The cow eye-Function and effect of light on milk yield
The purpose of this review was to study the cow eye physiology, focusing on how it registers light, and to see how light affects the cow?s milk yield. It has been showed in studies that more hours of light per day (16 hours of light a day) as opposed to about 9-12 hours of light a day, increases milk yield for dairy cows. This review contains suggestions on how this is connected with the physiology of the eye.
Vision is an important sense for many mammals, and is used to check out the animals surroundings. Sensor cells in the eyeball help in turning photons from the light into signals to the brain. The brain can then translate the information and start a range of responses in the animals.
Studies have shown relations between longer photoperiods (16 hours of light per day) and elevated prolactin levels, and also between increased levels of the growth hormone bovine somatotropoin (BST) and longer photoperiods.
Increased amount of light hours a day (16 hours) increase the production of prolactin, which can lead to increased milk production. Increased light hours decrease the secretion of melatonin, important for sleep patterns. Artificial light seem to work as well as natural light in this aspect.