Recovery and management after a dry season
Drought Extension Program team, Agriculture Victoria
This article summarises things to consider to improve short- and longer-term recovery from a dry period when stock have been on hand feeding.
The key considerations around releasing sheep from stock containment areas (SCAs) onto green pastures are:
- adapting them to consume green pasture after having been on full grain diets
- continuing to manage groundcover
- maximising winter pasture growth.
Ideally, sheep are held in the SCA until pastures have attained around 1200 kilograms of dry matter per hectare (kg DM/ha) of green pasture, allowing ongoing, rapid growth through winter, and protecting the soil after release of sheep.
SCAs were most recently used widely in Victoria to protect soil and pastures in 2006, and a survey of producers was conducted then. In the north-east and Kerang areas, sheep had been contained for between three and six months.
Some producers were forced to release sheep earlier than ideal for pastures, as a result of wet and muddy SCAs. The feedback from farmers in 2006 was that those who released stock while continuing grain feeding had no problems. This approach:
- helps animals adapt to the new diet
- helps ensure that they are getting adequate feed
- can reduce some of the potential risks of plant poisoning.
Be careful not to release hungry stock onto short phalaris pastures, as phalaris toxicity and sudden death can occur, particularly after a prolonged dry period. Feeding sheep before release (releasing them with a full stomach) and monitoring closely for the first couple of days is worthwhile. Grazing high-risk pastures with a small monitor mob of wethers first may also be a useful test, before grazing with high-value ewes.
Nitrate poisoning was considered a risk following the 2006 drought, as a result of sheep hungrily devouring high-nitrate pastures (for example, capeweed). However, most cases of nitrate poisoning occurred well after release from SCAs, even though a number of farmers released sheep onto capeweed, and most released onto pastures that had more than 1000kg DM/ha.
There are usually sporadic reports about calcium deficiency in ewes after drought. It is worth continuing to provide calcium as a supplement to ewes about to lamb, even when grain feeding ceases. Provision of roughage can also assist in mineral metabolism. The theory behind ongoing calcium deficiency is that peak demand for calcium is at the end of pregnancy and early in lactation. Ewes are unable to mobilise sufficient calcium from their bone stores, so continuing with supplementary limestone provides enough additional calcium absorbed through the intestines.
Worms will be the other big disease issue to monitor as the autumn progresses, with weaners and lambing ewes particularly at risk. As ewes get close to lambing, their immunity to worms drops. Stock lighter in condition than ideal and/or on low nutrition will be more susceptible and will crash more quickly, so do some regular worm tests on key mobs from six weeks after the autumn break.
If you want to restock by purchasing sheep, follow key biosecurity steps to make sure you don't bring in another problem — for example, weed seeds, lice or footrot. Your stock containment areas provide a good option for quarantining and monitoring bought-in stock.
Guidelines for introducing stock:
- Check animals for health status before purchasing.
- Purchase livestock from suppliers who have a food safety or quality assurance program, and can provide information about animal treatments and the health status of their animals such as a National Vendor Declaration (NVD) or Sheep Health Statement.
- Segregate, observe and treat (as required) newly introduced animals.
- Ensure that introduced livestock have had time to empty out after delivery, before their release onto paddocks.
- For livestock that leave and return to the property (for example, following agistment), assess their vulnerability to infection, hygiene arrangements and contact with other livestock while they were away. If risky, separate them from other livestock. Observe and treat (if needed) the animals before returning them to their companions.
- Inspect and maintain adequate boundary fences.
- Keep vulnerable stock away from livestock of unknown health status.
- Follow the National Livestock Identification System (NLIS) requirements specific to the species and jurisdiction.
- Take additional precautions if buying through saleyards, as these represent a high biosecurity risk.
For more information visit Farm Biosecurity.
To reduce your risk of bringing in drench resistance, sheep need to be quarantine drenched. WormBoss guidelines are as follows:
- Assume that purchased sheep are carrying worms with some degree of drench resistance to one or more drench groups.
- 'Quarantine' drench all sheep new to the property (particularly if sheep or rams are from a higher-rainfall district where drench resistance is more common).
