Animal health and nutrition – sheep
Healthy animals are more productive and use resources more efficiently, which means higher profit. (Of course, you also have an obligation under animal welfare to ensure your animals are healthy.)
Your primary skill with regard to animal health is knowing how to condition-score an animal. Understanding potential parasites and diseases of the area and how to protect against them – in short, what your animals need in order to remain healthy. |
Major diseases affecting sheep production in the Derwent Valley
Many different diseases and conditions affect sheep in the Derwent Valley. Here is some information on the main ones, with links to some sound information on them.
On this page (click to jump to section):
Internal parasites
Liver fluke
Sheep body lice
Foot abscess
Footrot
Reproduction losses
Flystrike
Mastitis
Ovine Johne's disease (OJD)
Dermatophilosis (dermo, lumpy wool)
Micronutrient deficiencies
Respiratory disease
Pregnancy toxaemia (twin lamb disease)
Vaginal prolapse
Pink eye
Nephritis
Redgut
Ryegrass staggers
Sarco, bladder worm & sheep measles
Arthritis
On this page (click to jump to section):
Internal parasites
Liver fluke
Sheep body lice
Foot abscess
Footrot
Reproduction losses
Flystrike
Mastitis
Ovine Johne's disease (OJD)
Dermatophilosis (dermo, lumpy wool)
Micronutrient deficiencies
Respiratory disease
Pregnancy toxaemia (twin lamb disease)
Vaginal prolapse
Pink eye
Nephritis
Redgut
Ryegrass staggers
Sarco, bladder worm & sheep measles
Arthritis
Internal parasites
Intestinal worms
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Scouring due to internal parasites
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Black scour worm, brown stomach worm and Nematodirus are common. Barber's pole worm, seen as anaemia, bottle jaw and deaths without scouring in summer/autumn, has not yet been diagnosed very often in sheep. Drench resistance is common, and sheep producers should consider conducting a DrenchCheck (a Wormtest, 10–14 days after drenching) on sheep or lambs with a recent moderate to high egg count to make sure that their current drench is working. For sound information on treatment and prevention go to the WORMBOSS web page.
Liver fluke
A liver damaged by liver fluke
Liver fluke are relatively common in the Derwent Valley and throughout the Central Highlands. Sheep can die suddenly from Black Disease, or show ill-thrift, bottle jaw, anaemia, and lie down when mustered.
Treatment: Triclabendazole is usually the best treatment from November to July as it kills immature fluke as well as mature fluke but has an ESI of 63 days. Treat slaughter stock then keep them on paddocks with trough water until slaughter if possible or use albendazole at the higher recommended dose rate on the label even though it only kills adults (10 day WHP/ESI). Consider treatment with a different flukicide family in late winter to kill adult fluke that may be resistant to triclabendazole (resistance has been demonstrated in Tasmania).
Prevention: Fence off fluke snail habitat and provide stock water from troughs if possible.
There's a useful fact sheet on liver fluke (Sheep Connect Tas).
Treatment: Triclabendazole is usually the best treatment from November to July as it kills immature fluke as well as mature fluke but has an ESI of 63 days. Treat slaughter stock then keep them on paddocks with trough water until slaughter if possible or use albendazole at the higher recommended dose rate on the label even though it only kills adults (10 day WHP/ESI). Consider treatment with a different flukicide family in late winter to kill adult fluke that may be resistant to triclabendazole (resistance has been demonstrated in Tasmania).
Prevention: Fence off fluke snail habitat and provide stock water from troughs if possible.
There's a useful fact sheet on liver fluke (Sheep Connect Tas).
Sheep body lice
Biting flanks and rubbing on objects
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Body lice are 2 mm long and move away from light
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Body lice are still a very common cause of rubbing and fleece damage in wool sheep. See LICEBOSS for full details on dealing with lice.
Foot abscess
Foot abscess breaking out above coronary band
Foot abscess can be a major problem especially in wet winters and springs, with heavy multiple-bearing ewes often dying from pregnancy toxaemia as a result.
