Disease Management

The VetEnt team is your ally in controlling, treating and containing outbreaks, as well as proactively working minimising potential outbreaks through vaccinations, effective prevention programmes and education.

On the left, we've compiled some useful information on a range of common diseases affecting sheep and beef livestock including symptoms, prevention and treatment.

Plus you can learn more about mastering disease management through the StockCare's farm advisor programme, or subscribe to our Sheep, Beef & Deer enewsletter with tips on seasonal disease management.

You can subscribe to the newsletter below right.  Feel free to give us a call to discuss any issues you're facing on-farm now or proactive measures you can take for prevention.

You may also be interested in: 

Clostridial disease (cattle)
Clostridial disease (sheep)
TB Testing
Barbers Pole
VetEnt's Sheep/Beef/Deer Services

Ryegrass staggers
Flystrike
Cattle Vaccination
Pink eye (cattle)
Pink eye (sheep)

Dehorning
Worms (cattle)
Worms (sheep)
Diagnose sheep beef diseases

 
   
 

Lice in Sheep

“Lice DO NOT fly, jump or circle the sheep’s body every 24 hours”

Symptoms of the Disease/Condition

Lice are external parasites that can live on most animals. They are very host specific so can only breed on their own hosts.

  • Sheep lice breed only on sheep and complete their entire life cycle on the animal. They usually spread by direct contact between sheep.
  • Lice-infested sheep will bite at themselves and rub against anything that is available. This damages the fleece by matting the fibres and tearing the tip of the staple.
  • Up to 90 per cent of lice are removed with the fleece at shearing. Shearing is by far the most effective time to achieve control through chemical application.
  • The economic effects of lice will depend on the severity of infestation, the class of sheep affected and the proportion of each mob affected.

There are two species of lice that affect NZ sheep:

1. Body or biting lice (Bovicola ovis): Most common. They are surface feeders feeding on skin debris - they don't suck blood.
2. Sucking lice (Linognathus pedalis & Linognathus ovillus): Uncommon. Suck blood. Live on the legs (pedalis) and face (ovillus).

Lice generally do not live for more than four or five days, in ideal conditions, once separated from sheep. If lice are unprotected and exposed to sunlight they are unlikely to survive for more than a couple of hours (eg on wool in trucks, yards, catching pens, fences or in the paddock). Lice can be transmitted on shearers' moccasins (surviving for up to 10 days), but microwaving boots for five minutes in a plastic bag kills these lice.

Sheep lice can transfer to goats and survive the remainder of their normal life span on the goat. Sheep and goats need to be running very closely together (eg yarded or shedded) for this to occur. Sheep lice will not breed on goats and are very unlikely to be the cause of re-infestation. Sheep lice will not transfer to other animals.

Lice do not move far from the site of hatching. Most movement is up and down the wool fibre and is governed by temperature and light. In hot, bright conditions lice stay close to the skin surface. In moderate (cool to warm) and shaded conditions, they move towards the tip of the fibre.

This is important, as lice are most likely to spread when near the tip of the fibre. Conditions that favour transfer will therefore occur between late afternoon and early morning (ie at sheep camps, while watering), on cloudy days and during the cooler months of the year.

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vet lice
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Cost/Impact on Herd/Farm Revenue

The main cost is lower value of wool because of fleece damage as result of rubbing and scratching by louse infested sheep.

  • A ewe shearing 6kg greasy wool with 75% yield (4.5kg clean) at wool worth $4.00 per kg clean income is $18.00.
  • A ewe with a medium lice burden shears 5.7kg greasy wool with 73% yield (4.16kg clean) at wool worth $3.80 income is $15.80.
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Management and control

Effective lice control is dependant on an appropriate mix of animal management and chemical usage. The degree to which chemicals are needed will vary with the level of control that can be achieved.

Every effort must be made to reduce the over-reliance on chemical control methods and reduce chemical residues on wool. This is particularly important in relation to chemicals applied later than six weeks after shearing.

Contact your nearest VetEnt clinic to learn more about how to manage lice in your flock.

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Liver Fluke (Fascioliasis)

Symptoms of the Disease/Condition

Liver fluke can infect sheep, cattle, horses, pigs, goats, alpacas and deer and a range of wild animals including wallabies and rabbits. Humans can also be infected by eating water cress from creeks in fluke-infested country.
Adult flukes live in the liver and bile ducts and can cause severe production losses and death in stock. Liver fluke has a complex life cycle with specific water snails as an intermediate host. Hence, liver fluke is more common on farms where there is lots of slow moving water for the snails and a climate that suits the development requirements for both the snails and the liver flukes.
Liver fluke infections tend to be more common on the east and west coasts of the North Island and the west coast of the South Island.

