It has been my experience that, once an individual sheep becomes unwell, it can be very difficult to save. In addition to the emotional stress about losing a pet or stud animal, there are animal welfare issues to consider. Also, sheep vets are not always available and, even if they are, although vets are the lowest paid profession, vet bills can become prohibitively high fairly quickly. When I see that one of my sheep has become unwell, I think to myself, "Have I made a mistake in its care that has allowed this situation to develop?". Obviously this is not always the case but often, when vets are called out to an unwell sheep, they are confronted by an 'emergency' that has been weeks in the making. Keeping sheep healthy is not so much about treating unwell sheep when they become sick but rather is all about prevention that stops them getting sick in the first place. There are three 'pillars of  health' that, if firmly in place, will vastly minimize the chance of health problems. These are good worm control, an effective vaccination program and good nutrition.

1. Pillar One -- Worm control – I attended a refresher course for vets on sheep health in 2023. I happened to sit beside a younger female veterinarian who does a lot of work with pet sheep. I asked her what were the main sheep health problems she saw in private practice. She replied that there were three problems. These were worms, worms and lastly worms. She was being a bit flippant but, nevertheless, her reply illustrated the problem that worms are in pet sheep.

There are four main types of intestinal worms in sheep. The most common one is the black scour worm (Trichostrongylus sp.). The others are the brown stomach worm (Teladorsagia sp.), the thin-necked intestinal worm (Nematodirus sp.) and Barber's Pole worm (Haemonchus contortus). All have a fairly straightforward lifecycle. Adult worms live in the intestinal tract of the sheep. These adults produce eggs, which are passed in the sheep’s droppings. Larvae hatch from the eggs to contaminate the pasture. The larvae survive for a period of time on the pasture. If ingested while grazing, these larvae mature into adult worms in the sheep’s gut, thus completing the lifecycle. All of the worms primarily cause diarrhoea, loss of appetite, thin condition, 'bottle jaw' (fluid retention below the jaw), dehydration, a general failure to thrive, and, when in high numbers, death. The symptoms displayed by infected sheep are due to the damage the worms cause to the digestive tract lining and subsequent interference with digestion and nutrient absorption. Even an untrained eye can recognise these obvious symptoms . Caught early enough, response to treatment with an appropriate  wormer tends to be effective. Barber's Pole worm is, however, a bit more insidious. It has a typical roundworm life cycle in that its eggs are passed in a sheep's faeces, hatch and moult three times in the environment to an L3 form, which is infectious and eaten by a sheep. Infective larvae eaten by the sheep develop into adults in about 3 weeks. Barber's Pole worm causes bleeding in the stomach. Some affected sheep may be in fat good condition and have normal droppings but, because they are bleeding internally, the first symptom they display is that they collapse or die (because they are so weak from blood loss). In other sheep with Barber's Pole worm, the blood loss may be more insipid. These sheep become generally weak, their gums become pale and they may develop 'bottle jaw'. 'Bottle jaw' occurs because, when bleeding , in addition to red blood cells, protein is also lost from the circulation. As the protein level in the blood becomes low, fluid will move from the blood stream through the blood vessel walls into the surrounding tissues. Due to gravity, this accumulates on the underside of the chest and abdomen, around the legs and also most noticeably under the jaw. This fluid under the jaw is described as 'bottle jaw'. Because of the Persians dewlap , 'bottle jaw' is not as obvious in them as in other breeds, however, with a Barber's Pole infection, the dewlap appears more prominent and appears thickened. Barbers Pole infection has an additional complication. Many wormers kill the adult worms in the intestinal tract but not the recently ingested larvae. These larvae mature into adult worms over three weeks. This means that in the three weeks after an effective treatment (that killed the adults), as more and more larvae mature, infection re-establishes and once again the sheep become unwell. No matter what the worm, if sheep are put back onto the pasture they were grazing prior to worming or indeed any contaminated pasture, they quickly ingest more eggs or larvae and become re-infected.

There are several ways around these problems.

1. Some of the drenches provide persistent action so that they not only kill adults and larvae in the digestive tract but also continue to kill additional larvae as they are taken in during grazing. For example, Closantel kills virtually all Barber's Pole larvae for at least four weeks after drenching and moxidectin (Cydectin®, Moximax®, Moxitak®, Sheepguard®, Topdec®) for at least two weeks. Moxidectin is also available in a long-acting injection, which will give protection for up to 4 months (Cydectin Long Acting® and Neovemox Long Acting®). White drenches (benzidimidazoles) are the recommended treatment for Nematodirus infections as these drenches are effective against both larval and adult stages. As re-infection can occur, lambs may require repeated treatment at two – three week intervals.
    
