Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Automatic milking and milk quality

The quality of milk is a very important aspect of milk production. Milk payment systems and consumer acceptance are, to a great extent, based on it. In dairy processing, milk quality can be a decisive factor for the value of the product. Features in automatic milking like a 24 hour operation, more frequent milking at different intervals, different cleaning procedures and complicated visual control, may influence milk quality.

Changes in milk quality after the introduction of automatic milking systems (AM-systems) on dairy farms in The Netherlands, Germany and Denmark were examined and the data were compared with milk quality results of farms with conventional milking technology. After introduction, a small, but significant increase in total bacterial count, somatic cell count, freezing point and free fatty acids was observed. The highest levels for total plate count and cell count are found in the first six months after introduction. After this period the milk quality slightly improves to a more stable level.

Risk factors related with milk quality concern general farm characteristics, animal health, AM-system, cleaning and cooling, housing, management skills of the farmer and the hygiene on the farm. Total plate count was significantly related to milk yield of the herd, cleaning of the area around the AM-system and the overall hygiene on the farm. Bulk milk somatic cell count appeared to be significantly related to milk yield of the herd and the number of milkings before replacement of the liners.

An increased milking frequency is not the only explanation of increased free fatty acid levels. Technical factors related to free fatty acids mainly concern the air inlet in the teat cups, bubbling (excessive air inlet) and a too long post run time of the milk pump. Precautionary measures like adjusted milking frequencies for cows in late lactation, and preventive maintenance will contribute to overcome free fatty acid problems. However, several questions regarding the causes and background of increased free fatty acid levels remain unclear.

Reported by

Applied Research, Animal Sciences Group WUR
8203 AD Lelystad