Improvements in milking management through imitation of calf behaviour
Approximately 20% of the milk within the udder of a cow is stored in the cistern and immediately available for milk removal, while activation of the milk ejection reflex is required for removing the remaining milk stored in the alveolar compartment. The aim of this literature review is to describe, evaluate and consider implications of the three different suckling activities that the calf displays during a suckling bout. In terms of milking, these phases are represented by pre-stimulation, stimulation during milking and post-stimulation. Pre-stimulation is commonly performed in order to induce the milk ejection reflex, whereby the hormone oxytocin is released and the alveoli in the secretory tissue are contracted. Time requirements regarding pre-stimulation must be considered in relation to lactation stage and milking interval. The pre-stimulation should be sufficient to cause an alveolar contraction that is maintained until start of milking. During the milking phase, the liner within the teat cup should carry out a continuous stimulation and cause a maintained elevated concentration of oxytocin in the circulation during the entire milking. This will maximise milk yield. Furthermore an increased rate of massage during the final minute of milking has been found to increase milk and fat yield. Hence, development of liner settings within modern milking equipment and changes in the pulsation cycle may result in a significant improvement within dairy production.