2. A vaccine is available against Barber's Pole worm called Barbervax® vaccine. This vaccine provides a major alternative to drench-based control and will help manage worms in the face of drench resistance. Barbervax® is of particular benefit in Barber’s pole-endemic regions where frequent drenching may be necessary to prevent sheep deaths. The vaccine is given to sheep and lambs as a series of subcutaneous injections of 1 mL, at no more than 6-week intervals to cover the Barber’s Pole worm-risk season (e.g. in the NSW Northern Tablelands, this is generally December to April). It is important to understand that the first two vaccinations are not able to provide protection but they prime the lamb’s immune system so that protection occurs following the third vaccination and lasts for up to 6 weeks. Further vaccinations need to be given each 6 weeks while there is a Barber’s Pole worm risk or more frequently in those years and situations where animals are exposed to very heavy challenge from Barber’s Pole worm. Once sheep have received a course of vaccine as lambs, a single booster injection in a subsequent season will typically provide 6 weeks of protection without the need for a second priming dose.
    
3. It is possible to select for sheep that are genetically inherently resistant to worms. As a general rule sheep that have been developed in hot arid areas such as Persians have not had the same selection pressure for worm resistance as breeds developed in wetter areas like Europe and so are more vulnerable to worms. Sheep can also develop a natural immunity and tolerance to worms through a low-grade exposure as they mature. Sheep that have not had an earlier exposure and therefore are unlikely to have any natural immunity should be closely monitored if introduced to pasture that is possibly contaminated.
    
4. Implement pasture rotation. If possible, sheep should be introduced onto 'clean' pasture that is free of eggs and larvae after a worm treatment. Often the aim though is to create low worm-risk pastures for high-risk classes of sheep (generally lambing ewes and weaners) by keeping stock out of selected paddocks. In cool moist conditions, larvae can survive on pasture for many months. After about 6 months, approximately 90% will have died. However, in hot dry conditions, egg and larvae persistence is greatly reduced. Even just a string of a few days over 35C can dramatically reduce the risk of pasture to sheep. Ideally pasture can be set aside and not grazed, ready to receive animals after worming. If this is not possible, then strategically worming during hot dry spells will decrease the subsequent worm exposure and increase the benefit of worming.

At Coolibah we rotate between several different wormers. The main wormer we use is Zolvix Plus®. This is relatively new and contains monepantel. The others that we use in rotation are Startect® (which contains derquantel and abamectin) and Tridectin® (which contains moxidectin, levamisole and albendazole ). We set two paddocks aside at Xmas and these are kept empty and not grazed in preparation for our ewe and ram lambs to be weaned into them in April each year.

For more information please go to the Australian Persian Sheep Association Site (APSA ) under “Common Health Problems of Sheep”

2.  Pillar Two -- Vaccinations

The main vaccinations that we think are important at Coolibah Stud are :-

1. 5 in 1 – This vaccine protects against diseases caused by a group of bacteria called Clostridia. These bacteria are found in the soil and also the intestinal tract of healthy sheep. It’s not so much the bacteria themselves that cause a problem but rather the toxins they produce under certain circumstances. Once the toxins are being produced and a sheep is looking unwell, it is virtually impossible to save it. Sometimes the trigger for toxin production can appear quite benign, and be something as simple as a change of diet or a cut or bruise. The first 5 in 1 vaccination is given at 4 weeks of age and a second at 8 weeks of age. After this, annual boosters are given.
    
2. Johne’s vaccination – Johne’s disease is caused by a particular type of microorganism called Mycobacterium. The organism causes a long-term damaging inflammatory infection of the bowel lining. This leads to  infected sheep being unable to digest food and absorb nutrients. An infected sheep gets thinner and weaker until it is too weak to graze and eventually dies. There is no effective treatment. In some areas, the disease is quite common. The Johne’s vaccination is called Gudair® and is given as soon as possible after 4 weeks of age. A single vaccination confers lifetime immunity. Sheep that have been vaccinated shortly after four weeks of age are deemed 'designated vaccinates' and can have a large 'V' embossed into their NLIS ear tag. All Coolibah Persians are vaccinated at 4 weeks of age against Johne’s, about half way down the neck on the righthand side. Many sheep develop a painless lump about 2 cm across at the vaccination site. This is normal and gradually disappears over the following weeks or months.
    
3. Foot Rot- Foot Rot is caused by a bacterium called Dichelobacter. There are about 8 different strains of Dichelobacter, labelled one to eight, which vary in the severity of the disease they cause. The higher the number, the more severe the disease. Type one causes a fairly mild disease, often described as 'scald', where the skin between the cleats becomes inflamed and sore, while type eight causes a severe infection that actually causes the outer horn of the cleat to separate from the underlying soft tissue of the foot. Types two to seven cause infections, whose symptoms are between these two extremes. Dichelobacter survives on the feet of infected sheep and can also survive in contaminated soil for about two weeks. Vaccination against Foot Rot should ideally be done before sheep come into contact with the disease. If, however, they have already been exposed and are infected, vaccination will decrease the severity of the disease and is an effective part of treatment and control. The Foot Rot vaccine is called Cooper’s Footvax®. Coolibah sheep are vaccinated at 8 weeks of age. Boosters can be given on an as-needs basis. In properties with Foot Rot, individual property-specific vaccines can be made.

