Windhoek – While no apparent causes of the spate of livestock abortions east of Windhoek, and in the Omaheke region were found last year, abortions among cattle still occur in these areas with a big increase in Boer goats.
Hundreds of samples submitted to the Windhoek Central Veterinary Laboratory (CVL), and to Onderstepoort and Path Care in the Western Cape could not find a single cause of the abortions, which resulted in huge losses for breeders. Boer goat farmers started reporting abortions among their prized herds last week and in many cases samples have been taken and sent to veterinarians. Once again, no apparent cause has been found so far and farmers keep injecting goats with proven antibiotics. The abortions caused cattle losses of up to 85 percent in the central and eastern areas of the Khomas Region as well as in the regions of Omaheke and Otjozondjupa. Various private and state veterinarians worked closely together to halt what was expected to be a deadly virus of an unknown strand.
Prominent farmers like Hueston Groenewaldt, Katuuo Katuuo and Wolfgang Ludwig from the central area have all reported losses due to abortions by their Boer goat ewes. Some farmers have suggested the possibility of poisonous plants as some of these are known to cause abortions among livestock. Another well-known farmer, Genno Himarwa, says in his experience these abortions only occur during very cold temperatures and he links it to stress due to the icy weather conditions, which started moving in again since last weekend. There are many reasons why a pregnant doe might abort. Some abortions are of non-infectious origin, such as butting by other goats that causes the foetus to die inside the womb, or the malformation of the foetus in-utero, which usually results in a spontaneous abortion of the pregnancy. The most frequent cause of abortions is improper feeding of pregnant does – usually under-feeding and often a shortage of energy (calories). Meanwhile, a heavy worm load cannot be discounted as the cause.
Some abortions can be traced to infectious organisms like chlamydia, toxoplasma gondii, Q-fever, border disease, listeriosis, neospora caninum, camplobacteriosis, akbane disease, and brucellosis. Because it occurs on a large scale every year, habitual abortion is one of the most important threats to the goat industry. On some farms, up to 50% of the goats may have aborted in the past.
Habitual abortion is caused by chronic over activeness of the doe’s adrenal cortex. It is closely associated with stress abortion, which is usually due to feed disturbance, causing blood sugar levels to drop. In feed-stress abortions, apparently normal, well-developed kids are expelled after the 90th day of pregnancy. Abortion due to the doe’s overactive adrenal cortex shows signs of oedema (unnatural collection of fluid) in the foetus. The heart rate is slow and heart failure occurs.
Deputy chief veterinary officer, John Shoopala, advises farmers that there are two ways of bringing the problem under control: cull animals which abort habitually and avoid selecting for excessive quantities of fine hair. The latter could lead to increased susceptibility to abortions. To control stress abortions, farmers are advised to provide good quality feed of the required quality to gestating does. Shoopala urges farmers to immediately report any case of abortion to the nearest state veterinarian.