Life Cycle.
Grazing animals ingest the metacercariae, which release immature flukes in the small intestine. The young flukes penetrate the intestinal wall, make their way to the liver, and then migrate through the liver tissue for 6–7 weeks before entering the bile ducts to become adults. Egg production starts 8–10 weeks after infection. Adult fluke can live for several years and produce over 20,000 eggs per day.

In sheep and cattle, the "acute" disease may not be obvious and animals may show abdominal pain or become jaundiced followed by sudden weakness and death. This is uncommon in NZ but must be considered as a cause of acute deaths when very hungry stock have access to snail/fluke infected wet environments. The sudden and massive ingestion of metacercariae leads to an invasion of the liver by the immature flukes which effectively “chew the liver to bits”.

The "chronic" form is more common, in which case sheep and cattle lose condition, have poor milk production, show chronic diarrhoea, develop a soft fluid swelling under the jaw ("bottle jaw"), become weak and may die. Closer examination will reveal pale eye linings and gums caused by the loss of blood. In NZ the chronic form probably has the greatest potential impact.

Diagnosis is best confirmed by autopsy. There is a blood and faecal test available and surveillance from the slaughter premises can provide evidence of the extent of liver fluke infection in animals from the property.

 

liver fluke cattle bottle jaw liver fluke acute Replacement Pic
liver fluke adult
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Cost/Impact on Herd/Farm Revenue

Damage may initially be caused by the immature stages of the fluke migrating through the animal's liver ("acute" liver fluke disease). These immature stages develop into adults which cause significant blood loss and liver damage in heavy infestations ("chronic" liver fluke disease). The liver lesions seen in sheep generally apply to cattle but the reactive fibrosis (scarring) is more marked and affected bile ducts show marked calcification.

Relatively small numbers of flukes can have a significant impact on wool production and pre-weaning lamb growth rates.
The effects of liver fluke infection on the productivity of adult cattle and the benefits from treatment are uncertain. Studies to determine the significance of subclinical infections in grazing cattle are inconclusive. Young cattle are more susceptible to liver fluke infection than older cattle.
It appears that nutrition levels, environmental conditions, age of the cattle, and level of infection play critical roles in determining the significance of infection. Cattle previously exposed to infection develop a substantial level of resistance to reinfection.
Liver fluke infection can make the animals more susceptible to the Clostridial disease called “Black disease”.

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Management and Control

There is a range of liver fluke drenches that are effective against liver fluke in cattle but they vary according to the age of the flukes.
Prevention has to rely on restricting access to high risk areas of the farm. Attempts to eradicate the disease have generally been unsuccessful because both snails and liver fluke need to be eradicated at the same time. All potential liver fluke hosts need to be considered – sheep , cattle, deer, goats, horses and rabbits to name a few!

Contact your nearest VetEnt clinic to learn more about how to manage liver fluke on your property.

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About VetEnt Group

Enjoy local service backed by nationwide support from NZ's largest vet group with over 75 vets nationwide, giving you more depth of expertise from shared knowledge and technical expertise.
 

Meet your local vet

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Name:
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I highly recommend VetEnt. They have been there with me for the past 5 years as my business has grown.  They are both proactive and leaders in their field. They are reliable and always go beyond the call of duty with their service

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For urgent appointments within the next 24 hours, please phone the clinic directly.

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Lice in Cattle

“Lice DO NOT fly, jump or circle the cattle’s body every 24 hours”

Symptoms of the Disease/Condition

Lice are external parasites that can live on most animals. They are very host specific so can only breed on their own hosts.

There are four species of lice that affect NZ cattle:

1. Body or biting lice (Bovicola bovis): Most common. More prevalent on beef cattle than dairy cattle. They are surface feeders feeding on skin debris - they don't suck blood.
2. Sucking lice (3 species- Linognathus vituli is the most common)): More prevalent on beef cattle than dairy cattle. Suck tissue fluids and blood. 

Lice generally do not live for more than four or five days off the host and are spread mainly by direct contact between cattle.

Cattle lice populations are highest in winter and lowest in summer.

Survival of lice is reduced by warm weather, cattle self grooming, loss of hair coat and good nutrition of the host. Cattle in poor condition tend to have heavier louse infestations.

Lice tend to prefer the white areas of black-and-white cattle.