Usually seen as swelling of one toe – hot, painful and discharge of pus in the acute stage. May affect all four feet in some cases, but usually one foot.
Treat: Pare away hoof to allow drainage of pus, inject long-acting broad-spectrum antibiotics and anti-inflammatories (under vet supervision), keep feet dry e.g. on slatted floor of shearing shed, place epsom salts on drainage point and bandage. Ensure fit to load if transported.
Prevention: Keep mob average BCS to 3–3.3, autumn or pre-lamb shear, reduce interdigital skin injury, walk through 5–10% formalin or 10% zinc footbath weekly.
Foot abscess in sheep fact sheet (NSW government, PDF)
Usually seen as swelling of one toe – hot, painful and discharge of pus in the acute stage. May affect all four feet in some cases, but usually one foot.
Treat: Pare away hoof to allow drainage of pus, inject long-acting broad-spectrum antibiotics and anti-inflammatories (under vet supervision), keep feet dry e.g. on slatted floor of shearing shed, place epsom salts on drainage point and bandage. Ensure fit to load if transported.
Prevention: Keep mob average BCS to 3–3.3, autumn or pre-lamb shear, reduce interdigital skin injury, walk through 5–10% formalin or 10% zinc footbath weekly.
Foot abscess in sheep fact sheet (NSW government, PDF)
Footrot
Score 5 footrot
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Score 3 footrot
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Footrot is still a significant problem on some properties, especially in wet years.
Treatment: Paring, footbathing, culling chronic cases, use of vaccine. Eradication by repeated foot inspections, judicious use of antibiotics (see your vet to ensure you use the right one) and culling all infected sheep can be executed over summer. Ensure culls are fit to load if transported.
Prevention: Ask for a Sheep Health Declaration when buying sheep and ensure section B1 confirms flock is free of virulent footrot, but still footbath and check feet on arrival. Maintain good boundary fences.
Fact sheet on footrot identification and control (Sheep Connect Tas, PDF)
Treatment: Paring, footbathing, culling chronic cases, use of vaccine. Eradication by repeated foot inspections, judicious use of antibiotics (see your vet to ensure you use the right one) and culling all infected sheep can be executed over summer. Ensure culls are fit to load if transported.
Prevention: Ask for a Sheep Health Declaration when buying sheep and ensure section B1 confirms flock is free of virulent footrot, but still footbath and check feet on arrival. Maintain good boundary fences.
Fact sheet on footrot identification and control (Sheep Connect Tas, PDF)
Reproduction losses
Aborted twins
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Swollen head and yellow stain typical of difficult birth
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Reproduction losses include excess empty ewes at scanning, abortion, newborn lamb deaths (exposure, difficult birth, slow birth, mis-mothering).
Excess empty ewes: Often nutritional cause, sometimes ram problem. Best to have a vet investigate.
Campylobacter abortion is relatively common, especially in intensive rotational grazing, confinement feeding and trail feeding situations.
Treatment for Campylobacter: Antibiotic treatment of ewes may slow the outbreak down – see your vet.
Prevention: A vaccine is available and covers both strains of Campylobacter; the course should be completed before joining. Mixed age ewes can experience outbreaks, so consider vaccinating all age groups. Aborting ewes can be run with unmated ewe weaners to give them immunity. Humans can also be affected so women of child-bearing age should not be exposed to aborting ewes or afterbirth.
More information on the disease (PDF)
Toxoplasmosis abortion: No treatment.
Prevention: Either try to expose unmated ewes to breeding cats or eliminate cats completely. Pet, stray and feral cats can all spread toxoplasmosis.
Toxoplasmosis fact sheet (PDF)
Difficult births: Scan ewes and feed single-bearing ewes less than twin-bearing ewes aiming for 4–6 kg lambs at birth.
Slow births: Make sure ewes have a diet balanced for calcium in late pregnancy, especially if on cereal crops or lush feed. You can make up your own loose lick 40% Causmag, 40% limestone, 20% salt, or use a commercial preparation.
