Abortions

In the past some farmers have accepted that there will be a number of ewes that lose their lambs each year and have put up with the losses as something that you have to live with. This is not the case and it is far better to have the first two or three abortions investigated so that you know what is going on. Some of the infections cause lambs to be born alive before their time and are responsible for lamb losses in the first few days of life.

Enzootic Abortion is the most common. It is caused by bacterium called Chlamydophila abortus  (previously known as Chlamydia psittici) picked up from carrier sheep. The dead lambs produced by this infection are not usually decomposed, but the placenta is thickened. The infection damages the placenta of the ewe and starves the lambs of their nutrients; twins are more likely to be lost than singles. The disease does not start to affect the placenta until ninety days into the pregnancy. Studies show that an imbalance occurs in the hormones associated with pregnancy when a ewe is affected by this infection and it is thought this is what is responsible for the loss of the lambs.

If you can get an early diagnosis from an aborted foetus and placenta long acting oxytetracycline does help to buy some time and produce viable lambs. Some of these may be difficult to rear. For best results the injection should be given at day 95 and day 120 of the pregnancy. It is not always easy to time these treatments exactly.

Enzootic abortion is a complicated disease. Sheep pick up the infection from the fluids and discharges at the time of lambing. They hold onto this infection and it is not until the following year that the pregnancy is lost. Infected ewes usually only abort once with enzootic abortion, but they will carry the infection for the rest of their lives and pass the infection onto younger ewes every time they lamb. Using antibiotics may help to save lambs, but it does little to stop the spread of infection in the lambing pens.

The way to stop Enzootic Abortion is to vaccinate the whole flock at least one month before they go to the ram. You will need to have some patience with this disease as there will still be some ewes that loose their lambs in the following year. In subsequent years you should see the full benefits of your control measures. Ewes only need to have the Enzovax vaccine once and it is important to inject replacement ewes every year.

Toxoplasma is a parasite carried by cats that will cause the cotyledons to become thickened with small white spots on the surface. Depending on the stage of pregnancy that the ewe was first affected typically one twin will be born two or three days early along with a mummified foetus. Cats are involved with the life cycle of this parasite, they have a tendency to contaminate feed stores and hay with their faeces or the ewes may get the infection directly from the fields that they graze.

Ewes can pick up the infection at any time of the year and it has been shown that they need only the smallest amount of infection to cause pregnancy loss. Controlling this disease is not as simple as getting rid of your farm cats. This does not work as others will soon take their place. It is known that younger cats shed more of the oocysts that are responsible for the infection. The better way is to keep a healthy population of farm cats by having them neutered they should then help to keep younger ones away. 

Toxoplasma can cause significant losses on some farms and is often responsible for ewes failing to become pregnant. The vaccine works well, but you have to be a little careful how you handle it as it is a live vaccine that is given in the summer before the flock goes to the ram. 

Salmonella infections can sometimes cause ewes to abort. Ewes can be affected at any stage of pregnancy and will often be very ill with the infection. The source of the infection is either from contaminated feed or other livestock. Wild birds can sometimes carry salmonella, but it is difficult to keep them out of farm buildings.

Listeria will also cause a significant number of abortions when contaminated silage is fed. This is a soil organism that multiplies when the silage heats up. Take care not to set the cutters too low or make silage from fields where there are molehills. Listeria will also cause meningitis when it is fed to sheep.

You should suspect this disease if you have any ewes that seem to be blind and press their heads into dark corners. Ewes with meningitis will respond to aggressive antibiotic treatment in the early stages of the disease. Ewes that abort with listeria show few signs that they are ill until they lose their lambs.

Foot Rot and Scald are the most common causes of lameness in sheep. It is impossible to avoid these all together, but they are easier to cope with if you have decent handling facilities. It is essential to have a footbath that you can stand the sheep in and a concrete yard where their feet can dry off before they go back onto the fields.

Scald is an inflammation of the skin between the claws. It occurs mainly in warm wet weather when the grass is long. The bacteria responsible Fusobacterium necrophorum is universally present in the soil and causes intense itching and severe lameness.

Foot rot is more serious, it often starts in the same way as Scald but another bacterium, Dichelobacter nodosus takes over invading the foot and causing the different layers of the hoof to separate and split. This bacterium cannot live in the soil for more than three weeks, it needs an infected foot to survive. Foot rot can spread in buildings during the winter housing period as long as the temperature is above ten degrees centigrade. We have had mild winters in recent years and it is quite common for these condition to occur throughout the winter.

