A complete set of clusters comprises a claw and four fully assembled cups. The components are four sets of teat shells, liners, short milk tubes, short pulse tubes, the long milk tube and long pulse tubing.
Correctly setting up clusters
Clusters that are correctly set up will be easy to put on and take off and will require no intervention from the milker while a cow is being milked. They will also ensure no cluster slip which can compromise teat health and increase the risk of mastitis.
Assessing cluster performance
When assessing the ability of clusters to milk out use the following measures:
Incomplete milking: A problem with incomplete milking exists if more than 20% of quarters contain strip yields (milk remaining) of 250ml or more. If there are consistent differences in strip yields between the same quarters on different cows it usually indicates poor cluster positioning or uneven weight distribution between the four cups.
Liner slip: If clusters and milking machinery are satisfactory, liner slips should not exceed more than 5 cows per 100 cows milked (excluding cows with very bad udder conformation).
Buying the right clusters
Most equipment companies will loan demonstration clusters to farmers who are doing an equipment upgrade. This is a good way to evaluate the personal feel and handling characteristics of different clusters as well as their milking performance. You could also visit other farmers who use the same clusters in their dairies.
Studies suggest that claws must have an effective volume of at least 150ml to provide stable vacuum below the teat, minimise crossflow and contamination between quarters, and minimise liner slip.
Other important characteristics of claws include:
- appropriate weight
- unrestricted inlet nipples and claw outlet to allow free flow of milk
- good visibility of milk flowing into the claw bowl from each quarter
- visibility of milk in the claw bowl to help detect problems and to indicate end of milking
- ruggedness in a tough environment
- easy to open and maintain
- good ‘personal feel and handling characteristics’