Milking machine tuning to improve udder health and to reduce teat end hyperkeratosis in dairy cows

The condition of teat ends of dairy cows is an extremely important parameter in mastitis control, because it is the first barrier against the pathogen invasion of the udder. This paper presents a study of the parameterisation of the milking machine and its effect on teat ends of more than 1000 Holstein-Friesian cows from 20 farms in Asturias in Spain. Data on the collector vacuum (VC), the liner type and the collapse force (FC) have been collected and were analysed. The goal is to establish several rules for tuning the milking machine in order to reduce damage caused by teat-cups. In a first approach of the problem, the characterisation of the liner by its FC is a function of the material and the liner geometry. This value is a dynamic parameter because it changes during the use of the liner due to mechanical stress and the action of fluids - milk and detergents - that produce changes in the collapse force of the liner during its useful life. The FC of the liner determines the selection of the VC by following a simple procedure: high values of FC need high values of VC and low values of FC need low values of VC. The Massage Residual Vacuum (MRV) is a variable that resumes both, liner condition and VC. The values of FC, VC, MRV and overpressure have been evaluated. The teat end condition has been classified in four different levels according to the definitions of the Teat Club International. The results of this study show that a low level of the teat end hyperkeratosis is achievable when the milking machine works with MRV values around 27 kPa. Moreover, the traditional and well-known overpressure parameter was found to have no influence on teat end condition.