A recent study about baseline productivity patterns and parasitism of N=Dama cattle in Côte d=Ivoire has found a calf mortality of 20% during the first 6 months of life (see http://www.kfpe.ch/projects/jeuneschercheurs/knopf.php). This mortality reduces both herd growth and milk production and is a major concern for cattle owners and herdsmen.

The aim of the present study is to establish risk factors and causes of calf mortality of traditionally managed N'Dama cattle in the Guinea Savannah. The ultimate goal is to improve calf survival and thereby cattle productivity, generating more rural income and supporting governmental efforts to raise Ivorian cattle production (only 31% resp 11% of red meat and milk products consumed are locally produced (1999)).

The project is carried out in close collaboration with the national veterinary laboratories and local farmers. Field work is conducted by an Ivorian veterinarian (DEA candidate) and a Swiss epidemiologist (PhD candidate).

Objectives
1. To assess herd management and herdsmen's perception of calf mortality
2. To determine causes of calf mortality by verbal and clinical autopsies
3. To determine the effect of tick control on calf survival
4. To assess the effect of nematodes on calf survival
5. To determine risk factors of calf mortality

Methods
From September 2002 until May 2003, 350 calves born alive into the participating village herds of Bringakro (12-15 herds) will be marked and followed up fortnightly until age 200 days or death. For each calf demographic, nutritional, herd management and health data are collected. Their role as potential risk factors will be assessed in the frame of a case control study. After the death of a calf, an interview with the herdsmen will be conducted for verbal assessment of causes of death. Additionally, each cadaver accessible within 24 hours of death, will be autopsied to clinically determine causes of death. To gain more insight into the role of parasites on calf mortality we will study the prevalence of gastro-intestinal nematodes, coccidiosis and ticks. We will further test the effect of a tick control strategy on calf survival in a randomized controlled trial. In an interview about herd management conducted with herdsmen of each herd, we will finally determine management practices and assess local priorities and scope for interventions.

Collaboration
Partnership between the Centre Suisse de Recherches Scientifiques en C_te d'Ivoire, Abidjan (O. Girardin); the Institut Zoologique de l' Université Cocody d' Abidjan (E. N'Goran, R. Taha); the Laboratoire Central Vétérinaire de Bingerville (C. Komoin-Oka); the Laboratoire Régional de Pathologie Animale du LANADA (Laboratoire National d'Appui au Développement Agricole), Korhogo (L. Yaba Achi); the Unit of Laboratory Diagnostics of the Veterinary Hospital of the University of Zürich (H. Lutz); and the Swiss Tropical Institute, Basel (M. Tanner, J. Zinsstag, M. Weiss, M. Wymann).