Louse numbers are usually higher on younger cattle than on adult cattle.

 

vet cattle lice vet lice cattle Replacement Pic
lice vet cattle
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Cost/Impact on Herd/Farm Revenue

Infested cattle show signs of irritation and rubbing which may cause hair loss from large areas of the body.Cattle with hair loss may be discounted at the sale yards.

The hide is commonly damaged due to hypersensitivity reactions to the parasites.

The effect of lice on production and growth rate is debatable.

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Management and control

There is a wide range of Pour On treatments for lice control in cattle. Some endectocide treatments for internal parasites in cattle have activity against active adult feeding lice.

Contact your nearest VetEnt clinic to learn more about how to manage lice in your herd.

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About VetEnt Group

Enjoy local service backed by nationwide support from NZ's largest vet group with over 75 vets nationwide, giving you more depth of expertise from shared knowledge and technical expertise.
 

Meet your local vet

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Match
Name:
Clinic:
Speciality:
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I highly recommend VetEnt. They have been there with me for the past 5 years as my business has grown.  They are both proactive and leaders in their field. They are reliable and always go beyond the call of duty with their service

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Pink Eye in Cattle

IBK-Infectious Bovine Keratoconjunctivitis

Pink eye is a painful and highly infectious eye disease of cattle which if not treated adequately can result in large numbers of animals affected and temporary or permanent blindness.

Causes

The primary cause of pinkeye is bacteria known as Moraxella bovis, but other bacteria and viruses are often involved. The high risk period is late spring and summer. Pink eye occurs predominantly in young cattle, but cattle of any age can be affected.

 

Risk factors

Risk factors for pinkeye include wind, dust, flies, stalky vegetation and high stocking rate. Damage to the surface of the eye (scratching from grass seed heads) and ultraviolet radiation can predispose the eye to infection. The bacteria can be present on flies and grass seed heads. Forcing cattle to graze low in stalky feed is a high risk for pinkeye.

 

Clinical signs

The first signs of pinkeye are weepy eyes. A central ulcer soon develops followed by cloudiness in the eye. If left untreated, this ulcer enlarges and pus forms in the eye leading to increased pressure and eventual rupture of the eye in extreme cases. Pink eye can cause prolonged and serious pain.

 

vet pinkeye vet pink eye Replacement Pic
vet pinkeye
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The Impact

Pink eye is an animal welfare issue causing prolonged and serious pain.

Consequences of pinkeye include:

  • depressed growth rates
  • loss or culling because of eye rupture and permanent blindness
  • disruption to seasonal grazing management
  • veterinary and labour costs to treat infected animals
  • lowered sale value of animals with eye lesions (weaner cattle)
  • Prolonged infection in an infected mob for 3-5 weeks.

The disease may exist for 3-5 weeks in some individuals, with a peak in a mob of about 3-4 weeks.

Despite this many farmers believe Pinkeye is not a significant problem and many choose to not treat or prevent the disease and let the disease take its course.

Diagnosis is made by clinical signs and in some cases swabs obtained from infected eyes. A veterinarian examination is required to confirm pinkeye.

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Management and control

Quick action is required to prevent the spread of pinkeye. Affected animals should be immediately removed from the mob for treatment. Infected animals must remain separated.

Antibiotic treatments are commonly used to treat pinkeye. These will be prescribed by your vet who will also show you how to treat animals, and decide if the whole mob should be treated.

Surgery to either protect they eye with the third eyelid, or close the eye completely is possible.

 

Prevention

A vaccine is available which is most effective if given 2-3 weeks prior to the expected pink eye season. It is less effective if given once the pinkeye has started. Grazing management, stocking rate, and animal wellness are all very important aspects of pinkeye prevention.

 

 

Contact your nearest VetEnt clinic to learn more about risk management of Pinkeye in your herd.

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About VetEnt Group

Enjoy local service backed by nationwide support from NZ's largest vet group with over 75 vets nationwide, giving you more depth of expertise from shared knowledge and technical expertise.
 

Meet your local vet

Meet the team

Match
Name:
Clinic:
Speciality:
Search For
Name

 

I highly recommend VetEnt. They have been there with me for the past 5 years as my business has grown.  They are both proactive and leaders in their field. They are reliable and always go beyond the call of duty with their service

Make an Appointment

For urgent appointments within the next 24 hours, please phone the clinic directly.

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Pink eye is a painful and highly infectious eye disease of cattle which if not treated adequately can result in large numbers of animals affected and temporary or permanent blindness.