ICAR Technical Series no. 7 - Nitra Proc.

Influence of duration of a and c phaseteat end conditions3,002,001,000,001 2 3 4 5 6 7 8 9 10 11 12Record numberfront teat adjustment Afront teat adjustment BFigure 2. Teat end conditions of the front teat duringexperiment 2.movements of the liner and then a certain degree of congestion. Neijenhuis(1999) observed that animals were more nervous on the platform whenthey were milked with short a and c phases with a small reduction of thediameter of the steak canal and a significant increasing of the teats wallthickness.Nevertheless, neither of our two experiments showed a marked effect ofthe duration of a and c phases on udders health and teat end conditionswere relatively similar to the different treatments. A tendency was foundin which teat end conditions became worst especially for cows with sharpteat ends shapes milked with the shortest phases.We also have to say that the two experiments were carried out with healthycows and that experiment 2 lasted only 5 months.ConclusionThe a and c pulsation phases are surely involved in the liner movementsand compressive loads applied by the liner on the teat. Loads particularlydepend on the shape, the internal diameter of the barrel and the flexibilityof the liner, milk flow rate and pulsation characteristics and the teat itself.Investigations should be made on liner movements related to the studiedphases in order to obtain more precisions on their action on milking andudder health.In any case the two experiments did not produce any proof that milkingwith short a and c phases will automatically increase clinical mastitis, SCCand damage teat end conditions.110Conference on "Physiological and technicalaspects of machine milking"