Between milking, the udder’s cistern is passively filled by milk from mammary alveoli. This cisternal milk represents around 20% of the total milk released during the next milking. It means that, during the next milking, 80% of the milk will actively be produced by alveoli cells. These cells need an interaction with a specific hormone to eject the milk in mammary ducts during milking: the oxytocin.
The cow needs a good visual, auditory and tactile stimulation to produce and release oxytocin into the blood. Naturally, the best stimulation for a cow is the contact with the calf: he hits the cow’s udder with his head in order to stimulate oxytocin production and milk releasing.
To reach an efficient milking, this “oxytocin reflex” needs to be reproduced in milking parlors. Different stimulation can help:
- Visual/ auditory: stimulation can begin once the cow enters in the milking parlor. Pump noise, and visualization of milking parlor can activate oxytocin production.
- Tactile: the best way in order to well stimulate the cow is to touch / forestrip the teats. Once the farmer touched the skin, a nervous message is transmitted to the cow’s brain. Finally, oxytocin is released into the blood and will reach alveoli cells in order to let them release the milk. This reflex takes 60 to 90 seconds from first tactile stimulation to milk let down.
Some farmers don’t stimulate the cows. They sometimes only wipe the teats and plug the milking cluster directly. In that case, the cisternal milk will directly be drawn by the liner. But after few seconds, the milk flow stops, because oxyticin still didn’t reach the alveoli cells. The real milk let down will really start after 1 or 2 minutes. This phenomenon is named bimodal milk flow. During this time, the liner is milking an “empty teats”. This phenomenon strongly increase teat lesions and mastitis risk.
A good pre-milking protocol is therefore crucial in mastitis management. It should be done within 60 to 90 seconds to have a good oxytocin reflex. During this time a good pre-dipping with 30 seconds contact time is recommended.
Benefits of a good pre-milking protocol