Farm Newsletter - February 2017

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Kerrie Moore
5 years ago
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1 Farm Newsletter - February 2017

Lung Worm in Cattle The disease is caused by the worm Dictyocaulus viviparus. Adult worms live in the animal s lungs where they produce eggs which hatch quickly.

These then mature on the pasture to stage three larvae, once eaten by an animal the larvae migrate through the gut wall towards the lungs.

2 Lung Worm in Cattle The disease is caused by the worm Dictyocaulus viviparus. Adult worms live in the animal s lungs where they produce eggs which hatch quickly. The first stage larvae then move up the windpipe are then swallowed and passed out in the faeces. These then mature on the pasture to stage three larvae, once eaten by an animal the larvae migrate through the gut wall towards the lungs. Over the next few weeks the larvae reach the lungs and mature into egg laying adults. An adult worm can produce several thousand eggs. All cattle are at risk of lungworm until they have been exposed to the larvae/ worms and developed immunity. It is essential that cattle keep this immunity but it can be lost if animals do not receive a degree of regular exposure. Causes of infection There are two main situations that can lead to an outbreak. 1. High levels of exposure caused by: The introduction of infection into a naïve herd (never been exposed to Dictyocaulus) Naïve animals entering an infected herd Inadequate anthelmintic control when at pasture Significantly increasing the number of cattle Warm, wet weather 2. An inadequate immune response caused by: Failure to vaccinate Prolonged dry weather leading to reduced larval dispersion Excessive anthelmintic usage Clinical signs An increased rate and depth of respiration, with a dry cough, in any age group of cattle while at grass should raise suspicions of infection. In some cases with adult animals, the symptoms may only be a drop in milk yield, weight loss and occasional coughing. Diagnosis Diagnosis requires veterinary clinical examination and usually laboratory testing of faeces or of blood samples. Accurate and fast diagnosis is important in order to provide effective treatment of affected animals and to avoid the unnecessary use of expensive anthelmintics. Treatment Lungworm can be treated with wormers (anthelmintics). Ensure they are effective against D. Vivaparus (your vet can help you to chose an appropriate product). Sick animals may also benefit from antibiotics and anti-inflammatories. All animals in the group should be assumed to be infected if one or two animals show clinical signs therefore treat the entire group.

Husk is a much less predictable disease than that caused by gut worms and requires a different approach to control. Husk will not be controlled by a dose and move strategy.

3 What is the prognosis? Prognosis is very much dependent on the level of infection and the amount of damage that has occurred. Some animals can die or have to be culled after a heavy, chronic lungworm infection. Secondary lung infection is also a common sequel to lungworm infection. Prevention. Husk is a much less predictable disease than that caused by gut worms and requires a different approach to control. Husk will not be controlled by a dose and move strategy. There are two strategies for controlling lungworm: 1) Vaccination - by far the most effective way to control husk 2) Suppression with regular worming Lungworm prevention is based upon development of immunity and is best achieved by vaccination. Periods of natural exposure to lungworm (and other parasites) during the grazing season to allow for immunity to develop, then infection controlled by applying strategic anthelmintic treatments, is a very risky strategy for lungworm prevention but would control PGE ( gut worms) in most situations. Therefore, PGE is often a secondary consideration to the more important lungworm disease. Vaccination is the best course of action to prevent lungworm infection. Vaccination uses irradiated live lungworm larvae to cause a controlled infection. A course of the vaccine is given to young stock with the second dose being given at least 2 weeks before turnout vaccinated and unvaccinated stock should not be mixed for at least 2 weeks after the second dose has been given. It is preferable for calves to be exposed to low levels of lungworm larvae throughout the grazing season to maintain this immunity. Footbathing Cattle Erythrocin powder is currently unavailable and will be for the foreseeable future. With increasing pressures from the government and industry to reduce antibiotic usage on farm it is perhaps a good opportunity to review foot bathing regimes on farm. Current research be Nick Bell from the Royal Veterinary College, London has shown that regular foot bathing with a disinfectant alone is sufficient to control Digital dermatitis provided they are used properly. The disinfectant agent appears to be unimportant but what is important is the frequency of use and replacement of solution to ensure the bath does not become over contaminated. Whole herd antibiotic usage should be reserved for extreme cases where a large percentage of the herd have active lesions requiring antibiotic treatment. Their research also suggests that individual treatment of cows with active lesions with a topical treatment is more effective at ensuring a cure than blanket treatment with an antibiotic foot bath. For more information or advice on treating digital dermatitis in your herd or advice on foot bathing please speak to a member of the farm team.