Recently a more aggressive type of Foot Rot has been identified. This condition will often affect both claws and the whole horn may become detached. It is unclear as to the exact cause of this new problem, it is thought that the spirochete that is responsible for Dermatitis in cattle may be involved, certainly it responds to the same treatments. This New Virulent foot rot will cause a great deal of damage to the feet.

You should turn your sheep over regularly and trim away any excess dead horn, as this is where the infection lies. Take care not to over trim the toes, they should not bleed. Zinc sulphate is the best thing to use in a footbath. If possible the ewes should stand in it for fifteen minutes, then stand on concrete to allow their feet to dry. Divide the flock into groups and give the worst affected animals the most time in the footbath. If you have alot of lameness you will need to do this every week.

If they are very lame or more than one foot is affected an injection of either long acting oxytetracycline or penicillin and streptomycin will be required. When things are getting out of control try the antibiotic Lincospectin in the footbath, this does not have a product license of sheep, but it does a good job. There will be some animals that you cannot get right whatever you do and these should be culled, as they are a source of infection for the others.

You may need to use the footbath on a weekly basis. It is helpful if you can rest pastures for three weeks before ewes return to them, as this will reduce the amount of infection in the soil. Scald is made worse by the length of the grass and electric fences may help to keep the pasture short and reduce the number of cases.

Resistance to Wormers

Some farms are having problems because the commonly used wormers are not working as well as we would expect them to. A recent survey by the Moredun Research Institute has revealed that eight out of ten lowland sheep in Scotland carry worms that are resistant to the white worm drenches (Benzimidazole) It has long been realized that gut worms can also become resistant to Levamasole and Ivomectin as well. It is the worms that cause problems to ewes later in the summer that are the ones that become resistant. When you worm the flock and turn them onto a relatively clean pasture, it is only the resistant worms that survive and go onto contaminate the pasture. It is better if you can to rotate the three different types of wormer each year for use on the sheep in the summer. There is no real need to dose sheep that are doing well and are not scouring.

Worm any new arrivals, but do not turn them out onto clean pastures if you can. If they do carry any resistant worms after you have dosed them it is better that they are exposed to some treatable worms so that there will be competition in the gut of the animals with worms that you know will respond to treatments. To find out if your wormer is working collect samples from ten ewes two weeks after a worm treatment. We will pool them together and find out if they still have a significant number of worms present in their gut.

Problems with Copper

Copper is essential for the health and well being of ewes and lambs, the problem is it can be toxic if too much is included in the diet so care must be taken to maintain the right balance.

Toxicity problems are most common towards the end of the winter when the ewes are housed. Texels, Charolais and Blue Faced Leicesters are the breeds that we have had problems with but toxicity can occur in any breed. Ewes should not be fed on a diet containing more than 10 part per million of available copper. Affected animals are depressed become anemic and are noticeable jaundiced. By the time you realize that there is anything wrong the liver of the ewe will be severely damaged and there is no effective treatment. You should not normally need to worry about swayback in pedigree sheep that are having supplementary feed on a regular basis. The only safe way to find out if you need  to give extra copper is to have some blood samples taken during the second month of pregnancy. Never feed a ration intended for cattle or pigs to your ewes, they cannot cope with this.

Flock Health Plan

It is difficult to give concise information as to what you should be doing and when with your flock. Things will vary depending on whether you have a lowland or an upland flock and whether or not you are interested in lambing early. The way that you manage your ewes will also depend on your individual circumstances. With sheep there is always something that you should be doing to them throughout the year. It is easy to leave something out or do things at the wrong time. 

All flocks in the United Kingdom are now supposed to have a written health plan. You should be able to adapt your plan from the following which is based on a lowland flock that is trying for early lamb production. Try saving this guide on a disc, delete the parts that do not apply and add other things that you do and I have left out. Your Veterinary surgeon will be keen to see a printed version of your health plan and may suggest further things that you could do or leave out. Each year you might like to take a few minutes to edit your version and keep it up to date.

We will start when the lambs are weaned.

The udders of all of the ewes should be checked and one dry cow tube, Cepravin works best, should be used in the glands of each ewe that you intend to breed from next year. Chronic infections are not easy to detect and will flare up when the ewe has stopped producing milk.