Mis-mothering: Lamb in smallest mob sizes on adequate feed (especially multiples), disturb as little as possible.
Excess empty ewes: Often nutritional cause, sometimes ram problem. Best to have a vet investigate.
Campylobacter abortion is relatively common, especially in intensive rotational grazing, confinement feeding and trail feeding situations.
Treatment for Campylobacter: Antibiotic treatment of ewes may slow the outbreak down – see your vet.
Prevention: A vaccine is available and covers both strains of Campylobacter; the course should be completed before joining. Mixed age ewes can experience outbreaks, so consider vaccinating all age groups. Aborting ewes can be run with unmated ewe weaners to give them immunity. Humans can also be affected so women of child-bearing age should not be exposed to aborting ewes or afterbirth.
More information on the disease (PDF)
Toxoplasmosis abortion: No treatment.
Prevention: Either try to expose unmated ewes to breeding cats or eliminate cats completely. Pet, stray and feral cats can all spread toxoplasmosis.
Toxoplasmosis fact sheet (PDF)
Difficult births: Scan ewes and feed single-bearing ewes less than twin-bearing ewes aiming for 4–6 kg lambs at birth.
Slow births: Make sure ewes have a diet balanced for calcium in late pregnancy, especially if on cereal crops or lush feed. You can make up your own loose lick 40% Causmag, 40% limestone, 20% salt, or use a commercial preparation.
Mis-mothering: Lamb in smallest mob sizes on adequate feed (especially multiples), disturb as little as possible.
Flystrike
Breach strike
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Lucilia cuprina, the primary strike fly
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Flystrike is common over the warmer months, especially if scouring/dags (usually due to worms) or fleece rot have made sheep more susceptible.
See FLYBOSS for all details on prevention and treatment.
See FLYBOSS for all details on prevention and treatment.
Mastitis
Chronic mastitis with abscess formation
Mastitis, particularly ‘black udder’, results in ewe and lamb deaths on many properties.
Acute mastitis treatment: Strip out as much milk as you can and administer antibiotic and anti-inflammatories by injection under veterinary supervision. If only one half of the udder is affected the ewe can produce nearly as much milk from the other half if she recovers. Chronic cases with hard udder should be culled.
More information on mastitis in sheep (WA government)
Acute mastitis treatment: Strip out as much milk as you can and administer antibiotic and anti-inflammatories by injection under veterinary supervision. If only one half of the udder is affected the ewe can produce nearly as much milk from the other half if she recovers. Chronic cases with hard udder should be culled.
More information on mastitis in sheep (WA government)
Ovine Johne’s disease (OJD)
Six-tooth ram with OJD
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Thickened intestines with prominent lymph channels
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A small percentage of adult sheep start wasting, with or without scouring, and don’t respond to drenching. The quickest diagnosis is by post mortem.
Treatment: No effective treatment available.
Prevention: Vaccinate lambs at marking or weaning with Gudair vaccine. If confirmed present in the flock, cull any sheep over 18 months of age that waste away and don’t respond to drenching. A small percentage of sheep don’t respond to the vaccine so a few cases can occur in vaccinated sheep.
OJD fact sheet (PDF)
Treatment: No effective treatment available.
Prevention: Vaccinate lambs at marking or weaning with Gudair vaccine. If confirmed present in the flock, cull any sheep over 18 months of age that waste away and don’t respond to drenching. A small percentage of sheep don’t respond to the vaccine so a few cases can occur in vaccinated sheep.
OJD fact sheet (PDF)
Dermatophilosis (‘dermo’, ‘lumpy wool’)
Dermo on the topline of a weaner
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Matted wool
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Dermo is more common in young sheep and in wet years. Wool staples become solid with dried exudate.
Treatment: Long-acting oxytetracycline antibiotic under veterinary supervision during dry period, wait for six weeks and shear. The wool is still valuable.
Prevention: Don’t yard sheep when wet to skin.
