Cottonseed supplementation for sheep
Cottonseed has been used extensively in Queensland as a feed supplement for sheep. It is a good source of energy (12-14 MJ ME/kg) and protein (19-24%), but should always be fed with adequate amounts of roughage (due to the scouring effects of the oil in cottonseed). It is important to monitor the performance of the sheep, and adjust feeding rates accordingly.
It is best not to feed cottonseed daily so that sheep don't gorge themselves and shy feeders have an opportunity to obtain some feed.
Health effects of cottonseed on sheep
Cottonseed should not be fed to weaner sheep under 5 months of age as their rumen is not developed enough to handle the ingredient gossypol (which is toxic to non-ruminant animals: horses, pigs and poultry).
Effects on fertility
Research data has demonstrated that cottonseed has no effect on ram fertility. There is also no evidence that cottonseed shouldn't be fed to lambing ewes.
Ad lib feeding
If allowed, sheep will eat up to 1000g of cottonseed per head per day in drought conditions when roughage levels are low. However, this is not recommended due to the scouring effects of the oil and the low levels of roughage in the diet.
Sheep will generally accept cottonseed as feed, but in some situations you may need to encourage them with more palatable feeds such as molasses or lucerne hay. It is usually only a matter of days before the whole flock accepts cottonseed.
Methods of feeding cottonseed
A common method of feeding cottonseed is to drop large mounds containing several days' supply into paddocks. The bulk carrier of the cottonseed will often do this when they deliver the feed.
Make sure the mound is placed on hard ground to minimise wastage. The cottonseed mound should be fenced with rolled weldmesh staked around the heap, or with an electric fence. The fencing should then be tightened onto the heap to restrict access but allow the sheep to feed in a semi ad-lib fashion.
Feeding in large paddock heaps reduces labour and results in minimal seed loss from dust; however, estimating feed intakes is difficult. Small mounds on hard ground can also be used, but some feed may be wasted if sheep walk or camp on the unfenced mound.
Trailed on the ground
When trailed onto hard ground little seed is lost, but there may be some dirt contamination in sandy soil. This method is best with 3-4 day feed outs (i.e. dump 3 or 4 days requirements at one time to give twice weekly feeding times). This will reduce labour, vehicle rushing, wastage, bullying, mismothering and force sheep to eat other roughage in the paddock if the supplement runs out.
Cottonseed can be fed in open troughs placed on the ground (provided there are enough troughs, volume and space to let the whole mob feed at the same time). Open troughs also give you the opportunity to mix cottonseed with cereal grains in advanced stages of drought when roughage and carbohydrate is scarce.
Hoppers or self-feeders
Some brands of hoppers or self-feeders are suitable for feeding cottonseed, but others - particularly grain feeders - are not, as the cottonseed does not flow into the trough. Check with the manufacturer before purchasing.
To overcome the problem of flow, mix cottonseed with grain at a ratio of about 40% cottonseed to 60% grain. At this rate of grain (or higher), the cottonseed flows easily, and intakes can be restricted by closing the shutter to a minimum release rate.
Feeding rates for different classes of sheep
The table below lists approximate feeding rates of cottonseed to sheep.
|Class of stock||Daily supplement (grams per head)|
|Weaner sheep (older than five months)||100|
|Dry ewes, wethers and rams||150|
Cottonseed should be limited to 10-20% of the total dry matter intake.
Handling and storing cottonseed
Cottonseed has unique characteristics that require completely different on-property handling and storage systems to other supplements. The fluffy nature of white cottonseed doesn't allow it to be moved through augers or silos. When moving large quantities, front-end loaders and tip trucks are required, and when moving smaller amounts and filling troughs, shovels and forks are needed.
Large open sheds that can accommodate front-end loaders are ideal for the storage of cottonseed, however the majority of properties don't have this type of infrastructure.
Storage out in the open
Cottonseed isn't greatly affected by weathering; therefore, you can store it on a well-drained site out in the open that is accessible to trucks and tractors.
Fencing and covering
Make sure the storage site you choose is well fenced so that animals and pets cannot get to the pile.
Covering is not required if the mound is maintained in a well-peaked shape that sheds water. Heaps in the open should not be covered with tarpaulins (unless only the top of the pile is covered), as the trapped moisture in the seed will cause mould and fungal growth. Also, because the cottonseed stack is not able to breathe, trapped heat could cause spontaneous combustion.
Fresh seed, straight from the gin, contains heat from handling friction and can spontaneously combust during storage. This heat should have gone by the time the cottonseed reaches the property. However, with very fresh seed, sometimes this doesn't happen, and continuous movement of the cottonseed stack is required to cool it down.
Cottonseed can also spontaneously combust if it is stored wet or stacked too high (greater than 5m). The moisture levels at time of purchase should be 14% or less.
Long-term storage and supply
Grain weevils are a potential threat to long-term storage and fumigation may be necessary. It's also advisable to store feed in bulk, as cottonseed is not always available to purchase.