Erastus Ngaruka
Small livestock producers in Namibia are faced with significant livestock health challenges, mostly associated with parasitism or parasite infestations.
Parasites can be classified into two main categories: internal and external parasites, and their prevalence is seasonal or depends on the prevailing environmental conditions. For example, internal parasites include types of tapeworms, roundworms and flukes, whereas external parasites are ticks, lice, fleas, mites and flies.
The prevalence of these parasites is seasonal as some prevail in winter, while others prefer the summer months for their survival. In addition, parasites are host-specific, meaning their survival or completion of their life cycle is dependent on the availability of a host organism or animal.
Other predisposing factors to parasite infestation are related to poor management of the kraal environment, and the absence of or an inappropriate parasite control schedule, amongst others.
Parasite infestation results in huge production and economic losses for small stock farmers in the country. Moreover, the control measures are cumbersome for some farmers who may not understand or have limited knowledge of the types of parasites, their life cycles, seasonality, symptoms and remedial actions to follow.
Common symptoms
Parasite infestation can be detected by marked symptoms or changes in animal conditions and behaviour, as well as through closer inspection of their presence on the body. Some of the parasite activities on an animal include blood sucking, feasting on skin, hair and pre-digested feed in the rumen.
The most observed symptoms, depending on the type of parasite, include anaemia, diarrhoea, bottle jaw, runny nose, hair loss and emaciation. Furthermore, the effects of internal parasites can be organ-specific, for example the liver fluke affects the liver, and the lungworm affects the lungs.
The two distinct seasons for Namibian farmers to focus on livestock management programmes are winter and summer, as both present varying challenges when it comes to parasite control. Even though some parasites such as roundworms and nasal worms prevail throughout the year, some are prominent during certain times of the year.
For example, during the summer months, there is a high prevalence of flukes, mosquitoes, ticks and flies, whereas during the winter months, a high prevalence of tapeworms, mites and fleas is observed. However, the unhatched eggs of some parasites can be carried over between seasons.
There are several cases of goats and sheep losses, especially after good rains, and most post-mortems reveal liver damage, thus indicating liver fluke infestations in many kraals. Liver fluke is an internal parasite characterised by a life cycle that depends on a snail (first intermediate host).
Snails prefer moist environments, thus leaving the parasite on the vegetation around standing water. This is how animals grazing around standing water are infested with liver fluke. One of the external symptoms of liver fluke infestation is bottle jaw (fluid-filled swelling below the jaw).
Other internal parasites to look out for are lungworms and nasal worms, both causing distress in the animal’s respiratory system. Lung worm infestation (in lungs) symptoms include runny nose, coughing and difficulty breathing, whereas nasal worm infestation (in nasal cavity) commonly show signs of runny nose and sneezing. These may also be confused with pasteurellosis.
Available remedies
There are many remedies which farmers can choose from to control internal and external parasites, and this choice should be based on the potency of the remedy against the targeted parasites.
These remedies are administered orally (through the mouth) to directly control internal parasites, while others are administered topically (body surface) to control external parasites.
There are also injectable solutions which can control both internal and external parasites at once. Some remedies have a broad-spectrum effect, controlling many parasites at once, whereas some are limited to a single parasite group or species. It is, therefore, important that farmers always read instructions on the product label to avoid unfavourable results.
The first and cheapest line of defence against parasites and diseases in small stock is to maintain a clean kraal environment. Secondly, farmers need to regularly observe their animals’ condition and behaviour.
One of the approaches that any farmer should follow is to conduct basic post-mortem examinations on an animal which is slaughtered at the farm, even for home consumption.
This presents an opportunity to study or inspect the animal body and the condition of the visceral organs (liver, lungs, kidneys etc.) for abnormalities that may be prevalent in the flock. Lastly, always consult local veterinarians, experienced farmers, or livestock experts for advice.
*Erastus Ngaruka is a technical advisor on livestock and rangeland at Agribank.