- Use a combination of no less than four unrelated drench actives, with at least one of these being monepantel (Zolvix®) or derquantel (with abamectin – Startect®). This can be done using multi-active (combination) and/or single-active products concurrently – drench sheep along the race with one product, then administer the next.
- Do not mix different drenches in the drenching pack unless the label states you can, as different products may be incompatible.
- Quarantine the sheep after treatment. Hold them in yards (small mobs) or a secure paddock (larger mobs) for at least 3 days to allow worm eggs present at the time of drenching to pass out of the gut.
- Provide adequate feed and water while the sheep are in quarantine.
- Keep the quarantine paddock free of sheep, goats or alpacas for 3 to 4 months in cooler weather, and 4 to 6 weeks when it is hot and dry (above 35°C during the day).
After quarantine, release the sheep, if possible, onto a paddock that is likely to be contaminated with worm larvae due to grazing by other sheep. This will 'dilute' (lower the proportion of) resistant worms surviving treatment with worm larvae already on your property.
If possible, WormTest the imported sheep 10 to 14 days after drenching for added confidence that treatment was successful.
One good thing about not growing much pasture in the drought years will be lower nutrient use, which means that there may be less need for fertiliser inputs such as phosphorus and potassium this year. Soil test results after droughts are usually higher than expected, especially in paddocks in which fertiliser was applied in the previous year, so reducing inputs may be a possibility to aid cash flow recovery.
Consider the following options to prioritise your fertiliser inputs:
- If paddocks are higher than the target P (phosphorus), consider either a below-maintenance application or none at all. A regular monitoring program using soil tests conducted at accredited laboratories will help you target the right nutrients for the right paddocks, providing peace of mind when making the decision to leave fertiliser off in years such as this.
- Prioritise fertiliser applications to paddocks with a good perennial base (first) and paddocks to be sown down.
- For paddocks that previously had a high percentage of weeds (for example, silver grass), consider either a maintenance rate only or not fertilising for this season (if funds are tight).
- If you have reduced stock numbers, the required maintenance rates of P may be lower.
- Buying in fodder such as hay and grain imports some key nutrients, including P, potassium (K), nitrogen (N) and sulfur (S). However, if sheep have been fed in SCAs, these imported nutrients will have been applied only to the SCA.
Now is a good time to review your fertiliser strategy for the year. Agriculture Victoria staff can run group workshops to assist producers with the decisions required to review fertiliser strategies. Contact your local DEDJTR Agriculture Victoria office if you are interested.
Many pastures will be run down after dry years, and weeds may become more prevalent. If hay or grain have been bought in, check all paddocks where the grain or hay has been fed out, as they may be a source of new weeds that can be quickly brought under control.
For perennial pastures that have been good in recent years, experience suggests not being too hasty to rush in and resow. If there is still a reasonable base, grazing management and some weed control may be a cheaper and more successful option to provide recovery. Thin pastures may benefit from a top-up with new species, which may be a cheaper option than resowing. SCAs are an increasingly used tool that can be used to protect both soil (and its associated nutrients) and pasture in dry seasons.
As we move into the winter period, N (as urea) and gibberellic acid can increase winter feed availability, if pasture species and fertility are adequate (see Sheep Notes, autumn 2014, 'Boosting winter feed with additives').
Soil and erosion risks
Heavy rains can cause quite a lot of damage if they occur before some decent groundcover is established. If you do experience heavy rains, keep a check on sensitive soil conservation works, table drains and access tracks.
Washing of soil and sheep manure into dams can cause significant water quality problems. Stock may not drink the dirty water or may become sick if they do. Setting up sediment traps with straw bales or shade cloth to reduce inflows might allow you to prevent major water storages from filling with sediments.
More information is available on our Managing dams page.
Preparing for the next drought
Hopefully, the next drought is a fair way off, but, given our inherent climate variability, we will continue to experience dry seasons. Document your experiences — noting what worked and didn't work this time around — with feeding infrastructure (for example, storage space, feed-out equipment), stock rations, pasture recovery, soil management and so on. This knowledge may help you to start to plan for future infrastructure needs now (for example, SCAs, better water or feed storage) or prevent you from making the same mistakes next time. These records will remind you, family members and staff what you did this time, and what got you through.