Lumpy wool fact sheet (NSW government, PDF)
Treatment: Long-acting oxytetracycline antibiotic under veterinary supervision during dry period, wait for six weeks and shear. The wool is still valuable.
Prevention: Don’t yard sheep when wet to skin.
Lumpy wool fact sheet (NSW government, PDF)
Micronutrient deficiencies
Goitre. Photo: David Dare
Selenium deficiency is widespread over most areas. Copper, cobalt/B12, iodine (deficiency causes goitre) and manganese (contracted tendons) deficiencies occur in certain areas and certain years (usually wetter years). Blood or liver testing in late winter are best to show selenium, B12 and copper status, but iodine deficiency is usually diagnosed in newborn lambs.
Treatment and prevention: Routine selenium supplementation, pre-lambing iodine, and B12 supplements are usually safe if the recommended dose rates are observed, but be careful with copper, and only supplement if a deficiency is diagnosed.
Treatment and prevention: Routine selenium supplementation, pre-lambing iodine, and B12 supplements are usually safe if the recommended dose rates are observed, but be careful with copper, and only supplement if a deficiency is diagnosed.
Respiratory disease
Pneumonia – normally pink lung looks more like liver
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Pleurisy (lungs stuck to the chest wall)
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Respiratory disease is more common than most realise. Mycoplasma ovipneumoniae, a well known cause of respiratory disease and lowered growth rates, has been diagnosed in a majority of Tasmanian lamb lines at slaughter and can result in significant carcase trimming and condemnation.
Pregnancy toxaemia (twin lamb disease)
Multiple-bearing ewes are most susceptible to pregnancy toxaemia
Pregnancy toxaemia is common in multiple-bearing ewes in the last six weeks of pregnancy. The ewe is depressed, may seem to be blind, does not respond well to calcium injections.
Treatment: Once the ewe shows symptoms, treatment is not usually effective.
Prevention: Scan ewes and then feed ewes bearing multiples well in the last seven weeks of pregnancy.
More on pregnancy and toxaemia in breeding ewes (NSW government)
Treatment: Once the ewe shows symptoms, treatment is not usually effective.
Prevention: Scan ewes and then feed ewes bearing multiples well in the last seven weeks of pregnancy.
More on pregnancy and toxaemia in breeding ewes (NSW government)
Vaginal prolapse
Vagina protrudes in late pregnancy
Vaginal prolapse is seen in late pregnancy, more commonly in ewes bearing multiples.
Treatment: There are plastic devices that can be inserted and also straps or harness that can be used once the prolapse has been replaced. A vet can place stitches to prevent recurrence.
Prevention: Remove tails at third joint (tip of vulva) when marking ewe lambs, keep pregnant ewes (especially twin-bearing ewes) on flatter ground in last few weeks of pregnancy, keep BCS 3 to 3.3. Don’t feed salt or swedes in last 1/3 of pregnancy. Offer hay if on low dry matter feed. Shear in last third of pregnancy. Maintain steady body weight from start of mating to scanning. Cull ewes that prolapse.
Guide on replacing vaginal prolapse in ewes (Farmers Weekly)
Treatment: There are plastic devices that can be inserted and also straps or harness that can be used once the prolapse has been replaced. A vet can place stitches to prevent recurrence.
Prevention: Remove tails at third joint (tip of vulva) when marking ewe lambs, keep pregnant ewes (especially twin-bearing ewes) on flatter ground in last few weeks of pregnancy, keep BCS 3 to 3.3. Don’t feed salt or swedes in last 1/3 of pregnancy. Offer hay if on low dry matter feed. Shear in last third of pregnancy. Maintain steady body weight from start of mating to scanning. Cull ewes that prolapse.
Guide on replacing vaginal prolapse in ewes (Farmers Weekly)
Pink eye
Inflamed eye
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Pus inside the eye
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Pink eye can occur any time of the year and can cause blindness.
Treatment: If only a few sheep are affected and are on good feed and water, leave alone to self-heal as mustering can increase spread within mob. If you do treat, it is best to use antibiotic injections – see your vet. Eye ointments/sprays are less effective.
