Deliverable D17 and D18 available

The last two deliverables from WP7 "Optimal cleaning of equipment for automatic milking" are D17 and D18.

D17 reports the 'Frequency of system cleaning'. The effect on the bacteriological quality of the milk of two and three system cleanings per day was studied in field experiments in the Netherlands and Sweden. Milk quality was analysed for total bacterial count (TBC), coliform count (CC), psychrotrophic count (PC) and thermoduric count (TC). In both countries the difference for TBC was small but significant for the two different cleaning frequencies. In the Netherlands also a significant difference was obtained for the other groups of bacteria. It is suggested that the less frequent change of filters could attribute to the raise in CC. When AM-systems have a sanitary design, are optimised for cleaning and well maintained and controlled, a good milk quality can be achieved with two system cleanings per day. Defects in the construction and/or procedures however will have a larger effect on milk quality.

D18 concerns 'Effectiveness of optimised teat cup cleaning in the prevention of mastitis pathogens transfer'. The removal of a mastitis pathogen (Streptococcus agalactiae) by flushing teat cup liners with water and with a disinfectant is compared with no flushing. The log reduction in number of Str.ag. was 1,80 and 2,26 for respectively cold water and the disinfectant. The extra log reduction with a disinfectant was small and did not compensate for the negative effects of using disinfectants in a milking system. 46 Cows were challenged with Str.ag. by milking with contaminated liners. Two liners were flushed after contamination, the other two liners were not flushed. The udder health of the cows was measured during one week after the challenge. In none of the foremilk samples Streptococcus agalactiae could be recovered and none of quarters showed signs of an inflammation. The effect of a cluster flush on the rate of new infections could not be established in this experiment.

Message date: May 28, 2004