4 Sheep News It s Scanning Time! This is the time of year when sheep scanners are very busy. Scanning information is a valuable source of data for your farm enterprise helping us with the management and feeding of pregnant ewes, identifying barren ewes and potential infectious disease within the flock, and providing information about how your ewes have performed over the last 12 months. I am very happy to assess your scanning data and discuss its implications with you, whether its good or disappointing this year. Wherever possible the data should be separated to give a separate result for ewe lambs, 2 tooths and adult ewes. As well as the barren rate and overall scanning percentage, the breakdown of singles, twins and triplets also provides valuable information. The target barren rate for a lowland sheep flock would be less than 2%, and a barren rate of greater than 4% would warrant veterinary investigation. MSD are again running their BarrenEwe Check scheme, which provides subsidised blood samples to be taken from 6-8 barren ewes, that have not previously been vaccinated using Toxovax, to be checked for the presence of Toxoplasma. Toxoplasma can cause both high barren rates and abortions in ewes. Please also remember that there have been confirmed cases of Schmallenberg in the UK this year, disease is reliant on infected midges biting your sheep during pregnancy. Dependant upon the time that midge exposure occurs high barren rates, deformed lambs or abortions may occur. There are other factors that can affect your barren rate and scanning percentage. Often this investigation is retrospective, but can give us pointers as to where to concentrate attention next year. Nutrition plays a vital role in ovulation rates, both retrospectively and in the run up to tupping. Ewes that are in poor body condition after lambing, or at tupping time, have lower conception rates than fit ewes. The ewe s ovaries start to prepare for the next breeding season, 5-6 months before tupping occurs ie May time. If a ewe is in poor body condition at this time, she will not ovulate as well at the next breeding season. Parasites such as haemonchus and liver fluke drain protein from the body leading to poor body condition and nutritional stress, again decreasing fertility. Similarly, lame ewes are stressed, eat less than their healthy counterparts and lose weight if the lameness does not resolve quickly, again leading to decreased ovulation rates. Trace element deficiencies can also exacerbate poor fertility. Finally, ram power and ram fertility also needs to be checked as a potential cause of poor fertility. What to Do If Your sheep start aborting A low level of abortion in the run up to lambing is quite common. The target is for less than 2% of your flock to abort. Should levels rise above this, or if 3 or more ewes abort in any one day, then veterinary investigation is warranted. There are several infectious causes of abortion in sheep, so identification of the cause is key for possible treatment and prevention in future years. If you are suffering from an outbreak of abortion, please con-

5 tact the surgery for advice. WHAT TO DO IN THE FACE OF AN ABORTION OUTBREAK Assume the cause is infectious until proven otherwise Arm length protective disposable gloves should be worn to assist all lambings Isolate ewes which abort, remove bedding and disinfect the area in which they lambed Keep ewes isolated from all other breeding sheep until all vaginal discharges have stopped (minimum 1 month) Do not foster female lambs (potential breeding replacements) onto ewes that have aborted Contact the surgery to discuss investigations Checking on ewe nutrition prior to lambing Nutrition of the pregnant ewe can have a major impact on ewe and lamb health, and thus the future productivity of the flock for the coming year. With 75% of lamb growth occurring in the last 6 weeks of pregnancy, getting it right at this stage is critical. Nutritional problems late in pregnancy can result in twin lamb disease, reduced lamb birth weight, oversized lambs, lack of colostrum quality and/or quantity and high levels of perinatal mortality. Blood sampling sheep in late pregnancy can give you an indicator as to how the ewes are performing on this years diet. The best time to carry this out is 3 weeks before lambing. At least 5 ewes should be sampled in each management group: triplets, twins and gimmers/ewe lambs. Singles can also be sampled, this is especially important if you are planning to twin spare lambs onto them, to check protein status which is an indicator of potential milk supply. If the sheep have not been scanned or fed according to fetal number sampling 20 random sheep is recommended. Ewes with known disease problems should not be sampled as they will not be representative of the whole group. When feeding sheep in late pregnancy you only have one chance to get things right and it is crucial to make sure that nutritional management is working as planned as lambing approaches. Blood sampling for metabolic profiles is an effective way of checking your ewes diet, as well as providing us with an opportunity to check trough space allocation, body condition of the ewes, forage analysis and overall diet plan. It will also allow us to continue to dispense medicines through out the coming year as all flocks must have an annual visit to allow us to prescribe medicines to you. Please speak to one of our vets for more information about this service, SHEEP MEETING DATE I am planning to hold a sheep meeting on Thursday 23 rd February. During this meeting I plan to introduce you to our new flock club, as well as discussing the information that can be gained from looking at your scanning data. We will also discuss the importance of good year-round sheep nutrition and how to look after your replacements for ongoing productivity.

Farm Newsletter - February

Farm Newsletter - February 1 2016 Calf Nutrition - Part 2; 2nd March 2016, The Surgery- Southley Road, South Molton 7:30pm Thank you to everyone that joined us for the first in our series of calf rearing