Parasitism and farmers' practices in heifers under organic farming management

Summary

Organic farmers are requested to allow cattle grazing as much as possible. However, this can lead to parasitism issues and thereby affect livestock performance. This study aimed to determine 'good practices' with respect to parasitism control in grazing heifers under organic farming conditions using a participatory approach. Six organic farms, including three dairy and three beef production systems, were monitored in 2015 and 2016. Recorded variables included the heifers' growth and parasitic pressure in terms of eggs abundance in faeces for three distinct parasites, grass availability, the nutritional value of grass and feed supplement, if any, and the farmer's practices regarding the grass and herd management. The relationship between recorded variables was investigated by principal component analysis (PCA). The PCA revealed a positive correlation between heifers' growth and the number of plots. However, heifers' growth and the number of plots were both negatively correlated with stocking rate, occurrence of anti-parasite treatment, and parasitic pressure. In conclusion, this study highlighted the importance of rotational grazing and low stocking rate for control of parasitic pressure and ensuring heifers' development.