Role of bacterial disease on daily rhythm of some metabolic parameters in dairy cow

The existence of daily rhythmicity of serum total proteins, their fractions and some biochemical parameters in healthy cows (group A) and in cows affected by Brucella abortus (group B) was assessed in order to clarify the role of circadian timing processes in healthy and disease in cows. On each subject, blood samples were collected, every 4 h over a 24-h period, starting at 12:00 on day 1 and finishing at 12:00 on day 2, via intravenous cannulas inserted into the jugular vein. On all samples, serum total proteins and their fractions (α1-, α2-, β1-, β2- and γ-globulins), gammaglutamyl transferase (GGT), alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, creatinine and urea were assessed. The application of one-way analysis of variance showed a significant effect of time of day in group A only on creatinine and urea. In group B, a significant effect of the time of day was observed on total proteins, albumin, β-globulins, GGT, creatinine and urea. Daily rhythmicity was exhibited by creatinine and urea in healthy cow. Whereas, daily rhythmicity of total proteins, albumin, β-globulins, GGT, creatinine and urea was observed in cows affected by B. abortus. Our results improve the knowledge about changes of circadian system during pathological events in dairy cow.