Internal Parasites and Game

When able to range extensively in their natural habitat, the exposure of game to harmful internal parasites is relatively low, and these are mostly prevalent in old, sick or thin animals. Problems with internal parasites often arise, however, with intensive farming or when the animals do not adapt well to a new environment. For example, internal parasite infestations can occur when breeding with scarce game species in small camps, or when game is moved to a new environment where they battle to adapt, and this then necessitates parasite control.Both external and internal parasites are relatively easily managed in cattle and sheep as a result of the many effective dips available in the market, as well as the fact that the practical application of these straightforward and manageable. Normally the animals are held in a crush while the correct chemical dosage is administered.The success of applications depends completely on the correct dosing procedure: the dosages work on the principal of a precise amount of milligrams of the active ingredient per kg live weight of the animal. Obviously, the live weight of cattle or sheep in a crush can be fairly easily ascertained, and the correct dosage thus individually applied. Although there is a margin of tolerance with the dosage application, as accurate measuring as possible should be striven for as greater deviations lead to over or under dosing. Over dosing can obviously be extremely dangerous and depending on the active ingredient involved can result in various side effects including a negative effect on fertility, abortions, permanent kidney and liver damage, and even mortalities.

[quote_center]…the farmer soon finds himself in situation where dosing is not effective and the initial problem is now much greater[/quote_center]

Under dosing, on the other hand, is just as dangerous as this can lead to the build up of resistance in the specific parasite against the specific active ingredient being applied. The life cycle of most parasites is extremely short and consequently mutations within a population can occur very rapidly. The consequence of under dosing thus is that the farmer soon finds himself in situation where dosing is not effective and the initial problem is now much greater.

Since game species cannot generally be herded into a crush, a problem arises. Unfortunately, without taking the eventual negative effects into consideration, a system has evolved whereby deworming chemicals are mixed into lick blocks. There is unfortunately no way in which the animals’ intake of the ‘medicated’ block can be accurately determined and estimated intakes can easily vary by 100% or more as a result of veld condition and dominance at the lick block.

It is thus obvious that both the overdosing as well as the under dosing of a large amount of animals within the population will be the end result of this approach with the resultant negative effects.

How to deal with Internal Parasites in Game

As discussed above, relatively low populations of internal parasites occur in game living in extensivefarming situations. Infestations are mostly seen in animals in poor condition as a result of age or sometimes where an injury has occurred. Besides poor condition, other indicators are a slightly hunched back and a coarse ‘winter’ coat especially on the back. These are the animals which, in a completely natural situation, would become the first lion food. If these animals are of relatively low economic value, the best suggestion would be to have that animal culled from the herd in order to prevent further infestation.With the intensive farming of scarce species, however, the approach needs to be completely different. Uncontrolled internal parasite infestations can lead to serious economic losses as cows which begin to lose weight as a result of internal parasitic infestations will not ovulate regularly and this will result in lower calf percentages. Obviously such situations need to be addressed urgentlyEffective dosing here is critical and the negative effects of over or under dosing must be avoided at all costs. The approach taken should rest on the following principles:

  1. The whole group of animals must be treated

  2. The process must be managed and monitored daily. Dosing usually occurs over a 5 day period but this may change from group to group.

  3. The animals must already be used to a certain amount of the ration per feeding time before the application of medicine begins.

  4. The biomass of the group must be estimated as accurately as possible.

  5. All competition at the feeding troughs must be eliminated.

It is clear, thus, that it is critically important that there is close co-operation between the farmer, theveterinarian, and the feed supplier. It is important that the farmer seeks advice from the veterinarian in order to identify the nature and extent of the infestation. On the basis of what he discovers the veterinarian will determine which medicine, the amount, and the length of treatment of the animals.

At Driehoek Feeds we ensure that the prescribed chemical treatment is thoroughly mixed in, at thecorrect dosage. Good temperature control is very important as the active ingredient can be destroyed above certain temperatures during the pelletising process. To ensure success, the farmer must ensure that the recommendations with regards to the medicated product are adhered to as closely as possible.

With intensive farming it is desirable to dose twice a year. Dosing usually occurs in the winter when the parasites are mostly inside their host and then after the first spring rains when the camps are heavily infested with worm eggs. Egg counts are not costly and should be done strategically throughout the year by supplying your veterinarian with dung samples.

[quote_center]There are unfortunately very few products available on the market which can be prescribed by a veterinarian for dosing through feed.[/quote_center]

It is clear, thus, that the ad hoc use of a ‘medicated’ lick block to control internal parasites will not only have a minimal chance for success, but can also easily exacerbate the parasite problem. Dosing medicines are expensive and can also be dangerous. There are unfortunately very few products available on the market which can be prescribed by a veterinarian for dosing through feed. Other products currently available can only be administered through a stomach tube after the animal has been immobilized which obviously becomes a very costly operation. Drs Manie Du Plessis and Karel Toet, well known veterinarians from Limpopo Wildlife Services in Modimolle, are of the opinion that it is very possible that in the near future too much resistance to the available products for deworming may develop which will prohibit effective parasite control. This emphasizes that the incorrect application of the available doses must be avoided at all costs.

It is self evident that one cannot afford to lose valuable breeding stock as a result of weight loss because of internal parasite infestation. It is also important to ensure too, that one does not suffer negative long term effects resulting from the incorrect use of the limited chemicals available on the market. Contact a veterinarian with experience in the game breeding field or contact Driehoek Feeds who will put you in touch with professionals who can assist in addressing the problem in a scientific manner. The short cut is often ultimately the most expensive one!

Information provided by Driehoekvoere