Monograph

Printer-friendly versionSend by emailPDF version

A parasite is an organism which lives at the expense of another organism. Parasites are widely present in the animal kingdom and are constantly present in the digestive tract of ruminants. This is normal as long as population levels remain low.

However, when an excessive number of parasites become present the clinical signs begin to appear: loss of appetite, weight loss, diarrhea, anemia, ruffled fur, etc. At this stage it is often too late to cure the disease.

 

Worms

Roundworms and Thread worms

Gastrointestinal worms of small ruminants

The female worms lay their eggs in the animal's digestive tract. The eggs are then eliminated via excrement. At this stage the disease is already well advanced and curative treatment does not always enable the animal to avoid death. In some cases, animals may not show any clinical signs of disease apart from severe retarded growth.

Gastrointestinal parasites should be treated before they cause any serious disease, especially as the appropriate prevention measures are both relatively cheap to implement and highly effective.

Once on the ground the eggs hatch, freeing infective larvae which then contaminate pasture. They are ingested along with the grass by other animals and settle in the gut where they reach the adult stage in several weeks.

The cycle continues…

Gastrointestinal worms cycle of small ruminants

Strongylus life cycle

Contamination of pasture by goat no. 1 and ingestion of infective larvae by goat no. 2.

Strongylus are the most common round worms. Some feed off food ingested by the host animal, others, particularly harmful, attack the intestinal lining and feed off the host animal's blood. It is the case for Haemoncus sp.

Small ruminants are the main victims of strongylus. In some herds the death rate may reach 20 to 30%.

In bovines, strongylus affect mainly young animals up to 1 year. Even creole bovines which are a lot less susceptible than cross-breeds can lose up to 10 kilogrammes on weaning if they are not treated.

Two other types of round worm can be found in calves under two months:

• strongyloid, weakly pathogenic

• ascaris, may cause significant economic loss.

 

Tapeworm (or cestodes)

These are mainly of the taenia (Moniezia genus) type. Affected animals are identified by the detection of small, whitish rings in the faeces which look a little like grains of rice. In small ruminants these worms can cause digestive and nervous disorders.

 

Flat worms (or trematodes)

Several cases of fluke, a highly dangerous liver parasite, have been observed in Guadeloupe.

 

Unicellular parasites

These are mainly of the coccidia type. These are tiny unicellular parasites which develop in the intestinal cells of the host animal.

They mainly affect small ruminants under three months in which they cause inappetence and blood-spotted diarrhea. Coccidia pose a significant problem in intensive farming. Symptoms generally appear in periods of stress (farrowing, transport, etc...).

 

Natural control methods

Certain precautions must be first of all taken with regards to pasture management. Antiparasite treatment must also be implemented in a rational manner.

It is important to avoid grazing in pasture during high risk periods for parasite infestation.

When infested animals arrive on a plot of "clean" land they contaminate pasture through their excrement.

After hatching the larvae become infective after eight days, at which time they are capable of contaminating animals present in pasture.

In small ruminants, they lose their infective ability after 28 days (later in bovines whose manure dries more slowly than goats' droppings).

In small ruminants, the peak in the risk of infestation is between 8 and 28 days after production of contaminated excrement.

To reduce the risk of contamination it is important to:

• leave animals in pasture for a short period of time only: eight days maximum for goats and 14 days for bovines.

• avoid placing new animals in pasture within 28 days.

This implies regular rotation in pasture use.

Farming conditions must also be taken into consideration.

The risk of parasitism is much higher:

• for certain types of animals: small ruminants and European or cross-bred bovines

• at certain stages: young animals and females after farrowing

• and in certain circumstances: wet season and irrigated pasture.

In any case, particular attention must be paid to farming techniques (choice of pasture, grazing time, etc.). It is also important to combine these natural control methods with the appropriate antiparasite treatment.

 

Natural control methods and additional treatment

Antiparasite products must be used reasonably.

Dosage must be strictly respected:

• if the dosage is too low the product will be uneffective

• if the dosage is too high this may endanger animals

 

Furthermore it is advisable to use the same product during two consecutive years before using another product in order to limit parasite resistance to the product. This phenomenon was observed with Panacur ND and Amprol ND, which it is preferable not to use in our regions.

Worming products for ruminants (marketed in Guadeloupe)

O: oral (liquid, powder or tablets); I: injectable; P: pour-on

S: strongylus; A: ascaris; T: taenia; F: fluke

* Benzimidazole group, avoid use (high resistance).

Anti-coccidia treatment for ruminants (marketed in Guadeloupe)

These products are generally sold in powder form for oral administration.

(*) To avoid (resistance problems).

Follow treatment schemes (dosage, length of treatment, frequency of administration, etc.)

Strongylus, ascaris and taenia must be controlled.

 

Treatment of small ruminants:

Young animals: treatment at 1.5 months and during weaning

Adults: at least every two months in humid environments and every three months in dry climates or if the animals are restrained.

Animals must also be treated for coccidia on weaning.

 

Treatment of cattle:

Young animals: at three months, on weaning (six or seven months) and at 12, 18 and 24 months.

Adults: once yearly. Cows should be treated ideally two days after calving (high risk of infestation).

This treatment must be used in animals presenting clinical signs of disease but also in all animals on the farm as all can become infected and thus contaminate the other animals.

 

"Prevention is better than cure !"

These preventive measures (pasture rotation and reasonable use of antiparasite treatment) are essential to ensuring herd profitability.

Navigation

New forum topics

Syndicate