Normal variation in alanine aminotransferase activity in sheep and cattle

Abstract

The activity of alanine aminotransferase (Al. T) was determined in serum and liver biopsy samples collected from cows over a period of more than a year. There were statistically significant fluctuations in both liver and serum activities during the period of observation. On the whole serum and liver activities appeared to fluctuate independently of one another and of climatic changes. The only possible correlation was between the rate of increase in hours of daylight and the increases in serum and liver activities in the period January to March. The cows were calving at intervals throughout the year, and their liver and serum Al.T activities did not change significantly during the last three months of pregnancy and the first 3 months of lactation.