The incidence of sub-clinical facial eczema in selected Waikato dairy herds

The incidence of subclinical facial eczema in 10 Waikato dairy herds was investigated using the serum enzyme γ-glutamyltransferase (GGT) as an indicator of liver disease. Although only 127 (9.4%) of the 1357 milking cows and 4 (2.6%) of the 155 calves and yearlings bled were recognised to have had clinical facial eczema, 39% of the cows and 48% of the young stock had abnormal serum GGT concentrations, indicating recent liver damage.

Determining serum GGT activity, or body-condition grade, in May or July had no value in predicting which animals would suffer metabolic diseases, or calving problems, in the following spring. Severe liver damage did not apparently affect subsequent reproductive performance.