Practical aspects of milking dairy cows
Milking dairy cows is a complex action, which has to take into account the physiological aspects of the animal, hygiene, quantity and quality of milk, as well as the work ergonomics. The milking of dairy cows must be carried out within a specified time (8 min), which coincides with the secretion of the oxytocin hormone, which is responsible for the ejection of milk. Workers are careful that the milking is complete, to extract the entire amount of milk and fat, and to prevent mastitis. Those who carry out milking must ensure that the milking machine does not cause pain to the animal, as it may retain milk. Also, the physiology of milking is very complex and involves many factors that favor the ejection and evacuation of milk.
Regardless of the milking system adopted, the practical performance of milking involves the observance of some basic rules: the cows are milked at the same hours of the day and at regular intervals; milking is carried out quietly, in similar environmental conditions. These rules aid the development of favourable conditioned reflexes, and avoid triggering the mechanisms of inhibition of milk ejection (adrenaline synthesis). The training of milking staff is directly related to the efficiency of milking (a worker serves 30-35 cows per hour) and milk and udder hygiene (it is very important to clean teats before the start of milking and at the end of milking). The degree of hygiene is quantified by the total number of germs and the number of somatic cells.