Ovine Abortions

January brings a new year and new lambs. It has been good to see that the lamb prices have been better lately and the hope is that this will continue throughout 2010. Sometimes sheep problems start before lambing, there will always be some ewes that are unable get their lambs to full term. Most flocks will get two or three abortions either because there has been a genetic incompatibility between the ewe and the ram or maybe the ewe has been knocked or trodden on when she was heavily pregnant and the placenta has been damaged. It is always difficult to decide if the occasional abortion is just one of those things or whether they need to be investigated. Enzootic abortion occurs as a result of a bacterial infection on the placenta and it will respond to antibiotics if they are given promptly to limit the losses so that you can get some lambs to survive. So it is worthwhile if you have more than three ewes abort to take one foetus and as much placenta that you can find to the Veterinary Laboratories Agency in Shrewsbury.

Diagnosis

The lab is good at finding enzootic abortion, toxoplasma, salmonella and listeria. Occasionally other organisms can cause ewes to abort, but they do not usually cause significant losses. Often the lamb that you take in will be the last one to be lost and by the time all of the results come back things will have settled down and you will be busy with normal lambings. Negative results can be frustrating, but it is reassuring to know that there is nothing you need to do to protect your lamb crop.

Internal Parasites

Pregnant ewes will also succumb to fluke. Now is the time that fluke numbers will be building up in the liver when the ewe is under metabolic stress. Ewes with fluke have poor appetites and may go off their legs as if they have twin lamb disease. As the functions of the liver start to fail often the lambs will die in the uterus and it will be difficult for the ewe to cope with the toxins that are produced. It is still not too late to treat sheep for fluke. The drenches are safe throughout pregnancy as long as you take your time and do not stress the ewes when you are treating them.

Barren Ewe Check

Intervet are again running their barren ewe check from now until the end of March. If you have more than one hundred breeding ewes you will have the opportunity to have blood samples from eight of your barren ewes examined to see if they have significant toxoplasma titres. Toxoplasmosis can be a significant cause of pregnancy failure in ewes of all ages. Some animals may go on to have a viable lamb as only one foetus may be affected and you may not realise that your flock has been affected. In the past this has been shown to be a useful monitoring exercise to discover more about the disease status of your flock.

Discontinued Drug

Many of you like us will have Dalophyline Gel with your lambing kit. Sadly Arnolds have stopped making this product and we cannot get any more. Over the years dalophyline gel has saved many lambs and calves as it works rapidly as soon as you put it into the mouth of the new born. Even the smallest amount would get lambs breathing deeply within just a few seconds, seldom would you need to give a second dose. The next best respiratory stimulant is Dopram Drops, sometimes you will need to administer these several times to keep the lamb breathing.

Preventing Disease

Drugs are no substitute for clean conditions and dry lambing pens. The problem is you may not be able to keep the ewes as clean as you would like as lambing tends to occur at the wettest and coldest time of the year and no matter how many pens you have there will be times when ewes are slow to take to their lambs or you will have pressure of numbers and struggle to find each ewe a clean pen to lamb in. Also we tend to assume that because a lamb is sucking it is getting an adequate intake of colostrum. Sometimes this might not happen if the teat canal is narrow or if the ewe milks light on one side. We do find that farms that give antibiotics to all of the lambs at birth as a tablet, injection or a drench get few or no cases of watery mouth, navel infections ,joint ill pneumonia or diarrhoea. There is little evidence that this can lead to antibiotic resistance in older animals. It certainly stops a lot of the neonatal losses and stops a build up of infection in the pens for the late lambing ewes.

External Parasites

Also this winter keep an eye out for the first signs of sheep scab. If you have had scab before you will know that it is difficult to eliminate it completely, and that it tends to come back with differing degrees of severity each winter. Few farms use a sheep dip now, it is certainly not a good thing to do to pregnant ewes in the middle of the winter. When your ewes are first housed look out for the first signs of scab. There will be some rubbing when the flock is closely confined, others will start to nibble their backs and front legs before there is any significant wool loss. Look out for animals with wool in their mouths and try to send some time each day just watching the ewes, not at feeding times, so that you will be aware of any changes in behaviour.

Treatment Options

Dectomax or Cydectin injections can be used to control sheep scab. For preference it is better to start the treatments before the ewes have lambed as there can be problems treating very small lambs for scab. Both of these drugs have the added advantage of treating round worm infections as well so they should help as part of your worm control programme. If you have a big flock and lamb over several months make sure you treat all of the ewes that go through your lambing pens as it will not be possible to effectively disinfect them against scab between batches.

Essential Minerals

Copper is a trace element that all sheep need. There is a delicate balance between sufficient and excess for different breeds that can be difficult to achieve. On some hill farms it can be difficult to get enough of the mineral into the ewes and lambs will develop with a defect in their spinal canal that can lead to paralysis. Some lowland ewes are housed for prolonged periods in the winter and they may be getting more supplementary feed and more minerals than they need. In excess copper accumulates in the liver which will stop functioning as it should, you will see a yellowish tinge in the eyes and around the mouth of ewes that are affected by copper poisoning. There are blood tests that can be done both to prevent sway back and to detect the early signs of copper toxicity as both of these conditions can be treated if you catch them early enough.

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