If you have yet to buy your sheep, you should carefully consider the breed of sheep and why you want to get them. In Australia there is a wide variety of sheep breeds currently produced.
Different breeds are bred for specific reasons; shedding sheep like Wiltshire Horn and hairy sheep like Dorpers are bred for meat production and usually require no shearing or crutching. Merino sheep on the other hand produce thick woollen coats which require routine shearing and crutching.
Before you bring any livestock onto your property give them a good look over. If there are any signs of scouring, pulled wool or general unwell symptoms, consider getting your vet to give them a check up. This might save problems further down the track with poor performers.
It is also very important to quarantine any new animals brought onto your property. New animals should be kept in a quarantine area to ensure that they are not carrying any parasites which can be passed onto your existing stock. This also allows foreign weed seeds to be excreted in this area rather than spread all over your farm.
Flystrike
Flystrike is the insect pest condition that everyone associates with sheep. It is a painful condition that, if not treated promptly, can result in death.
Flystrike is caused by blowflies which are attracted to smelly, warm, moist environments such as faeces build ups (dags); sweaty, moist skin folds; or open wounds.
Animals will often become flystruck around their anus, although this is not the only region prone to flystrike. Rams can become flystruck in between their horns or on their pizzle.
Flies are more abundant during humid times of the year.
Flystrike is caused when adult blowflies lay eggs on the skin of the sheep, which hatch into maggots. The maggots feed on the sheep’s flesh while they grow, before they drop to the ground and pupate, to hatch eventually into adult flies and begin the process again.
While the maggots are living on the sheep, it develops from being extremely irritating to painful, and sheep can die through shock or infection if the condition is allowed to persist for a number of days.
Once sheep are infested you will need to shear the affected area and expose the maggots. You will then need to treat with one, or more, chemical application(s) to kill the maggots, and disinfect the wounds.
Prevention is far kinder than cure and needs to be part of your normal management routine.
People who own Merino and other long wool sheep should implement tailing and crutching of their stock. Tailing and crutching of animals reduces the amount of wool in the anus region, resulting in less area for dags to form.
You can apply chemicals to repel the flies and keep incidents of flystrike to a minimum. Even after the use of chemicals, it is still necessary to regularly monitor sheep at risk. Treat individually affected sheep, as the effectiveness of chemicals will reduce over time.
Details of current chemical treatments are available from Managing flystrike in sheep, or the FlyBoss website.
Hairy sheep such as the Dorpers or shedding sheep such as the Wiltshire breeds are less likely to be affected but can have some problems and will need monitoring. One or more flystruck sheep in a flock indicates that there are likely to be more incidents.
All sheep need to be observed at least every two days and affected sheep should be treated immediately.
If an animal cannot stand unassisted due to the severity of flystrike injuries, it should be examined by a vet or humanely destroyed.
Animals which have died, or had to be destroyed, need to be deep buried to prevent access by scavenging animals and the development of fly larvae.
Worms
There are two major types of worms that affect sheep in Western Australia; barber’s pole and scour worms.
The adult worm lays eggs in the digestive system of the sheep. The eggs pass out of the sheep and hatch as larvae in the pasture, where they are ingested by the sheep through grazing, become adult worms, and the cycle begins again.
Worms can cause damage to the lining of the gut, poor appetite, diarrhoea (scour worms), or weakness and death due to blood depletion (barber’s pole worm).
By the time a sheep is visibly affected, the infestation is severe.
The main signs of barber’s pole worm are weakness and anaemia (pale membranes of the mouth and eyes).
Scour worms will result in weight loss, weakness and diarrhoea (scouring).
Carrying out a regular worm egg count (WEC) by submitting faecal samples to a veterinarian is the best way to keep a handle on worm burdens.
Drenching should only be carried out when necessary, as worms can become resistant to the drench if it is used indiscriminately, making control more difficult.
Good nutrition can help sheep to overcome the effects of worms, and also to develop a natural resistance to worms.
Livestock owners should consider rotationally grazing their animals as part of their worm prevention strategy. Rotational grazing is the practice of moving stock from one paddock to another once the feed becomes relatively low or after a set time in a paddock.
By moving sheep from one paddock to the next any worm eggs which have been expelled by the sheep and hatched will be less likely to be picked up.
When you see visible signs of worm infestation, such as diarrhoea, investigate the cause immediately.
Once an accurate diagnosis is made, treatment of affected animals to prevent the problem getting worse is strongly recommended.
You should also seek advice in relation to a whole of flock preventative worming program.
Affected animals, which do not respond to treatment, and are not likely to recover, should be examined by a vet or humanely destroyed.
The effect worms can have on your flock will vary depending on how bad the infestation is, the resilience of your animals, and the type of worm.
Discuss with your vet for advice specific to your flock, or visit the WormBoss website.
Lice
The third parasite to check for is lice. A heavy infestation of sheep lice can cause severe irritation. This can lead to the affected animal becoming distressed, suffering from a loss of appetite and subsequently losing weight and condition.
Lice are a common parasite in sheep flocks, and some animals are more resilient than others to a heavy infestation.
Sheep lice spread easily from sheep to sheep through direct contact. The presence of one infested sheep indicates a potential infestation throughout the flock. Infested sheep should be treated with an appropriate product ideally after shearing.
On occasion, sheep will need to be treated when unshorn to prevent significant wool damage.
Details of current chemical treatments are available from Sheep lice control for ewes and lambs and A treatment plan for farms with lice, and the LiceBoss website.
If individual animals are found to be suffering from a heavy lice infestation, and rubbing to the point of causing wounds, they should be treated ahead of any planned routine flock treatment.
To help prevent lice infestations, quarantine any sheep that you acquire from outside your property until you can be sure they are lice free. Build and maintain sheep-proof fences to keep out infested strays.
Pests
Many seasoned sheep owners describe running a flock of sheep as a wonderfully rewarding activity. Unfortunately, at some point you will almost certainly observe a parasite and pest infestation in your sheep.
You need to monitor your animals at least every two days and be able to recognise if your sheep are suffering from an infestation.
Some owners regularly weigh their sheep (for example, every four weeks) to assess their condition and growth. This is a time-consuming, but valuable management method. Regular weighing is also a good time to check your sheep for parasites.
Your vet is a good source of information and you may find that local farmer groups or breed groups can also offer support.
The department also has an array of sheep care references.
Animal welfare and the law
The law governing offences of cruelty to animals is the Animal Welfare Act 2002 (the Act).
‘Cruelty’ does not only mean beating or starving an animal. If an animal "suffers harm, which could be alleviated by the taking of reasonable steps", the person in charge of that animal could be prosecuted.
By failing to treat your animal, you could be guilty under the law if ‘reasonable steps’ in terms of prevention and treatment are not undertaken.
In WA, the Act is administered by the Department of Primary Industries and Regional Development.
Animal welfare tips
Sheep need to be monitored at least once every two days by someone who can spot the signs of a pest infestation.
All new animals to the property need to be held in a quarantine area before being introduced to other stock.
Quarantine yards are a good place to hold sick or infested animals especially if they need regular treatment. It will also help with preventing parasites from spreading to other animals.