Abstract

Facial eczema (FE) significantly impacts on the health and productivity of cattle (Towers & Smith 1978) and presents significant welfare concerns. The clinical manifestations of FE arise from damage to the liver. When spore count challenges are low to moderate and sustained, low-grade, chronic liver damage can then result in sub-clinical FE, a condition characterised by suboptimal productivity with little or no clinical signs. It is likely that sub-clinical FE goes un-noticed by many herd managers.

Whenever there is a significant FE challenge, farmers tend to recognise the presence of disease by identifying photosensitization in individual cows. It is possible for images of affected animals to be made public via animal welfare groups. This presents a risk to New Zealand’s ‘clean green image’ and reputation for sustaining a high level of animal welfare in farmed livestock. However, photosensitisation represents only the tip of the iceberg of a herd-level FE problem. Research has shown that only a small proportion of cows within a herd affected by FE have photosensitisation, with a much greater proportion having significant liver damage without any obvious clinical signs (Di Menna et al. 2009). The causative agent of FE (a fungus, Pithomyces chartarum) was first identified in New Zealand in 1958. Since then protocols for management of the problem have been developed, mostly involving regular administration of zinc (Zn) salts to cattle by mouth. However, over the years a number of alternative management ideas for controlling facial eczema have also been tried and farmers have been discussing these methods with some conviction for years.

W, Cuttance, and E Cuttance

Proceedings of the New Zealand Society of Animal Production, Volume 77, Rotorua, 100-103, 2017