Sheep

Sheep

Sheep Abortion/Stillbirth

It is normal to have a small number of abortions in any flock but when numbers go over 2% it will start cutting into profits so it is time to take action!

In order to develop the most appropriate course of action and prevent abortion storms in subsequent years, the specific cause must be identified. Diagnosis is based on clinical signs and flock history, combined with laboratory tests. Samples from both the foetus and placenta will be needed and often a blood sample from the ewe.

Controlling an abortion outbreak requires strict sanitation and separation of aborting ewes. Infected foetuses, placental tissues, and bedding must be properly disposed of (burned or buried). All aborting ewes or those with vaginal discharges should be immediately isolated from the main flock. Aborted ewes should not be used as foster mothers for female offspring, unless infectious causes of abortion can be eliminated. Pregnant ewes should never be fed on the ground. Breeding stock from flocks that have experienced abortion storms should not be purchased.

It is important to remember that some causes of abortion can also infect humans. Gloves and protective clothing must be worn when assisting lambing or looking after weak lambs. Pregnant women are particularly susceptible.

There are many potential causes of abortion in ewes but the commonest infectious causes are Toxoplasmosis, Enzootic Abortion of Ewes(EAE) and Campylobacter.

EAE causes stillbirths, weak lambs and abortions in the last 2-3 weeks of pregnancy. It is spread by carrier sheep and abortion products. Ewes can be vaccinated in the autumn at least one month before tupping.

Toxoplasmosis can cause losses at any stage of pregnancy and once infected ewes develop immunity so won't abort in subsequent years, but can infect naive sheep. Abortion, stillbirth, weak lambs and mummified foetuses result. Toxoplasmosis can be spread by cats so preventing contamination of feed by cat faeces may help. Ewes can be vaccinated at least one month prior to tupping.

Campylobacter is another common cause of abortion and is highly infectious from ewe to ewe. It can also be introduced into a flock from carrion eating birds such as crows. Unfortunately, there is no vaccine available but carry-over from one year to the next is minimal.

In summary:

  • Contact us to investigate if losses go over 2%
  • Foetal & placental samples will be required
  • Be aware of the potential risk to humans
  • Isolate aborting ewes immediately
  • Destroy aborted material and contaminated bedding
  • Consider vaccinating all replacements for EAE and toxoplasmosis
  • Protect feed from cats and vermin
  • Maintain a closed flock as much as possible
  • Purchase flock replacements as maiden sheep because older, pregnant ewes are high risk

Please contact us for further information or advice.

Worming

Worm control is a vital part of health and production management in sheep flocks. The presence of anthelmintic resistance (AR) has risen sharply in recent years and some UK flocks are already having problems with "triple" resistance.
AR is now considered a major threat to the future of sheep production and welfare.

Although you may still be achieving good levels of worm control, please read our guidelines below to see if there is anything else you can do to protect your flock.
Some of the previously recommended control strategies were found to increase susceptibility to the development of AR.

The risks of developing Anthelmintic Resistance in your flock can be reduced by:

  1. Quarantine drenching
    • Use Zolvix or a combination of a yellow drench (levamisole) and moxidectin
    • Keep off pasture for 48 hours after treatment
    • Turnout to dirty pasture
  2. Testing for AR
  3. Dose correctly for body weight
  4. Withhold food for 24 hrs before dosing but never in late gestation
  5. Use wormers only when necessary
    • Ewes
      • tupping - treat only thin, young or clinically affected ewes
      • turnout - leave a proportion untreated or treat early in post lactation period
    • lambs
      • nematodiris
        • consider the risk using the NADIS parasite forecast and local factors
        • use a white (benzimidazoles) or yellow drench
      • use faecal egg counts (FEC) to predict the need to treat for other worms
  6. Delay movement after treatment
  7. Leave some animals untreated
  8. Reduce dependency on wormers by
    • Grazing management
    • Using FEC monitoring to optimise the timing of anthelmintic use
    • Use rams that are bred for resistance to worms
    • Consider incorporating forages with anthelminthic properties eg. Chicory

For further information or advice on parasite control for your flock please speak to one of our vets. More information can also be found on the SCOPS website.

For parasite forecasts click here http://www.nadis.org.uk/parasite-forecast.aspx.

Blowfly Strike

Blowfly strike is a major welfare concern and an important cause of ill thrift and death in affected animals. It can occur at anytime of year, but there is particular risk from April to October depending on the weather.

Preventative measures include:

  • avoiding grazing on damp well-sheltered pastures during risk periods
  • shearing and crutching as required
  • preventing scour by monitoring faecal egg counts (FEC)
  • taking steps to avoid footrot and treating cases promptly as it attracts flies
  • avoiding ear tagging lambs during high risk periods to reduce open wounds
  • remove dead animals promptly
  • inspect at risk sheep daily
  • time preventative chemical treatments carefully

Treatment

  • Affected animals must be treated immediately.
  • Apply a pyrethroid pour-on or correctly diluted dip solution to kill the maggots. Please follow the products directions so as not to cause toxicity.
  • Antibiotics and pain killers are indicated where there are open wounds.
  • Severely affected animals should be euthanased.

Fluke

Liver fluke is a flat worm that lives in the liver and bile ducts once it reaches adulthood. The eggs are passed out in dung and infect snails. The larvae develop and migrate to blades of grass where they are ingested by grazing animals. The larvae and its snail host rely on a warm, moist environment to survive.

Sheep of all ages can be affected with the most acute forms of infection being seen in autumn.

As well as reducing performance, infections left unchecked can result in liver damage and death.

Signs of infection may not initially be noticeable but include:

  • Drop in growth rate.
  • Drop in fertility.
  • Pale gums.
  • Bottle jaw.

Diagnosis

  • Faecal egg counts are used to diagnose and give an idea of the scale of the problem.
  • In early acute stages fluke may not have reached adulthood so no eggs will be seen.
  • Post-mortem testing and abattoir returns can be very helpful.

Control

Reduce the access of stock to snail habitats by improving drainage and fencing.

All mammals can be infected by fluke so sheep pose a risk to cattle and vice versa.

All purchased animals should be treated during quarantine. Use an effective flukicide and dose for the correct weights. Not all products are effective against all stages of fluke, so ensure you choose your product carefully.

Sheep treatment

In high risk areas:

  • Use forecasts from NADIS to monitor level of risk.
  • Treat with a product effective against immature fluke in September.
  • If badly affected, treat again 6 weeks later.
  • Treat against adults in spring.

In less affected areas:

  • Check if there is a problem by faecal egg counts, post-mortem testing or abattoir returns.
  • If fluke are present dose against immature fluke in October, pre-tupping or two weeks post-housing.
  • Treat against adults in Spring.

For more information speak to one of our vets and we can help you put together a control strategy.