Livestock Disease Trends – March 2014

Wireworms: Late continuous rainfall, especially in the summer rainfall areas, led to severe wireworm infestations in smallstock

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Internal parasites

Wireworms: Late continuous rainfall, especially in the summer rainfall areas, led to severe wireworm infestations in smallstock. Reports of mortalities were received, and some farmers are still unaware of the different anthelmintic groups that should continuously be assessed for efficacy.

Group Code Generic class of actives Example of active molecules
1 Macrocyclic lactones Abamectin; eprinomectin; ivermectin; moxidectin
2 Benzimidazoles (white drugs) Albendazole; fenbendazole; ricobendazole; triclabendazole
3 Imidathiazoles (clear drugs) Levamisole
4 Salicylanilides Closantel; niclosamide; resorantel; rafoxanide
5 Nitrophenols Nitroxinyl
6 Sulphonamides Clorsulon
7 Organophosphors Trichlorfon
8 Isoquinolones Praziquantel
9 Others Piperazine
10 Spiroindoles Derquantel

The way to asses the efficacy is to consult your vet and do a faecal egg count reduction test (FECRT).

Tapeworms: Lambs were mostly affected and resistance to drugs has been recorded. Actives that should be evaluated for efficacy are: benzimidazoles, salicylanilides (niclosamide, resorantel) and isoquinolones (praziquantel).

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Liver flukes: Reports are received monthly of animals affected by liver fluke. Clinical signs are bottle jaw and anaemia, signs similar to wireworm infestation. Before moving animals into camps where the intermediate hosts (water snails) are present, the liver fluke burden should be cleared out so as to prevent the water snails becoming infected . Discuss the treatment protocol with your vet.

Conical fluke: Beware of outbreaks when moving animals into camps where the intermediate host snails are present.

Parafilaria infestation: Reports were received from the bushveld areas. Cattle due for slaughter should be treated at least 70 days beforehand to allow lesions caused by this parasite to heal.

Measles (cysticercus): Biosecurity measures should be stepped up to prevent animals becoming infected with this parasite. Supply toilets and teach workers about the life-cycle and dangers of this zoonotic disease.

Coccidiosis: Numerous outbreaks were reported.

Others: Reports of brown stomach-worm (in kids on pasture) were received, as was one on opthalmia caused by the eye worm (Thelazia rhodesii).

External parasites

Ticks: After the rains and hot weather tick numbers increased, along with tick-transmitted diseases such as African and Asiatic redwater, anaplasmosis and heartwater. Make sure that the actives used for tick control are still controlling ticks satisfactorily.

Actives that can be used for controlling blue ticks are as follows:

Active groups Example of activities
Organophosphors Chlorfenvinphos
Amidines Amitraz; simiasol
Pyrethroids Alphamethrin; cyhalomethrin; cypermethrin; deltamethrin; fenvalerate; flumethrin
Macrocyclic lactones Abamectin; doramectin; eprinomectin; ivermectin; moxidectin
Acaricide growth regulator Fluazuron

Tests can be done on ticks to assess the efficacy of the acaricides used. Contact your vet for more information.

Lice: Infestations of sucking (blue) and biting (red) lice were reported. These parasites are usually a big problem in winter.

Insects: The following were reported: flies, blowflies, screw-worm, nasal bot and midges.

Venereal diseases 

It’s important to keep biosecurity measures regarding venereal (trichomonosis and vibriosis) diseases intact. Now is the time to assess conception rates in the flock/herd through pregnancy examinations and scanning. By testing bulls coming out of the herd, you can establish if venereal diseases are present in the herd and take corrective actions.

Zoonotic diseases

Brucellosis is still a huge problem. Test animals and remove positive ones from the farm. Be careful when animals are bought – quarantine and test them before introducing them into the herd.

Vaccinate heifers with Strain 19 vaccine before the age of eight months.

Bacterial diseases 

Anthrax, blackquarter, swelled head, red gut, blood gut, tetanus, botulism, pulpy kidney, salmonellosis, Johnes disease, enzootic abortion, E. coli, lumpy wool, Senkobo disease and Fusibacterium necrophorum were reported.

Bacterial diseases can be controlled through properly planned vaccination programmes.

Viral diseases

The prevalence of bovine malignant catarrh (snotsiekte) is increasing and both forms of the disease (wildebeest- and sheep-associated) were reported.

Bovine respiratory disease (PI 3, IBR, BVD, BRSV) can be controlled through vaccinations. Other viral diseases such as enzootic bovine leucosis, warts and orf were reported.


The following poisonings were reported: ink berry, geeldikkop, Senecio, Lantana, kikuyu, Nenta, prussic acid and blue-green algae.

Illegal products 

Many illegal products are being sold to farmers. Use only products that have been registered according to Act 36 of 1947.

Feedlot Reports

Sheep feedlots

  • Many sheep had anaemia due to wireworm infestation. These sheep also had adaptation problems and numerous deaths occurred in these groups.
  • Conical fluke caused diarrhoea in sheep and clinical signs commenced within days after sheep arrived at feedlots.
  • Outbreaks of diarrhoea due to salmonellosis caused many mortalities and led to excessive costs for treatment and preventative measures.

Salmonella typhimurium was in all cases the causative pathogen and an autogenous vaccine helped contain the disease. As this disease is becoming more of a problem it may become necessary to vaccinate animals prophylactically.

Salmonella organisms are fairly resistant and can survive for long periods in the environment. In the animal the large intestine is damaged and a general septicaemia affecting all organs is generally seen. Less severe infections may also cause mortalities, but it could be difficult to make a diagnosis at post mortem. Taking samples for histology helps to confirm a diagnosis.

* A few cases of pulpy kidney as well as blood gut associated with acidosis were seen. Blue tongue also occurred.

Cattle feedlots

  • Acidosis combined with cases of bloat and red gut were seen. It often occurred during very wet conditions and feedlots having problems with the mixing of rations. Liver abscesses also occurred when the rumen wall was damaged.
  • Anaplasmosis and red water cases occurred and a few batches of calves were infested with blue ticks. 
  • Livers infested with liverfluke had to be condemned resulting in a loss of about R100/ liver.
  • Foot rot was prevalent due to the long periods of rainy weather. Lameness due to injury was quite often seen.
  • Morbidity and mortalities due to respiratory problems are on the increase.