Treatment: If only a few sheep are affected and are on good feed and water, leave alone to self-heal as mustering can increase spread within mob. If you do treat, it is best to use antibiotic injections – see your vet. Eye ointments/sprays are less effective.
Nephritis
Swollen kidney with white patches
Nephritis means inflamed kidneys. This condition has appeared in abattoir reports over the last couple of years, with detection mainly from June to December. Up to 7% of lambs and 11% of adult sheep are affected in some months. More investigation needs to be done, but the condition may slow growth rates and delay finishing. There are some indications that bacteria released into the blood stream from infection elsewhere (e.g. pneumonia, through marking wounds) could be the problem.
Redgut
Redgut: Intestines full and brick red and on the left side where the rumen should be
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Redgut is a major concern for producers finishing lambs on irrigated lucerne and clover. Lambs die very quickly and are usually found dead and bloated, so treatment is not usually possible.
Prevention: Most of the recommended interventions only appear to reduce the incidence. Only three days on, two days off seems to eliminate the problem but usually slows growth rates as well.
Fact sheet on Redgut (Livestock Logic, PDF)
Prevention: Most of the recommended interventions only appear to reduce the incidence. Only three days on, two days off seems to eliminate the problem but usually slows growth rates as well.
Fact sheet on Redgut (Livestock Logic, PDF)
Ryegrass staggers
Sheep with ryegrass staggers drowned in dam. Photo: Biomin
Ryegrass staggers is common from January to late autumn in some years, usually in young sheep but older sheep and young cattle can also be affected. Ryegrass endophyte toxins cause hyperthermia (high body temperature) as well as nervous symptoms, and sheep seek water and often drown. Ewes may be less fertile due to hyperthermia during mating.
Treatment: Drift affected stock off onto non-toxic paddock, nurse any that are down. Recovery can take 4–6 weeks.
Prevention: Keep young sheep off known toxic paddocks from December till first decent autumn rains. In longer term consider low endophyte ryegrass or alternative pasture species.
Perennial ryegrass toxicosis fact sheet (MLA, PDF)
Treatment: Drift affected stock off onto non-toxic paddock, nurse any that are down. Recovery can take 4–6 weeks.
Prevention: Keep young sheep off known toxic paddocks from December till first decent autumn rains. In longer term consider low endophyte ryegrass or alternative pasture species.
Perennial ryegrass toxicosis fact sheet (MLA, PDF)
Sarco, bladder worm and sheep measles
Sarco 'rice grain' lesions in muscle
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Sheep measles
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Bladder worm on liver
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These conditions are not obvious while the sheep is alive but are quite common in abattoir reports, cause a lot of carcase trimming and condemnation of organs such as livers and hearts. Sometimes significant numbers of whole carcasses are condemned as well.
Prevention fact sheets (Sheep Connect Tas, PDFs):
Sarco
Sheep measles
Bladder worm
Prevention fact sheets (Sheep Connect Tas, PDFs):
Sarco
Sheep measles
Bladder worm
Arthritis
Arthritis of hip joint in young lamb
Infectious arthritis causes lameness and swollen joints in lambs. It can be due to Erysipelas or a number of other bacteria that enter through wounds or other infections such as pneumonia.
Treatment: Your veterinarian can supply appropriate antibiotics.
Prevention: If Erysipelas has been diagnosed as the main problem, then the ewes can be vaccinated. Otherwise making sure lambs get a good drink of colostrum within a few hours of birth and removing tails at the third joint at marking will help reduce the problem.
Arthritis fact sheet (NSW government, PDF)
Treatment: Your veterinarian can supply appropriate antibiotics.
Prevention: If Erysipelas has been diagnosed as the main problem, then the ewes can be vaccinated. Otherwise making sure lambs get a good drink of colostrum within a few hours of birth and removing tails at the third joint at marking will help reduce the problem.
Arthritis fact sheet (NSW government, PDF)
