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How to reduce lamb mortality


Every lamb that is lost represents a significant loss to the sheep farmer as the cost associated with keeping the ewe has already been incurred. Michael Gottstein, Head of Sheep KT Programme, looks at the key issues that sheep farmers should concentrate on as the main lambing season approaches

Introduction

Every lamb that is lost represents a significant loss to the sheep farmer as the cost associated with keeping the ewe has already been incurred. It is estimated that on average one in every five or six lambs that are conceived does not make it to market. Apart from financial loss associated with lost lambs there is also a significant cost to treating sick/weak lambs and a significant time / labour input dealing with these lambs. What are the key issues that sheep farmers should concentrate on as the main lambing season approaches?

Nutrition

Adequate and appropriate nutrition is essential in ensuring that ewes are free from metabolic diseases such as twin lamb disease, milk fever and prolapse. Critical is feeding ewes according to litter size, expected lambing date and body condition score. In practical terms this means at a minimum separating singles, twin and triplet bearing ewes. In addition to penning sheep according to litter size we should also pen thin single bearing ewes with the twins and pen thin twin bearing ewes triplet bearing ewes so that they get extra concentrate supplementation. The amount of concentrate feed to should be fed to each category of sheep will depend on factors such as; forage type, forage quality (DMD, DM, pH and ammonia content) and feeding method. Feeding levels should be targeted to deliver lambs that born large enough to maximise survival while at the same time minimising lambing difficulty associated with oversized lambs. Optimum lamb birth weights for lowland lambs are; Single 5.5-6kg, Twin 4.5 -5kg and Triplets 3.5 – 4kg.

It is also important to feed the ewe adequate protein to ensure she has a sufficient supply of good quality colostrum. To achieve this a lot of farmers are now feeding 100grams of Soyabean meal per lamb carried per day (i.e. 200g for ewes with twins, 300grams for triplets) for the last two weeks of pregnancy. This can either be included in the compound ration or if this does not contain a high enough inclusion rate of Soyabean meal then the additional Soyabean meal can be simply sprinkled on top of the concentrate feed for the last two weeks of pregnancy.

Trough Space

As important as providing enough feed for the sheep it is also important that they have sufficient trough space to all be able to eat at the same time. In most situations with lowland ewes this will require between 500 and 600mm of trough space per ewe. Failure to provide sufficient trough space is often associated with higher incidences of prolapse. Please check out this video on:   Pre Lambing Nutrition 

Causes of Mortality

The two main causes of mortality in new born lambs are infection and hypothermia/starvation. Successfully reducing lamb mortality involves addressing these two issues by paying particular attention to hygiene and colostrum feeding.

Hygiene

Lambs are born with little immunity. They are born into an environment with lots of bugs around them. Aim to reduce the risk of them coming into contact with these bugs. Clean straw, disinfected lambing pens, clean and sterilised lambing equipment and a clean operator assisting in the lambing process (e.g. clean cloths and clean disposable gloves worn during the lambing process).

Please follow these links below for more video details

Sterilizing equipment for lambing

Reducing lamb mortality with hygiene 

Navel Disinfection

The navel is essentially a tube giving direct access for bugs to the internal organs of the lamb. That is why it is very important that it is disinfected properly to prevent bugs from entering into it while it is drying and shrivelling up. The navel of the lamb should be disinfected as soon as is practical after birth and again four to six hours later. Immersing the navel in the disinfection fluid is preferable to spraying.

Colostrum – Nature’s antibiotic

Colostrum, the first milk produced by the ewe is a wonderful product that has three very important characteristics which every new born lamb needs. 

  1. It provides antibodies against disease which the lamb may encounter in early life (before it has a chance to develop its own immune system).
  2. It acts as a laxative cleaning out the digestive tract of the new born lamb
  3. It supplies the lamb with a complete feed to meet all of its nutritional needs.

Key points regarding the management and feeding of colostrum to lambs are;

  • Ensure that each lamb gets 5% of its body weight of ewes colostrum in the first four hours of life is critical to getting the lamb off to a good start. 5% of a lamb’s bodyweight for the average 5kg lamb is 250ml. Most farmers probably give two or three 60ml syringes per lamb which is totally inadequate for all but the smallest of lambs and giving a small feed stimulates the gut of the lamb to start closing thus preventing immunoglobulin transfer later on.
  • Make sure that all lambs get at least some ewe colostrum. Colostrum substitutes while useful to have on hand are not an effect substitute for ewes colostrum in terms of supplying lambs with relevant immunoglobulin’s to diseases for which your ewes have been vaccinated. Where a ewe has insufficient colostrum to meet the needs of her lambs divide the colostrum available equally between her lambs and make up the short fall with colostrum from another ewe in the flock (best case scenario) or failing that make up the shortfall with a colostrum substitute or cows colostrum.
  • Note; if using cow’s colostrum it is important to mix the colostrum from two or more cows. Some cows have antibodies in their colostrum with will cause death in lambs. Also be aware that Johnes disease in cows is transmissible to sheep in the colostrum.
  • If the lambs are not able to suck then the colostrum should be administered using a stomach tube.

For advice on the correct procedure for stomach tubing lambs please follow this link:                   Reducing Infection with Colostrum 

Conclusion

Keeping extra lambs alive is in everyone’s interest. Reducing mortality and illness in new born lambs increases profits, reduces labour associated with nursing sick lambs and reduces the need for antibiotics to help fight disease.  

You'll find more information on sheep here on the Teagasc Sheep homepage