Image Measurement System for Estimating Serum Vitamin A Level of Beef Cattle Using a Monochrome Camera

To develop an alternative method to blood sampling for measuring serum vitamin A of beef cattle, the relation between vitamin A level and reflection of pupil or tapetum at 500 nm wavelength was confirmed using a monochrome camera. The camera was applied to cattle's eye directly to acquire pupil images. For obtaining tapetum images, eyeballs of slaughtered cattle were used. From acquired images, the pupil or tapetum area was manually extracted and the mean grayscale value was measured by image processing software. The relationship between the mean grayscale value and the serum VA level was obtained. Although a linear correlation could not be obtained by these experiments, the possibility for quadratic curve approximation was implied. This method should be useful for measuring serum vitamin A nondestructively.