| Information sheets | | | Elsenburg infopaks | | | Animals, diseases: 23 |
Lamb mortalities
Afrikaans | Xhosa
The extensive damage that predators can do among young lambs is well-known. There are, however. a couple of diseases that can also cause heavy losses.
As a result of the kraal system that is often necessary to protect lambs during the night, folds are herded together in kraals at night. This inevitably leads to severe contagion with various infections. Newborn lambs are very susceptible to such contagious diseases that can invade the body through the umbilical chord, the mouth and the nostrils. It is therefore important that sick animals should be kept separately in a "hospital camp" that could be cleaned with a chlorine disinfectant and that should be allowed to stand empty for long periods. In cold, damp winter conditions it is also advisable to seal the umbilical chord of newborn lambs with teat dip. Even where animals are not kept in kraals, severe contagions can develop in the vicinity of mangers where animals flock together and where they spend much of their time. Leaking mangers also create ideal conditions for the development of contagions.
Colostrum is a lamb's most important protection against infections. Pregnant ewes transfer a wide range of antibodies in their colostrum. It is therefore essential that lambs should drink well during the first 12 hours so that the antibodies can be absorbed effectively. Weak lambs and lambs that have come through a difficult birth, can benefit by the intake of milked-out colostrum. Where facilities are available, frozen colostrum can be stored.
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Escherichia coli (E coli) is a bacterial infection that could be regarded as the most important cause of mortality among lambs under the age of one month. Most sheep and goats carry a wide range of bacteria in their alimentary canal and, although they themselves are immune against it, they excrete the bacteria in their droppings and that way they contaminate the environment. The victims are usually the lambs that do not yet have the resistance against the infections. E coli usually enters the body when the lamb sucks at a dirty teat. Dust in the air could be contaminated and the umbilical chord is also an important place of entering for bacteria. The bacteria could colonise the alimentary canal and so cause enteritis, which becomes visible as yellow or hemorrhagic diarrhoea. The lamb dehydrates and the animal dies quickly. |
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E coli produces various bacterial toxins that affect the lamb. In addition the bacteria could penetrate the intestinal wall and are then transmitted by means of the bloodstream throughout the body to cause a condition that affects various organs and which is usually fatal, like
meningitis. E coli also tends to settle in the joints where arthritis develops which makes it difficult for the lamb to keep up with the mother. The lamb dies when it is totally worn out.
It is therefore essential that conditions should be hygienic. E coli vaccination is also effective in treating the problem and could be administered to ewes two months before the lambing season to ensure that the colostrum contains antibodies against E coli. In serious cases lambs themselves could be vaccinated from about two weeks of age. Antibiotics like tetracycline could be used to treat sick lambs and a solution of saline and sugared water could be administered to prevent dehydration. Medication containing live Lactobacillus organisms is sometimes used to line the alimentary canal with beneficial bacteria that will suppress E coli through competition. |
Enzootic abortion, caused by Chlamydia, also results in deaths among young lambs. The lambs are often weak at birth with enteritis, pneumonia or arthritis. The lambs remain sickly and often die from other complications. The regular use of vaccination against enzootic abortion is beneficial where such problems occur frequently.
Tetanus often leads to unnecessary deaths among lambs. Clostridium tetani is a bacterium that thrives in wounds with a poor blood supply. It produces a toxin that attacks the nervous system and which causes protracted spasms in animals so that they die from asphyxiation when the muscles in the respiratory tract are affected. In lambs infection occur in wounds caused by castration or docking. Elastic bands create ideal conditions for the bacteria because it cuts off the blood supply, and is especially dangerous in the case of older lambs that are docked and then castrated. A good cheap vaccination against Tetanus is available and administration of it two weeks prior to castration could prevent deaths. On some farms severe contagions develop and this then makes vaccination essential. Hygienic conditions could however contribute to a large extent to the prevention of these problems.
MP van Aardt
ELSENBURG / SPRINGBOK Veterinary Services
