Novel solutions for the sustainable control of nematodes in ruminants - Studies  in Morocco

Background & description of the project

Sheep are the main source of income for rural communities in Morocco.  There are about 15 million sheep in Morocco and they graze extensively  over nearly the whole country, however the pastures are relatively poor and animals must travel large distances to meet the nutritional requirements.  The extensive animal movement also makes it easy for disease to spread among different flocks.   Among the parasitic infections, gastro-intestinal (GI) nematodes are highly prevalent and cause a significant decrease in sheep productivity. The main GI nematodes in sheep are dominated by the abomasal species Teladorsagia circumcincta followed by Trichostrongylus spp. and Haemonchus contortus. In the small intestine, Nematodirus spp dominates Trichostrongylus spp. For the large intestine, Trichuris ovis is the most prevalent species although Oesophagostomum spp and Charbertia ovina are also present.. Seasonal variations are  well documented and vary largely depending on location e.g. the climate is humid in the North and West, semi arid in the centre and the East and arid in the South.

Classical methods for controlling parasitic infections are exclusively based on the use of chemical anthelmintic drugs as pasture management is not a feasible solution on collective pastures. Currently, three broad spectrum anthelmintic families are used in small ruminants: Imidazothiazole, macrocyclic lactones and benzimidazoles. The benzimidazoles are the most frequently used and are represented by up to 17 generic drugs.  The most frequently used drugs are benzimidazoles (65%) followed by imidazothiazoles  (20%) and ivermectins (10%). Other drugs (rafoxanide, closantel, triclabendazole) are used less (< 5%).  Control of helminth infections are mainly curative, based on mass treatments by 90% of farmers throughout the country versus 10% of treatments conducted by the vets. Under dosing is frequent and results from incorrect estimation of body weight. Dosing is mainly based on age categories by both by farmers and vet practitioners. Historically, treatments were given two to three times a year but in the last decade, treatments are now given up to 9 times a year (particularly in the Chaouia plain, the site of the parasol project). Deworming is generally conducted in the winter (pregnancy –lactation period), in spring and early summer.  Control of helminth infections in meat sheep in Morocco remains anarchic and hazardous. This situation had inevitably lead to the development of resistance in gastro-intestinal nematodes of sheep to the benzimidazoles, which was diagnosed  in 1999.

Anthelmintic resistance is currently at an early stage in Morocco. However, current methods for controlling worms may lead to the development of resistance to multi drug classes, as seen in the South African sheep farms if worm control strategies remain unchanged.

Goal of the project

The PARASOL project aims to develop sustainable, low–input methods for internal parasite control based upon the use of Targeted Selective Treatments (TST) in which only ruminants showing clinical symptoms or reduced productivity are treated. TST strategies will minimise the rate of development of resistance by maintaining an untreated parasite population in refugia and also reducing the risk of residues in food and the environment. 

Project outcomes

The PARASOL project aims to provide farmers, veterinarians and advisors with clear guidance and protocols for sustainable, low input, user and consumer-friendly nematode control. The information will be disseminated and published in veterinary and agricultural journals, brochures, leaflets and the web site of the project.

Studies in Morocco

Moroccan study sites for the PARASOL project are the Chaouia plain and the Middle Atlas where two main sheep breeds  “Sardi” and “Timahdit”  are reared. Studied farms are affiliated to the NGO Association Ovine et Caprine  “ANOC”. 

Study sites for the PARASOL project

Investigations underway are:

• Questionnaire surveys on the acceptability of TST

 

Direct interview with farmers on the acceptability of Targeted Selective Treatments (TST)

• Validation of a parasitological indicator (faecal egg count (epg)) versus a physiological or pathophysiological markers (LIVGAIN (weight), BODCON, DISCO & FAMAHA)  to guide  framers to  target  animals in need of treatment..

Training on the TST methods in profit  of the technical staff of the project, NGO “ANOC” & farmers

• Impact of TST on Benzimidazole (Bzs) resistance and productivity of sheep under farm grazing conditions.
  
  

Summary of Parasol-Studies in Morooco (PDF, 2.7 MB)

All pictures: © Boumadiane Berrag