Monday, February 25, 2013
Abortion in Sheep
There are many circumstances which can lead a ewe to abort a pregnancy.
Many abortions are caused from environmental conditions that are controllable. Some of these conditions include moldy feed with mold spores infecting the placenta and reducing nourishment to the fetus. Injury is often a cause of aborting pregnancy. A ram may run with pregnant ewes and bump them away from hay or feed. Narrow doorways where sheep rush through for feed can result in bumping or other injury causing stress resulting in abortion. Ewes being chased by dogs or other wild animals can be detrimental to the pregnancy cycle.
Bacterial disease like Vibriosis can invade the uterus, placenta and fetus during late pregnancy. Enzootic abortion of ewes is caused by an organism called Chlamydia which causes late term abortions, still birth and weak lambs. It is an obligate parasite (doesn’t live freely in the environment) of sheep and spread to susceptible ewes by contact with aborting ewes infected fetal membrane, uterine discharge or a dead fetus.
Toxoplasmosis is a microscopic protozoan (coccidium) of cats. In unnatural hosts such as sheep and other species including humans, the organism causes infection of the brain, eyes, uterus, fetal membrane and the fetus itself. Infections occur when cats defecate, leaving the infectious organism on hay, grain or other food consumed by sheep. Ground-up grain is a common target because it’s much like a ready-made sand pile.
Since abortion symptoms are all very similar, it may take analysis from your livestock vet to identify the exact cause. Closed herds with strict sanitation and proper vaccinations will lower abortion rates and improve the overall health of your flock.
Friday, February 8, 2013
This disease is commonly called “overeating”. It causes sudden death of lambs that are eating well and growing rapidly. Enterotoxaemia is caused by the bacteria Clostridium perfringeus. which is normally found in the intestinal tracts of sheep. When large quantities of high energy feeds, such as grain or milk are ingested, the bacteria grow rapidly producing a toxin absorbed by the gut which kills the lamb.
Lambs cannot spread the bacteria. This organism is normally present in lambs but the large intake of high energy feeds is what enables the rapid bacterial growth and production of toxins.
There are two different types; type C, which tends to occur in very young lambs and type D, which normally occurs in lambs that are being fed grain while still nursing or even after weaning when they are fed ratios high in concentrates.
Excellent vaccines are available and should be used in all sheep. Ewes should be vaccinated with Clostridium Perfringe type C and D toxoid prior to lambing. This will provide immunity to the newborn lamb through the ewe’s colostrums. Lambs should be vaccinated at birth, six weeks later and once more when weaning or when feed ratios are high in protein.
Have a great weekend!Andy Karras