing wheat stubbles.
Vitamin E deficiency can occur if sheep graze stubbles for an extended period without access to green feed so supplement with vitamin E (drenched or injected) or provide access to adjacent areas of perennial grasses and shrubs for a source of vitamin E.
4. Have the right infrastructure in place
Stubbles are a drier feed, so producers need to have good fences and a source of water. Sheep will require 3-5 litres per sheep/per day to graze stubbles (more during hot weather).
5. Select paddocks carefully
Graze carefully on paddocks that are susceptible to wind erosion because grazing stubbles can break down ground cover, and sheep will often camp in susceptible areas such as hill crests and sandy patches. Extended grazing may result in sheep tracks that increase erosion risks.
