Circadian profile and production rate of melatonin in the cow.

  title={Circadian profile and production rate of melatonin in the cow.},
  author={Xavier Berthelot and Michel Laurentie and J. P. Ravault and J Ferney and P. L. Toutain},
  journal={Domestic animal endocrinology},
  volume={7 3},
Five adult pasture-bred French Friesian cows were used to qualify the circadian profile and characterized pulsatility of plasma melatonin, and to estimate melatonin secretion rate, around the summer solstice. Plasma concentrations of melatonin were low (5 pg/ml) during the photophase, began to rise at sunset (light intensity less than 20 lx) and reached a maximum (about 90 pg/ml) in the middle of the scotophase. The mean amplitude of peaks was 48.67 +/- 23.01 pg/ml, their mean duration was 32… CONTINUE READING