In the early spring if the ewes are outside they should be wormed at least twice with a three week gap between doses.

The lambs should be wormed every three weeks and they should be on a creep feed containing a coccydiostat. An alternative is to drench them with Vecoxan from six weeks of age, repeating the dose three weeks later if they are tightly stocked or if the weather is wet.

When the youngest lambs are eight weeks of age vaccinate them with Heptavac P Plus. Repeat the dose four weeks later.

The ewes and rams should be sheared before the weather gets too hot and there is an increased risk from fly strike.

If you do not dip in the summer you should use a pour on insecticide every six to eight weeks to prevent blow Fly Strike and ticks.

Fifty days before expected breeding date implant ewes with Regulin at the base of one ear to encourage early breeding. Ensure ewes have a condition score of three to three and a half.

One month before breeding vaccinate replacement ewes against Enzootic Abortion taking care when you handle this live vaccine. Flocks that are affected by Toxoplasmosis should be vaccinated in a similar way at this time.

Check Rams, paying particular attention to their feet and check their testicles to make sure that they are equal in size and that there are no abnormal swellings. It is often Rams that bring Caseous Lymphadenitis into a flock. Be suspicious of any small swellings on their head and neck and have them properly investigated. 

Sixteen days before breeding. Insert progesterone sponges.

Two days before breeding. Remove sponges carefully (arrange for the spent sponges to be burnt) Inject PMSG to encourage ewes to ovulate Move flock onto small field with fresh grass and introduce vasectomised ram.

After forty-eight hours replace vasectomised ram with fertile rams, use one ram for every ten ewes if you can.

If you are not going for very early lambing a vasectomised ram can be used for two weeks before the planned mating time to get the flock cycling and compress the lambing period.

Change the raddle on the rams every three weeks.

Eighty to one hundred days after the first breeding have the flock scanned.

Consider blood testing a representative sample of the barren ewes to see if they have titres to Toxoplasma.

Continue to worm the lambs every three weeks into the autumn. Worm the ewes and rams late in the autumn before housing, use a combined fluke drench at this time if this is a problem on your farm.

If you are troubled by scab dip the whole flock in the autumn. If you have a small flock you might be able to control this problem by injecting one of the wormers. Remember the whole flock must be done and they must have an adequate dose so weigh some of the ewes first. It is sometimes better to wait until all of the lambs have been sold before these products are used because of the long meat withholding times.

Ten weeks before lambing dose the pregnant ewes with copper to prevent swayback in the lambs. It is hill farms that have particular trouble with copper, blood test should be done if you are unsure as to whether you have a problem.

Eight weeks before lambing vaccinate the whole flock against orf. It is not necessary to do this if you do not see this disease in the lambs each year. This is a live vaccine and should not be used in flocks that do not have orf.

Eight weeks before lambing vaccinate any newly purchased ewes with Heptavac P Plus to ensure that they have both parts of the course.

Save the concentrate ration for the ewes that are carrying twins and triplets. Introduce it six weeks prior to lambing and gradually increase the amount fed until the first lambs arrive.

Four weeks before lambing Vaccinate all of the ewes with Heptavac P Plus, the timing of this helps to protect the lambs when they are first born.

Two weeks before lambing watch out for shy feeders and ewes with the early signs of twin lamb disease. Drench any animals that you suspect may be affected before the viability of their lambs is put at risk.

Lambing time. This is always hectic and easier to cope with if the weather is dry even when you have good housing. Try to use as much clean straw as possible in the lambing pens to keep the ewes clean. Ewes are very susceptible to infections and every ewe that you have helped to lamb should be given an antibiotic injection.

Dose all newly born lambs with antibiotics to prevent watery mouth and joint infections. Probiotics are used on some farms when the lambs are first born, these always seen to make the lambs want to suck more vigorously.

If you have problems with white muscle disease dose lambs with a Vitamin E Selenium injection before they leave the lambing pens.

If you get particular problems with Orf in growing lambs they should be vaccinated with the live vaccine as they do not gain any immunity to this disease from suckling colostrum. The dose can be given from birth, but it is usually better to get a group of sixty to seventy lambs and vaccinate them from the one dispenser all at the same time. Remember to keep these animals away from lambs that have not been vaccinated as they can pass the infection on from the scratch sites.

Start to feed a coccydiostat to the lambs. Watch out for the early signs of mastitis in the ewes, check any animals that are reluctant to allow their lambs to suck.