More information can be found on the Australian Persian Sheep Association Site (APSA ) site under “Common Health Problems of Sheep” and also under “Vaccinations”.

3. Pillar Three -- Nutrition

Persians are great foragers and feed converters. I have been lucky enough to see Persians in seven sub-Saharan countries but one situation sticks in my mind. It was in Namibia in sandy country with some dunes. A group of about 30 Persians were being tended by a local young shepherd as they moved across the sand. There was not much for them to eat - a dried leaf, a bit of bark and some dry grass - and yet they were in beautiful condition. In most Australian grazing conditions, Persians maintain weight easily and can become fat. If your Persian is losing weight, that means that it is not getting enough calories to meet its requirements. This can make it vulnerable to disease. Similarly, Persians, like all sheep, are more likely to become unwell if the diet that is provided is deficient in key nutrients.

I remember a Persian breeder in South Africa telling me that “Persians hate green”. This is not strictly true because they do  well on green pasture, but what he was referring to is that they can do very well on good-quality dry standing feed. Dry feed requires more chewing, chewing encourages rumination and rumination leads to good digestion and nutrient absorption. So, pasture grass and good-quality hay form the basis of the diet of most sheep.

A number of other foods are, however, commonly used. One of these is Lucerne. Persians, like all sheep, love lucerne. Lucerne hay may have anywhere from 16 to 20% protein, while grass hay may only have 4-12% protein, depending on the quality of the hay. Lucerne is commonly used as a high-protein supplement. It is, however, high in calcium, which can be a problem if a lot is fed to growing sheep. The level of calcium and phosphorus should be about the same in the diet. Diets that contain a lot of lucerne can cause phosphorus deficiency, which may affect correct bone development. Whether grazed or used as fodder, lucerne however has a high nutritive value relative to other fodder at comparable growth stages: it is high in protein, metabolisable energy, vitamins and minerals, all of which can increase animal production.

As mentioned above, pasture hay is commonly fed to sheep. Make sure the variety of hay you give your flock is leafy and fine. Sheep don't like coarse hay.  Leafy lucerne or immature grass hay will usually attract sheep. Hay made with a legume harvested during growth is usually best for lambs, as it will provide finer stems.

It is worth noting that ewes fed high-estrogen clover may suffer from temporary infertility, which can be reversed within a month of changing the diet. Vulva and mammary gland swelling will be visible in some breeds including Persians. Effects are less severe in white clover, but high phytoestrogens can cause reduced ovulation and delayed oestrus.

Grain is another good feed option. Cereal grains are an excellent source of energy, so they provide a good option for feeding sheep when grass and other supplements are in short supply. Sheep have an established microbiome, i.e. a population of bacteria in their digestive tract that has developed to digest what that sheep is eating. If the diet changes rapidly, the microbiome might not have time to accommodate for this. This can lead to an inability of the sheep to digest its food, which in turn leads to the production of gas (bloating) and a condition called lactic acidosis, in which not only are the nutrients in the food not available to the sheep but a toxic byproduct called lactic acid accumulates in the blood. In its most severe form, this condition can be fatal. When changing the diet of sheep, but particularly with grain and grain-based supplements (such as pellets), introduce the new food slowly, as part of a mixed diet, over a week or so to reduce these problems.

For many breeders, pellets offer an easy way of providing a high-protein, nutritious, balanced supplement. The better brands are made by veterinary companies and are formulated to provide a complete and balanced diet. Once familiar with them, sheep love them too.

Mineral supplementation is essential for long-term health. It can be truly boggling to see the huge array of products available in a produce store. The products that are available are poorly regulated and some don’t appear to be based on a lot of science. It makes no sense to select particular minerals and just supplement those. It is much better to use a complete and balanced supplement and better still one that is registered. Being registered means that the product has passed the checks and balances put in place by the appropriate government departments that ensure product quality.

At Coolibah, our sheep primarily eat pasture grass and hay cut on the property but this is not enough to meet their requirements all year round. Through times of increased nutritional demand - pre-mating, the second half of pregnancy , lactation and growth - our sheep are supplemented with Laucke’s Full Feed® sheep pellets. We use a veterinary mineral supplement called  Sheep Weathershield with Copper® made by Propharma in Melbourne. Importantly, it contains selenium to guard against White Muscle Disease, as well as all of the other essential minerals and in the correct balance, too. It comes as a white powder and we make it available in non-tip-over troughs in each sheep shed. It can, however, be provided in the paddock as it is hydrophobic, i.e. repels water if it is rained on.